Guatemala the Republic of Guatemala, is a country in Central America bordered by Mexico to the north and west and the Caribbean to the northeast, Honduras to the east, El Salvador to the southeast and the Pacific Ocean to the south. With an estimated population of around 16.6 million, it is the most populated country in Central America. Guatemala is a representative democracy; the territory of modern Guatemala once formed the core of the Maya civilization, which extended across Mesoamerica. Most of the country was conquered by the Spanish in the 16th century, becoming part of the viceroyalty of New Spain. Guatemala attained independence in 1821 as part of the Federal Republic of Central America, which dissolved by 1841. From the mid to late 19th century, Guatemala experienced civil strife. Beginning in the early 20th century, it was ruled by a series of dictators backed by the United Fruit Company and the United States government. In 1944, authoritarian leader Jorge Ubico was overthrown by a pro-democratic military coup, initiating a decade-long revolution that led to sweeping social and economic reforms.
A U. S.-backed military coup in 1954 installed a dictatorship. From 1960 to 1996, Guatemala endured a bloody civil war fought between the US-backed government and leftist rebels, including genocidal massacres of the Maya population perpetrated by the military. Since a United Nations-negotiated peace accord, Guatemala has witnessed both economic growth and successful democratic elections, though it continues to struggle with high rates of poverty, drug trade, instability; as of 2014, Guatemala ranks 31st of 33 Latin American and Caribbean countries in terms of the Human Development Index. Guatemala's abundance of biologically significant and unique ecosystems includes a large number of endemic species and contributes to Mesoamerica's designation as a biodiversity hotspot; the name "Guatemala" comes from the Nahuatl word Cuauhtēmallān, or "place of many trees", a derivative of the K'iche' Mayan word for "many trees" or more for the Cuate/Cuatli tree Eysenhardtia. This was the name the Tlaxcaltecan soldiers who accompanied Pedro de Alvarado during the Spanish Conquest gave to this territory.
The first evidence of human habitation in Guatemala dates back to 12,000 BC. Evidence, such as obsidian arrowheads found in various parts of the country, suggests a human presence as early as 18,000 BC. There is archaeological proof. Pollen samples from Petén and the Pacific coast indicate that maize cultivation had developed by 3500 BC. Sites dating back to 6500 BC have been found in the Quiché region in the Highlands, Sipacate and Escuintla on the central Pacific coast. Archaeologists divide the pre-Columbian history of Mesoamerica into the Preclassic period, the Classic period, the Postclassic period; until the Preclassic was regarded as a formative period, with small villages of farmers who lived in huts, few permanent buildings. However, this notion has been challenged by recent discoveries of monumental architecture from that period, such as an altar in La Blanca, San Marcos, from 1000 BC; the Classic period of Mesoamerican civilization corresponds to the height of the Maya civilization, is represented by countless sites throughout Guatemala, although the largest concentration is in Petén.
This period is characterized by urbanisation, the emergence of independent city-states, contact with other Mesoamerican cultures. This lasted until 900 AD, when the Classic Maya civilization collapsed; the Maya abandoned many of the cities of the central lowlands or were killed off by a drought-induced famine. The cause of the collapse is debated, but the drought theory is gaining currency, supported by evidence such as lakebeds, ancient pollen, others. A series of prolonged droughts, among other reasons such as overpopulation, in what is otherwise a seasonal desert is thought to have decimated the Maya, who relied on regular rainfall; the Post-Classic period is represented by regional kingdoms, such as the Itza, Kowoj and Kejache in Petén, the Mam, Ki'che', Chajoma, Tz'utujil, Poqomchi', Q'eqchi' and Ch'orti' in the highlands. Their cities preserved many aspects of Maya culture; the Maya civilization shares many features with other Mesoamerican civilizations due to the high degree of interaction and cultural diffusion that characterized the region.
