1.
Pest Control (Doctor Who audio)
–
Pest Control is an exclusive to audio Doctor Who story, produced as part of BBC Books New Series Adventures line, and the first entry in the series to be produced. Written by author Peter Anghelides and read by series star David Tennant, pest Control was released on CD on 8 May 2008 and is also available for download. The story is accompanied by a soundtrack and sound effects created by Simon Hunt. The Doctor and Donna land on the distant planet of Rescension, when a far greater threat emerges, the Doctor must convince the two sides to work together before they are all wiped out
Pest Control (Doctor Who audio)
–
Pest Control
2.
Agricultural aircraft
–
Agricultural aircraft are also used for hydroseeding. Generally agricultural aircraft have piston or turboprop engines, the only known exception is the Polish PZL M-15 Belphegor which has a jet engine. Crop dusting with insecticides began in the 1920s in the United States, the first widely used agricultural aircraft were converted war-surplus biplanes, such as the De Havilland Tiger Moth and Stearman. In the US and Europe, agricultural aircraft are small, simple. Most have spraying systems attached to the edges of their wings. All tend to be of simple, rugged STOL design, sometimes a Ram air turbine is used as an auxiliary power source for the pumping machinery instead of taking power directly from the engine. In places where dedicated use as an aircraft is uneconomic, utility types such as the Antonov An-2 biplane. In the case of helicopters, tanks are placed on or outside the body of the aircraft, while a spray rig, hydroseeding is often done by helicopters using tanks and drop systems much like those used for aerial firefighting. To reduce drift of the materials, agricultural pilots attempt to fly just above the crops being treated. Fields are often surrounded by such as trees, telephone lines. Purpose-built agricultural airplanes have strengthened cockpits to protect the pilot if an accident occurs, aerial spraying has been controversial since the 1960s, due to environmental concerns about pesticide drift. It is now subject to restrictions, for example spraying pesticide is generally banned in Sweden
Agricultural aircraft
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Gehling PZL-106AR Kruk
Agricultural aircraft
–
The
Antonov An-2 was a mass-produced aircraft often used for agricultural work.
Agricultural aircraft
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Polish M-18 Dromader waterbomber used in
Western Australia.
Agricultural aircraft
–
A
Grumman Ag Cat applies a low-
insecticide bait on a
soybean field.
3.
Western corn rootworm
–
The Western corn rootworm, Diabrotica virgifera virgifera, is one of the most devastating corn rootworm species in North America, especially in the midwestern corn-growing areas such as Iowa. A related species, the Northern corn rootworm, D. barberi co-inhabits in much of the range, two other subspecies of D. virgifera are described, including the Mexican corn rootworm, a significant pest in its own right, attacking corn in that country. Corn rootworm larvae can destroy significant percentages of corn if left untreated, in the United States, current estimates show that 30,000,000 acres of corn are infested with corn rootworm. There are many similarities in the cycles of the northern and western corn rootworm. Both overwinter in the egg stage in the soil, eggs, which are deposited in the soil during the summer, are American football-shaped, white, and less than 0.004 inches long. Larvae hatch in late May or early June and begin to feed on corn roots, newly hatched larvae are small, less than.125 inches long, white worms. Corn rootworms go through three instars, pupate in the soil and emerge as adults in July and August. Larvae have brown heads and a marking on the top of the last abdominal segment. Larvae have three pairs of legs, but these are not usually visible without magnification, after feeding for several weeks, the larvae dig a cell in the soil and molt into the pupal stage. The pupal stage is white and has the shape of the adult. Adult rootworms are about.25 inches long, Western corn rootworms are yellowish with a black stripe on each wing cover. Northern corn rootworm beetles are solid in color and vary from tan to pale green. Timing of egg hatch varies from year to year due to temperature differences, males begin to emerge before females. Emergence often continues for a month or more, Western corn rootworm females need to feed for about two weeks before they can lay eggs. Temperature and food quality influence the pre-oviposition period, females typically lay eggs in the top 8 inches of soil, although they may be laid more than 12 inches deep, particularly if the soil surface is dry. Western corn rootworm females are likely to lay some of their eggs below the 8-inch depth than northern corn rootworm females. Rootworm larvae can complete development only on corn and a few species of grasses. Rootworm larvae reared on other grasses emerged as adults later and had smaller head capsule size as compared to larvae reared on corn
Western corn rootworm
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Western corn rootworm
4.
Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species are given a two-part name, a binomial. The first part of a binomial is the genus to which the species belongs, the second part is called the specific name or the specific epithet. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
Species
–
John Ray
Species
–
Carl Linnaeus believed in the fixity of species.
5.
Pest (organism)
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A pest is a plant or animal detrimental to humans or human concerns, alternative meanings include organisms that cause nuisance and epidemic disease associated with high mortality. In its broadest sense, a pest is a competitor of humanity, a pest is any living organism, whether animal, plant or fungus, which is invasive or troublesome to plants or animals, human or human concerns, livestock, or human structures. It is a concept, as an organism can be a pest in one setting but beneficial. Animals are called pests when they cause damage to agriculture by feeding on crops or parasitising livestock, such as codling moth on apples, an animal could also be a pest when it causes damage to a wild ecosystem or carries germs within human habitats. Examples of these include those organisms which vector human disease, such as rats and fleas which carry the disease, mosquitoes which vector malaria. A species can be a pest in one setting but beneficial or domesticated in another, Many weeds are also seen as useful under certain conditions, for instance Pattersons curse is often valued as food for honeybees and as a wildflower, even though it can poison livestock. The animal groups of greatest importance as pests are insects, mites, nematodes, the term plant pest has a specific definition in terms of the International Plant Protection Convention and phytosanitary measures worldwide. A pest is any species, strain or biotype of plant, animal, plants may be considered pests themselves if an invasive species. Pigeons and seagulls eat human food and carry disease Many birds, such as crows, eat crops Canada goose, widely regarded as pests in the United States, woodpeckers peck at rooftops and also nest in them. They cause structural damage to houses, in particular, the species poses a serious threat to the ecosystems of Australia where it was named The Most Important Pest/Problem. Cowbirds are brood parasites, which cause declines in local songbird populations, bullfrogs cause problems to the ecosystems. Cane toads have had negative effects on many ecosystems to which they have been introduced. The toads skin is toxic, killing many wild and domestic animals that attempt to eat it. Mice, rats, and other small rodents damage crops and stored produce Big cats, such as lions and cougars Rabbits decimate native plant populations in Australia, Deroceras reticulatum is a worldwide slug pest. Local importance slug pests include, Deroceras spp, arion spp. and some species of Veronicellidae, Veronicella sloanei. Helix aspersa damages citrus fruits in California, Cernuella virgata, Theba pisana, achatina fulica damages vegetables and ornamental plants in the Pacific region. Succinea costaricana damages ornamental plants in Costa Rica, ovachlamys fulgens damages ornamental plants and orchids in Costa Rica. Other pest species include Amphibulima patula dominicensis, Zachrysia provisoria and Bradybaena similaris, some snails and slugs of quarantine significance to the United States
Pest (organism)
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Carpet beetle larvae damaging a specimen of
Sceliphron destillatorius in an entomological collection
Pest (organism)
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Pests often occur in high densities, making the damage they do even more detrimental
Pest (organism)
–
Caterpillars cause crop damage
Pest (organism)
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Termites cause structural damage
6.
Integrated pest management
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Integrated pest management, also known as integrated pest control is a broad-based approach that integrates practices for economic control of pests. IPM aims to suppress pest populations below the economic injury level, IPM emphasizes the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms. Entomologists and ecologists have urged the adoption of IPM pest control since the 1970s, IPM allows for safer pest control. This includes managing insects, plant pathogens and weeds, globalization and increased mobility often allow increasing numbers of invasive species to cross national borders. IPM poses the least risks while maximizing benefits and reducing costs, for their leadership in developing and spreading IPM worldwide, Perry Adkisson and Ray F. Smith received the 1997 World Food Prize. Shortly after World War II, when synthetic insecticides became widely available, around the same time, entomologists in the US Cotton Belt were advocating a similar approach. This was viewed as an alternative to calendar-based programs, supervised control was based on knowledge of the ecology and analysis of projected trends in pest and natural-enemy populations. Supervised control formed much of the basis for the integrated control that University of California entomologists articulated in the 1950s. Integrated control sought to identify the best mix of chemical and biological controls for an insect pest. Chemical insecticides were to be used in the manner least disruptive to biological control, the term integrated was thus synonymous with compatible. IPM extended the concept of integrated control to all classes of pests and was expanded to include all tactics, controls such as pesticides were to be applied as in integrated control, but these now had to be compatible with tactics for all classes of pests. Other tactics, such as host-plant resistance and cultural manipulations, became part of the IPM framework, IPM combined entomologists, plant pathologists, nematologists and weed scientists. In 1979, President Jimmy Carter established an interagency IPM Coordinating Committee to ensure development, an American IPM system is designed around six basic components, Acceptable pest levels—The emphasis is on control, not eradication. IPM holds that wiping out an entire pest population is impossible. IPM programmes first work to establish acceptable pest levels, called action thresholds and these thresholds are pest and site specific, meaning that it may be acceptable at one site to have a weed such as white clover, but not at another site. Allowing a pest population to survive at a reasonable threshold reduces selection pressure and this lowers the rate at which a pest develops resistance to a control, because if almost all pests are killed then those that have resistance will provide the genetic basis of the future population. Retaining a significant number of unresistant specimens dilutes the prevalence of any resistant genes that appear, similarly, the repeated use of a single class of controls will create pest populations that are more resistant to that class, whereas alternating among classes helps prevent this. Preventive cultural practices—Selecting varieties best for local growing conditions and maintaining healthy crops is the first line of defense, Plant quarantine and cultural techniques such as crop sanitation are next, e. g. removal of diseased plants, and cleaning pruning shears to prevent spread of infections
Integrated pest management
–
An IPM
boll weevil trap in a cotton field (
Manning, South Carolina).
