Honors biology unit 9

Adaptation

Heritable traits that help an organism survive and reproduce

Allele frequency

How often a allele (a variant of a gene) appears in a population

Analogous structure

Biological features in different species that perform similar functions, but do not share a common ancestor

Artificial selection

Intentional breeding/selection by humans for certain traits or combinations of traits

Behavioral isolation

Some members of the population have different courtship behaviors, mating songs, dances, etc

Biological evolution

Any change in frequency of alleles (heritable traits over time (generations))

Biological fitness

The number of offspring an individual contributes to the next generation relative to other members of their species

Bottleneck effect

When a populations size is reduced for at least one generation

Charles Darwin

A naturalist abroad the HMS Beagle who recorded his observations and collected specimens in his five year journey

Fossil

The remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock

Founder effect

When one or a few individuals start a new population in a new location

This new population has different allele frequencies than the original population

Gene pool

The total collection of genes, including all the different variants (alleles), within reproducing population or species

Genetic drift

Random process by which allele frequencies change in a population

Genetic equilibrium

A state where alleles and genotype frequencies in a population remain constant from one generation to another

Geographic isolation

Part of a population is separated by a geographical element, like distance, body of water, mountain, or natural disaster

Homologous structure

Organisms sharing so many of the same bone structures, but their bones are used for different functions

Mutation

A permanent change in an organisms DNA sequence that can affect its appearance, behavior, and physiology

Natural selection

Non-random process by which populations become better adapted to their environment

= better adapted individuals produce more offspring than other members of their species

Phylogenetic tree

A diagram that depicts the evolutionary relationship between organism, species, and genes

Reproductive isolation

These mechanisms can lead to reproductive isolation, where parts of the population cannot mate with others. Over time, the members of the isolated population will become so different that they can no longer mate and produce fertile offspring with the original offspring

Selection

Result of “forces” that cause non-random changes in the allele frequencies of a population

Sexual selection

Non-random process by which traits that increase reproductive success become more common in a population

Speciation

An evolutionary process where a new species is formed from and existing species

Species

A group of living organism consisting of similar individuals capable of exchanging genes or interbreeding

Temporal isolation

Some members of the population mate and reproduce at a different time or in a different season that the rest of the population

Theory

A supposition or a system of ideas intended to explain something, especially one based on general principles independent of the thing to be explained

Vestigial structure

An anatomical feature or behavior that was functional in an ancestor, but is no longer useful in the current form of an organism