Chapter 14: How Biological Diversity Evolves Flashcards

Vocabulary flashcards covering the concepts of speciation, reproductive isolating mechanisms, modes of speciation, macroevolution patterns, and geological time scales from Chapter 14.

Species

A Latin word meaning “kind” or “appearance”.

Biological species concept

Defines a species as a group of populations whose members have the potential to interbreed with one another in nature and produce fertile offspring.

Speciation

The process by which new species arise.

Reproductive isolation

The end of gene flow between populations, which is always a part of speciation.

Prezygotic Barriers

Reproductive isolating mechanisms that prevent mating or fertilization between individuals of different species.

Temporal isolation

A prezygotic barrier where mating or fertilization occurs at different seasons or times of day.

Habitat isolation

A prezygotic barrier where populations live in different habitats and do not meet.

Behavioral isolation

A prezygotic barrier where little or no sexual attraction exists between populations, often due to specific courtship rituals, songs, or displays.

Mechanical isolation

A prezygotic barrier where structural differences or anatomical incompatibility of sex organs prevent fertilization.

Gametic isolation

A prezygotic barrier where female and male gametes fail to unite in fertilization, often due to incompatibility of surface proteins.

Postzygotic Barriers

Reproductive isolating mechanisms that occur after fertilization has taken place.

Reduced hybrid viability

A postzygotic barrier where hybrid zygotes fail to develop or fail to reach sexual maturity.

Reduced hybrid fertility

A postzygotic barrier where hybrids fail to produce functional gametes, such as in the case of a mule.

Hybrid breakdown

A postzygotic barrier where hybrids are feeble or sterile.

Allopatric Speciation

Speciation that occurs by geographic isolation, such as a physical barrier like a desert or river.

Sympatric Speciation

The process where new species arise without any geographic isolation, often seen in plants through polyploidy.

Polyploidy

A mechanism of sympatric speciation in plants involving the doubling of chromosome numbers through hybridization.

Parapatric Speciation

A mode of speciation where populations maintaining contact along a common border evolve into distinct species, often involving hybrid zones.

Macroevolution

Major events in the history of life on Earth referring to evolutionary changes at or above the species level, including the origin of new taxonomic groups.

Geologic time scale

A sequence that divides Earth’s history into a consistent series of geologic periods.

Radiometric dating

A method used to measure the age of rocks and fossils.

Half-life

The time it takes for half of the atoms in a sample of radioisotope to decay.

Continental Drift

The movement of Earth's continents relative to each other by appearing to drift across the ocean bed.

Pangaea

A supercontinent formed $250$ million years ago when plate movements brought all land masses together.

Plate Tectonics Theory

The theory that Earth’s crust is divided into giant irregular shaped plates that float on the mantle, causing continental drift.

Biogeography

The study of patterns in the geographic distribution of species.

Stasis

A pattern of macroevolution where a lineage persists for millions of years with little or no change.

Exaptation

The adaptation of an existing structure for a completely different purpose.

Mass extinction

A pattern of macroevolution where a species has been permanently lost.

Adaptive radiation

A pattern of macroevolution where a lineage rapidly diversifies into several new species.

Coevolution

The joint evolution of two closely interacting species.