Ch.17 Speciation and Macroevolution

What is macroevolution?

Evolution on a large scale that includes the origin of new species and major evolutionary changes over long time periods.

What is speciation?

The process in which one species splits into two or more new species.

What is the Biological Species Concept?

A species is a group of populations whose members can interbreed and produce fertile offspring.

What is reproductive isolation?

Barriers that prevent members of different species from successfully interbreeding.

What are the two major categories of reproductive barriers?

Prezygotic barriers and postzygotic barriers.

What do prezygotic barriers do?

They prevent mating or fertilization between species.

What do postzygotic barriers do?

They act after fertilization and prevent hybrid offspring from surviving or reproducing.

List types of prezygotic barriers.

Habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation.

List types of postzygotic barriers.

Hybrid inviability, hybrid sterility, and hybrid breakdown

What is allopatric speciation?

Speciation that occurs when populations are geographically separated.

What is sympatric speciation?

Speciation that occurs within the same geographic area, often due to polyploidy, habitat differences, or sexual selection.

What is polyploidy?

A condition in which an organism has more than two complete sets of chromosomes.

What is autoploidy?

Polyploidy that occurs within a single species due to errors in cell division

What is alloploidy?

Polyploidy that results from hybridization between two different species followed by chromosome doubling

What is adaptive radiation?

The evolution of many diverse species from a common ancestor, often in isolated environments like islands.

What is convergent evolution?

When unrelated species evolve similar traits due to similar environmental pressures.

What is divergent evolution?

When related species become more different over time due to different selective pressures.

What field studies the link between evolution and development?

Evo-devo (evolutionary developmental biology).

What are homeotic genes?

Master control genes that determine where major body structures form during development.

What are punctuated equilibria?

Long periods of little change interrupted by short periods of rapid evolutionary change

What is gradualism?

The idea that species evolve slowly and steadily over long periods of time.

What is horizontal gene transfer?

The movement of genes between organisms without reproduction, common in bacteria and important in early evolution.

Why do mitochondria and chloroplasts contain bacterial DNA?

Because they originated from bacteria through horizontal gene transfer and endosymbiosis