Integrated pest management
–
Pesticide types
7.
Tillage
–
Tillage is the agricultural preparation of soil by mechanical agitation of various types, such as digging, stirring, and overturning. Examples of human-powered tilling methods using hand tools include shovelling, picking, mattock work, hoeing, examples of draft-animal-powered or mechanized work include ploughing, rototilling, rolling with cultipackers or other rollers, harrowing, and cultivating with cultivator shanks. There is a continuum, however. Any type of gardening or farming, but especially larger-scale commercial types, Tillage is often classified into two types, primary and secondary. There is no boundary between them so much as a loose distinction between tillage that is deeper and more thorough and tillage that is shallower and sometimes more selective of location. Harrowing and rototilling often combine primary and secondary tillage into one operation, Tillage can also mean the land that is tilled. The word cultivation has several senses that overlap substantially with those of tillage, in a general context, both can refer to agriculture. Within agriculture, both can refer to any kind of soil agitation, additionally, cultivation or cultivating may refer to an even narrower sense of shallow, selective secondary tillage of row crop fields that kills weeds while sparing the crop plants. Reduced tillage leaves between 15 and 30% residue cover on the soil or 500 to 1000 pounds per acre of small grain residue during the critical erosion period and this may involve the use of a chisel plow, field cultivators, or other implements. See the general comments below to see how they can affect the amount of residue, intensive tillage leaves less than 15% crop residue cover or less than 500 pounds per acre of small grain residue. Intensive tillage often involves multiple operations with such as a mold board, disk. Then a finisher with a harrow, rolling basket, and cutter can be used to prepare the seed bed. Conservation tillage leaves at least 30% of crop residue on the soil surface and this slows water movement, which reduces the amount of soil erosion. Conservation tillage also benefits farmers by reducing consumption and soil compaction. By reducing the number of times the farmer travels over the field, farmers realize significant savings in fuel, in most years since 1997, conservation tillage was used in US cropland more than intensive or reduced tillage. However, conservation tillage delays warming of the due to the reduction of dark earth exposure to the warmth of the spring sun. No-till - Never use a plow, disk, etc. ever again, strip-Till - Narrow strips are tilled where seeds will be planted, leaving the soil in between the rows untilled. Mulch-till Rotational Tillage - Tilling the soil every two years or less often, ridge-Till Zone tillage Zone tillage is a form of modified deep tillage in which only narrow strips are tilled, leaving soil in between the rows untilled
Tillage
–
Cultivating after an early rain
8.
Pesticide
–
Pesticides are substances that are meant to control pests or weeds. The most common of these are herbicides which account for approximately 80% of all pesticide use, most pesticides are intended to serve as plant protection products, which in general, protect plants from weeds, fungi, or insects. In general, a pesticide is a chemical or biological agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes, although pesticides have benefits, some also have drawbacks, such as potential toxicity to humans and other species. According to the Stockholm Convention on Persistent Organic Pollutants,9 of the 12 most dangerous, the term includes substances intended for use as a plant growth regulator, defoliant, desiccant, or agent for thinning fruit or preventing the premature fall of fruit. Also used as substances applied to either before or after harvest to protect the commodity from deterioration during storage. Pesticides can be classified by target organism, chemical structure, biopesticides include microbial pesticides and biochemical pesticides. Plant-derived pesticides, or botanicals, have been developing quickly and these include the pyrethroids, rotenoids, nicotinoids, and a fourth group that includes strychnine and scilliroside. Many pesticides can be grouped into chemical families, prominent insecticide families include organochlorines, organophosphates, and carbamates. Organochlorine hydrocarbons could be separated into dichlorodiphenylethanes, cyclodiene compounds, and they operate by disrupting the sodium/potassium balance of the nerve fiber, forcing the nerve to transmit continuously. Their toxicities vary greatly, but they have phased out because of their persistence. Organophosphate and carbamates largely replaced organochlorines, both operate through inhibiting the enzyme acetylcholinesterase, allowing acetylcholine to transfer nerve impulses indefinitely and causing a variety of symptoms such as weakness or paralysis. Organophosphates are quite toxic to vertebrates, and have in some cases replaced by less toxic carbamates. Thiocarbamate and dithiocarbamates are subclasses of carbamates, prominent families of herbicides include phenoxy and benzoic acid herbicides, triazines, ureas, and Chloroacetanilides. Phenoxy compounds tend to selectively kill broad-leaf weeds rather than grasses, the phenoxy and benzoic acid herbicides function similar to plant growth hormones, and grow cells without normal cell division, crushing the plants nutrient transport system. Many commonly used pesticides are not included in these families, including glyphosate, Pesticides can be classified based upon their biological mechanism function or application method. Most pesticides work by poisoning pests, a systemic pesticide moves inside a plant following absorption by the plant. With insecticides and most fungicides, this movement is usually upward and outward, increased efficiency may be a result
Pesticide
–
A
crop-duster spraying pesticide on a field
Pesticide
–
A
Lite-Trac four-wheeled self-propelled crop sprayer spraying pesticide on a field
Pesticide
–
A sign warning about potential pesticide exposure.
Pesticide
–
Preparation for an
application of hazardous herbicide in USA.
9.
Biological pest control
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Biological control is a method of controlling pests such as insects, mites, weeds and plant diseases using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms and it can be an important component of integrated pest management programs. Natural enemies of pests, also known as biological control agents, include predators, parasitoids, pathogens. Biological control agents of plant diseases are most often referred to as antagonists, Biological control agents of weeds include seed predators, herbivores and plant pathogens. DeBach and K. S. Hagen in 1964, however, the practice has previously been used for centuries. Without such ants, southern citrus fruits will be severely insect-damaged, the ants used are known as huang gan ants. Biological control techniques as we know them today started to emerge in the 1870s, during this decade, in the USA, the Missouri State Entomologist C. V. Riley and the Illinois State Entomologist W. LeBaron began within-state redistribution of parasitoids to control crop pests. The United States Department of Agriculture initiated research in biological control following the establishment of the Division of Entomology in 1881. The first importation of a parasitoid into the United States was this of Cotesia glomerata in 1883–1884, imported from Europe to control the imported cabbage white butterfly, Pieris rapae. In 1888–1889 the vedalia beetle, Rodolia cardinalis, which is a ladybug, was introduced from Australia to California to control the cottony cushion scale, Icerya purchasi. This had become a problem for the newly developed citrus industry in California. This great success led to further introductions of beneficial insects into the USA, as a result, nine parasitoids of gypsy moth, seven of brown-tail moth, and two predators for both moths became established in the USA. Although the gypsy moth was not fully controlled by natural enemies, the frequency, duration, and severity of its outbreaks were reduced. This program also led to the development of concepts, principles. The first reported case of a biological control attempt in Canada involves the hymenopteran parasitoid Trichogramma minutum. Between 1884 and 1908, the first Dominion Entomologist, James Fletcher, continued introductions of other parasitoids, there are three basic biological pest control strategies, importation, augmentation and conservation. Importation or classical biological control involves the introduction of a pests natural enemies to a new locale where they do not occur naturally, early instances were often unofficial and not based on research, and some introduced species became serious pests themselves. To be most effective at controlling a pest, a control agent requires a colonizing ability which allows it to keep pace with the spatial and temporal disruption of the habitat
Biological pest control
–
Syrphus fly larva feeding on
aphids.
Biological pest control
–
Hippodamia convergens, the convergent lady beetle, is commonly sold for biological control of
aphids.
Biological pest control
–
Parasitic wasp
Cotesia congregata on tobacco hornworm
Manduca sexta.
Biological pest control
–
A turnaround flowerpot, filled with straw to attract
Dermaptera -species
10.
