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Homogamy (biology)
Homogamy is used in biology in four separate senses: *Inbreeding can be referred to as homogamy. *Homogamy refers to the maturation of male and female reproductive organs (of plants) at the same time, which is also known as simultaneous or synchronous hermaphrodism and is the antonym of dichogamy. Many flowers appear to be homogamous but some of these may not be strictly functionally homogamous, because for various reasons male and female reproduction do not completely overlap. *In the daisy family, the flower heads are made up of many small flowers called florets, and are either homogamous or heterogamous. Heterogamous heads are made up of two types of florets, ray florets near the edge and disk florets in the center. Homogamous heads are made up of just one type of floret, either all ray florets or all disk florets. *Homogamy can be used as a form of choosing a mate based on characteristics that are wanted in a sexual partner. Inbreeding As opposed to outcrossing or outbreed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sunflower 2007
The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as bird food, in some industrial applications, and as an ornamental in domestic gardens. Wild ''H. annuus'' is a widely branched annual plant with many flower heads. The domestic sunflower, however, often possesses only a single large inflorescence (flower head) atop an unbranched stem. The binomial name ''Helianthus annuus'' is derived from the Greek ''Helios'' 'sun' and ''anthos'' 'flower', while the epithet ''annuus'' means 'annual' in Latin. The plant was first domesticated in the Americas. Sunflower seeds were brought to Europe from the Americas in the 16th century, where, along with sunflower oil, they became a widespread cooking ingredient. With time, bulk of industrial-scale production has shifted to Eastern Europe, and () Russia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cichorium Intybus-alvesgaspar1
''Cichorium'' is a genus of plants in the tribe Cichorieae within the family Asteraceae. The genus includes two cultivated species commonly known as chicory or endive, plus several wild species. Common chicory (''Cichorium intybus'') is a bushy perennial herb with blue or lavender (or, rarely, white or pink) flowers. It grows as a wild plant on roadsides in its native Europe, and in North America, where it has become naturalized. It is grown for its leaves, when it is known as leaf chicory, endive, radicchio, Belgian endive, French endive, or witloof. Other varieties are grown for their roots, which are used as a coffee substitute, similar to dandelion coffee. True endive (''Cichorium endivia'') is a species grown and used as a salad green. It has a slightly bitter taste. Curly endive and the broad-leafed escarole are true endives. ''Cichorium'' is used as a food plant by the larvae of some Lepidoptera species including setaceous Hebrew character, turnip moth, and the grass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inbreeding
Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious or recessive traits resulting from incestuous sexual relationships and consanguinity. Animals avoid incest only rarely. Inbreeding results in homozygosity, which can increase the chances of offspring being affected by recessive traits. In extreme cases, this usually leads to at least temporarily decreased biological fitness of a population (called inbreeding depression), which is its ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially referred to as ''inbred''. The avoidance of expression of such deleterious recessive alleles caused by inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermaphrodite
In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrates) do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which either partner can act as the female or male. For example, the great majority of tunicata, tunicates, pulmonate molluscs, opisthobranch, earthworms, and slugs are hermaphrodites. Hermaphroditism is also found in some fish species and to a lesser degree in other vertebrates. Most plants are also hermaphrodites. Animal species having different sexes, male and female, are called Gonochorism, gonochoric, which is the opposite of hermaphrodite. There are also species where hermaphrodites exist alongside males (called androdioecy) or alongside females (called gynodioecy), or all three exist in the same species ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dichogamy
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, a sequential hermaphrodite produces eggs (female gametes) and sperm (male gametes) at different stages in life. Species that can undergo these changes from one sex to another do so as a normal event within their reproductive cycle that is usually cued by either social structure or the achievement of a certain age or size. In animals, the different types of change are male to female (protandry or protandrous hermaphroditism), female to male (protogyny or protogynous hermaphroditism), bidirectional (serial or bidirectional hermaphroditism). Both protogynous and protandrous hermaphroditism allow the organism to switch between functional male and functional female. Bidirectional hermaphrodites have the capacity for sex change in either directi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteraceae
