Human Evolution and Speciation

Fill-in-the-blank study flashcards reviewing key evolutionary biology and speciation concepts, mechanisms, and definitions.

__________ is defined as the change in allele frequencies in a population over generations.

Evolution

An alternative version of a gene is called an __________.

allele

How common an allele is in a population is known as __________.

allele frequency

All the alleles in a population are known as the __________.

gene pool

The process by which individuals with advantageous inherited traits are more likely to survive and reproduce is __________.

natural selection

An inherited characteristic that helps an organism survive and reproduce is an __________.

adaptation

A change in DNA that can create a new allele is called a __________.

mutation

Differences in genes/alleles between individuals are known as __________.

genetic variation

Random changes in allele frequencies, especially in small populations, are referred to as __________.

genetic drift

The movement of alleles between populations is called __________.

gene flow

An ancestral organism shared by two or more species is a __________.

common ancestor

Preserved remains or evidence of an ancient organism are known as a __________.

fossil

A structure with the same evolutionary origin but potentially different functions is a __________.

homologous structure

A reduced structure inherited from an ancestor that has little or no current function is a __________.

vestigial structure

The evolutionary history and relationships of organisms is known as __________.

phylogeny

DNA found in mitochondria that is commonly used to compare evolutionary relationships is __________.

mtDNA

DNA found in the nucleus is termed __________.

nDNA

The evolutionary changes that have occurred in the human lineage over time are termed __________.

human evolution

A group of organisms that can reproduce with each other and produce fertile offspring is a __________.

species

The formation of a new species is known as __________.

speciation

When a physical barrier separates populations and prevents/reduces gene flow, it is called __________.

geographic isolation

When populations can no longer successfully reproduce with each other to produce fertile offspring, they have achieved __________.

reproductive isolation

Populations becoming increasingly genetically different over time is referred to as __________.

divergence

A type of natural selection where one extreme phenotype is favoured is __________.

directional selection

A type of natural selection where the intermediate phenotype is favoured is __________.

stabilising selection

When both extreme phenotypes are favoured while the intermediate is selected against, it is called __________.

disruptive selection

Populations around a geographic barrier that can interbreed with neighbouring populations, but populations at the ends cannot, are termed a __________.

ring species

An ancestor and all of its descendants is called a __________.

clade

Anything that prevents populations from successfully reproducing with each other is a __________.

reproductive barrier

Speciation caused by geographic isolation is called __________.

allopatric speciation

When one ancestral species rapidly diversifies into multiple species adapted to different environments, it is called __________.

adaptive radiation