Insecticide
–
An insecticide is a substance used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a factor behind the increase in agricultural 20th centurys productivity. Nearly all insecticides have the potential to significantly alter ecosystems, many are toxic to humans, Insecticides can be classified in two major groups, systemic insecticides, which have residual or long term activity, and contact insecticides, which have no residual activity. Furthermore, one can distinguish three types of insecticide, natural insecticides, such as nicotine, pyrethrum and neem extracts, made by plants as defenses against insects. Organic insecticides, which are chemical compounds, mostly working by contact. The mode of action describes how the pesticide kills or inactivates a pest and it provides another way of classifying insecticides. Mode of action is important in understanding whether an insecticide will be toxic to unrelated species, such as fish, birds, Insecticides are distinct from insect repellents, which do not kill. Systemic insecticides become incorporated and distributed throughout the whole plant. When insects feed on the plant, they ingest the insecticide, systemic insecticides produced by transgenic plants are called plant-incorporated protectants. For instance, a gene that codes for a specific Bacillus thuringiensis biocidal protein was introduced into corn, the plant manufactures the protein, which kills the insect when consumed. Contact insecticides are toxic to insects upon direct contact and these can be inorganic insecticides, which are metals and include arsenates, copper and fluorine compounds, which are less commonly used, and the commonly used sulfur. Contact insecticides can be organic insecticides, i. e. organic chemical compounds, synthetically produced, or they can be natural compounds like pyrethrum, neem oil etc. Contact insecticides usually have no residual activity, efficacy can be related to the quality of pesticide application, with small droplets, such as aerosols often improving performance. Many organic compounds are produced by plants for the purpose of defending the host plant from predation, a trivial case is tree rosin, which is a natural insecticide. Specific, the production of oleoresin by conifer species is a component of the response against insect attack. Many fragrances, e. g. oil of wintergreen, are in fact antifeedants, the technique has been expanded to include the use of RNA interference RNAi that fatally silences crucial insect genes. RNAi likely evolved as a defense against viruses, midgut cells in many larvae take up the molecules and help spread the signal
Insecticide
–
FLIT manual spray pump for insecticides from 1928
Insecticide
–
Pesticide types
Insecticide
–
Extant
11.
Natural selection
–
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in heritable traits of a population over time, Charles Darwin popularised the term natural selection, and compared it with artificial selection. Variation exists within all populations of organisms and this occurs partly because random mutations arise in the genome of an individual organism, and offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits, the environment of a genome includes the molecular biology in the cell, other cells, other individuals, populations, species, as well as the abiotic environment. Individuals with certain variants of the trait may survive and reproduce more than individuals with other, less successful, variants, therefore, factors that affect reproductive success are also important, including sexual selection and fecundity selection. Over time, this process can result in populations that specialise for particular ecological niches, in other words, natural selection is a key process in the evolution of a population. Natural selection can be contrasted with artificial selection, in which humans intentionally choose specific traits, Natural selection is one of the cornerstones of modern biology. The concept of natural selection originally developed in the absence of a theory of heredity, at the time of Darwins writing. The union of traditional Darwinian evolution with subsequent discoveries in classical genetics formed the synthesis of the mid-20th century. The addition of molecular genetics has led to developmental biology. While genotypes can slowly change by random genetic drift, natural selection remains the primary explanation for adaptive evolution, empedocles idea that organisms arose entirely by the incidental workings of causes such as heat and cold was criticised by Aristotle in Book II of Physics. He posited natural teleology in its place, and believed that form was achieved for a purpose, nevertheless, he accepted in his biology that new types of animals, monstrosities, can occur in very rare instances. And in like manner as to the parts in which there appears to exist an adaptation to an end. Yet it is impossible that this should be the true view, for teeth and all other natural things either invariably or normally come about in a given way, but of not one of the results of chance or spontaneity is this true. We do not ascribe to chance or mere coincidence the frequency of rain in winter, but frequent rain in summer we do, nor heat in the dog-days, therefore action for an end is present in things which come to be and are by nature. The struggle for existence was later described by the Islamic writer Al-Jahiz in the 9th century, the classical arguments were reintroduced in the 18th century by Pierre Louis Maupertuis and others, including Darwins grandfather, Erasmus Darwin. Until the early 19th century, the view in Western societies was that differences between individuals of a species were uninteresting departures from their Platonic ideals of created kinds. However, the theory of uniformitarianism in geology promoted the idea that simple and this theory, Lamarckism, was an influence on the Soviet biologist Trofim Lysenkos antagonism to mainstream genetic theory as late as the mid 20th century
Natural selection
–
Morpha typica and morpha carbonaria,
morphs of the
peppered moth resting on the same tree. The light-coloured morpha typica (below the bark's scar) is hard to see on this pollution-free tree,
camouflaging it from
predators.
Natural selection
–
Diagrammatic representation of the
divergence of modern
taxonomic groups from their
common ancestor
Natural selection
–
Male peppered moth
Natural selection
–
Charles Darwin 's illustrations of beak variation in the
finches of the
Galápagos Islands, which hold 13 closely related
species that differ most markedly in the shape of their beaks. The beak of each species is suited to its preferred food, suggesting that beak shapes evolved by natural selection.
12.
Predation
–
In an ecosystem, predation is a biological interaction where a predator feeds on its prey. Predators may or may not kill their prey prior to feeding on it, but the act of predation often results in the death of the prey, thus predation is often, though not always, carnivory. Other categories of consumption are herbivory, fungivory, and detritivory, all of these are consumer-resource systems. It can often be difficult to separate various types of feeding behaviors. For example, some parasites prey on their host and then lay their eggs on it, for their offspring to feed on it while it continues to live, the key characteristic of predation is the predators direct impact on the prey population. Selective pressures imposed on one another leads to an evolutionary arms race between prey and predator, resulting in various antipredator adaptations. Ways of classifying predation include grouping by trophic level or diet, by specialization, Predators can be classified by their interactions with their prey. Two factors are considered here, how close the predator and prey are, and whether the prey is killed by the predator. A true predator is one that kills and eats another living thing, Predators may hunt actively for prey in pursuit predation, or sit and wait for prey to approach within striking distance, as in ambush predators. Some predation entails venom that subdues a prey before the predator ingests it, as in the box jellyfish, or disables it, in some cases, the venom contributes to the digestion of the prey, as in rattlesnakes and some spiders. In contrast, baleen whales eat millions of microscopic plankton at once, seed and egg predation are true predation, as seeds and eggs are potential organisms. Predators need not eat prey entirely, for example, some predators cannot digest bones, some may eat only part of an organism, but still consistently cause its death. Grazing organisms do not often kill their prey, while some herbivores like zooplankton live on unicellular phytoplankton and therefore, by the individualized nature of the organism, kill their prey, many others only eat a small part of the plant. Grazing livestock may pull some grass out at the roots, but most is simply grazed upon, kelp is frequently grazed in subtidal kelp forests, but regrows at the base of the blade continuously to cope with browsing pressure. Animals may also be grazed upon, female mosquitos land on hosts briefly to gain sufficient proteins for the development of their offspring, starfish may be grazed on, being capable of regenerating lost arms. Parasites can at times be difficult to distinguish from grazers and their feeding behavior is similar in many ways, however they are noted for their close association with their host species. This close living arrangement may be described by the symbiosis, living together. Parasitic organisms range from the mistletoe, a parasitic plant
Predation
–
A
South China tiger (Panthera tigris amoyensis) as the predator feeding on the
blesbuck as the prey
Predation
–
Indian python swallowing a small
chital deer at
Mudumalai National Park
Predation
–
Meat ants feeding on a
cicada; some species can
prey on individuals of far greater size, particularly when working cooperatively.
Predation
–
Leopard (Panthera pardus pardus) killing a young
bushbuck (Tragelaphus sylvaticus) in
Kruger National Park.
13.
Parasitism
–
In biology/ecology, parasitism is a non-mutual relationship between species, where one species, the parasite, benefits at the expense of the other, the host. Traditionally parasite referred primarily to organisms visible to the naked eye, Parasites can be microparasites, which are typically smaller, such as protozoa, viruses, and bacteria. Examples of parasites include the plants mistletoe and cuscuta, and animals such as hookworms, unlike predators, parasites typically do not kill their host, are generally much smaller than their host, and will often live in or on their host for an extended period. Both are special cases of consumer-resource interactions, Parasites show a high degree of specialization, and reproduce at a faster rate than their hosts. Classic examples of parasitism include interactions between vertebrate hosts and tapeworms, flukes, the Plasmodium species, and fleas, parasitism differs from the parasitoid relationship in that parasitoids generally kill their hosts. Parasites reduce host biological fitness by general or specialized pathology, such as parasitic castration and impairment of secondary sex characteristics, Parasites increase their own fitness by exploiting hosts for resources necessary for their survival, e. g. food, water, heat, habitat, and transmission. Although parasitism applies unambiguously to many cases, it is part of a continuum of types of interactions between species, rather than an exclusive category, in many cases, it is difficult to demonstrate harm to the host. In others, there may be no apparent specialization on the part of the parasite, coined in English in 1611, the word parasitism comes from the Greek παρά + σιτισμός feeding, fattening. Parasites are classified based on their interactions with their hosts and on their life cycles, an obligate parasite is totally dependent on the host to complete its life cycle, while a facultative parasite is not. A direct parasite has one host while an indirect parasite has multiple hosts. For indirect parasites, there always be a definitive host. Parasites that live on the outside of the host, either on the skin or the outgrowths of the skin, are called ectoparasites and those that live inside the host are called endoparasites. Endoparasites can exist in one of two forms, intercellular parasites or intracellular parasites, intracellular parasites, such as protozoa, bacteria or viruses, tend to rely on a third organism, which is generally known as the carrier or vector. The vector does the job of transmitting them to the host, an example of this interaction is the transmission of malaria, caused by a protozoan of the genus Plasmodium, to humans by the bite of an anopheline mosquito. Those parasites living in a position, being half-ectoparasites and half-endoparasites, are called mesoparasites. An epiparasite is one that feeds on another parasite and this relationship is also sometimes referred to as hyperparasitism, exemplified by a protozoan living in the digestive tract of a flea living on a dog. Social parasites take advantage of interactions between members of social organisms such as ants, termites, and bumblebees, an extreme example of social parasitism is the ant species of Tetramorium inquilinum of the Alps, which spend their whole lives on the back of Tetramorium host ants. With tiny and deprecated bodies they have evolved for one single task, if they fall off, they most likely would not have the strength to climb back on top of another ant, and eventually they will die
Parasitism
–
Brood parasitism is a form of parasitism
Parasitism
–
A
Tetragnatha montana spider parasitized by an
Acrodactyla quadrisculpta larva.
