Natural selectionNatural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which is intentional, whereas natural selection is not. Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations.
Big Five personality traitsThe Big Five personality traits is a suggested taxonomy, or grouping, for personality traits, developed from the 1980s onward in psychological trait theory. Starting in the 1990s, the theory identified five factors by labels, for the US English population, typically referred to as: openness to experience (inventive/curious vs. consistent/cautious) conscientiousness (efficient/organized vs. extravagant/careless) extraversion (outgoing/energetic vs. solitary/reserved) agreeableness (friendly/compassionate vs.
Effective population sizeThe effective population size (Ne) is a number that, in some simplified scenarios, corresponds to the number of breeding individuals in the population. More generally, Ne is the number of individuals that an idealised population would need to have in order for some specified quantity of interest (typically change of genetic diversity or inbreeding rates) to be the same as in the real population. Idealised populations are based on unrealistic but convenient simplifications such as random mating, simultaneous birth of each new generation, constant population size, and equal numbers of children per parent.
Life history theoryLife history theory is an analytical framework designed to study the diversity of life history strategies used by different organisms throughout the world, as well as the causes and results of the variation in their life cycles. It is a theory of biological evolution that seeks to explain aspects of organisms' anatomy and behavior by reference to the way that their life histories—including their reproductive development and behaviors, post-reproductive behaviors, and lifespan (length of time alive)—have been shaped by natural selection.
Molecular evolutionMolecular evolution is the process of change in the sequence composition of cellular molecules such as DNA, RNA, and proteins across generations. The field of molecular evolution uses principles of evolutionary biology and population genetics to explain patterns in these changes. Major topics in molecular evolution concern the rates and impacts of single nucleotide changes, neutral evolution vs. natural selection, origins of new genes, the genetic nature of complex traits, the genetic basis of speciation, the evolution of development, and ways that evolutionary forces influence genomic and phenotypic changes.
Courtship displayA courtship display is a set of display behaviors in which an animal, usually a male, attempts to attract a mate; the mate exercises choice, so sexual selection acts on the display. These behaviors often include ritualized movement ("dances"), vocalizations, mechanical sound production, or displays of beauty, strength, or agonistic ability. In some species, males will perform ritualized movements to attract females.
Brain–body mass ratioBrain–body mass ratio, also known as the brain–body weight ratio, is the ratio of brain mass to body mass, which is hypothesized to be a rough estimate of the intelligence of an animal, although fairly inaccurate in many cases. A more complex measurement, encephalization quotient, takes into account allometric effects of widely divergent body sizes across several taxa. The raw brain-to-body mass ratio is however simpler to come by, and is still a useful tool for comparing encephalization within species or between fairly closely related species.
Sperm competitionSperm competition is the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction. Competition can occur when females have multiple potential mating partners. Greater choice and variety of mates increases a female's chance to produce more viable offspring. However, multiple mates for a female means each individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase male's chance of reproductive success.
Brain sizeThe 'size of the brain' is a frequent topic of study within the fields of anatomy, biological anthropology, animal science and evolution. Brain size is sometimes measured by weight and sometimes by volume (via MRI scans or by skull volume). Neuroimaging intelligence testing can be used to study the volumetric measurements of the brain. Regarding "intelligence testing", a question that has been frequently investigated is the relation of brain size to intelligence.
Disruptive selectionDisruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups. In this more individuals acquire peripheral character value at both ends of the distribution curve. Natural selection is known to be one of the most important biological processes behind evolution.
