Week 1-2

Question 1

Levels of analysis in the study of animal behavior

Answer 1

Proximate level = (immediate timeline) immediate explanation for why something is happening
* Development
* Mechanism

Ultimate level = (evolutionary timeline) evolutionary reasons an individual may look/behavior in such way
* Evolutionary history
* Adaptive function

Question 2

Darwinian puzzle

Answer 2

A trait observed in an organism that seemingly contradicts the theory of natural selection, appearing to reduce an individual’s fitness or reproductive success, thus posing a question about how such a trait could have evolved under evolutionary pressure

Ex: a peacock’s large showy tail and altruistic acts in animals where individuals sacrifice their own fitness to help others

Question 3

Natural selection (gene-centered view)

Answer 3

Only genes replicate themselves; organisms do not.

Organisms are vehicles within which genes travel.

Adaptive evolution occurs through the differential survival of competing genes, which increase the frequency of those alleles whose phenotypic effects promote their own propagation

Question 4

Principle of parsimony

Answer 4

When reconstructing evolutionary relationships between organisms, the preferred hypothesis is the one that requires the fewest evolutionary changes, essentially choosing the simplest explanation that fits the data

Question 5

Convergent evolution

Answer 5

Process where distantly related organisms independently evolve similar traits or behaviors to adapt to similar environmental pressures

Question 6

Divergent evolution

Answer 6

Process that occurs when closely related species or populations become more dissimilar over time, often leading to the development of new species

Question 7

Eusociality

Answer 7

Highest level of organization of sociality.

Adults live in groups, cooperative care of juveniles (individuals care for brood that is not their own), reproductive division of labor (not all individuals get to reproduce), and overlap of generations live together

Ex: Anthropods (insects like ants, bees, wasps, termites), crustaceans (shrimp), naked mole rats

Question 8

Group selection

Answer 8

Species with self-sacrificing individuals are more likely to survive than groups without altruists, leading to the evolution of group-benefiting altruism (selection will favor altruism traits that favor the fitness groups over the fitness of the individual)

> hypothesis rejected today because selfishness outcompetes altruism

Question 9

Altruism

Answer 9

Cooperative behavior that lowers the donor’s reproductive success while increasing the reproductive success of the recipient

Question 10

Kin selection

Answer 10

Type of natural selection that favors the reproductive success of the relatives an organism helps, even at a cost to the organism’s own fitness

Question 11

Direct fitness

Answer 11

Measure of the reproductive success of an individual based on the number of its offspring that live to reproduce

Question 12

Indirect fitness

Answer 12

Measure of reproductive success of an altruistic individual based on the number of relatives (genetically similar individuals) that the altruist helps reproduce that would not otherwise have survived to do so

Question 13

Inclusive fitness

Answer 13

Total measure of an individual’s contribution of genes to the next generation generated by both the direct fitness and the indirect fitness

= Indirect fitness + Direct fitness

Question 14

Multilevel selection theory

Answer 14

Selection can occur at multiple levels of biological organization

Selection between genes in an individual > selection between individuals within a group > selection between groups within a population

Question 15

Haplodiploidy

Answer 15

Sex-determination system in which males develop from unfertilized eggs and are haploid, and females develop from fertilized eggs and are diploid

Question 16

Haplodiploidy hypothesis

Answer 16

Relatively higher relatedness of full sisters in haplodiploid populations promotes altruism among siblings and, consequently, the evolution of eusociality (increase in indirect fitness)

All males have same genes, increasing relatedness between the diploid daughter cells (on average, two sisters share 75% of genes)

Question 17

Monogamy hypothesis

Answer 17

Lifetime monogamy ensures that siblings are highly related, making obligately sterile workers (individuals completely incapable of reproducing) and ultimately eusociality more likely to evolve

• Monogamy is required for emergency but not for maintenance of eusocial groups
• Monogamy appears to have been essential for evolution of sterile workers in Hymenoptera

Question 18

Microsatellite

Answer 18

Tool to measure genetic relatedness

Section of DNA that contains repeated sequences of DNA, usually 1–6 base pairs long, that are repeated multiple times in a row (the combination of letters and the patterns in which they repeat can be unique between individuals)

Question 19

Single nucleotide polymorphism (SNP)

Answer 19

Tool to measure genetic relatedness

Variation in a DNA sequence that occurs when a single nucleotide base is different from the reference sequence (SNPs are simpler to score than microsatellites and cheaper and easier to develop)