Parasitism
–
A
Lithognathus fish parasitized by a
Cymothoa exigua parasite.
Parasitism
–
Human head lice (
Pediculus humanus capitis) are ectoparasites.
14.
Agriculture
–
Agriculture is the cultivation and breeding of animals, plants and fungi for food, fiber, biofuel, medicinal plants and other products used to sustain and enhance human life. Agriculture was the key development in the rise of human civilization. The study of agriculture is known as agricultural science, the history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. Industrial agriculture based on large-scale monoculture farming has become the dominant agricultural methodology, genetically modified organisms are an increasing component of agriculture, although they are banned in several countries. Agricultural food production and water management are increasingly becoming global issues that are fostering debate on a number of fronts, the major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. Specific foods include cereals, vegetables, fruits, oils, meats, fibers include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo, other useful materials are also produced by plants, such as resins, dyes, drugs, perfumes, biofuels and ornamental products such as cut flowers and nursery plants. The word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, field, Agriculture usually refers to human activities, although it is also observed in certain species of ant, termite and ambrosia beetle. To practice agriculture means to use resources to produce commodities which maintain life, including food, fiber, forest products, horticultural crops. This definition includes arable farming or agronomy, and horticulture, all terms for the growing of plants, even then, it is acknowledged that there is a large amount of knowledge transfer and overlap between silviculture and agriculture. In traditional farming, the two are often combined even on small landholdings, leading to the term agroforestry, Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least 11 separate regions of the Old and New World were involved as independent centers of origin, wild grains were collected and eaten from at least 105,000 years ago. Pigs were domesticated in Mesopotamia around 15,000 years ago, rice was domesticated in China between 13,500 and 8,200 years ago, followed by mung, soy and azuki beans. Sheep were domesticated in Mesopotamia between 13,000 and 11,000 years ago. From around 11,500 years ago, the eight Neolithic founder crops, emmer and einkorn wheat, hulled barley, peas, lentils, bitter vetch, chick peas and flax were cultivated in the Levant. Cattle were domesticated from the aurochs in the areas of modern Turkey. In the Andes of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, coca, llamas, alpacas, sugarcane and some root vegetables were domesticated in New Guinea around 9,000 years ago. Sorghum was domesticated in the Sahel region of Africa by 7,000 years ago, cotton was domesticated in Peru by 5,600 years ago, and was independently domesticated in Eurasia at an unknown time
Agriculture
–
Agriculture
Agriculture
–
Fields in
Záhorie (
Slovakia) - a typical Central European agricultural region.
Agriculture
–
Domestic sheep and a
cow (heifer) pastured together in
South Africa.
Agriculture
–
A
Sumerian harvester's sickle made from baked clay (ca. 3000 BC).
15.
Cats
–
The domestic cat is a small, typically furry, carnivorous mammal. They are often called house cats when kept as pets or simply cats when there is no need to distinguish them from other felids. Cats are often valued by humans for companionship and for their ability to hunt vermin, there are more than 70 cat breeds, though different associations proclaim different numbers according to their standards. Cats are similar in anatomy to the felids, with a strong flexible body, quick reflexes, sharp retractable claws. Cat senses fit a crepuscular and predatory ecological niche, cats can hear sounds too faint or too high in frequency for human ears, such as those made by mice and other small animals. They can see in near darkness, like most other mammals, cats have poorer color vision and a better sense of smell than humans. Cats, despite being solitary hunters, are a species and cat communication includes the use of a variety of vocalizations. Cats have a high breeding rate, under controlled breeding, they can be bred and shown as registered pedigree pets, a hobby known as cat fancy. Failure to control the breeding of pet cats by neutering, as well as the abandonment of former household pets, has resulted in numbers of feral cats worldwide. In certain areas outside cats native range, this has contributed, along with destruction and other factors. Cats have been known to extirpate a bird species within specific regions, a genetic study in 2007 concluded that domestic cats are descended from Near Eastern wildcats, having diverged around 8,000 BC in the Middle East. As of a 2007 study, cats are the second most popular pet in the US by number of pets owned, in a 2010 study they were ranked the third most popular pet in the UK, after fish and dogs, with around 8 million being owned. The domestic cat is believed to have evolved from the Near Eastern wildcat, the felids are a rapidly evolving family of mammals that share a common ancestor only 10–15 million years ago and include lions, tigers, cougars and many others. Within this family, domestic cats are part of the genus Felis, members of the genus are found worldwide and include the jungle cat of southeast Asia, European wildcat, African wildcat, the Chinese mountain cat, and the Arabian sand cat, among others. The domestic cat was first classified as Felis catus by Carl Linnaeus in the 10th edition of his Systema Naturae published in 1758, because of modern phylogenetics, domestic cats are usually regarded as another subspecies of the wildcat, F. silvestris. This has resulted in mixed usage of the terms, as the cat can be called by its subspecies name. Wildcats have also referred to as various subspecies of F. catus, but in 2003. The most common name in use for the cat remains F. catus
Cats
–
Domestic cat
Cats
–
A 19th century drawing of a tabby cat
Cats
–
Cat skull
Cats
–
Thermograph
16.
Ferret
–
The ferret is the domesticated form of the European polecat, a mammal belonging to the same genus as the weasel, Mustela of the family Mustelidae. They typically have brown, black, white, or mixed fur and they have an average length of 51 cm including a 13 cm tail, weigh about 1. 5–4 pounds, and have a natural lifespan of 7 to 10 years. Ferrets are sexually dimorphic predators with males being larger than females. Several other Mustelids also have the word ferret in their names, including an endangered species. The history of the ferrets domestication is uncertain, like that of most other domestic animals and they are still used for hunting rabbits in some parts of the world, but increasingly, they are kept only as pets. As a result, some parts of the world have imposed restrictions on the keeping of ferrets, the name ferret is derived from the Latin furittus, meaning little thief, a likely reference to the common ferret penchant for secreting away small items. The Greek word ictis occurs in a written by Aristophanes, The Acharnians. Whether this was a reference to ferrets, polecats, or the similar Egyptian mongoose is uncertain, Ferrets have a typical Mustelid body-shape being long and slender. Their average length is about 50 cm including a 13-cm tail and their pelage has various colorations including brown, black, white or mixed. They weigh between 0.7 kg to 2.0 kg and are sexually dimorphic as the males are larger than females. The average gestation period is 42 days and females may have 2 or 3 litters each year, the litter size is usually between 3 and 7 kits which are weaned after 3 to 6 weeks and become independent at 3 months. They become sexually mature at approximately 6 months and the life span is 7 to 10 years. Ferrets spend 14–18 hours a day asleep and are most active around the hours of dawn and dusk, unlike their polecat ancestors, which are solitary animals, most ferrets will live happily in social groups. A group of ferrets is commonly referred to as a business and they are territorial, like to burrow, and prefer to sleep in an enclosed area. Like many other mustelids, ferrets have scent glands near their anus, Ferrets can recognize individuals from these anal gland secretions, as well as the sex of unfamiliar individuals. Ferrets may also use urine marking for sex and individual recognition, as with skunks, ferrets can release their anal gland secretions when startled or scared, but the smell is much less potent and dissipates rapidly. Most pet ferrets in the US are sold de-scented, in many other parts of the world, including the UK and other European countries, de-scenting is considered an unnecessary mutilation. If excited, they may perform a behaviour called the war dance, characterized by frenzied sideways hops, leaps
Ferret
–
Ferret profile
Ferret
–
Ferret
Ferret
–
Ferret dentition
Ferret
–
Male ferret
17.
