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Asplenium Viviparum
''Asplenium'' is a genus of about 700 species of ferns, often treated as the only genus in the family Aspleniaceae, though other authors consider ''Hymenasplenium'' separate, based on molecular phylogenetic analysis of DNA sequences, a different chromosome count, and structural differences in the rhizomes. The type species for the genus is ''Asplenium marinum''. The most common vernacular name is spleenworts, applied to the more "typical" species. '' A. nidus'' and several similar species are called bird's-nest ferns, the ''Camptosorus'' group is known as walking ferns, and distinct names are applied to some other particularly well-known species. Taxonomy and genetics Many groups of species have been separated from ''Asplenium'' as segregate genera. These include ''Camptosorus'', ''Ceterach'', ''Phyllitis'', and ''Tarachia'', but these species can form hybrids with other ''Asplenium'' species and because of this are usually included in a more broadly defined ''Asplenium''. Som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asplenium Trichomanes
''Asplenium trichomanes'', the maidenhair spleenwort, is a small fern in the spleenwort genus ''Asplenium''. It is a widespread and common species, occurring almost worldwide in a variety of rocky habitats. It is a variable fern with several subspecies. The binomial nomenclature, specific epithet ''trichomanes'' refers to a Greek word for fern. Description ''Asplenium trichomanes'' grows 10 to 30 cm tall forming tufts arising from a short, scaly rhizome. The scales are dark. The evergreen fronds are long and narrow, gradually tapering towards the tip. They are simply divided into small, yellow-green to dark-green, roundish Frond, pinnae. The stipe (botany), stipe and rachis of the frond are dark all along their length. The fronds can reach 40 cm in length but are more commonly 8–20 cm. The Sorus, indusia are linear to oval, straight, and attached to the upper-side of the fertile vein. There are (2) 4 to 8 sori per pinna and each are 1 to 3.5 mm long. Diplo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid (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 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 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, with differences in flowering tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asplenium Viviparum
''Asplenium'' is a genus of about 700 species of ferns, often treated as the only genus in the family Aspleniaceae, though other authors consider ''Hymenasplenium'' separate, based on molecular phylogenetic analysis of DNA sequences, a different chromosome count, and structural differences in the rhizomes. The type species for the genus is ''Asplenium marinum''. The most common vernacular name is spleenworts, applied to the more "typical" species. '' A. nidus'' and several similar species are called bird's-nest ferns, the ''Camptosorus'' group is known as walking ferns, and distinct names are applied to some other particularly well-known species. Taxonomy and genetics Many groups of species have been separated from ''Asplenium'' as segregate genera. These include ''Camptosorus'', ''Ceterach'', ''Phyllitis'', and ''Tarachia'', but these species can form hybrids with other ''Asplenium'' species and because of this are usually included in a more broadly defined ''Asplenium''. Som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mother Spleenwort
''Asplenium bulbiferum'', known as mother spleenwort, is a fern species native to New Zealand only. It is also called hen and chicken fern and, in the Māori language, pikopiko, mouku or mauku. Its fronds are eaten as a vegetable. It grows small bulbils on top of its fronds. Once grown to about , these offspring fall off and, provided the soil they land in is kept moist, develop a root system and grow into new ferns. This additional means of reproduction can be employed with greater ease than propagation by spores. There are a number of similar Southern Hemisphere species which have a similar mode of reproduction, including '' Asplenium daucifolium''. ''Asplenium bulbiferum'' commonly grows in most bush areas in New Zealand. It thrives in many situations from shade to partial sunlight. Similar species It is often confused with ''Asplenium gracillimum'' which is a fern species native to both New Zealand and Australia. ''A. gracillimum'' is the fertile allotetraploid Pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Phylogenetics
Computational phylogenetics is the application of computational algorithms, methods, and programs to phylogenetic"origin,_source,_birth")_is_the_study_of_the_evolutionary_his_... "origin, source, birth") is the study of the evolutionary his ... "origin, source, birth") is the study of the evolutionary his ... "origin, source, birth") is the study of the evolutionary his ... "origin, source, birth") is the study of the evolutionary his ... "tribe, clan, race", and wikt:γενετικός, γενετικός [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeny
A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. All life on Earth is part of a single phylogenetic tree, indicating common ancestry. In a ''rooted'' phylogenetic tree, each node with descendants represents the inferred most recent common ancestor of those descendants, and the edge lengths in some trees may be interpreted as time estimates. Each node is called a taxonomic unit. Internal nodes are generally called hypothetical taxonomic units, as they cannot be directly observed. Trees are useful in fields of biology such as bioinformatics, systematics, and phylogenetics. ''Unrooted'' trees illustrate only the relatedness of the leaf nodes and do not require the ancestral root to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladistic
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups (" clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived characteristics ( synapomorphies'')'' that are not present in more distant groups and ancestors. However, from an empirical perspective, common ancestors are inferences based on a cladistic hypothesis of relationships of taxa whose character states can be observed. Theoretically, a last common ancestor and all its descendants constitute a (minimal) clade. Importantly, all descendants stay in their overarching ancestral clade. For example, if the terms ''worms'' or ''fishes'' were used within a ''strict'' cladistic framework, these terms would include humans. Many of these terms are normally used paraphyletically, outside of cladistics, e.g. as a 'grade', which are fruitless to precisely delineate, especially when including extinct species. R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introduction To Evolution
Evolution is the process of change in all forms of life over generations, and evolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms' observable traits. Genetic changes include mutations, which are caused by damage or replication errors in organisms' DNA. As the genetic variation of a population drifts randomly over generations, natural selection gradually leads traits to become more or less common based on the relative reproductive success of organisms with those traits. The age of the Earth is about 4.5 billion years. The earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago. Evolution does not attempt to explain the origin of life (covered instead by abiogenesis), but it does explain how early lifeforms evolved into the complex ecosystem that we see today. Based on the similarities between all present-day organisms, all life on Earth is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastome
Chloroplast DNA (cpDNA) is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nucleus. The existence of chloroplast DNA was identified biochemically in 1959, and confirmed by electron microscopy in 1962. The discoveries that the chloroplast contains ribosomes and performs protein synthesis revealed that the chloroplast is genetically semi-autonomous. The first complete chloroplast genome sequences were published in 1986, ''Nicotiana tabacum'' (tobacco) by Sugiura and colleagues and ''Marchantia polymorpha'' (liverwort) by Ozeki et al. Since then, a great number of chloroplast DNAs from various species have been sequenced. Molecular structure Chloroplast DNAs are circular, and are typically 120,000–170,000 base pairs long. They can have a contour length of around 30–60 micrometers, and have a mass of about 80 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroplast
A chloroplast () is a type of membrane-bound organelle known as a plastid that conducts photosynthesis mostly in plant and algal cells. The photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water in the cells. The ATP and NADPH is then used to make organic molecules from carbon dioxide in a process known as the Calvin cycle. Chloroplasts carry out a number of other functions, including fatty acid synthesis, amino acid synthesis, and the immune response in plants. The number of chloroplasts per cell varies from one, in unicellular algae, up to 100 in plants like ''Arabidopsis'' and wheat. A chloroplast is characterized by its two membranes and a high concentration of chlorophyll. Other plastid types, such as the leucoplast and the chromoplast, contain little chlorophyll and do not carry out photosynthesis. Chloroplasts are highly dynamic—they circulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, the equivalent Latin term ''cladus'' (plural ''cladi'') is often used in taxonomical literature. The common ancestor may be an individual, a population, or a species (extinct or extant). Clades are nested, one in another, as each branch in turn splits into smaller branches. These splits reflect evolutionary history as populations diverged and evolved independently. Clades are termed monophyletic (Greek: "one clan") groups. Over the last few decades, the cladistic approach has revolutionized biological classification and revealed surprising evolutionary relationships among organisms. Increasingly, taxonomists try to avoid naming taxa that are not clades; that is, taxa that are not monophyletic. Some of the relationships between organisms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polypodiales
The order Polypodiales encompasses the major lineages of polypod ferns, which comprise more than 80% of today's fern species. They are found in many parts of the world including tropical, semitropical and temperate areas. Description Polypodiales are unique in bearing sporangia with a vertical annulus interrupted by the stalk and stomium. These sporangial characters were used by Johann Jakob Bernhardi to define a group of ferns he called the "Cathetogyratae"; the Pteridophyte Phylogeny Group has suggested reviving this name as the informal term cathetogyrates, to replace the ambiguously circumscribed term "polypods" when referring to the Polypodiales. The sporangia are born on stalks 1–3 cells thick and are often long-stalked. (In contrast, the Hymenophyllales have a stalk composed of four rows of cells.) The sporangia do not reach maturity simultaneously. Many groups in the order lack indusia, but when present, they are attached either along the edge of the indusium or in its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
