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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] |
Homogamy (sociology)
Homogamy is marriage between individuals who are, in some culturally important way, similar to each other. It is a form of assortative mating. The union may be based on socioeconomic status, class, gender, caste, ethnicity, or religion, or age in the case of the so-called Age disparity in sexual relationships#Statistics, age homogamy. It can also refer to the socialization customs of a particular group in that people who are similar tend to socialize with one another. Criteria for mates There are three criteria with which people evaluate potential mates: warmth and loyalty, attractiveness and vitality, and status and resources. These three categories can heavily shape themselves around the secondary traits of ethnicity, religion, and socio-economic status. Ethnicity can be tied to perceptions of biological vitality and attractiveness. Socio-economic status relates directly to status and resources. Religious or spiritual beliefs interpersonal behavior; people tend to be warmer ... [...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] |
Journal Of Demographic Economics
''Journal of Demographic Economics'' (JODE) is a peer-reviewed academic journal at the intersection of demography and economics. It is published by Cambridge University Press and edited by the Institute of Economic and Social Research of the UCLouvain. The Journal of Demographic Economics publishes four issues a year. The Journal of the Demographic Economics (JODE) welcomes both empirical and theoretical papers on issues relevant to Demographic Economics with a preference for combining abstract economic or demographic models together with data to highlight major mechanisms of the interplay between demographics and economics. JODE intends to be the premier demography & economics outlet for empirical contributions that are firmly grounded in theory as well as theoretical papers that are motivated by empirical regularities and findings. The editor-in-chief of JODE is David de la Croix (UClouvain) and Murat Iyigun (University of Colorado at Boulder) is the Co-Editor. In August 2021, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Socioeconomic Status
Socioeconomic status (SES) is an economic and sociological combined total measure of a person's work experience and of an individual's or family's economic access to resources and social position in relation to others. When analyzing a family's SES, the household income, earners' education, and occupation are examined, as well as combined income, whereas for an individual's SES only their own attributes are assessed. Recently, research has revealed a lesser recognized attribute of SES as perceived financial stress, as it defines the "balance between income and necessary expenses". Perceived financial stress can be tested by deciphering whether a person at the end of each month has more than enough, just enough, or not enough money or resources. However, SES is more commonly used to depict an economic difference in society as a whole. Socioeconomic status is typically broken into three levels (high, middle, and low) to describe the three places a family or an individual may fal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sociology
Sociology is a social science that focuses on society, human social behavior, patterns of Interpersonal ties, social relationships, social interaction, and aspects of culture associated with everyday life. It uses various methods of Empirical research, empirical investigation and critical analysis to develop a body of knowledge about social order and social change. While some sociologists conduct research that may be applied directly to social policy and welfare, others focus primarily on refining the Theory, theoretical understanding of social processes and phenomenology (sociology), phenomenological method. Subject matter can range from Microsociology, micro-level analyses of society (i.e. of individual interaction and agency (sociology), agency) to Macrosociology, macro-level analyses (i.e. of social systems and social structure). Traditional focuses of sociology include social stratification, social class, social mobility, sociology of religion, religion, secularization, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Major Histocompatibility Complex And Sexual Selection
The major histocompatibility complex in sexual selection concerns how major histocompatibility complex (MHC) molecules allow for immune system surveillance of the population of protein molecules in a host's cells. In 1976, Yamazaki et al. demonstrated a sexual selection mate choice by male mice for females of a . Major histocompatibility complex genes, which control the immune response and effective resistance against pathogens, have been able to maintain an extremely high level of allelic diversity throughout time and throughout different populations. Studies suggest that the MHC is involved in mate choice for many vertebrates through olfactory cues. There are several proposed hypotheses that address how MHC-associated mating preferences could be adaptive and how an unusually large amount of allelic diversity has been maintained in the MHC. The vast source of genetic variation affecting an organism's fitness stems from the co-evolutionary arms race between hosts and parasites. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Major Histocompatibility Complex
