Lectures 2 & 3: Evolution and Genetics

Question 1

Proximate Causes

Answer 1

Reasons for how be behave that are immediate, physiological, environmental, or neural

Question 2

Ultimate Causes

Answer 2

Answers to how we behave that are genetic, evolutionary adaptations, or selection pressures

Question 3

Central Dogma

Answer 3

DNA –> mRNA –> Protein

Duplication, transcription, translation

Question 3

From Gene to Protein

Answer 3

1. Promoter sequence is where RNA polymerase latches onto to produce mRNA (transcription
2. Splicing of the mRNA happens (exons are kept, introns are spliced out)
3. mRNA is translated to a protein via the ribosome via a start and stop sequence

Question 3

Gene

Answer 3

Region of DNA that encodes some function (via the synthesis of either RNA or proteins)

Question 4

Diploid

Answer 4

Having pairs of chromosomes (homologous pairs) (humans except for sex chromosomes)

Question 4

Chromosome

Answer 4

Genetic book which holds DNA

Question 5

Allele

Answer 5

One of multiple forms of a gene (blood type A allele, B allele, or O allele, but it is a blood type gene)

Question 6

Codominance

Answer 6

Both alleles expressed, blood type AB

Question 7

Meiosis

Answer 7

Cell division that results in gamete cells which contain half the number of chromosomes (haploid)

Question 7

Recombination

Answer 7

Shuffling of DNA from homologous chromosomes

Question 7

Coefficient of genetic Relatedness

Answer 7

R: The probability that two individuals share an allele due to recent common ancestry (ranges from 0-1)

Question 8

Somatic Mutations

Answer 8

Mutations that occur in non-germ line cells (not sex cells); not heritable

Question 9

Hereditary/Germline Mutation

Answer 9

Mutation in sex cells; heritable but does not affect the parent’s body

Question 10

Directional Selection

Answer 10

Moves a population with regards to a trait; a trait becomes expressed more or less on average throughout the species after many generations

Question 10

Darwin’s Principles of Evolution

Answer 10

1. Organisms produce more progeny than can survive; there is competition for resources
2. Sexual reproduction causes genotype variation
3. Genotype variation causes phenotype variation (traits)
4. Traits are inheritable
5. Environment selects for particular traits over others

Question 11

Disruptive Selection

Answer 11

Splitting of a population into two extremes. For examples, in a forest there are only very dark and very light tree trunks, so moths have adapted to have one of those two colors from the original moths that had a neutral color that did not allow for camouflage

Question 12

Convergent Evolution

Answer 12

Development of similar traits in different species due to shared selection pressure; bats and birds, fins of fishes and dolphins, etc.

Question 12

Homoplasy

Answer 12

Shared trait w/o a recent shared ancestor

Question 12

Homology

Answer 12

Shared trait due to a shared ancestor

Question 13

Richard Dawkins

Answer 13

• Writer of “The Selfish Gene”
• Asked what does evolution act on; survival of the fittest…. what?
• Said genes are the units of selection, and that individuals are vessels in which these genes are carried
  - Individuals, like sentinel meerkats, can protect their genes by protecting their family who has their genes, and not necessarily by protecting the individual themselves
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Question 14

Evolutionary Stable Strategy (ESS) Game

Answer 14

• Game proposed b Maynard Smith
• It works as follows:
  - Description of how organisms interact and how well they are doing
  - A “mutation gene” changes how individuals interact
  - We will test if the gene disappears or prospers and if it increased or decreased the state of the individuals

Question 15

Altruism

Answer 15

2 definitions:

1. Behavior that benefits another at a cost to oneself
2. Behavior that increases the fitness of another individual while decreasing the fitness of the actor

Examples: Honey bees who sting you to protect the honey in the hive, vampire bats that take care of their sick bats, and ring-tailed lemurs that show communal rearing of offspring

Question 16

Units of Selection

Answer 16

• Does natural selection select for individual organisms? group organisms? species? genes?
• If individuals are the unit of selection, genes that reduce individuals’ fitness would be expected to disappear

Question 17

Inclusive Fitness

Answer 17

• The ability of an organism to pass on its genes to the next generation, taking into account the shared genes passed on by the organism’s close relatives

Question 18

Kin Selection

Answer 18

• An evolutionary strategy that favors the reproductive success of an organism’s relatives, even at a cost to the organisms own survival and reproduction; altruism towards kin/realtives
• We should live in small groups of relatives or show kin recognition

Question 19

ESS Game Results

Answer 19

• In all-dove community, 40 life points were gained in an average encounter
• A mutation happened, introducing hawks,
  In a stable hawk/dove community, each gets only 8 LP in an average encounter
• The doves were better off before
• If evolution would select for the most well-adapted organisms, it would get rid of hawk mutation
• Genes can be selected even if not in the species best interest