Mongoose
–
Mongoose is the popular English name for 29 of the 34 species in the 14 genera of the family Herpestidae, which are small feliform carnivorans native to southern Eurasia and mainland Africa. The other five species in the family are the four kusimanses in the genus Crossarchus, Herpestidae is placed within the suborder Feliformia, together with the cat, hyena, and civet families. The word mongoose is likely derived from the Marathi name mungūs or probably ultimately from Telugu name mangisu, the form of the English name was altered to its -goose ending by folk-etymology. It has no connection with the word goose. Historically, it has also been spelled mungoose, the plural form is mongooses, or, rarely, mongeese. Mongooses live in southern Asia, Africa, and southern Europe, as well in Fiji, Puerto Rico, and some Caribbean and Hawaiian islands, the 34 species range from 24 to 58 cm in length, excluding the tail. Mongooses range in weight from the dwarf mongoose, at 320 g, to the cat-sized white-tailed mongoose. Some species lead predominantly solitary lives, seeking out food only for themselves, while others travel in groups, sharing food among group members and offspring. Mongooses bear a resemblance to mustelids, having long faces and bodies, small, rounded ears, short legs. Most are brindled or grizzly, a few have strongly marked coats and their nonretractile claws are used primarily for digging. Mongooses, much like goats, have narrow, ovular pupils, most species have a large anal scent gland, used for territorial marking and signaling reproductive status. The dental formula of mongooses is similar to that of viverrids,3.1. 3-4. 1-23.1. 3-4. 1-2. Mongooses also have receptors for acetylcholine that, like the receptors in snakes, are shaped so that it is impossible for snake venom to attach to them. Mongooses are one of four known species with mutations in the nicotinic acetylcholine receptor that protect against snake venom. Pigs, honey badgers, hedgehogs, and mongooses all have modifications to the pocket that prevents the snake venom α-neurotoxin from binding. These represent four separate, independent mutations, in the mongoose, this change is effected uniquely, by glycosylation. Researchers are investigating whether similar mechanisms protect the mongoose from hemotoxic snake venoms, in contrast to the arboreal, nocturnal viverrids, mongooses are more commonly terrestrial and many are active during the day. The Egyptian mongoose is sometimes held as an example of a solitary mongoose, Mongooses mostly feed on insects, crabs, earthworms, lizards, birds, and rodents
Mongoose
–
Yellow mongoose, Cynictis penicillata
Mongoose
–
Mongoose Temporal range:
Oligocene to present
Mongoose
–
Herpestes lemanensis skull from the
Oligocene,
Muséum national d'histoire naturelle, Paris
Mongoose
–
Indian gray mongoose, Herpestes edwardsii
18.
Crop rotation
–
Crop rotation is the practice of growing a series of dissimilar or different types of crops in the same area in sequenced seasons. It is done so that the soil of farms is not used for one set of nutrients. It helps in reducing erosion and increases soil fertility and crop yield. Growing the same crop in the place for many years in a row disproportionately depletes the soil of certain nutrients. Crop cycle is used in conventional and organic farming systems. Middle Eastern farmers practiced crop rotation in 6000 BC without understanding the chemistry, alternately planting legumes, in the Bible, chapter 25 of the Book of Leviticus instructs the Israelites to observe a Sabbath of the Land. Every seventh year they would not till, prune or even control insects, the Roman writer, Cato the Elder, recommended that farmers save carefully goat, sheep, cattle, and all other dung. From the times of Charlemagne, farmers in Europe transitioned from a crop rotation to a three-field crop rotation. Under a two-field rotation, half the land was planted in a year, then, in the next year, the two fields were reversed. From the end of the Middle Ages until the 20th century, Europes farmers practised three-field rotation, dividing available lands into three parts. One section was planted in the autumn with rye or winter wheat, followed by spring oats or barley, the second section grew crops such as peas, lentils, or beans, and the third field was left fallow. The three fields were rotated in this manner so that three years, a field would rest and be fallow. Under the two-field system, if one has a total of 600 acres of fertile land, under the new three-field rotation system, one would plant 400 acres. But the additional crops had a significant effect than mere quantitative productivity. Since the spring crops were mostly legumes, they increased the overall nutrition of the people of Northern Europe, farmers in the region of Waasland pioneered a four-field rotation in the early 16th century, and the British agriculturist Charles Townshend popularised this system in the 18th century. The sequence of four crops, included a crop and a grazing crop. The four-field crop rotation became a key development in the British Agricultural Revolution, the rotation between arable and ley is sometimes called ley farming. George Washington Carver studied crop-rotation methods in the United States, teaching southern farmers to rotate soil-depleting crops like cotton with soil-enriching crops like peanuts, such practices aimed to increase yields, to prepare soil for specialist crops, and to reduce waste and inefficiency by simplifying planting and harvesting
Crop rotation
–
Agriculture
Crop rotation
–
Satellite image of circular crop fields in
Kansas in late June 2001. Healthy, growing crops are green.
Corn would be growing into leafy stalks by then.
Sorghum, which resembles corn, grows more slowly and would be much smaller and therefore, (possibly) paler.
Wheat is a brilliant yellow as harvest occurs in June. Fields of brown have been recently harvested and plowed under or lie fallow for the year.
Crop rotation
–
Effects of crop rotation and monoculture at the Swojec Experimental Farm,
Wroclaw University of Environmental and Life Sciences. In the front field, the "Norfolk" crop rotation sequence (potatoes, oats, peas, rye) is being applied; in the back field, rye has been grown for 45 years in a row.
19.
Companion planting
–
Companion planting is a form of polyculture. Companion planting is used by farmers and gardeners in both industrialized and developing countries for many reasons, many of the modern principles of companion planting were present many centuries ago in cottage gardens in England and forest gardens in Asia, and thousands of years ago in Mesoamerica. In China, mosquito ferns have been used for at least a thousand years as companion plants for rice crops and they host a cyanobacterium that fixes nitrogen from the atmosphere, and they block light from plants that would compete with the rice. Companion planting was practiced in various forms by the peoples of the Americas prior to the arrival of Europeans. These peoples domesticated squash 8,000 to 10,000 years ago, then maize, then common beans, the cornstalk served as a trellis for the beans to climb, and the beans fixed nitrogen, benefitting the maize. Companion planting was promoted in the 1970s as part of the organic gardening movement. It was encouraged for pragmatic reasons, such as natural trellising and it is also a technique frequently used in permaculture, together with mulching, polyculture, and changing of crops. This practice is called trap cropping, the smell of the foliage of marigolds is claimed to deter aphids from feeding on neighbouring crops. Marigolds with simple flowers also attract nectar-feeding adult hoverflies, the larvae of which are predators of aphids, various legume crops benefit from being commingled with a grassy nurse crop. For example, common vetch or hairy vetch is planted together with rye or winter wheat to make a cover crop or green manure. The terms undersowing and overseeding both involve intercropping as a type of companion planting, undersowing conveys the idea of sowing the second crop among the young plants of the first crop. A connotation of understory growth is conveyed, albeit exaggerated, overseeding conveys the idea of broadcasting the seeds of the second crop over the existing first crop. This is analogous to overseeding a lawn to improve the mix of grasses present, there are a number of systems and ideas using companion planting. Organic gardening may make use of companion planting, since many synthetic means of fertilizing, weed reduction, the host-plant finding process occurs in phases, The first phase is stimulation by odours characteristic to the host-plant. This induces the insect to try to land on the plant it seeks, but insects avoid landing on brown soil. So if only the host-plant is present, the insects will quasi-systematically find it by simply landing on the only green thing around, when it does an inappropriate landing, it flies off to any other nearby patch of green. It eventually leaves the area if there are too many inappropriate landings, the second phase of host-plant finding is for the insect to make short flights from leaf to leaf to assess the plants overall suitability. The number of leaf-to-leaf flights varies according to the insect species, the insect must accumulate sufficient stimuli from the host-plant to lay eggs, so it must make a certain number of consecutive appropriate landings
Companion planting
–
Companion planting of carrots and onions.
Companion planting
–
Gardening
20.
Selective breeding
–
Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties, cultigens, or cultivars. Two purebred animals of different breeds produce a crossbreed, and crossbred plants are called hybrids, flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals, major crops are usually the provenance of the professionals. There are two approaches or types of selection, or selective breeding. The second is called controlled natural selection, which is natural selection in a controlled environment. In this, the breeder does not choose which individuals being tested survive or reproduce, there are also selection experiments, which is a third approach and these are conducted in order to determine the strength of natural selection in the wild. However, this is often an observational approach as opposed to an experimental approach. In animal breeding, techniques such as inbreeding, linebreeding, in plant breeding, similar methods are used. Charles Darwin discussed how selective breeding had been successful in producing change over time in his 1859 book and its first chapter discusses selective breeding and domestication of such animals as pigeons, cats, cattle, and dogs. Darwin used artificial selection as a springboard to introduce and support the theory of natural selection, the deliberate exploitation of selective breeding to produce desired results has become very common in agriculture and experimental biology. Selective breeding can be unintentional, e. g. resulting from the process of human cultivation, for example, in some grains, an increase in seed size may have resulted from certain ploughing practices rather than from the intentional selection of larger seeds. Most likely, there has been an interdependence between natural and artificial factors that have resulted in plant domestication, Selective breeding was practiced by the Romans. Treatises as much as 2,000 years old give advice on selecting animals for different purposes, the notion of selective breeding was later expressed by the Persian Muslim polymath Abu Rayhan Biruni in the 11th century. He noted the idea in his book titled India, which included various examples, the agriculturist selects his corn, letting grow as much as he requires, and tearing out the remainder. The forester leaves those branches which he perceives to be excellent, the bees kill those of their kind who only eat, but do not work in their beehive. Selective breeding was established as a practice by Robert Bakewell during the British Agricultural Revolution in the 18th century. Arguably, his most important breeding program was with sheep, using native stock, he was able to quickly select for large, yet fine-boned sheep, with long, lustrous wool. The Lincoln Longwool was improved by Bakewell, and in turn the Lincoln was used to develop the subsequent breed, named the New Leicester and it was hornless and had a square, meaty body with straight top lines. Bloodlines of these original New Leicesters survive today as the English Leicester, Bakewell was also the first to breed cattle to be used primarily for beef
Selective breeding
–
A
Belgian Blue cow. The defect in the breed's
myostatin gene is maintained through linebreeding and is responsible for its accelerated lean muscle growth.