Advances such as writing and the calendar did not originate with the Maya. Maya influence can be detected from Honduras, Northern El Salvador to as far north as central Mexico, more than 1,000 km from the Maya area. Many outside influences are found in Maya art and architecture, which are thought to be the result of trade and cultural exchange rather than direct external conquest. After they arrived in the New World, the Spanish started several expeditions to Guatemala, beginning in 1519. Before long, Spanish contact resulted in an epidemic. Hernán Cortés, who had led the Spanish conquest of Mexico, granted a permit to Captains Gonzalo de Alvarado and his brother, Pedro de Alvarado, to conquer this land. Alvarado at first allied himself with the Kaqchikel nation to fight against their traditional rivals the K'iche' nation
Shrubland, scrub, brush, or bush is a plant community characterised by vegetation dominated by shrubs also including grasses and geophytes. Shrubland may either occur or be the result of human activity, it may be the mature vegetation type in a particular region and remain stable over time, or a transitional community that occurs temporarily as the result of a disturbance, such as fire. A stable state may be maintained by regular natural disturbance such as browsing. Shrubland may be unsuitable for human habitation because of the danger of fire; the term "shrubland" was coined in 1903. Shrubland species show a wide range of adaptations to fire, such as heavy seed production and fire-induced germination. In botany and ecology a shrub is defined as a much-branched woody plant less than 8 m high and with many stems. Tall shrubs are 2–8 m high, small shrubs 1–2 m high and subshrubs less than 1 m high. A descriptive system adopted in Australia to describe different types of vegetation is based on structural characteristics based on plant life-form, plus the height and foliage cover of the tallest stratum or dominant species.
For shrubs 2–8 m high the following structural forms result: dense foliage cover — closed-scrub mid-dense foliage cover — open- sparse foliage cover — tall open shrublandFor shrubs <2 m high the following structural forms result: dense foliage cover — closed-heath mid-dense foliage cover — open-heath sparse foliage cover — low shrubland sparse foliage cover — low open shrubland Similarly, shrubland is a category used to describe a type of biome plant group. In this context, shrublands are dense thickets of evergreen sclerophyll shrubs and small trees, called: Chaparral in California Matorral in Chile and Spain Maquis in France and elsewhere around the Mediterranean Macchia in Italy Fynbos in South Africa Kwongan in Southwest Australia Cedar scrub in Texas Hill CountryIn some places shrubland is the mature vegetation type, in other places the result of degradation of former forest or woodland by logging or overgrazing, or disturbance by major fires. A number of World Wildlife Fund biomes are characterized as shrublands, including: Desert scrublands Xeric or desert scrublands occur in the world's deserts and xeric shrublands ecoregions, or in areas of fast-draining sandy soils in more humid regions.
These scrublands are characterized by plants with adaptations to the dry climate, which include small leaves to limit water loss, thorns to protect them from grazing animals, succulent leaves or stems, storage organs to store water, long taproots to reach groundwater. Mediterranean scrublandsMediterranean scrublands occur in the Mediterranean forests and scrub biomes, located in the five Mediterranean climate regions of the world. Scrublands are most common near the seacoast, have adapted to the wind and salt air of the ocean. Low, soft-leaved scrublands around the Mediterranean Basin are known as garrigue in France, phrygana in Greece, tomillares in Spain, batha in Israel. Northern coastal scrub and coastal sage scrub occur along the California coast, strandveld in the Western Cape of South Africa, coastal matorral in central Chile, sand-heath and kwongan in Southwest Australia. Interior scrublandsInterior scrublands occur in semi-arid areas where soils are nutrient-poor, such as on the matas of Portugal which are underlain by Cambrian and Silurian schists.
