Exam II - Chapter 13 Flashcards Preview

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Flashcards in Exam II - Chapter 13 Deck (16):

What is meant by secondary contact?

interbreeding of 2 formally allopatric populations that have become genetically differentiated


what is reinforcement?

increase of reproductive isolation between populations through the selection against hybrid offspring


pre-zygotic isolation and 4 examples

divergence in traits between populations that prevents fertilization 1. mechanical isolation - "lock & key": physically can't mate2. behavioral isolation - different mating calls/dances3. temporal isolation- breed at different times of year4. gamete incompatibility


post-zygotic isolation and 2 examples

hybrid offspring that are sterile/infertile 1. zygote inviability 2. hybrid sterility - horse x donkey = sterile mule


connected series of populations that have diverged sufficiently across their ranges so that the population at ends of series are too different to interbreed

ring species


populations that live nearby are genetically more similar to each other than populations that live farther apart

isolation by distance


when does hybridization result in either reinforcement or speciation? --not completely sure about this question

reinforcement: when hybrids are sterilespeciation: when hybrids are fertile


speciation that occurs when populations are in separate, non-overlapping geographic areas- they are separated by geographic barriers. They are unlike;y to breed even if given the chance.

allopatric speciation


Speciation that occurs when populations are in same geographic area - differences in phenotypes decrease the likelihood of interbreeding between populations

sympatric speciation


2 types of physical isolation (allopatric speciation)

1. dispersal 2. vicariance - barrier is created


2 types of mutational isolation (sympatric speciation)

1. genome duplication - results in polyploidy 2. polyploidy - causes instance reproductive isolation without physical isolation


evolutionary process by which new species arise; causes 1 evolutionary lineage to split into 2 or more



species are groups of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups

biological species concept


species designation and identification based on morphological differences between populations; how fossils are assigned to species

morphospecies concept


species are the smallest possible groups whose members are descended from a common ancestor and who all posses defining or derived characteristics that distinguish them from other such groups; they are the "tips" of phylogenetic trees

phylogenetic species concept


consists of interbreeding populations that evolve independently of other species; smallest evolutionary individual unit