5/17/24 - Lecture 24: Speciation I: Species Concepts and Speciation Patterns

Question 1

Microevolution

Answer 1

Changes in allele frequencies across generations (small-scale changes, short time frames)

Question 2

Macroevolution (speciation)

Answer 2

Accumulation of many microevolutionary changes, such that a new group arises (large-scale changes, long time frames)

Question 3

Biological species concept

Answer 3

A species is a group of actually or potentially interbreeding natural populations that are reproductively isolated from other groups

Question 4

Lineage (phylogenetic) species concept

Answer 4

A species is a group of organisms that share a common ancestor and hence are genetically similar

Question 5

Morphological species concept

Answer 5

A species is a group of organisms that have similar physical traits

Question 6

Allopatric (vicariance)

Answer 6

Original population split, leading to speciation

Question 7

Allopatric (founder effect)

Answer 7

Small sample of individuals splits off from population, leading to speciation

Question 8

Sympatric (ecological)

Answer 8

Population in same place subdivides, for example by taking up slightly different habitats, leading to speciation

Question 9

Pre-zygotic barriers to interbreeding

Answer 9

Behavioral
Temporal
Habitat
Gametic
Mechanical

Question 10

Post-zygotic barriers to interbreeding

Answer 10

Reduced hybrid fitness

Question 11

How does the strength of reproductive barriers vary across sympatry and allopatry?

Answer 11

In sympatry, prezygotic barriers are stronger compared to allopatry.