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Male Intrasexual Competition
In ethology, male-male intrasexual competition occurs when two males of the same species compete for the opportunity to mate with a female. Sexually dimorphic traits, size, sex ratio, and the social situation may all play a role in the effects male-male competition has on the reproductive success of a male and the mate choice of a female. Larger males tend to win male-male conflicts due to their sheer strength and ability to ward off other males from taking over their females. For instance, in the fly ''Dryomyza anilis'', size shows the strongest correlation to the outcome of male-male conflicts over resources like territory and females. Influencing factors Sex ratio There are multiple types of male-male competition that may occur in a population at different times depending on the conditions. Competition variation occurs based on the frequency of various mating behaviours present in the population. One factor that can influence the type of competition observed is the popula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethology
Ethology is the scientific study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionarily adaptive trait. Behaviourism as a term also describes the scientific and objective study of animal behaviour, usually referring to measured responses to stimuli or to trained behavioural responses in a laboratory context, without a particular emphasis on evolutionary adaptivity. Throughout history, different naturalists have studied aspects of animal behaviour. Ethology has its scientific roots in the work of Charles Darwin and of American and German ornithologists of the late 19th and early 20th century, including Charles O. Whitman, Oskar Heinroth, and Wallace Craig. The modern discipline of ethology is generally considered to have begun during the 1930s with the work of Dutch biologist Nikolaas Tinbergen and Austrian biologists Konrad Lorenz and Karl von Frisch, the three recipients of the 1973 Nobel Prize in Physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dryomyza Anilis
''Dryomyza anilis'' is a common fly from the family Dryomyzidae. The fly is found through various areas in the Northern hemisphere and has brown and orange coloration with distinctive large red eyes. The life span of the fly is not known, but laboratory-reared males can live 28–178 days. ''D. anilis'' has recently been placed back in the genus ''Dryomyza'', of which it is the type species. ''Dryomyzidae'' were previously part of '' Sciomyzidae'' but are now considered a separate family with two subfamilies. Male ''D. anilis'' engage in territorial behavior, guarding carcasses to attract potential mates. Males also guard females, and conflicts over females are frequent. Females typically mate with multiple males. Mating occurs through several rounds of copulation and egg-laying. During mating, males engage in a series of "tapping" rituals where they use their claspers to tap the female's genitals, increasing the chance of them fertilizing the female's eggs. Females lay several ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Female Intrasexual Competition
Female intrasexual competition is competition between women over a potential mate. Such competition might include self-promotion, derogation of other women, and direct and indirect aggression toward other women. Factors that influence female intrasexual competition include the genetic quality of available mates, hormone levels, and interpersonal dynamics. There are two modes of sexual selection: intersexual selection and intrasexual selection. Intersexual selection includes the display of desirable sexual characteristics to attract a potential mate. Intrasexual selection is competition between members of the same sex other over a potential mate. Compared to males, females tend to prefer subtle rather than overt forms of intrasexual competition.Benenson, Joyce F. "The development of human female competition: allies and adversaries." Philosophical Transactions of the Royal Society B: Biological Sciences 368, no. 1631 (2013): 20130079. However, they are also less likely to resolve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winner And Loser Effects
The winner and loser effect is an aggression phenomenon in which the winner effect is the increased probability that an animal will win future aggressive interactions after experiencing previous wins, while the loser effect is the increased probability that an animal will lose future aggressive interactions after experiencing previous losses. Overall these effects can either increase or decrease an animals aggressive behaviour, depending on what effect affects the species of concern. Animals such as ''Agkistrodon contortrix'', ''Rivulus marmoratus'', and ''Sula nebouxii'' show either both or one of these effects. The outcomes of winner and loser effects help develop and structure hierarchies in nature and is used to support the game theory model of aggression. Causation A theory underlying the causation of the winner and loser effect deals with an animals perception on its own and other members resource holding potential. Essentially if an animal perceives that it has a high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhacophorus Omeimontis
''Zhangixalus omeimontis'' is a species of frog in the family Rhacophoridae endemic to China. Its common name is Omei whipping frog or Omei treefrog, in reference to its type locality, Mount Emei () in Sichuan. It is found in southern and central China in Yunnan, Sichuan, Guangxi, Guizhou, Hunan, and Hubei provinces. It is a relatively common frog that inhabits forests, and sometimes farmland. It breeds in still water (pools and ponds). Agriculture and logging are threats to this species. Description ''Zhangixalus omeimontis'' are moderately large frogs: males grow to a snout–vent length of about and females to . Maximum sizes can be even higher, reaching at least in males and in females. They tend to be bigger and older at cooler sites (i.e., at higher altitudes). Maximum age is at least eight years. Tadpoles are up to in length. Reproduction ''Zhangixalus omeimontis'' breed between mid-April and late July. Breeding takes place during night-time. Males arrive before fem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Japanese Rice Fish
