Molecular phylogenetics is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominately in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to determine the processes by which diversity among species has been achieved; the result of a molecular phylogenetic analysis is expressed in a phylogenetic tree. Molecular phylogenetics is one aspect of molecular systematics, a broader term that includes the use of molecular data in taxonomy and biogeography. Molecular phylogenetics and molecular evolution correlate. Molecular evolution is the process of selective changes at a molecular level throughout various branches in the tree of life. Molecular phylogenetics makes inferences of the evolutionary relationships that arise due to molecular evolution and results in the construction of a phylogenetic tree; the figure displayed on the right depicts the phylogenetic tree of life as one of the first detailed trees, according to information known in the 1870s by Haeckel.
The theoretical frameworks for molecular systematics were laid in the 1960s in the works of Emile Zuckerkandl, Emanuel Margoliash, Linus Pauling, Walter M. Fitch. Applications of molecular systematics were pioneered by Charles G. Sibley, Herbert C. Dessauer, Morris Goodman, followed by Allan C. Wilson, Robert K. Selander, John C. Avise. Work with protein electrophoresis began around 1956. Although the results were not quantitative and did not improve on morphological classification, they provided tantalizing hints that long-held notions of the classifications of birds, for example, needed substantial revision. In the period of 1974–1986, DNA-DNA hybridization was the dominant technique used to measure genetic difference. Early attempts at molecular systematics were termed as chemotaxonomy and made use of proteins, enzymes and other molecules that were separated and characterized using techniques such as chromatography; these have been replaced in recent times by DNA sequencing, which produces the exact sequences of nucleotides or bases in either DNA or RNA segments extracted using different techniques.
In general, these are considered superior for evolutionary studies, since the actions of evolution are reflected in the genetic sequences. At present, it is still a expensive process to sequence the entire DNA of an organism. However, it is quite feasible to determine the sequence of a defined area of a particular chromosome. Typical molecular systematic analyses require the sequencing of around 1000 base pairs. At any location within such a sequence, the bases found in a given position may vary between organisms; the particular sequence found in a given organism is referred to as its haplotype. In principle, since there are four base types, with 1000 base pairs, we could have 41000 distinct haplotypes. However, for organisms within a particular species or in a group of related species, it has been found empirically that only a minority of sites show any variation at all, most of the variations that are found are correlated, so that the number of distinct haplotypes that are found is small. In a molecular systematic analysis, the haplotypes are determined for a defined area of genetic material.
Haplotypes of individuals of related, yet different, taxa are determined. Haplotypes from a smaller number of individuals from a different taxon are determined: these are referred to as an outgroup; the base sequences for the haplotypes are compared. In the simplest case, the difference between two haplotypes is assessed by counting the number of locations where they have different bases: this is referred to as the number of substitutions; the difference between organisms is re-expressed as a percentage divergence, by dividing the number of substitutions by the number of base pairs analysed: the hope is that this measure will be independent of the location and length of the section of DNA, sequenced. An older and superseded approach was to determine the divergences between the genotypes of individuals by DNA-DNA hybridization; the advantage claimed for using hybridization rather than gene sequencing was that it was based on the entire genotype, rather than on particular sections of DNA. Modern sequence comparison techniques overcome this objection by the use of multiple sequences.
