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30 Cards in this Set
- Front
- Back
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Paraphyly
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A classification scheme in which a set of species includes a common ancestor and some, but not all, of that ancestor's descendents.
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Synapomorphy
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A shared, derived character
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Eusociality
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overlap in generations, cooperative care of young and nonreproductive
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Phenotypic plasticity
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The expression of a trait depends on the environment in which it is expressed.
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Paralogy
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a group of organisms have common descent if they have a common ancestor.
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Natural Selection
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survival: a natural process resulting in the evolution of organisms best adapted to the environment
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Allopatric speciation
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geographic speciation is speciation that occurs when biological populations of the same species become isolated due to geographical changes such as mountain building or social changes such as emigration
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Sympatric Speciation
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is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region.
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Observation of Evolution and the underlying cause
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descent with modification from common ancestors ; change in population DNA allele frequencies
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List the several evoluntionary phenomenas that HIV illustrate
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Drug resistance evolution
Adaptation of disease to host defenses Evolution is short sighted. Not for “good of the species”. Adaptation of host to diseases Evolution of virulence Origins of HIV – phylogenetic trees |
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What was the first anti-retroviral drug and the problems with it
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AZT - an analog of a nucleotide
Problems : - Mutation causes resistance to AZT very quickly ( about 6 months) - Viruses change directionally |
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What was the first anti-retroviral drug and the problems with it
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AZT - an analog of a nucleotide
Problems : - Mutation causes resistance to AZT very quickly ( about 6 months) - Viruses change directionally |
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CCR5 mutant gene
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HIV doesn't affect the host
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Evidence for evolution
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1. Species change over time
2. Species have a common ancestor 3. Species evolved over a long period of time |
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Biogeography
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closely related species occur in same area. Evidence they descended from a common ancestor
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clade
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monophyletic group
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node
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place of common ancestory
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homology
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similarity owing to descent from a common ancestor
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homoplasy
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same character state but not from common ancestry.
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topology
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tree form
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distance methods
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works based off of differences/similariies of DNA sequences
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Likelyhood methods
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probability of the data given that paramater. Parameter is an average from a sub sample of a certain population.
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Polytomies
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when bootstrap confidence is <50
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indels
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insertions or deletions usually due to unequal crossing over.
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homologs
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genes in different species that are similar to each other because they originated from a common ancestor.
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paralogous
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Paralogs typically have the same or similar function, but sometimes do not: due to lack of the original selective pressure upon one copy of the duplicated gene, this copy is free to mutate and acquire new functions.
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Effective population size
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size of an ideal population that undergoes genetic drift at a constant rate. Sensitive to # of males and females, non-random # of mates, non random variance in family sizes.
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Evolution is short-sighted
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e.g.
HIV eventually evolves to use naïve T-cells (starts out on other T-cells, then “learns” to use CXCR4 co-receptor) But, accelerates death of host and impedes transmission |
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Why kill your host?
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Transmission rate correlated with pathogenicity
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Soapberry bugs
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Demonstrate selection for short beaks due to flat-fodden golden rain trees.
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