Selective breeding
–
Diagrammatic representation of the
divergence of modern
taxonomic groups from their
common ancestor
Selective breeding
–
This
Chihuahua mix and
Great Dane shows the wide range of dog breed sizes created using selective breeding.
Selective breeding
–
Selective breeding transformed
teosinte 's few fruitcases (left) into modern
maize 's rows of exposed kernels (right).
21.
Cultivars
–
The term cultivar most commonly refers to an assemblage of plants selected for desirable characteristics that are maintained during propagation. More generally, cultivar refers to the most basic classification category of cultivated plants governed by the ICNCP, most cultivars have arisen in cultivation, but a few are special selections from the wild. Popular ornamental garden plants like roses, camellias, daffodils, rhododendrons, trees used in forestry are also special selections grown for their enhanced quality and yield of timber. Cultivars form a part of Liberty Hyde Baileys broader grouping. Cultivar was coined by Bailey and it is regarded as a portmanteau of cultivated and variety. A cultivar is not the same as a variety, a taxonomic rank below subspecies. In recent times, the naming of cultivars has been complicated by the use of statutory plant patents, the International Union for the Protection of New Varieties of Plants offers legal protection of plant cultivars to people or organisations who introduce new cultivars to commerce. UPOV requires that a cultivar be distinct, uniform and stable, to be distinct, it must have characteristics that easily distinguish it from any other known cultivar. To be uniform and stable, the cultivar must retain these characteristics under repeated propagation, a cultivar is given a cultivar name, which consists of the scientific Latin botanical name followed by a cultivar epithet. The cultivar epithet is usually in a vernacular language, for example, the full cultivar name of the King Edward potato is Solanum tuberosum King Edward. The King Edward part of the name is the cultivar epithet, the origin of the term cultivar arises from the need to distinguish between wild plants and those with characteristics that have arisen in cultivation. This distinction dates back to the Greek philosopher Theophrastus, the Father of Botany, botanical historian Alan Morton notes that Theophrastus in his Enquiry into Plants had an inkling of the limits of culturally induced changes and of the importance of genetic constitution. In Species Plantarum, Linnaeus listed all the known to him. Most of the listed by Linnaeus were of garden origin rather than being wild plants. Over time there was an increasing need to distinguish between plants growing in the wild, and those with variations that had produced in cultivation. In the nineteenth century many garden-derived plants were given names, sometimes in Latin. In the twentieth century an improved international terminology was proposed for the classification and it is essentially the equivalent of the botanical variety except in respect to its origin. However, Bailey was never explicit about the etymology of the word, and it has suggested that it is a contraction of the words cultigen and variety
Cultivars
–
Osteospermum 'Pink Whirls' A cultivar selected for its intriguing and colourful flowers
Cultivars
–
Liberty Hyde Bailey (1858–1954) coined the word cultigen in 1918 and cultivar in 1923.
Cultivars
–
A cultivar of the orchid genus
Oncidium
Cultivars
–
Leucospermum 'Scarlet Ribbon' A cross performed in Tasmania between L. glabrum and L. tottum
22.
Oecophylla smaragdina
–
Oecophylla smaragdina is a species of arboreal ant found in tropical Asia and Australia. These ants form colonies with nests in trees, each nest being made of leaves stitched together using the silk produced by the ant larvae. Workers and major workers are mostly coloured orange, workers are 5–6 millimetres long, they look after larvae and farm scale bugs for honeydew. Major workers are 8–10 millimetres long, with strong legs. They forage, assemble and expand the nest, queens are typically 20–25 millimetres long, and normally greenish-brown. It is a species, making its nests among the foliage of trees. Nests are constructed during the night, with major workers weaving towards the exterior and minor workers completing the interior structure. The ant colony may have several nests in one tree, or the nests may be spread over several adjacent trees, colonies can reach up to half a million individuals, in one instance, a colony occupied 151 nests distributed among twelve trees. Each colony has a queen, in one of these nests. The average life of a colony may be eight years. Weaver ants of this species are important parts of the ecosystem in tree canopies in humid tropical regions, the nests of this species are constructed by the workers, with leaves being woven together and secured by silk produced by the larvae. First a row of line up along the edge of a green leaf and, grasping a nearby leaf. Other workers on the far side of the leaves, each carrying a larva in its mouth and this produces a suture of fine silken threads that secures the leaves together. More leaves are attached in a manner to enlarge the nest. Weaver ants feed on insects and other invertebrates, their prey being mainly beetles, flies and they do not sting, but have a painful bite into which they can secrete irritant chemicals from their abdomens. In Singapore, colonies are found in sea hibiscus and great morinda trees which entice the ants with nectar. In Indonesia, the trees supporting colonies include banana, coconut, oil palm, rubber tree, cacao, teak, jackfruit, mango, Chinese laurel, petai, jengkol, duku, rambutan, jambu air and kedondong. The ants also attend aphids, scale insects and other homopterans to feed on the honeydew they produce, for this purpose, they drive away other ant species from the parts of the canopy where these sap-sucking insects live
Oecophylla smaragdina
–
Oecophylla smaragdina
Oecophylla smaragdina
Oecophylla smaragdina
–
A Queen of Oecophylla smaragdina that has shed its wings
Oecophylla smaragdina
–
Weaver ant nest on a
Mango tree
23.
Pesticides
–
Pesticides are substances that are meant to control pests or weeds. The most common of these are herbicides which account for approximately 80% of all pesticide use, most pesticides are intended to serve as plant protection products, which in general, protect plants from weeds, fungi, or insects. In general, a pesticide is a chemical or biological agent that deters, incapacitates, kills, or otherwise discourages pests. Target pests can include insects, plant pathogens, weeds, mollusks, birds, mammals, fish, nematodes, although pesticides have benefits, some also have drawbacks, such as potential toxicity to humans and other species. According to the Stockholm Convention on Persistent Organic Pollutants,9 of the 12 most dangerous, the term includes substances intended for use as a plant growth regulator, defoliant, desiccant, or agent for thinning fruit or preventing the premature fall of fruit. Also used as substances applied to either before or after harvest to protect the commodity from deterioration during storage. Pesticides can be classified by target organism, chemical structure, biopesticides include microbial pesticides and biochemical pesticides. Plant-derived pesticides, or botanicals, have been developing quickly and these include the pyrethroids, rotenoids, nicotinoids, and a fourth group that includes strychnine and scilliroside. Many pesticides can be grouped into chemical families, prominent insecticide families include organochlorines, organophosphates, and carbamates. Organochlorine hydrocarbons could be separated into dichlorodiphenylethanes, cyclodiene compounds, and they operate by disrupting the sodium/potassium balance of the nerve fiber, forcing the nerve to transmit continuously. Their toxicities vary greatly, but they have phased out because of their persistence. Organophosphate and carbamates largely replaced organochlorines, both operate through inhibiting the enzyme acetylcholinesterase, allowing acetylcholine to transfer nerve impulses indefinitely and causing a variety of symptoms such as weakness or paralysis. Organophosphates are quite toxic to vertebrates, and have in some cases replaced by less toxic carbamates. Thiocarbamate and dithiocarbamates are subclasses of carbamates, prominent families of herbicides include phenoxy and benzoic acid herbicides, triazines, ureas, and Chloroacetanilides. Phenoxy compounds tend to selectively kill broad-leaf weeds rather than grasses, the phenoxy and benzoic acid herbicides function similar to plant growth hormones, and grow cells without normal cell division, crushing the plants nutrient transport system. Many commonly used pesticides are not included in these families, including glyphosate, Pesticides can be classified based upon their biological mechanism function or application method. Most pesticides work by poisoning pests, a systemic pesticide moves inside a plant following absorption by the plant. With insecticides and most fungicides, this movement is usually upward and outward, increased efficiency may be a result
Pesticides
–
A
crop-duster spraying pesticide on a field
Pesticides
–
A
Lite-Trac four-wheeled self-propelled crop sprayer spraying pesticide on a field
Pesticides
–
A sign warning about potential pesticide exposure.
