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Mating System
A mating system is a way in which a group is structured in relation to sexual behaviour. The precise meaning depends upon the context. With respect to animals, the term describes which males and females mating, mate under which circumstances. Recognised systems include monogamy, polygamy (which includes polygyny, polyandry, and polygynandry), and promiscuity, all of which lead to different mate choice outcomes and thus these systems affect how sexual selection works in the species which practice them. In plants, the term refers to the degree and circumstances of outcrossing. In human sociobiology, the terms have been extended to encompass the formation of relationships such as marriage. In plants The primary mating systems in plants are outcrossing (cross-fertilisation), autogamy (self-fertilisation) and apomixis (asexual reproduction without fertilization, but only when arising by modification of sexual function). Mixed mating systems, in which plants use two or even all three ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animals
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a bilaterally symmetric body plan. The Bilateria include the protostomes, containing animals such as nematodes, arthropods, flatworms, annelids and molluscs, and the deuterostomes, containing the echinoderm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Selfing Model
The effective selfing model is a mathematical model that describes the mating system of a plant population in terms of the degree of self-fertilisation present. Overview It was developed in the 1980s by Kermit Ritland, as an alternative to the simplistic mixed mating model. The mixed mating model assumes that every fertilisation event may be classed as either self-fertilisation, or outcrossing with a completely random mate. That is, it assumes that inbreeding is caused solely by self-fertilisation. This assumption is often violated in wild plant populations, where inbreeding may be due to outcrossing between closely related plants. For example, in dense stands, mating often occurs between plants in close proximity; and in plants with short seed dispersal distances, plants are often closely related to their nearest neighbours. When both these criteria are met, plants will tend to be closely related to the near neighbours with which they mate, resulting in significant inbreeding. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polygynandry
Polygynandry is a mating system in which both males and females have multiple mating partners during a breeding season. In sexually reproducing diploid animals, different mating strategies are employed by males and females, because the cost of gamete production is lower for males than it is for females. The different mating tactics employed by males and females are thought to be the outcome of stochastic reproductive conflicts both ecologically and socially. Reproductive conflicts in animal societies may arise because individuals are not genetically identical and have different optimal strategies for maximizing their fitness; and often it is found that reproductive conflicts generally arise due to dominance hierarchy in which all or a major part of reproduction is monopolized by only one individual. In the wasp ''Polistes carolina'', the dominant queen amongst female wasps is determined by whoever arrives at the nest first rather than the largest foundress, who is expected to be th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
