Speciation and Reproductive Isolation

A set of vocabulary flashcards relating to the concepts of speciation, reproductive isolation, and the biological species concept.

Speciation

The process by which one species splits into two species.

Microevolution

Changes in allele frequency in a population over time.

Macroevolution

Broad patterns of evolutionary change above the species level.

Biological species concept

A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring.

Reproductive isolation

Biological barriers that impede members of two species from interbreeding and producing viable, fertile offspring.

Hybrid

Offspring that result from interspecific mating.

Prezygotic barriers

Barriers that block fertilization from occurring.

Postzygotic barriers

Barriers that prevent hybrid zygotes from developing into viable, fertile adults.

Habitat isolation

Two species occupy different habitats within the same area and rarely encounter each other.

Temporal isolation

Species breed at different times, preventing them from mixing their gametes.

Behavioral isolation

Unique courtship rituals or behaviors act as barriers to mating.

Mechanical isolation

Morphological differences prevent successful mating.

Gametic isolation

Sperm of one species may not be able to fertilize eggs of another species.

Reduced hybrid viability

Hybrids may develop abnormally or fail to survive due to genetic incompatibility.

Reduced hybrid fertility

Hybrids may be sterile due to chromosomal differences between parent species.

Hybrid breakdown

First-generation hybrids are vigorous but their subsequent generations are weak or sterile.

Fossils

Remains or traces of ancient organisms, often difficult to classify under the biological species concept.

Asexual organisms

Organisms that reproduce without the fusion of gametes, posing challenges for the biological species concept.

Gene flow

Transfer of genetic variation between populations, which can blur the line between species.

Morphological species concept

Distinguishes species based on body shape and structural features.

Ecological species concept

Defines a species by its ecological niche and its interactions with the environment.

Grolar bears

Hybrid offspring of grizzly bears and polar bears, demonstrating occasional gene flow between species.

Viable offspring

Hybrid offspring that are capable of surviving and reproducing.

Fertile offspring

Hybrid offspring that can produce viable gametes.

Barriers to mating

Factors that prevent different species from interbreeding successfully.

Mating rituals

Specific behaviors or displays that facilitate mating between species.

Ecological niche

The role a species plays in its environment, including its habitat, resource use, and interactions.

Alelle frequency

How often an allele appears in a population.

Species

A group of individuals that actually or potentially interbreed in nature.

Viability

The ability of an organism to survive and develop.

Molecular phylogenetics

The analysis of the genetic relationships between species to understand evolutionary pathways.

Natural selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

Speciation mechanisms

Various processes by which new species arise, including allopatric and sympatric speciation.