The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae were first described in the year 1740. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger family is unclear as the quantity of extant species in each family is unknown. Most species of Asteraceae are annual, biennial, or perennial herbaceous plants, but there are also shrubs, vines, and trees. The family has a widespread distribution, from subpolar to tropical regions in a wide variety of habitats. Most occur in hot desert and cold or hot semi-desert climates, and they are found on every continent but Antarctica. The primary common characteristic is the existence of sometimes hundreds of tiny individual florets which are held together by protective involucres in flower heads, or more technicall ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outcrossing
Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing can be a useful technique in Animal husbandry, animal breeding. The outcrossing breeder intends to remove the traits by using "new blood." With dominant traits, one can still see the expression of the traits and can remove those traits whether one outcrosses, line breeds or inbreeds. With recessive traits, outcrossing allows for the recessive traits to migrate across a population. Many traits are Mendelian and therefore exhibit a more complicated intermediate phenotype. The outcrossing breeder then may have individuals that have many deleterious genes that may be expressed by subsequent inbreeding. There is now a gamut of deleterious genes within each individual in many dog breeds. Increasing the variation of genes or alleles within the gene pool may pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inbreeding
Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and other consequences that may arise from expression of deleterious or recessive traits resulting from incestuous sexual relationships and consanguinity. Animals avoid incest only rarely. Inbreeding results in homozygosity, which can increase the chances of offspring being affected by recessive traits. In extreme cases, this usually leads to at least temporarily decreased biological fitness of a population (called inbreeding depression), which is its ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially referred to as ''inbred''. The avoidance of expression of such deleterious recessive alleles caused by inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-pollination
Self-pollination is a form of pollination in which pollen from the same plant arrives at the Stigma (botany), stigma of a flower (in flowering plants) or at the ovule (in gymnosperms). There are two types of self-pollination: in autogamy, pollen is transferred to the Stigma (botany), stigma of the same flower; in geitonogamy, pollen is transferred from the anther of one flower to the stigma of another flower on the same flowering plant, or from Microsporangia, microsporangium to ovule within a single (Monoecy, monoecious) gymnosperm. Some plants have mechanisms that ensure autogamy, such as flowers that do not open (cleistogamy), or stamens that move to come into contact with the stigma. The term selfing that is often used as a synonym, is not limited to self-pollination, but also applies to other types of self-fertilization. Occurrence Few plants self-pollinate without the aid of pollen vectors (such as wind or insects). The mechanism is seen most often in some legumes such as p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autogamy
Autogamy, or self-fertilization, refers to the fusion of two gametes that come from one individual. Autogamy is predominantly observed in the form of self-pollination, a reproductive mechanism employed by many flowering plants. However, species of protists have also been observed using autogamy as a means of reproduction. Flowering plants engage in autogamy regularly, while the protists that engage in autogamy only do so in stressful environments. Occurrence Protists ''Paramecium aurelia'' ''Paramecium aurelia'' is the most commonly studied protozoan for autogamy. Similar to other unicellular organisms, ''Paramecium aurelia'' typically reproduce asexually via binary fission or sexually via cross-fertilization. However, studies have shown that when put under nutritional stress, ''Paramecium aurelia'' will undergo meiosis and subsequent fusion of gametic-like nuclei. This process, defined as hemixis, a chromosomal rearrangement process, takes place in a number of steps. First, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homozygosity
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assortative Mating
Assortative mating (also referred to as positive assortative mating or homogamy) is a mating pattern and a form of sexual selection in which individuals with similar phenotypes or genotypes mate with one another more frequently than would be expected under a random mating pattern. A majority of the phenotypes that are subject to assortative mating are body size, visual signals (e.g. color, pattern), and sexually selected traits such as crest size. The opposite of assortative is disassortative mating. Causes Several hypotheses have been proposed to explain the phenomenon of assortative mating. Assortative mating has evolved from a combination of different factors, which vary across different species. Assortative mating with respect to body size can arise as a consequence of intrasexual competition. In some species, size is correlated with fecundity in females. Therefore, males choose to mate with larger females, with the larger males defeating the smaller males in courting the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