Once the divergences between all pairs of samples have been determined, the resulting triangular matrix of differences is submitted to some form of statistical cluster analysis, the resulting dendrogram is examined in order to see whether the samples cluster in the way that would be expected from current ideas about the taxonomy of the group. Any group of haplotypes that are all more similar to one another than any of them is to any other haplotype may be said to constitute a clade, which may be visually represented as the figure displayed on the right demonstrates. Statistical techniques such as bootstrapping and jackknifing help in providing reliability estimates for the positions of haplotypes within the evolutionary trees; every living organism contains deoxyribonucleic acid, ribonucleic acid, proteins. In general related organisms have a high degree of similarity in the molecular structure of these substances, while the molecules of organisms distantly related s
The eudicots, Eudicotidae or eudicotyledons are a clade of flowering plants, called tricolpates or non-magnoliid dicots by previous authors. The botanical terms were introduced in 1991 by evolutionary botanist James A. Doyle and paleobotanist Carol L. Hotton to emphasize the evolutionary divergence of tricolpate dicots from earlier, less specialized, dicots; the close relationships among flowering plants with tricolpate pollen grains was seen in morphological studies of shared derived characters. These plants have a distinct trait in their pollen grains of exhibiting three colpi or grooves paralleling the polar axis. Molecular evidence confirmed the genetic basis for the evolutionary relationships among flowering plants with tricolpate pollen grains and dicotyledonous traits; the term means "true dicotyledons", as it contains the majority of plants that have been considered dicots and have characteristics of the dicots. The term "eudicots" has subsequently been adopted in botany to refer to one of the two largest clades of angiosperms, monocots being the other.
The remaining angiosperms include magnoliids and what are sometimes referred to as basal angiosperms or paleodicots, but these terms have not been or adopted, as they do not refer to a monophyletic group. The other name for the eudicots is tricolpates, a name which refers to the grooved structure of the pollen. Members of the group have tricolpate pollen; these pollens have three or more pores set in furrows called colpi. In contrast, most of the other seed plants produce monosulcate pollen, with a single pore set in a differently oriented groove called the sulcus; the name "tricolpates" is preferred by some botanists to avoid confusion with the dicots, a nonmonophyletic group. Numerous familiar plants are eudicots, including many common food plants and ornamentals; some common and familiar eudicots include members of the sunflower family such as the common dandelion, the forget-me-not and other members of its family, buttercup and macadamia. Most leafy trees of midlatitudes belong to eudicots, with notable exceptions being magnolias and tulip trees which belong to magnoliids, Ginkgo biloba, not an angiosperm.
The name "eudicots" is used in the APG system, of 1998, APG II system, of 2003, for classification of angiosperms. It is applied to a monophyletic group, which includes most of the dicots. "Tricolpate" is a synonym for the "Eudicot" monophyletic group, the "true dicotyledons". The number of pollen grain furrows or pores helps classify the flowering plants, with eudicots having three colpi, other groups having one sulcus. Pollen apertures are any modification of the wall of the pollen grain; these modifications include thinning and pores, they serve as an exit for the pollen contents and allow shrinking and swelling of the grain caused by changes in moisture content. The elongated apertures/ furrows in the pollen grain are called colpi, along with pores, are a chief criterion for identifying the pollen classes; the eudicots can be divided into two groups: the basal eudicots and the core eudicots. Basal eudicot is an informal name for a paraphyletic group; the core eudicots are a monophyletic group.
A 2010 study suggested the core eudicots can be divided into two clades, Gunnerales and a clade called "Pentapetalae", comprising all the remaining core eudicots. The Pentapetalae can be divided into three clades: Dilleniales superrosids consisting of Saxifragales and rosids superasterids consisting of Santalales, Berberidopsidales and asteridsThis division of the eudicots is shown in the following cladogram: The following is a more detailed breakdown according to APG IV, showing within each clade and orders: clade Eudicots order Ranunculales order Proteales order Trochodendrales order Buxales clade Core eudicots order Gunnerales order Dilleniales clade Superrosids order Saxifragales clade Rosids order Vitales clade Fabids order Fabales order Rosales order Fagales order Cucurbitales order Oxalidales order Malpighiales order Celastrales order Zygophyllales clade Malvids order Geraniales order Myrtales order Crossosomatales order Picramniales order Malvales order Brassicales order Huerteales order Sapindales clade Superasterids order Berberidopsidales order Santalales order Caryophyllales clade Asterids order Cornales order Ericales clade Campanulids order Aquifoliales order Asterales order Escalloniales order Bruniales order Apiales order Dipsacales order Paracryphiales clade Lamiids order Solanales order Lamiales order Vahliales order Gentianales order Boraginales order Garryales order Metteniusales order Icacinales Eudicots at the Encyclopedia of Life Eudicots, Tree of Life Web Project Dicots Plant Life Forms
Plants are multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae. Plants were treated as one of two kingdoms including all living things that were not animals, all algae and fungi were treated as plants. However, all current definitions of Plantae exclude the fungi and some algae, as well as the prokaryotes. By one definition, plants form the clade Viridiplantae, a group that includes the flowering plants and other gymnosperms and their allies, liverworts and the green algae, but excludes the red and brown algae. Green plants obtain most of their energy from sunlight via photosynthesis by primary chloroplasts that are derived from endosymbiosis with cyanobacteria, their chloroplasts contain b, which gives them their green color. Some plants are parasitic or mycotrophic and have lost the ability to produce normal amounts of chlorophyll or to photosynthesize. Plants are characterized by sexual reproduction and alternation of generations, although asexual reproduction is common.
