Exam 2 Flashcards
(29 cards)
what is the usual way in which a genome adds a new gene?
an existing gene is duplicated, after which one mutates to diverge to lead to a second outcome (new enzymes, etc.)
it was said in class that ontogeny does not recapitulate phylogeny. What is a better way to describe how embryos provide support for the idea of common ancestry of species?
as an embryo develops, it changes from a general ancestral-type embryo into an even more specific embryo leading to its own adult form.
How do the color of peppered moths change during the period of industrial pollution? How did it change after the enactment of strict ant-air pollution regulations?
- The peppered form decreased and the dark form spread
- vice versa
how did beak size of the medium ground finch evolve on Daphne Major Island during the drought of the 1970’s, and why?
beak size evolved to be larger, as only the largest - beaked finches could eat the only remaining, large seeds
what is the name of the English scientist who won two nobel prizes for his pioneering work on sequencing proteins and amino acids>
Frederich Sanger
Why is it that, when comparing 2 species, their DNA sequences are a little less similar than the amino acid sentences of their proteins?
There can be DNA changes that don’t change the amino acid coded for, so the DNA has changed but not the protein
Name two of the 20th century population geneticists who showed how Darwin’s evolutionary ideas and Mendel’s genetic ideas could be combine into a “Synthetic Theory of Evolution”.
Fisher, Haldane, Wright, Dobzhansky
How is evolution defined, genetically?
a change over time in the allele frequencies of genes
In population genetics, what does each of these represent?
p,q, p2, q2, 1pq
p: allele frequency of one allele, usually the dominant
q: …. recessive
p2: genotype frequency of one homozygote, usually the dominant
q2: …. recessive
2pq: genotype frequency of the heterozygote
what are the three elements of the “Hardy-Weinberg Equilibrium”?
- initial allele frequencies don’t change (p+q)
- one generation of random matching establishes the genotype frequencies (p2, 2pq, q2)
- thereafter, genotypre frequencies don’t change
What are the 5 conditions necessary for a population to be in the Hardy - Weinberg equilibrium, and what are the names of the 5 evolutionary forces that are in operation if those conditions are violated?
5 conditions:
- no mutations
- random mating
- very large population
- no dispersal
- no differential survival or reproduction of genotypes
5 evolutionary forces:
- mutation
- sexual selection
- genetic drift
- gene flow
- natural selection
Which of the genetic causes of evolution are “stochastic”?
mutation, genetic drift, gene flow
How important are mutations, in the overall evolutionary process?
crucial, it cannot continue without them swapping variations
What are the main effects of genetic drift within a population? When occurring independently in two different populations?
with in –> some alleles are fixed or lost, overall genetic diversity decreases
between –> the two populations become less similar
what are the two common phenomena in nature in which genetic drift is important> Name an example for each.
founder effect –> many, such as spongy moths
bottleneck –> many, such as elephant seals or cheetahs
what is the usual, common effect of gene flow when occurring between two populations?
to make them more alike genetically
Give an example from class of each of the following:
directional selection against a recessive allele
heterozygote advantage
disruptive selection
male competition selection
female choice selection
- directional selection against a recessive allele: the peppered moth from peppered to dark
- Heterozygote advantage: sickle cell
- disruptive selection: white admuid vs. red-spotted purple butterflies
- male competition selection: elephant seals
female choice selection: long-tailed widowbirds
What are the two types of sexual selection, using Dr. Burk’s preferred name?
mate competition and mate choice
What change from the Hardy-Weinberg genotypes would be expected in the case of positive assortative mating? In the case of Negative Assortative mating? For each type of assortative mating, name one species that is an example.
positive Assortative mating: an excess of homozygotes –> snow/blue geese
negative - an excess of heterozygotes –> Drosophilia “rare male effect”
From the much - used sickle cell anemia example, give a possible fitness set and the expected long-term outcome for each of these scenarios:
- a country such as the US, where there is little or no malaria, but we still cannot treat sickle cell anemia completely effectively
- a country in the future where malaria is still common, but we are able to treat sickle cell anemia completely effectively
- a country in the future in which malaria has been eradicated, and we are able to treat sickle cell anemia completely effectively
- AA AS SS
W 1 1. <1
directional selection against S, which will decline gradually
- AA AS SS
W <1 1 1
directional selection against A, which will decline gradually
- AA AS. SS
W. 1. 1. 1
Hardy-Weinberg equilibrium, no subsequent change in the frequency of A or S
What factor did Robert Trivers say explained why males are most often the competitive sex and females are most often the discriminating sex?
Asymmetry in parental investment, with female female doing more (primarily due to anisogamy
what are the 6 general categories of mate (usually male) competition?
- greater assertiveness
- lesser discrimination
- signaling competition
- aggressive competition
- alternative/conditional tactics
- sperm competition
name one kind of “direct benefits” mate choice and one kind of “indirect benefits” mate choice
direct –> food, parental care, good territory, etc
indirect –> “good genes” in general or male-specific attractor traits
What is the name of the mating system in which is usual for both males and females to have multiple mates? Of the mating system in which it is usual for successful males to have multiple mates but females only one mate?
- polygynandry
- polygyny