Pesticides
–
Preparation for an
application of hazardous herbicide in USA.
24.
Sumer
–
Living along the valleys of the Tigris and Euphrates, Sumerian farmers were able to grow an abundance of grain and other crops, the surplus of which enabled them to settle in one place. Proto-writing in the dates back to c.3000 BC. The earliest texts come from the cities of Uruk and Jemdet Nasr and date back to 3300 BC, modern historians have suggested that Sumer was first permanently settled between c.5500 and 4000 BC by a West Asian people who spoke the Sumerian language, an agglutinative language isolate. These conjectured, prehistoric people are now called proto-Euphrateans or Ubaidians, some scholars contest the idea of a Proto-Euphratean language or one substrate language. Reliable historical records begin much later, there are none in Sumer of any kind that have dated before Enmebaragesi. Juris Zarins believes the Sumerians lived along the coast of Eastern Arabia, todays Persian Gulf region, Sumerian civilization took form in the Uruk period, continuing into the Jemdet Nasr and Early Dynastic periods. During the 3rd millennium BC, a cultural symbiosis developed between the Sumerians, who spoke a language isolate, and Akkadian-speakers, which included widespread bilingualism. The influence of Sumerian on Akkadian is evident in all areas, from lexical borrowing on a scale, to syntactic, morphological. This has prompted scholars to refer to Sumerian and Akkadian in the 3rd millennium BC as a Sprachbund, Sumer was conquered by the Semitic-speaking kings of the Akkadian Empire around 2270 BC, but Sumerian continued as a sacred language. Native Sumerian rule re-emerged for about a century in the Neo-Sumerian Empire or Third Dynasty of Ur approximately 2100-2000 BC, the term Sumerian is the common name given to the ancient non-Semitic-speaking inhabitants of Mesopotamia, Sumer, by the East Semitic-speaking Akkadians. The Sumerians referred to themselves as ùĝ saĝ gíg ga, phonetically /uŋ saŋ gi ga/, literally meaning the black-headed people, the Akkadian word Shumer may represent the geographical name in dialect, but the phonological development leading to the Akkadian term šumerû is uncertain. Hebrew Shinar, Egyptian Sngr, and Hittite Šanhar, all referring to southern Mesopotamia, in the late 4th millennium BC, Sumer was divided into many independent city-states, which were divided by canals and boundary stones. Each was centered on a dedicated to the particular patron god or goddess of the city. The Sumerian city-states rose to power during the prehistoric Ubaid and Uruk periods, classical Sumer ends with the rise of the Akkadian Empire in the 23rd century BC. Following the Gutian period, there is a brief Sumerian Renaissance in the 21st century BC, the Amorite dynasty of Isin persisted until c.1700 BC, when Mesopotamia was united under Babylonian rule. The Sumerians were eventually absorbed into the Akkadian population, 2500–2334 BC Akkadian Empire period, c. 2218–2047 BC Ur III period, c, 2047–1940 BC The Ubaid period is marked by a distinctive style of fine quality painted pottery which spread throughout Mesopotamia and the Persian Gulf. It appears that this culture was derived from the Samarran culture from northern Mesopotamia and it is not known whether or not these were the actual Sumerians who are identified with the later Uruk culture
Sumer
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Map of Sumer
Sumer
–
The
Samarra bowl, at the
Pergamonmuseum, Berlin. The
swastika in the center of the design is a reconstruction.
Sumer
–
Fragment of
Eannatum 's
Stele of the Vultures
25.
Sulphur
–
Sulfur or sulphur is a chemical element with symbol S and atomic number 16. It is abundant, multivalent, and nonmetallic, under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a yellow crystalline solid at room temperature. Chemically, sulfur reacts with all elements except for gold, platinum, iridium, tellurium, though sometimes found in pure, native form, sulfur usually occurs as sulfide and sulfate minerals. Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India, ancient Greece, China, in the Bible, sulfur is called brimstone. Today, almost all elemental sulfur is produced as a byproduct of removing sulfur-containing contaminants from natural gas, the greatest commercial use of the element is the production of sulfuric acid for sulfate and phosphate fertilizers, and other chemical processes. The element sulfur is used in matches, insecticides, and fungicides, many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, grapefruit, and garlic are due to organosulfur compounds. Hydrogen sulfide gives the characteristic odor to rotting eggs and other biological processes, sulfur is an essential element for all life, but almost always in the form of organosulfur compounds or metal sulfides. Three amino acids and two vitamins are organosulfur compounds, many cofactors also contain sulfur including glutathione and thioredoxin and iron–sulfur proteins. Disulfides, S–S bonds, confer mechanical strength and insolubility of the keratin, found in outer skin, hair. Sulfur is one of the chemical elements needed for biochemical functioning and is an elemental macronutrient for all organisms. Sulfur is derived from the Latin word sulpur, which was Hellenized to sulphur, the spelling sulfur appears toward the end of the Classical period. In 12th-century Anglo-French, it was sulfre, in the 14th century the Latin ph was restored, for sulphre, the parallel f~ph spellings continued in Britain until the 19th century, when the word was standardized as sulphur. Sulfur was the form chosen in the United States, whereas Canada uses both, the IUPAC adopted the spelling sulfur in 1990, as did the Nomenclature Committee of the Royal Society of Chemistry in 1992, restoring the spelling sulfur to Britain. Sulfur forms polyatomic molecules with different chemical formulas, the best-known allotrope being octasulfur, cyclo-S8. The point group of cyclo-S8 is D4d and its dipole moment is 0 D. Octasulfur is a soft, bright-yellow solid that is odorless and it melts at 115.21 °C, boils at 444.6 °C and sublimes easily. At 95.2 °C, below its melting temperature, cyclo-octasulfur changes from α-octasulfur to the β-polymorph, the structure of the S8 ring is virtually unchanged by this phase change, which affects the intermolecular interactions. At higher temperatures, the viscosity decreases as depolymerization occurs, molten sulfur assumes a dark red color above 200 °C
Sulphur
–
Sulfur, 16 S
Sulphur
–
Spectral lines of sulfur
Sulphur
–
Nearly exhausted sulfur vat from which railroad cars are loaded, Freeport Sulphur Co., Hoskins Mound, Texas (1943).
Sulphur
–
Most of the yellow and orange hues of
Io are due to elemental sulfur and sulfur compounds, produced by active volcanoes.
26.
Insecticides
–
An insecticide is a substance used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a factor behind the increase in agricultural 20th centurys productivity. Nearly all insecticides have the potential to significantly alter ecosystems, many are toxic to humans, Insecticides can be classified in two major groups, systemic insecticides, which have residual or long term activity, and contact insecticides, which have no residual activity. Furthermore, one can distinguish three types of insecticide, natural insecticides, such as nicotine, pyrethrum and neem extracts, made by plants as defenses against insects. Organic insecticides, which are chemical compounds, mostly working by contact. The mode of action describes how the pesticide kills or inactivates a pest and it provides another way of classifying insecticides. Mode of action is important in understanding whether an insecticide will be toxic to unrelated species, such as fish, birds, Insecticides are distinct from insect repellents, which do not kill. Systemic insecticides become incorporated and distributed throughout the whole plant. When insects feed on the plant, they ingest the insecticide, systemic insecticides produced by transgenic plants are called plant-incorporated protectants. For instance, a gene that codes for a specific Bacillus thuringiensis biocidal protein was introduced into corn, the plant manufactures the protein, which kills the insect when consumed. Contact insecticides are toxic to insects upon direct contact and these can be inorganic insecticides, which are metals and include arsenates, copper and fluorine compounds, which are less commonly used, and the commonly used sulfur. Contact insecticides can be organic insecticides, i. e. organic chemical compounds, synthetically produced, or they can be natural compounds like pyrethrum, neem oil etc. Contact insecticides usually have no residual activity, efficacy can be related to the quality of pesticide application, with small droplets, such as aerosols often improving performance. Many organic compounds are produced by plants for the purpose of defending the host plant from predation, a trivial case is tree rosin, which is a natural insecticide. Specific, the production of oleoresin by conifer species is a component of the response against insect attack. Many fragrances, e. g. oil of wintergreen, are in fact antifeedants, the technique has been expanded to include the use of RNA interference RNAi that fatally silences crucial insect genes. RNAi likely evolved as a defense against viruses, midgut cells in many larvae take up the molecules and help spread the signal
Insecticides
–
FLIT manual spray pump for insecticides from 1928
Insecticides
–
Pesticide types
Insecticides
–
Extant
27.
