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Floral Isolation
Floral Isolation is a form of reproductive isolation found in angiosperms. Reproductive isolation is the process of species evolving mechanisms to prevent reproduction with other species. In plants, this is accomplished through the manipulation of the pollinator’s behavior (ethological isolation) or through morphological characteristics of flowers that favor intraspecific pollen transfer (morphological isolation). Preventing interbreeding prevents hybridization and gene flow between the species ( introgression), and consequently protects genetic integrity of the species. Reproductive isolation occurs in many organisms, and floral isolation is one form present in plants. Floral isolation occurs prior to pollination, and is divided into two types of isolation: morphological isolation and ethological isolation. Floral isolation was championed by Verne Grant in the 1900s as an important mechanism of reproductive isolation in plants. Morphological Isolation Mecha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salvia Mellifera Flowers 2003-03-12
''Salvia'' () is the largest genus of plants in the sage family Lamiaceae, with nearly 1000 species of shrubs, herbaceous perennials, and annuals. Within the Lamiaceae, ''Salvia'' is part of the tribe Mentheae within the subfamily Nepetoideae. One of several genera commonly referred to as sage, it includes two widely used herbs, ''Salvia officinalis'' (common sage, or just "sage") and ''Salvia rosmarinus'' (rosemary, formerly ''Rosmarinus officinalis''). The genus is distributed throughout the Old World and the Americas (over 900 total species), with three distinct regions of diversity: Central America and South America (approximately 600 species); Central Asia and the Mediterranean (250 species); Eastern Asia (90 species). Etymology The name ''Salvia'' derives from Latin (sage), from (safe, secure, healthy), an adjective related to (health, well-being, prosperity or salvation), and (to feel healthy, to heal). Pliny the Elder was the first author known to describe a plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bee Orchid - Ophrys Apifera (14081140989)
Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamily Apoidea. They are presently considered a clade, called Anthophila. There are over 16,000 known species of bees in seven recognized biological families. Some speciesincluding honey bees, bumblebees, and stingless beeslive socially in colonies while most species (>90%)including mason bees, carpenter bees, leafcutter bees, and sweat beesare solitary. Bees are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants. The most common bees in the Northern Hemisphere are the Halictidae, or sweat bees, but they are small and often mistaken for wasps or flies. Bees range in size from tiny stingless bee species, whose workers are less than long, to ''Megachile pluto'', the large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive Isolation
The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.Strickberger, M. 1978. ''Genética''. Omega, Barcelona, España, p.: 874-879. .Futuyma, D. 1998. ''Evolutionary biology'' (3ª edición). Sinauer, Sunderland. The mechanisms of reproductive isolation have been classified in a number of ways. Zoologist Ernst Mayr classified the mechanisms of reproductive isolation in two broad categories: pre-zygotic for those that act before fertilization (or before mating in the case of animals) and post-zygotic for those that act after it.Mayr, E. 1963. ''Animal species and evolution''. Harvard University Press, Cambridge. The mechanisms are genetically controlled and can appear in species whose ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flowering Plant
Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants that produce their seeds enclosed within a fruit. They are by far the most diverse group of land plants with 64 orders, 416 families, approximately 13,000 known genera and 300,000 known species. Angiosperms were formerly called Magnoliophyta (). Like gymnosperms, angiosperms are seed-producing plants. They are distinguished from gymnosperms by characteristics including flowers, endosperm within their seeds, and the production of fruits that contain the seeds. The ancestors of flowering plants diverged from the common ancestor of all living gymnosperms before the end of the Carboniferous, over 300 million years ago. The closest fossil relatives of flowering plants are uncertain and contentious. The earliest angiosperm fossils ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybridization (biology)
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different breeds, varieties, species or genera through sexual reproduction. Hybrids are not always intermediates between their parents (such as in blending inheritance), but can show Heterosis, hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductive isolation, reproductively isolated by strong barriers to hybridisation, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization and others after it. Similar barriers exist in plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introgression
Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Introgression is a long-term process, even when artificial; it may take many hybrid generations before significant backcrossing occurs. This process is distinct from most forms of gene flow in that it occurs between two populations of different species, rather than two populations of the same species. Introgression also differs from simple hybridization. Simple hybridization results in a relatively even mixture; gene and allele frequencies in the first generation will be a uniform mix of two parental species, such as that observed in mules. Introgression, on the other hand, results in a complex, highly variable mixture of genes, and may only involve a minimal percentage of the donor genome. Definition Introgression or introgressive hybri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salvia Mellifera
''Salvia mellifera'' (black sage, also known as seel by the Mahuna) is a small, highly aromatic, evergreen shrub of the genus ''Salvia'' (the sages) native to California, and Baja California, Mexico. It is common in the coastal sage scrub of Southern California and northern Baja California. Black sage has a dark appearance, especially during drought. Description Black sage is a perennial shrub that grows approximately tall. It is covered with simple hairs with some glandular hairs, which makes it highly aromatic. The leaves are oblong-elliptic to obovate in shape and are about long. The upper surface of the leaf is somewhat glabrous, while the lower surface of the leaf is hairy. The inflorescence occurs in wide clusters. The flowers are usually a pale blue or lavender color, and rarely a pale rose color. The upper lip of the flower is 2-lobed. The style and stamens are slightly exserted. The fruit produced by the black sage is a schizocarp composed of four brown nutlets. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salvia Apiana
''Salvia apiana'', the white sage, bee sage, or sacred sage is an evergreen perennial shrub that is native to the southwestern United States and northwestern Mexico, found mainly in the coastal sage scrub habitat of Southern California and Baja California, on the western edges of the Mojave and Sonoran deserts. Description ''Salvia apiana'' is a shrub that reaches tall and wide. The whitish evergreen leaves are and persist throughout the year; they are opposite with crenulate margins. Leaves are thickly covered in hairs that trigger oil glands; when rubbed oils and resins are released, producing a strong aroma. The flowers are very attractive to bees, which is described by the specific epithet, ''apiana''. Several flower stalks, sometimes pinkish colored, grow above the foliage in the spring. Flowers are white to pale lavender. Distribution and habitat White sage is a common plant that requires well-drained dry soil, full sun, and little water. The plant occurs on dry slop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudocopulation
Pseudocopulation describes behaviors similar to copulation that serve a reproductive function for one or both participants but do not involve actual sexual union between the individuals. It is most generally applied to a pollinator attempting to copulate with a flower. Some flowers mimic a potential female mate visually, but the key stimuli are often chemical and tactile. This form of mimicry in plants is called Pouyannian mimicry. Orchids commonly achieve reproduction in this manner, secreting chemicals from glands (osmophores) in the sepals, petals, or labellum, that are indistinguishable from the insect's natural pheromones. The pollinator then has a pollinium attached to its body, which it transfers to the stigma of another flower when it attempts another 'copulation'. Pollinators are often bees, and wasps of the order Hymenoptera, and flies. The cost to the pollinating insects might be seen as negligible, but study of ''Cryptostylis'' (an Australian orchid) pollinators show ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botany
Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek word (''botanē'') meaning " pasture", " herbs" "grass", or " fodder"; is in turn derived from (), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these three groups of organisms remaining within the sphere of interest of the International Botanical Congress. Nowadays, botanists (in the strict sense) study approximately 410,000 species of land plants of which some 391,000 species are vascular plants (including approximately 369,000 species of flowering plants), and approximately 20,000 are bryophytes. Botany originated in prehistory as herbalism with the efforts of early humans to identify – and later cultivate – ed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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