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50 Cards in this Set

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Abundance of any particular allele among members of a population

Allele Frequency

All the alleles of all the genes in a population; a pool of genetic resources.

Gene Pool

Mutation that alters phenotype so drastically that it causes death.

Lethal Mutation

Change in an allele's frequency in a population.

Microevolution

A mutation that has no effect on survival or reproduction.

Neutral Mutation

Example: attached earlobes, freckles, red hair.

A group of organisms of the same species who live in a specific location and breed with one another more often than they breed with members of other populations.

Population

Theoretical state in which an allele's frequency never changes in a population's gene pool.

Genetic Equilibrium

Mode of natural selection in which phenotypes at one end of a range of variation are favored.

Directional Selection

Mode of natural selection in which traits at the extremes of a range of variation are adaptive, and intermediate forms are not.

Disruptive Selection

Mode of natural selection in which an intermediate form of a trait is adaptive, and extreme forms are not.

Stabilizing Selection

Maintenance of two of more alleles of a gene at high frequency in a population.

Balanced Polymorphism

Natural selection in which a trait's adaptive value depends on its frequency in a population.

Frequency-dependent Selection

Difference in appearance between males and females of a species.

Sexual Dimorphism

Mode of natural selection in which some individuals outreproduce others of a population because they are better at securing mates.

Sexual Selection

Reduction in population size so severe that it reduces genetic diversity.

Bottleneck

Refers to an allele for which all members of a population are homozygous.

Fixed

After a small group of individuals found a new population, allele frequencies in the new population differ from those in the original population.

Founder Effect

The movement of alleles into and out of a population.

Gene Flow

Change in allele frequency due to chance alone.

Genetic Drift

Mating among close relatives.

Inbreeding

The end of gene flow between populations.

Reproductive Isolation

Evolutionary process in which new species arise.

Speciation

Speciation pattern in which a physical barrier ends gene flow between populations.

Allopatric Speciation

Speciation pattern in which populations speciate while in contact along a common border.

Parapatric Speciation

Speciation pattern in which speciation occurs within a population, in the absence of a physical barrier to gene flow.

Sympatric Speciation

A burst of genetic divergences from a lineage gives rise to many new species.

Adaptive Radiation

The joint evolution of two closely interacting species; each species is a selective agent for traits of the other.

Coevolution

Evolutionary adaptation of an existing structure for a completely new purpose.

Exaptation

Feathers for flight are related to insulating feathers in dinosaurs.

Refers to a species that no longer has living members.

Extinct

An evolutionary adaptation that gives its bearer the opportunity to exploit a particular environment much more efficiently or in a new way.

Key Innovation

Large-scale evolutionary patterns and trends.

Macroevolution

A macroevolutionary pattern in which a lineage persists with little or no change over evolutionary time.

Stasis

Quantifiable, heritable chracteristic or trait.

Character

A group whose members share one or more defining derived traits.

Clade

Making hypotheses about evolutionary relationships among clades.

Cladistics

Evolutionary tree diagram that shows evolutionary connections among a group of clades.

Cladogram

A novel trait present in a clade but not in the clade's ancestors.

Derived trait

Diagram showing evolutionary connections.

Evolutionary Tree

An ancestor in which a derived trait evolved, together with all of its descendants.

Monophyletic Group

Evolutionary history of a species or group of species.

Phylogeny

The two lineages that emerge from a node on a cladogram.

Sister Groups

List the 5 conditions that must be met to maintain genetic equilibrium.

1. Population must be very large


2. No gene flow between populations


3. Mutations never occur


4. Mating is random


5. No natural selection. All individuals survive and reproduce the same number of offspring.

Mechanism of reproductive isolation in which individuals live in different places so they never meet up for sex.

Ecological Isolation

Example: two species of garter snake. One lives on land and the other in water.

Mechanism of reproductive isolation in which individuals reproduce at different times.

Temporal Isolation

Example: Different breeding seasons for the eastern spotted skunk and the western spotted skunk.

Mechanism of reproductive isolation in which individuals ignore or do not get the required cues for sex.

Behavioral Isolation

Example: elaborate courtship ritual specific to species, specific songs or displays.

Mechanism of reproductive isolation in which physical incompatibilities prevent individuals from interbreeding.

Mechanical Isolation

Example: different pollinators in plant species only fertilize certain plants species.

Mechanism of reproductive isolation in which molecular incompatibilities prevent gametes of a different species from forming a zygote.

Gamete Incompatability

Example: Incompatability of the surface proteins in gametes between red and purple sea urchins do not fuse.

Mechanism of reproductive isolation in which hybrid embryos die early or new individuals die before they can reproduce.

Hybrid Inviability

Example: ligers have more health problems and shorter life expectancy.

Mechanism of reproductive isolation in which hybrid individuals or their offspring do not make functional gametes.

Hybrid Sterility

Example: Mules cannot interbreed with one another.

An evolutionary adaptation that gives its bearer the opportunity to exploit a particular environment much more efficiently or in a new way.

Key Innovation

Example: the evolution of lungs.