Chapter 17: Speciation and Macroevolution

These flashcards cover key concepts related to speciation and macroevolution as discussed in the lecture notes.

Macroevolution

Evolution on a large scale, involving speciation, or the splitting of one species into two or more species.

Microevolution

Changes in allele frequencies in a population over generations.

Speciation

The process by which one species splits into two or more species.

Phylogenetic species concept

Uses a phylogeny based on common ancestry to identify species.

Morphological species concept

Classifies species based on distinct physical characteristics called diagnostic traits.

Biological species concept

Defines species based on reproductive isolation and the inability to produce fertile offspring.

Prezygotic isolation

Mechanisms that prevent fertilization from occurring between species.

Postzygotic isolation

Mechanisms that prevent hybrid offspring from developing or reproducing after fertilization.

Allopatric speciation

Speciation that results from populations becoming separated by a geographic barrier.

Sympatric speciation

Speciation that occurs without a geographic barrier, often involving changes in diet or microhabitat.

Adaptive radiation

Rapid evolution of multiple species from a common ancestor to fill different ecological niches.

Convergent evolution

The independent evolution of similar traits in unrelated species due to similar environmental pressures.

Reproductive isolation

The set of mechanisms that prevent gene flow between species, maintaining their distinctiveness.

Cryptic species

Species that are morphologically indistinguishable from each other but genetically different.

Pax6 gene

A gene responsible for eye development in all animal species.

Hox genes

Regulatory genes that determine the arrangement of body structures during embryonic development.

Natural selection

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

Gradualism

The model of evolution that proposes gradual changes over long periods lead to new species.

Punctuated equilibrium

An evolutionary model that suggests species remain stable for long periods interrupted by short bursts of rapid change.