Speciation III: Patterns and Drivers

These flashcards cover key concepts related to speciation mechanisms, reproductive isolation, and the evolutionary principles discussed in the lecture.

What are the two main types of speciation mechanisms discussed in the lecture?

Allopatric and sympatric speciation.

What is reproductive isolation?

The mechanisms that prevent different species from interbreeding.

What does 'vicariance' refer to in the context of speciation?

The geographic separation of a species into separate populations through physical barriers.

What significant geological event contributed to allopatric speciation in the Isthmus of Panama?

The closure of the Isthmus of Panama 3-3.5 million years ago.

What is the Founder Effect?

A type of allopatric speciation where a small group from a population establishes a new population with reduced genetic diversity.

In the context of speciation, what is secondary contact?

The situation where previously isolated populations come back into contact and may hybridize.

What is meant by 'stable hybrid zones'?

Regions where hybrid populations can persist over time without significant changes.

What are prezygotic barriers?

Reproductive barriers that prevent mating or fertilization between species.

What is polyploidy and how does it impact speciation?

The condition where organisms have more than two complete sets of chromosomes, which can lead to reproductive isolation and speciation.

Which type of isolation develops more quickly according to the notes?

Prezygotic isolation.

How does nondisjunction relate to polyploidy?

Nondisjunction during meiosis can lead to gametes with abnormal chromosome numbers, resulting in polyploidy.

What is the outcome of reinforcement in speciation?

It solidifies the barriers to reproduction between diverging populations.

What term describes the process when hybrid individuals can reproduce and establish a population?

Species fusion.

What type of species do sympatric populations result from?

Populations that live in the same geographic area but diverge due to other barriers.

What indicates a stable hybrid zone?

A balance between the two parent species and hybrids that can coexist.

Which of the following is an example of a reproductive barrier: allopatric or sympatric?

Both can provide reproductive barriers; allopatric through physical separation and sympatric through ecological factors.