Process of social evolution - part 1

Question 1

what is the fundamental question regarding the evolution of eusociality

Answer 1

why be part of a society instead of going at it alone?

Question 2

what is the problem regarding the evolution of eusociality

Answer 2

how do the genes for the social action remain in the population?

Question 3

All social actions can be categorized based on the ____________________ (individual initiating the action) ___________________ (individual engaged by the actor).

Answer 3

• effects on the actor
• and the recipient

Question 4

define selfishness

Answer 4

Social action in which the actor gains offspring and the recipient loses.

Question 5

define cooperation

Answer 5

Social action in which actor and recipient both gain offspring

Question 6

define spite

Answer 6

Social action in which actor and recipient both lose offspring.

Question 7

define alturism

Answer 7

Social action in which the actor loses offspring, while the recipient gains

Question 8

define natural selection

Answer 8

Change in the frequency of genes in a population through differential survival and reproduction of individuals because of their phenotypes

Question 9

define inclusive fitness theory

Answer 9

“inclusive” of both the direct and indirect ways in which a gene can persist in a population

Question 10

The key insight of William Hamilton (1964) was that when _______________ with the recipient of an altruistic act, it provides an _________________________________.

Answer 10

• genes are shared
• indirect path for those genes to persist

Question 11

define relatedness

Answer 11

The probability that a copy of a gene at a given locus in one individual is present in another individual

Question 12

Focus is on whether relatedness (r) is ____________________________ than it is ________________________________.

Answer 12

• higher among two individuals
• generally within the population

Question 13

__________ is the most common reason in nature for organisms to have ____________________ relatedness

Answer 13

• Kinship
• above-average

Question 14

define clones

Answer 14

Asexual reproduction of full genetic copies, resulting in relatedness of 1 between individuals (r = 1)

Question 15

Parent-offspring relatedness

Answer 15

in diploid, sexually reproducing species a parent shares half of its genes with an offspring, with no additional shared copies from a randomly selected mate. (r = 0.5)

Question 16

Siblings relatedness

Answer 16

In diploid, sexually reproducing species, siblings share 50% of the genes from the maternal half of the genome and 50% of the genes from the paternal half, on average (r = 0.5)

Question 17

relatedness of female siblings in haplodiploid species

Answer 17

Female siblings share 50% of the maternal half of their genes and 100% of the genes from the paternal half, on average (r = 0.75)

Question 18

relatedness of female-male siblings in haplodiploid species

Answer 18

Male siblings have only half of maternal genome and none of paternal genome (haploid), so sisters share only half of the 50% of the maternal genome with brothers, on average. (r = 0.25)

Question 19

haplodiploid societies - relatedness of a queen and her workers, daughter queen, and son

Answer 19

all r = 0.5

Question 20

haplodiploid societies - relatedness of worker and daughter queen

Answer 20

r = 0.75

Question 21

haplodiploid societies - relatedness of worker and worker’s son

Answer 21

r = 0.5

Question 22

haplodiploid societies - relatedness of worker and queen’s son

Answer 22

r = 0.25

Question 23

Relatedness asymmetries and potential problems?

Answer 23

Workers would rather help their son and the daughter queen and not their mother’s son bc they are more related to their own son and the daughter queen

Question 24

Hamilton’s rule as a simple algebraic expression

Answer 24

m + rn > 0

Question 25

Hamilton’s rule - explain the m variable

Answer 25

• change in the actors offspring number (positive or negative, depending on the action).
• “Direct” component of fitness

Question 26

Hamilton’s rule - explain the n variable

Answer 26

change in the recipients offspring number (positive or negative).

Question 27

Hamilton’s rule - explain the r variable and rn

Answer 27

• relatedness of actor and recipient
• rn is the “indirect” component of fitness.

Question 28

sign of m and n variables - selfishness

Answer 28

m is always positive, n is always negative

Question 29

critical r values - selfishness

Answer 29

can evolve at any r value

Question 30

selfishness - evolution

Answer 30

evolution is very common

Question 31

sign of m and n variables - cooperation

Answer 31

m and n are always positive

Question 32

critical r values - cooperation

Answer 32

can evolve at any r value

Question 33

cooperation - evolution

Answer 33

The evolution of cooperative acts is favored in isolation, but is often disrupted by the evolution of more, powerful selfish acts.

Question 34

signs of the m and n variables - spite

Answer 34

both m and n are always negative

Question 35

critical r values - spite

Answer 35

Spite can only evolve when r < 0

Question 36

spite - evolution

Answer 36

• Evolution of spite is very rare (remains controversial)
• Most apparent cases of spite, when viewed in isolation, are typically related to larger context of direct benefits through selfishness or other beneficial acts

Question 37

signs of m and n variables - altruism

Answer 37

m always negative, n always positive

Question 38

general expression of hamilton’s rule - altruism

Answer 38

-m + rn > 0

Question 39

critical r values - altruism

Answer 39

Altruism can only evolve when r > 0

Question 40

altruism - evolution

Answer 40

Evolution of an altruistic act favored when benefit to recipient is high and relatedness is positive

Question 41

Hamilton’s rule for altruistic acts is alternatively expressed as what

Answer 41

m < rn OR c < rb

Question 42

what category of sociality requires altruism

Answer 42

• semisocial and eusocial
• bc they require altruism, they are favored by increased relatedness