The major histocompatibility complex (MHC) is a large locus on vertebrate DNA containing a set of closely linked polymorphic genes that code for cell surface proteins essential for the adaptive immune system. These cell surface proteins are called MHC molecules. This locus got its name because it was discovered via the study of transplanted tissue compatibility. Later studies revealed that tissue rejection due to incompatibility is only a facet of the full function of MHC molecules: binding an antigen derived from self-proteins, or from pathogens, and bringing the antigen presentation to the cell surface for recognition by the appropriate T-cells. MHC molecules mediate the interactions of leukocytes, also called white blood cells (WBCs), with other leukocytes or with body cells. The MHC determines donor compatibility for organ transplant, as well as one's susceptibility to autoimmune diseases. In a cell, protein molecules of the host's own phenotype or of other biologic entities ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome 6
Chromosome 6 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 6 spans more than 170 million base pairs (the building material of DNA) and represents between 5.5 and 6% of the total DNA in cells. It contains the major histocompatibility complex, which contains over 100 genes related to the immune response, and plays a vital role in organ transplantation. Genes The human leukocyte antigen lies on chromosome 6, with the exception of the gene for β2-microglobulin (which is located on chromosome 15), and encodes cell-surface antigen-presenting proteins among other functions. Number of genes In 2003, the entirety of chromosome 6 was manually annotated for proteins, resulting in the identification of 1,557 genes, and 633 pseudogenes. The following are some of the newer gene count estimates. Because researchers use different approaches to genome annotation their predictions of the number of genes on each chromosome var ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Stratification
Population structure (also called genetic structure and population stratification) is the presence of a systematic difference in allele frequencies between subpopulations. In a randomly mating (or ''panmictic'') population, allele frequencies are expected to be roughly similar between groups. However, mating tends to be non-random to some degree, causing structure to arise. For example, a barrier like a river can separate two groups of the same species and make it difficult for potential mates to cross; if a mutation occurs, over many generations it can spread and become common in one subpopulation while being completely absent in the other. Genetic variants do not necessarily cause observable changes in organisms, but can be correlated by coincidence because of population structure—a variant that is common in a population that has a high rate of disease may erroneously be thought to cause the disease. For this reason, population structure is a common confounding variable in medi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Deviation
In statistics, the standard deviation is a measure of the amount of variation or dispersion of a set of values. A low standard deviation indicates that the values tend to be close to the mean (also called the expected value) of the set, while a high standard deviation indicates that the values are spread out over a wider range. Standard deviation may be abbreviated SD, and is most commonly represented in mathematical texts and equations by the lower case Greek letter σ (sigma), for the population standard deviation, or the Latin letter '' s'', for the sample standard deviation. The standard deviation of a random variable, sample, statistical population, data set, or probability distribution is the square root of its variance. It is algebraically simpler, though in practice less robust, than the average absolute deviation. A useful property of the standard deviation is that, unlike the variance, it is expressed in the same unit as the data. The standard deviation of a popu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copeia
''Ichthyology & Herpetology'' (formerly ''Copeia'') is a quarterly peer-reviewed scientific journal covering research in ichthyology and herpetology that was originally named after Edward Drinker Cope, a prominent American researcher in these fields. It is the official journal of the American Society of Ichthyologists and Herpetologists. According to the ''Journal Citation Reports'', ''Copeia'' has a 2021 impact factor of 1.857, ranking it 65th out of 176 journals in the category "Zoology". History On December 27, 1913, John Treadwell Nichols published the first issue of ''Copeia''. This issue consisted of a single piece of paper folded to form four pages of information with five articles. The cover of the pamphlet bore the inscription: "Published by the contributors to advance the science of coldblooded vertebrates." In 2020, the American Society of Ichthyologists and Herpetologists voted to rename the journal, Ichthyology & Herpetology. Name change The journal was na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plethodon Cinereus
The red-backed salamander (''Plethodon cinereus'') is a small, hardy woodland salamander species in the family Plethodontidae. It is also known as the redback salamander, eastern red-backed salamander,Integrated Taxonomic Information System nternet2012. pdated 2012 Sept; cited 2012 Nov 26Available from: www.itis.gov or the northern red-backed salamander to distinguish it from the southern red-backed salamander (''Plethodon serratus''). The species inhabits wooded slopes in eastern North America, west to Missouri, south to North Carolina, and north from southern Quebec and the Maritime provinces in Canada to Minnesota. It is one of 56 species in the genus ''Plethodon''. Red-backed salamanders are notable for their color polymorphism and primarily display two color morph varieties ("red-backed" and "lead-backed"), which differ in physiology and anti-predator behavior. Description and ecology The red-backed salamander is a small terrestrial salamander, in total length (includin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