The Japanese rice fish (''Oryzias latipes''), also known as the medaka, is a member of genus ''Oryzias'' ( ricefish), the only genus in the subfamily Oryziinae. This small (up to about ) native of East Asia is a denizen of rice paddies, marshes, ponds, slow-moving streams and tide pools. It is euryhaline, occurring in both brackish and freshwater. It became popular as an aquarium fish because of its hardiness and pleasant coloration: its coloration varies from creamy-white to yellowish in the wild to white, creamy-yellow, or orange in aquarium-bred individuals. Bright yellow, red or green transgenic populations, similar to GloFish, have also been developed, but are banned from sale in the EU. The medaka has been a popular pet since the 17th century in Japan. After fertilization, the female carries her eggs attached anterior to the anal fin for a period before depositing them on plants or similar things. Ecology Medaka live in small ponds, shallow rivers, and rice fields ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resource (biology)
In biology and ecology, a resource is a substance or object in the environment required by an organism for normal growth, maintenance, and reproduction. Resources can be consumed by one organism and, as a result, become unavailable to another organism. For plants key resources are light, nutrients, water, and place to grow. For animals key resources are food, water, and territory. Key resources for plants Terrestrial plants require particular resources for photosynthesis and to complete their life cycle of germination, growth, reproduction, and dispersal: * Carbon dioxide * Microsite (ecology) * Nutrients * Pollination * Seed dispersal * Soil * Water Key resources for animals Animals require particular resources for metabolism and to complete their life cycle of gestation, birth, growth, and reproduction:Smith, T.M., and R.L. Smith. 2008. Elements of ecology, 7th ed. Benjamin Cummings, San Francisco, CA. * Foraging * Territory * Water Resources and ecological processes Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mate Choice
Mate choice is one of the primary mechanisms under which evolution can occur. It is characterized by a "selective response by animals to particular stimuli" which can be observed as behavior.Bateson, Paul Patrick Gordon. "Mate Choice." Mate Choice, Cambridge University Press, 1985 In other words, before an animal engages with a potential mate, they first evaluate various aspects of that mate which are indicative of quality—such as the resources or phenotypes they have—and evaluate whether or not those particular Phenotypic trait, trait(s) are somehow beneficial to them. The evaluation will then incur a response of some sort. These mechanisms are a part of evolutionary change because they operate in a way that causes the qualities that are desired in a mate to be more frequently passed on to each generation over time. For example, if female peacocks desire mates who have a colourful plumage, then this trait will increase in frequency over time as male peacocks with a colourful ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Male
Male (Mars symbol, symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization. A male organism cannot sexual reproduction, reproduce sexually without access to at least one ovum from a female, but some organisms can reproduce both sexually and Asexual reproduction, asexually. Most male mammals, including male humans, have a Y chromosome, which codes for the production of larger amounts of testosterone to develop male reproductive organs. Not all species share a common sex-determination system. In most animals, including Homo sapiens, humans, sex is determined genetics, genetically; however, species such as ''Cymothoa exigua'' change sex depending on the number of females present in the vicinity. In humans, the word ''male'' can also be used to refer to gender in the social sense of gender role or gender identity. Overview The existence of separate sexes has evol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reproductive Success
Reproductive success is an individual's production of offspring per breeding event or lifetime. This is not limited by the number of offspring produced by one individual, but also the reproductive success of these offspring themselves. Reproductive success is different from fitness in that individual success is not necessarily a determinant for adaptive strength of a genotype since the effects of chance and the environment have no influence on those specific genes. Reproductive success turns into a part of fitness when the offspring are actually recruited into the breeding population. If offspring quantity is not correlated with quality this holds up, but if not then reproductive success must be adjusted by traits that predict juvenile survival in order to be measured effectively. Quality and quantity is about finding the right balance between reproduction and maintenance. The disposable soma theory of aging tells us that a longer lifespan will come at the cost of reproduction a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex Ratio
The sex ratio (or gender ratio) is usually defined as the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. Many species deviate from an even sex ratio, either periodically or permanently. Examples include parthenogenic species, periodically mating organisms such as aphids, some eusocial wasps, bees, ants, and termites. The human sex ratio is of particular interest to anthropologists and demographers. In human societies, sex ratios at birth may be considerably skewed by factors such as the age of mother at birth and by sex-selective abortion and infanticide. Exposure to pesticides and other environmental contaminants may be a significant contributing factor as well. As of 2014, the global sex ratio at birth is estimated at 107 boys to 100 girls (1,000 boys per 934 girls).. Types In most species, the sex ratio varies according to the age profile of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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