Honors Biology Unit 9

Adaptive radiation

Process by which one species evolves and gives rise to many descendant species that occupy different ecological niches.

Allopatric speciation

Process of speciation that occurs with geographic isolation, most common form of speciation via evolution.

Behavioral barriers

Isolation caused by differences in courtship or mating behaviors.

Geographic/habitat barriers

Isolation caused by physical barriers that divide a population into two or more groups.

Temporal barriers

Isolation that exists when timing prevents reproduction between populations.

Mechanical barriers

Isolation existing when physical incompatibility prevents reproduction between populations.

Gametic barriers

Isolation existing when molecular incompatibility of eggs and sperm prevents reproduction.

Cladogram

A phylogenetic tree that specifies derived characteristics of clades.

Coevolution

Process in which two or more species evolve in response to changes in each other.

Convergent evolution

A process where different species develop similar traits independently due to similar environments or challenges.

Divergent evolution

A process where related species become more different over time due to different environmental pressures.

Evolution

Process that explains how species change over time through natural selection, mutations, and genetic drift.

Extinction

When a species or group of organisms completely disappears from the planet.

Fossil record

A historical archive of life on Earth, consisting of preserved remains or imprints of organisms.

Genetic drift

Change in allele frequencies due to chance alone, typically impacting small populations.

Macroevolution

Major evolutionary transitions from one type of organism to another, including the origin and extinction of species.

Microevolution

Change in allele frequency within a population, all still the same species.

Migration/gene flow

The movement of individuals and their genetic material from one population to another.

Mutations

Random changes in DNA that can form new alleles.

Natural selection

Process where individuals with favorable traits are more likely to survive and reproduce.

Phenotype

Expression of a trait produced by one or more genes.

Phylogenetic tree

Diagram showing how species are related through evolution by common ancestor.

Punctuated equilibrium

Theory stating there are rapid bursts of speciation followed by long periods of stability.

Reproductive isolation

Final stage in speciation where members of isolated populations can no longer breed successfully.

Speciation

Evolution of two or more species from one existing species.

Sympatric speciation

The evolution of one species into two groups without geographic isolation.

Taxonomy

The science of naming, describing and classifying organisms.

Binomial nomenclature

The scientific naming system, consisting of the genus and species name.

Temporal isolation

A type of reproductive isolation occurring when species reproduce at different times.