04. Biodiversity, Evolution, and Conservation Free Online FlashCards

What is evolution?

Evolution is a change in the inherited characteristics of a population over generations; individuals do not evolve during their lifetimes.

How does natural selection change a population?

Natural selection occurs when heritable traits that improve survival or reproduction cause their carriers to leave more offspring, making those traits more common.

What is gene flow?

Gene flow is the movement of alleles between populations through migration and reproduction; it can increase variation within a population and reduce differences between populations.

What is allopatric speciation?

Allopatric speciation occurs when a physical barrier separates populations, reducing gene flow until evolutionary differences produce reproductive isolation.

What is extirpation?

Extirpation is a local extinction: a species disappears from a particular area but survives elsewhere.

Why is genetic diversity important?

Genetic diversity is the variety of alleles and genotypes within a population or species; it provides raw material for evolutionary adaptation.

How do species richness and evenness differ?

Species richness is the number of species in an area, whereas species evenness is the relative abundance of those species.

What is habitat fragmentation?

Habitat fragmentation divides continuous habitat into smaller, more isolated patches, restricting movement and increasing edge exposure.

What makes a non-native species invasive?

An invasive species is a non-native organism whose introduction or spread causes ecological, economic, or human-health harm.

How do in situ and ex situ conservation differ?

In situ conservation protects organisms in their natural habitats, while ex situ conservation protects them outside those habitats, such as in zoos or seed banks.

What is genetic drift?

Genetic drift is a random change in allele frequencies, especially in small populations.

Which reproductive isolation mechanism characterizes a mule?

A mule is an example of hybrid sterility: the hybrid survives but generally cannot reproduce.