There are about 320 thousand species of plants, of which the great majority, some 260–290 thousand, are seed plants. Green plants provide a substantial proportion of the world's molecular oxygen and are the basis of most of Earth's ecosystems on land. Plants that produce grain and vegetables form humankind's basic foods, have been domesticated for millennia. Plants have many cultural and other uses, as ornaments, building materials, writing material and, in great variety, they have been the source of medicines and psychoactive drugs; the scientific study of plants is known as a branch of biology. All living things were traditionally placed into one of two groups and animals; this classification may date from Aristotle, who made the distincton between plants, which do not move, animals, which are mobile to catch their food. Much when Linnaeus created the basis of the modern system of scientific classification, these two groups became the kingdoms Vegetabilia and Animalia. Since it has become clear that the plant kingdom as defined included several unrelated groups, the fungi and several groups of algae were removed to new kingdoms.
However, these organisms are still considered plants in popular contexts. The term "plant" implies the possession of the following traits multicellularity, possession of cell walls containing cellulose and the ability to carry out photosynthesis with primary chloroplasts; when the name Plantae or plant is applied to a specific group of organisms or taxon, it refers to one of four concepts. From least to most inclusive, these four groupings are: Another way of looking at the relationships between the different groups that have been called "plants" is through a cladogram, which shows their evolutionary relationships; these are not yet settled, but one accepted relationship between the three groups described above is shown below. Those which have been called "plants" are in bold; the way in which the groups of green algae are combined and named varies between authors. Algae comprise several different groups of organisms which produce food by photosynthesis and thus have traditionally been included in the plant kingdom.
The seaweeds range from large multicellular algae to single-celled organisms and are classified into three groups, the green algae, red algae and brown algae. There is good evidence that the brown algae evolved independently from the others, from non-photosynthetic ancestors that formed endosymbiotic relationships with red algae rather than from cyanobacteria, they are no longer classified as plants as defined here; the Viridiplantae, the green plants – green algae and land plants – form a clade, a group consisting of all the descendants of a common ancestor. With a few exceptions, the green plants have the following features in common, they undergo closed mitosis without centrioles, have mitochondria with flat cristae. The chloroplasts of green plants are surrounded by two membranes, suggesting they originated directly from endosymbiotic cyanobacteria. Two additional groups, the Rhodophyta and Glaucophyta have primary chloroplasts that appear to be derived directly from endosymbiotic cyanobacteria, although they differ from Viridiplantae in the pigments which are used in photosynthesis and so are different in colour.
