Speciation and Macroevolution to add

This set of vocabulary flashcards covers key concepts of speciation and macroevolution, including species concepts, isolating mechanisms, modes of speciation, and evolutionary models.

Macroevolution

Evolution on a larger scale that involves speciation.

Speciation

The splitting of one species into two or more species, or the transformation of one species into a new species over time.

Species concepts

The different ways species are defined.

Morphological Species Concept

Classifies species based on diagnostic traits, which are distinct physical characteristics.

Diagnostic traits

Distinct physical characteristics used for classifying a group of organisms as a species.

Evolutionary Species Concept

Classifies species based on structural traits and implies that members of a species share an evolutionary pathway.

Phylogenetic Species Concept

Classifies species based on a common ancestor, defining a species as the smallest set of interbreeding organisms that share one.

Biological Species Concept

Classifies species based on their ability to interbreed and their reproductive isolation from other populations.

Reproductive isolation

Physiological, behavioral, and genetic processes that inhibit interbreeding between populations.

Reproductive Isolating Mechanisms

Mechanisms that inhibit gene flow between species, divided into prezygotic and postzygotic types.

Prezygotic Isolating Mechanisms

Mechanisms that prevent mating attempts or decrease the chances of fertilization occurring.

Habitat Isolation

A prezygotic mechanism where species are unable to interbreed because they occupy different habitats within the same geographical range.

Temporal Isolation

A prezygotic mechanism where species are unable to interbreed because they reproduce at different times of the year.

Behavioral Isolation

A prezygotic mechanism where species cannot interbreed because they display different courtship behaviors and patterns like dances, songs, or pheromones.

Mechanical Isolation

A prezygotic mechanism where species are unable to interbreed because they have incompatible mating structures.

Gamete Isolation

A prezygotic mechanism where species mate and gametes meet, but they do not fuse into a zygote.

Postzygotic Isolating Mechanisms

Mechanisms that prevent offspring from developing and/or reproducing after a zygote has formed.

Hybrid Inviability

A postzygotic mechanism where a zygote is not viable or the embryo cannot develop in the mother's womb, causing the offspring to die.

Hybrid Sterility

A postzygotic mechanism where the zygote develops into an adult, but the adult is sterile.

Allopatric Speciation

A mode of speciation where a single population becomes separated by a geographic or physical barrier.

Sympatric Speciation

A mode of speciation where a single population develops into two or more reproductively isolated groups without geographic isolation.

Polyploidy

A condition in plants where the chromosome number is beyond the diploid number ($2n$).

Autoploidy

A type of polyploidy where a diploid plant produces diploid gametes due to nondisjunction during meiosis; fusion with a haploid results in a sterile triploid ($3n$).

Alloploidy

A type of polyploidy where two different but related species hybridize, followed by the doubling of chromosomes.

Adaptive Radiation

A type of speciation where a species rapidly gives rise to a variety of new species as each adapts to a specific environment.

Convergent Evolution

Occurs when a biological trait evolves in two unrelated species as a result of exposure to similar environments.

Analogous traits

Traits that are similar in function but different in origin, such as a bird wing and a bat wing.

Homologous traits

Traits that are different in function but similar in origin, such as vertebrate forelimbs.

Gradualistic model of evolution

A model where evolution at the species level occurs gradually and speciation occurs after populations are already isolated.

Punctuated Equilibrium

A model of evolution where periods of equilibrium are punctuated by speciation, and species appear suddenly.