Evolution Bio Test

genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection, mechanism of evolution

nonrandom mating

Mating among individuals on the basis of their phenotypic similarities or differences, rather than mating on a random basis

gene flow

Movement of alleles into or out of a population due to the migration of individuals to or from the population

conditions of natural selection

variation, overpopulation, inheritance, competition, differential survival, reproduction

Variation

differences in physical and biological traits of an individual from the group to which it belongs, condition of natural selection

Overpopulation

The number of people in an area exceeds the capacity of the environment to support life at a decent standard of living, condition of natural selection

Inheritance

The process by which physical and biological characteristics are transmitted from the parent (or parents) to the offspring, condition of natural selection

competition

the struggle between organisms to survive in a habitat with limited resources, condition of natural selection

Differential survival

individuals with favorable characteristics tend to survive more, condition of natural selection

Reproduction

the production of offspring, condition of natural selection

types of gene flow

immigration and emigration

types of genetic drift

founder effect and bottleneck effect

founder effect

a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population, type of genetic drift

bottleneck effect

a reduction in the genetic diversity of a population caused by a reduction in its size (ie a natural disaster), type of genetic drift

r-selective species

those that reproduce rapidly/often and produce in large amounts, don't need to care for their offspring once born

K-selective species

those that reproduce very slowly and are slow to mature as well as that they produce one or two offspring at a time, need to nurture and care for offspring once born

allopatric speciation

The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.

sympatric speciation

The formation of new species in populations that live in the same geographic area

reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring, could be because it causes the production of infertile or weak offspring, or because of differences in geography, reproductive organs, or food

postzygotic isolation

reproductive isolation that occurs after members of two different species have mated and produced a hybrid offspring. Such hybrids are usually unable to reproduce

behavioral isolation

Form of reproductive isolation in which two populations have differences in courtship rituals or other types of behavior that prevent them from interbreeding

Speciation

the formation of new and distinct species in the course of evolution.

definition of evolution

change in allele frequencies in a population over multiple generations

definition of species

A group of organisms that can intrabreed and produce fertile offspring.

types of natural selection

directional, disruptive, and stabilizing selection: shape populations by favoring specific phenotypic traits over others

directional selection

Form of natural selection in which the entire curve moves; favors one extreme trait, shifting the population mean, occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

disruptive selection

form of natural selection in which a single curve splits into two; favors extreme traits, potentially causing divergence, occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes, favors intermediate traits, reducing variation, individuals in the middle of the distribution curve have higher fitness than individuals near the ends

HardyWeinberg equation/equilibrium

p+q = 1, p^2 + 2pq + q^2 = 1, (P=dom q=rec), represents the distribution of alleles in a population that is large, mating is random, all genotypes are equally likely to reproduce (no natural selection), no emigration or immigration, and no mutations occur, if distribution of genotypes matches the equilibrium no evolution is occurring

phylogenetic tree

A tree that shows the evolutionary relationships thought to exist among groups of organisms, traces emergence of new traits leading to new species

Microevolution

evolutionary change within a species or small group of organisms, especially over a short period.

Macroevolution

large-scale evolutionary changes that take place over long periods of time

Microevolution vs. Macroevolution

change in the gene pool of a population over several generations / large scale changes in a population that leads to the evolution of a new species

homologous structures

similar structures that related species have inherited from a common ancestor

analogous structures

Body parts that share a common function, but not structure

vestigial structures

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species, nonfunctional remnants of ancestral traits

5 mechanisms of evolution

natural selection, mutation, genetic drift, non-random mating, gene flow

Natural Selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits, mechanism of evolution

Mutation

change in a DNA sequence that affects genetic information, mechanism of evolution

prezygotic isolation

a barrier to successful breeding that occurs before fertilization, such as differences in mating time or behavior

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