These groups differ from green plants in that the storage polysaccharide is floridean starch and is stored in the cytoplasm rather than in the plastids. They appear to have had a common origin with Viridiplantae and the three groups form the clade Archaeplastida, whose name implies that their chloroplasts were derived from a single ancient endosymbiotic event; this is the broadest modern definition of the term'plant'. In contrast, most other algae not only have different pigments but have chloroplasts with three or four surrounding membranes, they are not close relatives of the Archaeplastida having acquired chloroplasts separately from ingested or symbiotic green and red algae. They are thus not included in the broadest modern definition of the plant kingdom, although they were in the past; the green plants or Viridiplantae were traditionally divided into the green algae (including
Gentiana cruciata, the star gentian or cross gentian, is a herbaceous perennial flowering plant in the Gentianaceae family. Gentiana cruciata is a hemicryptophyte scapose plant of small size, reaching on average 20–40 centimetres in height, it has erect stems, the leaves are large, ovate-lanceolate, about 3–8 centimetres long. The flowers are violet-blue; the flowering period extends from June to August. The flowers are hermaphrodite and pollinated by insects; the fruit is a capsule. The seeds are dispersed by gravity alone. Gentiana cruciata is widespread in Western Asia; this plant prefers dry calcareous soil in forest edges, bushy slopes, pastures and dry meadows, at an altitude of 200–1,600 metres above sea level. Phengaris rebeli is an endangered butterfly. Female P. rebeli lay their eggs on the upper side of G. cruciata leaves and three to four weeks the P. rebeli larvae emerge and begin to feed on the seeds and flowers of this grassland plant. After the P. rebeli reaches its fourth larval instar, it drops to the ground to be picked up by Myrmica schencki ants and brought to their nests.
Female P. rebeli prefer to lay eggs on G. cruciata growing in clumps rather than individual plants, on the taller plants, as they are less shaded and allow the eggs to grow and develop faster. Gentiana cruciata Calphoto
Nerium oleander is a shrub or small tree in the dogbane family Apocynaceae, toxic in all its parts. It is the only species classified in the genus Nerium, it is most known as nerium or oleander, from its superficial resemblance to the unrelated olive Olea. It is so cultivated that no precise region of origin has been identified, though southwest Asia has been suggested; the ancient city of Volubilis in Morocco may have taken its name from the Berber name alili or oualilt for the flower. Oleander is one of the most poisonous grown garden plants; the origins of the taxonomic name Nerium oleander, first assigned by Linnaeus in 1753, are disputed. The genus name Nerium is the Latinized form of the Ancient Greek name for the plant Nerion, in turn derived from the Greek for water,'neros', because of the natural habitat of the oleander along rivers and streams; the word Oleander appears as far back as the first century AD, when the Greek physician Pedanius Dioscorides cited it as one of the terms used by the Romans for the plant.
Merriam-Webster believes the word is a Medieval Latin corruption of Late Latin names for the plant: arodandrum or lorandrum, or more plausibly rhododendron, with the addition of Olea because of the superficial resemblance to the olive tree. Another theory posited is that Oleander is the Latinized form of a Greek compound noun:'οllyo', which means'I kill', the Greek noun for man,'aner', genitive'andros'; this is because of the Oleander's toxicity to humans. The etymological association of oleander with the bay laurel has continued into the modern day: in France the plant is known as "Laurier Rose", while the Spanish term, "Adelfa", is the descendant of the original Ancient Greek name for both the bay laurel and the oleander, which subsequently passed into Arabic usage and thence to Spain. Oleander grows to 2 -- 6 m tall, with erect stems; the leaves are in pairs or whorls of three and leathery, dark-green, narrow lanceolate, 5–21 cm long and 1–3.5 cm broad, with an entire margin filled with minute reticulate venation web typical of eudicots.
Leaves are light green and glossy when young, before maturing to a dull dark green/greenish gray. The flowers grow in clusters at the end of each branch, they are but not always, sweet-scented. The fruit is a long narrow pair of follicles 5–23 cm long, which splits open at maturity to release numerous downy seeds. Nerium oleander is either native or naturalized to a broad area from Mauritania and Portugal eastward through the Mediterranean region and the Sahara, to the Arabian peninsula, southern Asia, as far east as Yunnan in southern parts of China, it occurs around stream beds in river valleys, where it can alternatively tolerate long seasons of drought and inundation from winter rains. Nerium oleander is planted in many subtropical and tropical areas of the world. On the East Coast of the US, it grows as far north as Virginia Beach, while in California and Texas miles of oleander shrubs are planted on median strips. There are estimated to be 25 million oleanders planted along highways and roadsides throughout the State of California.