Florida scrub is another example of interior scrublands. Dwarf shrubs Some vegetation types are formed of dwarf-shrubs: creeping shrubs; these include the maquis and garrigues of Mediterranean climates, the acid-loving dwarf shrubs of heathland and moorland. Fynbos Maquis Prostrate shrub Semi-desert Shrub-steppe Shrub swamp Moorland
Wedelia is a flowering plant genus in the sunflower family. They are one of the genera called "creeping-oxeyes"; the genus is named in honor of German botanist and physician Georg Wolfgang Wedel, 1645–1721. There are difficulties regarding the classification of this genus. Further studies are needed to clarify its phylogenetic relationships. Many species were once considered part of Wedelia but have been now transferred to other genera, including Angelphytum, Baltimora, Chrysogonum, Elaphandra, Guizotia, Kingianthus, Melampodium, Moonia, Synedrella, Verbesina, Villanova and Zexmenia. Species USDA PLANTS Profile
Asterales is an order of dicotyledonous flowering plants that includes the large family Asteraceae known for composite flowers made of florets, ten families related to the Asteraceae. The order is a cosmopolite, includes herbaceous species, although a small number of trees and shrubs are present. Asterales are organisms. Asterales share characteristics on biochemical levels. Synapomorphies include the presence in the plants of oligosaccharide inulin, a nutrient storage molecule used instead of starch; the stamens are found around the style, either aggregated densely or fused into a tube an adaptation in association with the plunger pollination, common among the families of the order, wherein pollen is collected and stored on the length of the pistil. The name and order Asterales is botanically venerable, dating back to at least 1926 in the Hutchinson system of plant taxonomy when it contained only five families, of which only two are retained in the APG III classification. Under the Cronquist system of taxonomic classification of flowering plants, Asteraceae was the only family in the group, but newer systems have expanded it to 11.
In the classification system of Dahlgren the Asterales were in the superorder Asteriflorae. The order Asterales includes 11 families, the largest of which are the Asteraceae, with about 25,000 species, the Campanulaceae, with about 2,000 species; the remaining families count together for less than 1500 species. The two large families are cosmopolitan, with many of their species found in the Northern Hemisphere, the smaller families are confined to Australia and the adjacent areas, or sometimes South America. Only the Asteraceae have composite flower heads; the phylogenetic tree according to APG III for the Campanulid clade is as below. The core Asterales are Stylidiaceae, APA clade, MGCA clade, Asteraceae. Other Asterales are Rousseaceae and Pentaphragmataceae. All Asterales families are represented in the Southern Hemisphere. Although most extant species of Asteraceae are herbaceous, the examination of the basal members in the family suggests that the common ancestor of the family was an arborescent plant, a tree or shrub adapted to dry conditions, radiating from South America.
Less can be said about the Asterales themselves with certainty, although since several families in Asterales contain trees, the ancestral member is most to have been a tree or shrub. Because all clades are represented in the southern hemisphere but many not in the northern hemisphere, it is natural to conjecture that there is a common southern origin to them. Asterales are angiosperms; the Asterales order originated in the Cretaceous on the supercontinent Gondwana which broke up from 184 – 80 Mya, forming the area, now Australia, South America, Africa and Antarctica. Asterales contain about 14% of eudicot diversity. From an analysis of relationships and diversities within the Asterales and with their superorders, estimates of the age of the beginning of the Asterales have been made, which range from 116 Mya to 82Mya; however few fossils have been found, of the Menyanthaceae-Asteraceae clade in the Oligocene, about 29 Mya. Fossil evidence of the Asterales is rare and belongs to rather recent epochs, so the precise estimation of the order's age is quite difficult.
An Oligocene pollen is known for Asteraceae and Goodeniaceae, seeds from Oligocene and Miocene are known for Menyanthaceae and Campanulaceae respectively. The Asterales, by dint of being a super-set of the family Asteraceae, include some species grown for food, including the sunflower and chicory. Many are used as spices and traditional medicines. Asterales have many known uses. For example, pyrethrum is a natural insecticide with minimal environmental impact. Wormwood, derived from a genus that includes the sagebrush, is used as a source of flavoring for absinthe, a bitter classical liquor of European origin. W. S. Judd, C. S. Campbell, E. A. Kellogg, P. F. Stevens, M. J. Donoghue. Plant Systematics: A Phylogenetic Approach, 2nd edition. Pp. 476–486. Sinauer Associates, Massachusetts. ISBN 0-87893-403-0. J. Lindley. Nixus Plantarum, 20. Londini. Smissen, R. D.. Asterales. In: Nature Encyclopedia of Life Sciences. Nature Publishing Group, London. "Asterales -- Britannica Online Encyclopedia." Encyclopedia - Britannica Online Encyclopedia.
