Chapter 14

Questions :

What is taxonomy and why do we use it ?

Taxonomy is the branch of biology that names and classifies species. We can either classify organisms based on their phenotypical features or based on their ecological role or we can recognize species that represent specific evolutionary lineage. We use taxonomy to make order and to observe similarities and traits of in

terest throughout the history.

What is sympatric speciation ?

Sympatric speciation - new species arise within the same geographic area as parent species. This speciation is very important. There have been many issue when people brought species from different countries into new environment which cause issue to the natural environment. That's why new species arise only within the same geographic area. They have natural environment there and also natural predators and food to consume.

What is prezygotic barrier ?

Prezygotic barrier prevents mating or fertilization between species. There are main five types : temporal isolation, habitat isolation, behavioral isolation, mechanical isolation and gametic isolation. Animals have these barriers to prevent closely related species from interbreeding.

Diagram :

This diagram shows an example of taxonomy. We list species in specific order which helps us to recognize where the animals belong and their closely relates species.

5facts:

Groups isolated by diet or female mate choice may have lost the ability to interbreed.

Every time speciation occurs, the diversity of life increases.

Carolus Linnaeus developed binomial system naming of organisms.

The process of speciation depends on whether reproductive barriers prevent gene flow between populations.

The occasional hybridization between finch species introduces new genes into both populations.

Key terms :

reproductive barrier - biological feature, to prevent individuals of closely related species from interbreeding

temporal isolation - prezygotic barrier (PB), occurs when species breed at different time

habitat isolation - PB, two species live in the same general area but not in the same kinds of places

behavioral isolation - PB, there is little or no sexual attraction between females and males of different species

mechanical isolation - PB, female and male sex organs are not compatible

gametic isolation - PB, gametes of two different species do not unite to form a zygote

allopatric speciation - populations are separated by geographical barrier

polyploid - cells have more than two complete sets of chromosomes

hybrid zones - regions in which members of different species meet and mate

adaptive radiation - evolution of many diverse species from a common ancestor

Video :

Speciation

Summarize:

Chapter 14 continues to describe the process of evolution. Although this time the chapter more concentrates on speciation of species and different barriers that prevent species from interbreeding. The chapter also talks about hybrids and their process of evolution.