Because of its durability, oleander was planted prolifically on Galveston Island in Texas after the disastrous Hurricane of 1900. They are so prolific that Galveston is known as the'Oleander City'. Beyond the traditional Mediterranean and subtropical range of oleander, the plant can be cultivated in mild oceanic climates with the appropriate precautions, it is grown without protection in southern England and can reach great sizes in London and to a lesser extent in Paris due to the urban heat island effect. This is the case with North American cities in the Pacific Northwest like Portland and Vancouver. Plants may suffer damage or die back in such marginal climates during severe winter cold, but will rebound from the roots; some invertebrates are known to be unaffected by oleander toxins, feed on the plants. Caterpillars of the polka-dot wasp moth feed on oleanders and survive by eating only the pulp surrounding the leaf-veins, avoiding the fibers. Larvae of the common crow butterfly and oleander hawk-moth feed on oleanders, they retain or modify toxins, making them unpalatable to potential predators such as birds, but not to other invertebrates such as spiders and wasps.
The flowers require insect visits to set seed, seem to be pollinated through a deception mechanism. The showy corolla acts as a potent advertisement to attract pollinators from a distance, but the flowers are nectarless and offer no reward to their visitors, they therefore receive few visits, as typical of many rewardless flower species. Fears of honey contamination with toxic oleander nectar are therefore unsubstantiated. Oleander is a vigorous grower in warm subtropical regions, where it is extensively used as an ornamental plant in parks, along roadsides and in private gardens, it is most grown in its natural shrub form, but can be trained into a small tree with a single trunk. Hardy versions like white and pink oleander will tolerate occasional light frost down to −10 °C, though the leaves may be damaged; the toxicity of oleander renders it deer-resistant and its large size makes for a good windbreak – as
August Heinrich Rudolf Grisebach was a German botanist and phytogeographer. He was born in Hannover on 17 April 1814 and died in Göttingen on 9 May 1879. Grisebach studied at the Lyceum in Hanover, the cloister-school at Ilfeld, the University of Göttingen, he graduated in medicine from the University of Berlin in 1836. He undertook expeditions to Provence, the Balkans, Norway. In 1837 he became associate professor and in 1847 full professor at the medical faculty in Göttingen and was named director of the botanical garden there in 1875. While his main fields of interest were phytogeography and systematics the Gentianaceae and Malpighiaceae, he considered his Flora of the British West Indian Islands his most important work. Much of his collection the types of species described by him, are housed at the Göttingen University Herbarium, his taxonomic classification is set out in his Grundriss der systematischen Botanik. His son Eduard was an author and diplomat. Complete bibliography on WorldCat Plantae Wrightianae e Cuba Orientali at Botanicus Catalogus plantarum cubensium 1866, at Botanicus Plantae Wrightianae e Cuba Orientali by A. Grisebach at the Biodiversity Heritage Library.
Grisebach, A. Systematische Untersuchungen über die Vegetation der Karaiben, inbesondere der Insel Guadeloupe at the Biodiversity Heritage Library. Malpighiaceae/Grisebach
Gentius was a king of the Ardiaei, a powerful tribe in Illyria. He ruled in 181 -- 168 BC, his name appears to derive from PIE *g'en- "to beget", cognate to Latin gens, gentis "kin, race". He was the son of a king who kept firm relations with Rome. Gentius' principal city was Shkodra. In 180 BC, during his early reign, the Dalmatae and Daorsi declared themselves independent from his rule and the city of Rhizon abandoned him prior to his defeat, receiving immunity from the Romans, he married Etuta, the daughter of the Dardanian king Monunius II. In 171 BC, Gentius was allied with the Romans against the Macedonians, but in 169 BC he changed sides and allied himself with Perseus of Macedon; the southernmost city of the Ardiaei state was Lissos, a situation established since the First Illyrian War. He arrested two Roman legati. Gentius destroyed the cities of Epidamnos, which were allied with Rome. In 168 BC, he was defeated at Scodra by a Roman force under L. Anicius Gallus, in only twenty or thirty days, in 167 brought to Rome as a captive to participate in Gallus's triumph, after which he was interned in Iguvium.
