Biology Lecture Notes on Speciation and Evolution

These flashcards cover essential vocabulary and concepts related to speciation and evolution, making them a useful study tool for the exam.

Speciation

The process by which a new species develops from an existing species.

Allopatric speciation

Speciation occurring when populations are geographically separated.

Sympatric speciation

Speciation occurring when populations are in the same area but cannot interbreed due to behavioral differences, timing, etc.

Genetic drift

The change in allele frequencies of a population as a result of chance processes, particularly in small populations.

Prezygotic barriers

Reproductive barriers that prevent mating or fertilization between species.

Postzygotic barriers

Reproductive barriers that occur after fertilization, affecting the viability or fertility of hybrid offspring.

Hybrid inviability

A postzygotic barrier where a zygote is formed but does not develop properly.

Hybrid sterility

A postzygotic barrier where hybrid offspring are sterile, such as mules.

Hybrid breakdown

A postzygotic barrier where hybrid offspring are fertile but their offspring are non-viable or infertile.

Cline

A gradual variation in the characteristics of a species over its geographical range.

Convergent evolution

The development of superficially similar structures in unrelated organisms due to similar environmental pressures.

Analogous structures

Structures that are superficially similar but evolved independently.

Homologous structures

Structures that share a similar evolutionary history but have different functions.

Divergent evolution

The type of evolution where a common ancestor divides into different species with dissimilar characteristics.

Adaptive radiation

A rapid proliferation of forms from an ancestral type due to the sudden availability of ecological niches.

Fossils

Preserved remains in sedimentary rock layers that trace the evolutionary history of a species.

Instant speciation

The formation of a new species that occurs rapidly through changes such as polyploidy.

Natural selection

The process that results in the survival of organisms best adapted to their environment.

Juxtaposition of reproductive isolating mechanisms

Mechanisms that prevent species from interbreeding, impacting speciation.

Endemic

A species found only in a specific geographic area.