Web. 19 Jan. 2012. <http://www.britannica.com/EBchecked/topic/39703/Asterales>. "Asterales - Definition and More from the Free Merriam-Webster Dictionary." Dictionary and Thesaur
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
Trichomes, from the Greek τρίχωμα meaning "hair", are fine outgrowths or appendages on plants, algae and certain protists. They are of diverse function. Examples are hairs, glandular hairs and papillae. A covering of any kind of hair on a plant is an indumentum, the surface bearing them is said to be pubescent. Certain filamentous, algae have the terminal cell produced into an elongate hair-like structure called a trichome; the same term is applied to such structures in some cyanobacteria, such as Spirulina and Oscillatoria. The trichomes of cyanobacteria may be unsheathed, as in Oscillatoria, or sheathed, as in Calothrix; these structures play an important role in preventing soil erosion in cold desert climates. The filamentous sheaths form a persistent sticky network. Trichomes on plants are epidermal outgrowths of various kinds; the terms emergences or prickles refer to outgrowths. This distinction is not always applied. There are nontrichomatous epidermal cells that protrude from the surface. A common type of trichome is a hair.
Plant hairs may be multicellular, branched or unbranched. Multicellular hairs may have several layers of cells. Branched hairs can be tufted, or stellate, as in Arabidopsis thaliana. Another common type of trichome is the scale or peltate hair, that has a plate or shield-shaped cluster of cells attached directly to the surface or borne on a stalk of some kind. Common examples are the leaf scales of bromeliads such as the pineapple and sea buckthorn. Any of the various types of hairs may be glandular, producing some kind of secretion, such as the essential oils produced by mints and many other members of the family Lamiaceae. In describing the surface appearance of plant organs, such as stems and leaves, many terms are used in reference to the presence and appearance of trichomes; the most basic terms used are glabrous—lacking hairs— and pubescent—having hairs. Details are provided by: glabrous, glabrate -- lacking trichomes. Several basic functions or advantages of having surface hairs can be listed.
It is that in many cases, hairs interfere with the feeding of at least some small herbivores and, depending upon stiffness and irritability to the palate, large herbivores as well. Hairs on plants growing in areas subject to frost keep the frost away from the living surface cells. In windy locations, hairs break up the flow of air across the plant surface. Dense coatings of hairs reflect sunlight, protecting the more delicate tissues underneath in hot, open habitats. In addition, in locations where much of the available moisture comes from fog drip, hairs appear to enhance this process by increasing the surface area on which water droplets can accumulate. Both trichomes and root hairs, the rhizoids of many vascular plants, are lateral outgrowths of a single cell of the epidermal layer. Root hairs form from the hair-forming cells on the epidermis of a plant root. Root hairs vary between 5 and 17 micrometres in diameter, 80 to 1,500 micrometres in length. Root hairs can survive for two to three weeks and die off.
At the same time new root hairs are continually being formed at the top of the root. This way, the root hair coverage stays the same, it is therefore understandable that repotting must be done with care, because the root hairs are being pulled off for the most part. This is; the genetic control of patterning of trichomes and roots hairs shares similar control mechanisms. Both processes involve a core of related transcription factors that control the initiation and development of the epidermal outgrowth. Activation of genes that encode specific protein transcription factors are the major regulators of cell fate to produce trichomes or root hairs; when these genes are activated in a leaf epidermal cell, the formation of a trichrome is initiated within that cell. GL1, GL3. and TTG1 activate negative regulators, which serve to inhibit trichrome formation in neighboring cells. This system controls the spacing of trichomes on the leaf surface. Once trichome are developed they may branch. In contrast, root hairs only branch.