Citrus
–
Citrus is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops like oranges, lemons, grapefruit, pomelo, the most recent research indicates an origin in Australia, New Caledonia and New Guinea. Citrus fruit has been cultivated in an area since ancient times. At various times, citrus plants were thought to be native to Asia, Europe, but the European oranges were originally brought from India at around the time of Alexander the Great, and the native oranges of Florida actually originated with the Spanish Conquistadors. The lemon reached Europe during the time of classical Rome, the generic name originated from Latin, where it referred to either the plant now known as Citron or a conifer tree. It is somehow related to the ancient Greek word for cedar and this may be due to perceived similarities in the smell of citrus leaves and fruit with that of cedar. Collectively, Citrus fruits and plants are known by the Romance loanword agrumes. The large citrus fruit of today evolved originally from small, edible berries over millions of years, Citrus plants diverged from a common ancestor about 15 million years ago, which was about when it diverged from the closely related severinia, for example the Chinese box orange. These estimates are made using genetic mapping of plant chloroplasts, the three original species in the citrus genus that have been hybridized into most modern commercial citrus fruit are the mandarin orange, pummelo, and citron. Within the last few years, all common citrus fruits were created by crossing those original species. Something similar has occurred with the array of chili peppers originating in the hybridization of a few initial species. Natural and cultivated citrus hybrids include commercially important fruit such as oranges, grapefruit, lemons, limes, apart from these four core citrus species, there are Australian limes and the recently discovered Mangshanyegan. Kumquats and Clymenia sp. are now considered to belong within the citrus genus. Trifoliate orange, which is used as commercial rootstock, is an outgroup. Phylogenetic analysis suggests the species of Oxanthera from New Caledonia should be transferred to the genus Citrus and these plants are large shrubs or small to moderate-sized trees, reaching 5–15 m tall, with spiny shoots and alternately arranged evergreen leaves with an entire margin. The flowers are solitary or in corymbs, each flower 2–4 cm diameter, with five white petals and numerous stamens. The fruit is a hesperidium, a berry, globose to elongated, 4–30 cm long and 4–20 cm diameter. The outermost layer of the pericarp is a called the flavedo
Citrus
–
Citrus
Citrus
–
Slices of various citrus fruits
Citrus
–
Persian limes in a grocery store
Citrus
–
Mediterranean Mandarin (
Citrus ×deliciosa plantation, Son Carrió (
Mallorca)
28.
Industrialization
–
As industrial workers incomes rise, markets for consumer goods and services of all kinds tend to expand and provide a further stimulus to industrial investment and economic growth. Later commentators have called this the First Industrial Revolution, the invention of the assembly line gave this phase a boost. Coal mines, steelworks, and textile factories replaced homes as the place of work, by the end of the 20th century, East Asia had become one of the most recently industrialised regions of the world. The BRICS states are undergoing the process of industrialisation, there is considerable literature on the factors facilitating industrial modernisation and enterprise development. The concentration of labour into factories has increased urbanisation and the size of settlements, to serve, workers have to either leave their families or bring them along in order to work in the towns and cities where these industries are found. The family structure changes with industrialisation, the sociologist Talcott Parsons noted that in pre-industrial societies there is an extended family structure spanning many generations who probably remained in the same location for generations. In industrialised societies the nuclear family, consisting of parents and their growing children. Families and children reaching adulthood are more mobile and tend to relocate to where jobs exist, extended family bonds become more tenuous. Currently the international development community endorses development policies like water purification or primary education and Co-Operation amongst third world communities, the relationships among economic growth, employment, and poverty reduction are complex. Higher productivity is argued to be leading to lower employment, division of labour Newly industrialised country Idea of Progress Chandler Jr. Alfred D. The Visible Hand, The Management Revolution in American Business, belknap Press of Harvard University Press. Hewitt, T. Johnson, H. and Wield, D. industrialisation and Development, Oxford University Press, hobsbawm, Eric, The Age of Revolution. Kemp, Tom Historical Patterns of Industrialisation, Longman, London, ISBN 0-582-09547-6 Kiely, R industrialisation and Development, A comparative analysis, UCL Press, London. The Unbound Prometheus, Technological Change and Industrial Development in Western Europe from 1750 to the Present, Cambridge, New York, Press Syndicate of the University of Cambridge. Pomeranz, Ken The Great Divergence, China, Europe and the Making of the Modern World Economy by Tilly, industrialization as an Historical Process, European History Online, Mainz, Institute of European History,2010, retrieved,29 February 2011
Industrialization
–
The effect of Industrialisation shown by rising income levels since 1500. The graph shows the
gross domestic product (at
purchasing power parity)
per capita between 1500 and 1950 in
1990 International dollars for selected nations.
29.
Mechanization
–
Mechanization or mechanisation is the process of changing from working largely or exclusively by hand or with animals to doing that work with machinery. Machines, in fact, are interposed between the power and the work, for the purpose of adapting the one to the other, in some fields, mechanization includes the use of hand tools. In modern usage, such as in engineering or economics, mechanization implies machinery more complex than hand tools, after electrification, when most small machinery was no longer hand powered, mechanization was synonymous with motorized machines. Water wheels date to the Roman period and were used to grind grain, water powered bellows were in use on blast furnaces in China in 31 AD. By the 13th century, water powered sawmills and trip hammers, to full cloth and pound flax. Trip hammers are shown crushing ore in De re Metallica, clocks were some of the most complex early mechanical devices. Clock makers were important developers of machine tools including gear and screw cutting machines, clocks were some of the earliest mass-produced items, beginning around 1830. Water powered bellows for blast furnaces, used in China in ancient times, were in use in Europe by the 15th century, De re Metallica contains drawings related to bellows for blast furnaces including a fabrication drawing. Improved gear designs decreased wear and increased efficiency, mathematical gear designs were developed in the mid 17th century. French mathematician and engineer Desargues designed and constructed the first mill with epicycloidal teeth ca, in the 18th century involute gears, another mathematical derived design, came into use. Involute gears are better for meshing gears of different sizes than epicycloidal, gear cutting machines came into use in the 18th century. The Newcomen steam engine was first used, to water from a mine. John Smeaton introduced metal gears and axles to water wheels in the mid to last half of the 18th century, Smeaton also conducted a scientific investigation into the design of water wheels which led to significant efficiency increases. The Industrial Revolution started mainly with textile machinery, such as the spinning jenny, demand for metal parts used in textile machinery led to the invention of many machine tools in the late 1700s until the mid-1800s. After the early decades of the 19th century, iron increasingly replaced wood in gearing, in the 1840s self acting machine tools were developed. Self-acting tools displaced hand dexterity and allowed one unskilled operator to tend several machines, machinery was developed to make nails ca. The Fourdrinier paper machine paper machine for continuous production of paper was patented in 1801, one of the first mechanical devices used in agriculture was the seed drill invented by Jethro Tull around 1700. The seed drill allowed more uniform spacing of seed and planting depth than hand methods, increasing yields, Mechanized agriculture greatly increased in the late eighteenth and early nineteenth centuries with horse drawn reapers and horse powered threshing machines
Mechanization
–
A water-powered
mine hoist used for raising ore. This woodblock is from
De re metallica by George Bauer (pen name
Georgius Agricola, ca. 1555) an early mining textbook that contains numerous drawings and descriptions of mining equipment.
Mechanization
–
The
Salisbury cathedral clock ca. 1386. A clock is a mechanical instrument rather than a true machine. Although this clock had iron gears, many machines of the early Industrial Revolution used wooden parts until around 1800.
30.
Pyrethrum
–
Pyrethrum was a genus of several Old World plants now classified as Chrysanthemum or Tanacetum which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a name for plants formerly included in the genus Pyrethrum. Pyrethrum is also the name of a natural insecticide made from the flower heads of Chrysanthemum cinerariifolium and Chrysanthemum coccineum. Some members of the Chrysanthemum genus, such as the two, are placed in the Tanacetum genus instead by some botanists. Both genera are members of the family, Asteraceae. They are all perennial plants with an appearance and white petals. T. cinerariifolium is called the Dalmatian chrysanthemum, denoting its origin in that region of the Balkans and it looks more like the common daisy than other pyrethrums do. Its flowers, typically white with yellow centers, grow from numerous fairly rigid stems, plants have blue-green leaves and grow to 45 to 100 cm in height. The plant is important as a natural source of insecticide. The flowers are pulverized and the components, called pyrethrins, contained in the seed cases, are extracted. This is applied as a suspension in water or oil, or as a powder, pyrethrins attack the nervous systems of all insects, and inhibit female mosquitoes from biting. When present in less than those fatal to insects, they still appear to have an insect repellent effect. They are harmful to fish, but are far less toxic to mammals and birds than many synthetic insecticides and are not persistent, being biodegradable and they are considered to be amongst the safest insecticides for use around food. Kenya produced 90% of the worlds pyrethrum in 1998, called py for short, production in Tanzania and Ecuador is also significant. Currently the worlds major producer is Tasmania, Australia, C. coccineum, the Persian chrysanthemum, is a perennial plant native to Caucasus and looks somewhat like a daisy. It produces large white, pink or red flowers, the leaves resemble those of ferns, and the plant grows to between 30 and 60 cm in height. The flowering period is June to July in temperate climates, C. coccineum also contains insecticidal pyrethrum substances, but it is a poor source compared to C. cinerariifolium. Other species, such as C. balsamita and C. marshalli, also contain insecticidal substances, Pyrethrum has been used for centuries as an insecticide, and as a lice remedy in the Middle East
Pyrethrum
–
Tanacetum cinerariifolium
Pyrethrum
–
Tanacetum coccineum
Pyrethrum
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.JPG)
