Exam 5 chapter 27 Flashcards
What does speciation result from
Genetic isolation and lack of gene flow
Genetic divergence due to selection, drift and mutation
A species is defined as
An evolutionary independent population or group of populations
Describe the biological species concept
Species are reproductively isolated meaning they do not interbreed or they fail to produce viable, fertile offspring
Describe prezygotic isolation vs. postzygotic isolation
Prezygotic: individuals of different species are prevented from mating
Postzygotic: individuals can mate but the offspring die or can’t reproduce (mule)
Describe the morphospecies concept
Species differ in size, shape or other morphological features
Describe the phylogenetic species concept
Identifies species based on evolutionary history
What are subspecies
Live in discrete geographic areas
Have their own identifying traits
Are not distinct enough to be considered a separate species
Populations that live in different areas are said to be in
allotropy
are species that begin with geographic isolation known as sympatric speciation.
no
What are the two ways geographic isolation could occur
Dispersal: population moves to new habitat, colonizes it and forms new population
Vicariance: physical barrier splits population up
Populations or species that live in the same geographic area – close enough to interbreed – live in
sympatry
Define polyploidy
When an error in meiosis or mitosis doubles the chromosome number
Define autopolyploid
Mutation results in a doubling of the chromosome number and chromosomes all come from the same species
Define allopolyploid
Parents that belong to different species mate and produce offspring with two different sets of chromosomes
What is a hybrid zone
A geographic area where interbreeding between two populations occur and hybrid offspring are common