During the formation of trichomes and root hairs, many enzymes are regulated. For example, just prior to the root hair development, there is a point of elevated phosphorylase activity; the type and absence and location of trichomes are important diagnostic characters in plant identification and plant taxonomy. In forensic examination, plants such as Cannabis sativa can be identified by microscopic examination of the trichomes. Althoug
The flowering plants known as angiosperms, Angiospermae or Magnoliophyta, are the most diverse group of land plants, with 64 orders, 416 families 13,164 known genera and c. 369,000 known species. Like gymnosperms, angiosperms are seed-producing plants. However, they are distinguished from gymnosperms by characteristics including flowers, endosperm within the seeds, the production of fruits that contain the seeds. Etymologically, angiosperm means a plant; the term comes from the Greek words sperma. The ancestors of flowering plants diverged from gymnosperms in the Triassic Period, 245 to 202 million years ago, the first flowering plants are known from 160 mya, they diversified extensively during the Early Cretaceous, became widespread by 120 mya, replaced conifers as the dominant trees from 100 to 60 mya. Angiosperms differ from other seed plants in several ways, described in the table below; these distinguishing characteristics taken together have made the angiosperms the most diverse and numerous land plants and the most commercially important group to humans.
Angiosperm stems are made up of seven layers. The amount and complexity of tissue-formation in flowering plants exceeds that of gymnosperms; the vascular bundles of the stem are arranged such that the phloem form concentric rings. In the dicotyledons, the bundles in the young stem are arranged in an open ring, separating a central pith from an outer cortex. In each bundle, separating the xylem and phloem, is a layer of meristem or active formative tissue known as cambium. By the formation of a layer of cambium between the bundles, a complete ring is formed, a regular periodical increase in thickness results from the development of xylem on the inside and phloem on the outside; the soft phloem becomes crushed, but the hard wood persists and forms the bulk of the stem and branches of the woody perennial. Owing to differences in the character of the elements produced at the beginning and end of the season, the wood is marked out in transverse section into concentric rings, one for each season of growth, called annual rings.
Among the monocotyledons, the bundles are more numerous in the young stem and are scattered through the ground tissue. They once formed the stem increases in diameter only in exceptional cases; the characteristic feature of angiosperms is the flower. Flowers show remarkable variation in form and elaboration, provide the most trustworthy external characteristics for establishing relationships among angiosperm species; the function of the flower is to ensure fertilization of the ovule and development of fruit containing seeds. The floral apparatus may arise terminally from the axil of a leaf; as in violets, a flower arises singly in the axil of an ordinary foliage-leaf. More the flower-bearing portion of the plant is distinguished from the foliage-bearing or vegetative portion, forms a more or less elaborate branch-system called an inflorescence. There are two kinds of reproductive cells produced by flowers. Microspores, which will divide to become pollen grains, are the "male" cells and are borne in the stamens.
The "female" cells called megaspores, which will divide to become the egg cell, are contained in the ovule and enclosed in the carpel. The flower may consist only of these parts, as in willow, where each flower comprises only a few stamens or two carpels. Other structures are present and serve to protect the sporophylls and to form an envelope attractive to pollinators; the individual members of these surrounding structures are known as petals. The outer series is green and leaf-like, functions to protect the rest of the flower the bud; the inner series is, in general, white or brightly colored, is more delicate in structure. It functions to attract bird pollinators. Attraction is effected by color and nectar, which may be secreted in some part of the flower; the characteristics that attract pollinators account for the popularity of flowers and flowering plants among humans. While the majority of flowers are perfect or hermaphrodite, flowering plants have developed numerous morphological and physiological mechanisms to reduce or prevent self-fertilization.
Heteromorphic flowers have short carpels and long stamens, or vice versa, so animal pollinators cannot transfer pollen to the pistil. Homomorphic flowers may employ a biochemical mechanism called self-incompatibility to discriminate between self and non-self pollen grains. In other species, the male and female parts are morphologically separated, developing on different flowers; the botanical term "Angiosperm", from the Ancient Greek αγγείον, angeíon and σπέρμα, was coined in the form Angiospermae by Paul Hermann in 1690, as the name of one of his primary divisions of the plant kingdom. This included flowering plants possessing seeds enclosed in capsules, distinguished from his Gymnospermae, or flowering plants with achenial or schizo-carpic fruits, the whole fruit or each of its pieces being here regarded as a seed and naked; the term and its antonym were maintained by Carl Linnaeus with the same sense, but with restricted application, in the names of the orders of his class Didynamia. Its use with any