Exam Four Flashcards
(173 cards)
What is another term for macroevolution?
Speciation
Describe “species”
An evolutionary independent unit
Name four biological boundaries to gene flow
Physiological (cellular incompatibility), Morphological (anatomical), Behavioral (mate choice), Genetic (chromosomes, genes, alleles)
Describe the Biological Species Concept or BSC
If members of separate interbreeding populations mate and produce fertile offspring-> same species
If members of separate interbreeding populations cannot mate (physiology, morphology), will not mate (behavior), or mate and produce infertile (can be viable) offspring (genetics)-> different species
Describe the Morphospecies Concept or MSC
Traits/Characteristics
Skeletal and organ system
Describe the Phylogenetic Species Concept or PSC
Where well documented (molecular) phylogeny exists
Judgement on how much distance there needs to be for species vs subspecies
What are the three steps of speciation and what concept does it use?
1-Elimination or reduction in gene flow (1 population becomes 2)
2-Divergence, until
3-Separate species (by BSC)
Define allopatric speciation and describe the two forms
Different range, geographical barrier
Dispersal-From start to “habitat island”
Individuals are able to find compatible places randomly
Vicariance-Geographical barrier forms between a population
Define sympatric speciation
Same range
Define parapatric speciation and why it works
Nearby/Overlapping range
Reduction in gene flow, not elimination-little in ½ and 2/3 , almost none in ⅓
Which species concept is used for fossils?
MSC, morphospecies concept
What kind of speciation is Drosphila clines?
parapatric
What kind of speciation is Hawaiian Drosophia?
Allopatric-> Dispersal
What kind of speciation is snapping shrimp?
Allopatric-> Vicariance
What kind of speciation is hawthorne maggot fly?
Sympatric
What are the four levels of divergence?
Allele, Gene, Chromosome, and Genome
How does mutation lead to divergence at the allele level?
Same mutation do not occur in both populations->
New and different alleles appear in each population independently
How does selection lead to divergence at the allele level with the same selection pressures?
under directional selection patterns, different alleles can be fixed or lost
How does selection lead to divergence at the allele level with different selection pressures?
homozygote advantage pattern means that different alleles can be fixed or lost
How does selection lead to divergence at the allele level with quantitative traits?
Quantitative traits in a adaptive landscape (same selection pressure) can cause different alleles to be fixed or lost
How does nonrandom mating lead to divergence at the allele level?
Two populations can become fixed for contributing or non contributing alleles (inbreeding)
Many alleles fixed or lost
What can nonrandom mating lead to that aids in divergence? Give an example.
Nonrandom mating can become sexual selection, independent preferences in one population reinforce reduction in gene flow (even in the same or overlapping range)
Hawthorne and apple maggot flies
How can drift lead to divergence?
Different alleles fixed or lost in each population (with drift alone)
More likely that they will change then they will follow each other
Describe the founder effect in relation to divergence
Founder effect with small population (dispersal) means that initial allele frequencies are different and drift is much stronger