The date of his death is unknown. After his defeat, the Romans split the region into called meris; the extent of the first meris is not known, while the second was Labeates, the third was Acruvium, Rhizon and their environs. By 181 BC the loyal Pleuratus had been succeeded by his son Gentius. During his reign relations with the Ardiaean State and Rome started to dwindle; the coast and hinterland south of the Drin remained under Roman control since the First Illyrian Wars against Teuta. Gentius moved to increase power over kindred peoples living to the west. Among the islands the Greek city of Issa had retained some form of independence under Roman protection but Pharos remained an Illyrian possession. On the mainland the Delmatae and the Daorsi were at one time subjects, but the former defected soon after the accession of Gentius. Illyrian strength lay in the navy and ships and it was their interference with Adriatic shipping which once more aroused Roman interest in the area. In 180 BC a Roman praetor responsible for coastal protection arrived in Brudisium with some ships of Gentius said to have been caught in the act of piracy.
An embassy to Illyria failed to locate the king. No outcome of the affair is reported and it may well be that the Senate accepted a claim by Gentius' envoys that the charges were false. Ten years later,when Rome was gripped with war-fever against Perseus of Macedonia, Issa accused Gentius of plotting war with the king and now the Illyrian envoys were denied a hearing before the Senate. Instead the Romans seized 54 Illyrian lembi at anchor in the harbour of Epidamnos. On the eve of war a Roman senator was sent to Illyria to remind Gentius of his formal friendship with the Roman Republic. In 169 BC Gentius arranged the murder of his brother Plator killed because his plan to marry Etuta, daughter of the Dardanian king Monunius II, would have made him too powerful. Gentius married Plator's fiancée for himself, securing the alliance of the powerful Dardani. Perseus of Macedon having recaptured several Roman outposts in Roman occupied Illyria controlled the route leading west to the Ardiaean state.
At this point Perseus sent his first embassy to Gentius, consisting of the Illyrian exile Pleuratus and the Macedonian Adaeus and Beroea. They found Gentius at Lissos and informed him of Perseus' successes against the Romans and Dardani and the recent victory over the Penestae; the Illyrians replied. No promises were made on this point either by this embassy or another sent from Stuberra shortly afterwards. Perseus continued his efforts to involve Gentius in the war, preferably it was said, at no cost to his treasury; the Illyrian exile Plearatus raised 200 cavalry from the Penestae. The Roman invasion of Macedonia in 168 BC forced the king to promise a subsidy to Gentius, whose ships might be employed to attack the Romans. A sum of 300 talents was mentioned and Perseus sent his companion Pantauchus to make the arrangements. In the city of Meteon hostages were agreed and Gentius accepted the oath of the king, he sent Olympio with a delegation to Perseus to collect the money, the treaty was concluded with some ceremony at Dium on the Thermaic Gulf.
A formal parade of the Macedonian cavalry was held which may have impressed the Illyrians and the cavalry may have represented the Macedonians in the ratification of the treaty. The 300 talents were counted out of the royal treasure at Pella and the Illyrians were permitted to mark it with their own stamp. An advance of ten talents was forwarded to Gentius and when this was passed over by Pantauchus the king was urged to commence hostilities against the Romans; when Gentius imprisoned two Roman envoys sent by Appius Claudius at Lychnidus, Perseus recalled the rest of the subsidy in belief that Gentius was now his ally, come what may. Gentius accompanied the new anti-Roman orientation in Illyrian foreign policy with a series of measures to strengthen his state. First, he concentrated the finances by establishing a single tax over all the subjects and by taking royal control of the monetary workshops or mints of Lissus and Scodra, the two cities where he resided. At this time Gentius was issuing bronze coins.
In the Selcë hoard there are two coins of Gentius with Macedonian emblems. The other coins of Gentius have