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Evolution Unit 2 Exam

Terms in this set (62)

What would be the evolutionary advantage of being the individual meerkat that sounds the alarm?
D. You protect the entire group
What would be the evolutionary DISADVANTAGE of being the individual meerkat that stands guard and sounds the alarm?
B. You become the target of predators
Imagine that there is a gene that makes an individual stand guard and sound the alarm.
A. Explain how this gene would become more common in the population even if the individual that sounds the alarm dies before reproducing.
through their genetically related cousins or relatives
The gene to "SOUND THE ALARM" would pass on through:
Genetically related individuals who carry the gene
The gene to "BE SELFISH and NOT SOUND THE ALARM" would:
A & B;

A. Become more common in the population but the population would eventually die extinguishing the gene

B. Be Eliminated from the population because the individual carrying the gene would be kicked out of the population by the other ones
5. Imagine that there is a gene that makes an individual stand guard and sound the alarm.

C. Would this same strategy of standing guard and sounding alarms evolve if these animals were in groups of GENETICALLY UNRELATED individuals? WHY?
By learned behavior; an agreement between individual, those that don't follow rules will be kicked out
Would the Altruistic gene for soundng the alarm evolve in genetically unrelated groups?
B. No
Under which evolutionary pressures (ecological) would social behaviors be more likely to evolve?
A. If one cannot survive without being in a group for the environment is very harsh
Types of behaviors
1. Innate
2. Learned
Innate Behavior
born with the behavior
Innate Behavior Examples:
flight or fight behavior and reproduction
Learned Behavior
developed through social experiences
Learned Behavior Examples
speaking, reading , and walking
See Slide 14
On powerpoint
Main Types of social interactions
affect the fitness of individuals involved
Altruism
a close relative could be benefitted even if the individual's fitness decreased
Kin Selection
the idea that behaviors that help a genetic relative are favored by natural selection
Inclusive Fitness
a genetic based model formulated by William Hamilton (1964) that showed that an alllele that favors altruism could spread under certain conditions.
Formula
Inclusive= Direct+Indirect
Coefficient of relationship - r
probability that the homologous alleles in 2 different individuals (actor and recipient) are identical by descent.
Hamilton's Rule
an allele for altruistic behavior will spread if:
B r - C > 0 ,
B r - C > 0 ,
B = benefit to recipient, (units of surviving offspring);

C = cost to the actor, (units of surviving offspring);

r = coefficient of relationship between actor and recipient;
Direct Fitness
personal reproduction
Indirect Fitness
additional reproduction by relatives made possible by an individual's behavior (usually above and beyond normal when helped)
Coefficient of Relationship for Full Siblings
= 1/2
Coefficient of Relationship for Half Siblings
= 1/4
Coefficient of Relationship for Cousins
= 1/8
Calculate the coefficients of relationships for one brother and four cousins.
D. 1/2 and 1/2
Alarm calling in Belding's Ground squirrels
females are closely related but males(due to dispersement) are not.
In belding squirrels the individuals that do most of the calling are:
A. Females if their is a mother or a sibling in the group
The inbreeding coefficient in belding squirrel mothers and their offspring is _____and that between siblings is _____.
C. ½, ½
White-Fronted Bee-Eaters
young that are old enough to breed on their own will remain with a flock and help their parents rear their brothers, sisters of half-siblings. Helpers assist in nest builing, nest defense, or food delivery to incubating parents and the nestlings.
White-Fronted Bee-Eaters
Helping is more common when breeding opportunities are restricted because the habitat is saturated with nesting pairs or because there are not enough nesting sites available, or these are difficult to obtain. If young adults cannot obtain direct fitness they will settle for indirect fitness.
Kin recognition
important to assure that you are feeding the right nestlings, those that are genetically related to you.
Social insects are
an extreme form of reproductive altruism because most individuals in a colony wil NEVER reproduce.
Eusociality (true sociality) is used to describe social systems with the characteristics:
- overlap in generation between parents and their offspring

- cooperative brood care

- specialized castes of nonreproductive individuals
Hymenoptera (bees, wasps and ants)
pinnacle of eusociality
Hymenoptera
Haplodiploidy form of sex determination
Relationship to their SISTERS
r = ( 1 x ½ ) + (½ x ½ )
= ¾
(if they have the same father)
Relationship to their BROTHERS
r =( ½ x ½)
= ¼
Relationship to their OFFSPRING
r = ½
The coefficient of relatedness between a diploid queen been and its diploid daughters is ___.
B. ½,
The coefficient of relatedness between a diploid queen been and its haploid son is_____.
B. ½,
If the queen bee is equally related to both daughters and sons, she should lay a(n)________number of_________ eggs.
C. Equal, male and female
The coefficient of relatedness between a diploid worker bee and its haploid brother is_____.
C. ¼
The coefficient of relatedness between a diploid worker bee and its diploid sister worker bee is_____.
D. ¾
Female diploid worker bees are________ related to _________than to_________.
C. More closely, sister workers, brothers
In paper wasps females are not sterile and can reproduce on their own. Females have these options:
- initiate their own nest

- join another nest as helper

- sit and wait
Initiate Their Own Nest Cost
High Mortality
Initiate Their Own Nest Benefit
Have your own offspring
Join Another Nest As A Helper Cost
Delay production
Join Another Nest As A Helper Benefit
Indirect fitness, replace dominant female after her death
Sit And Wait Cost
Delay production
Sit And Wait Benefit
Adopt orphan nests or other nests by combat
A human mother is ________related to ALL her offspring, and should protect all of them.
A. ½
A human mother will ________the feeding by one child so that she can __________a second offspring.
A. Discourage, feed
Weaning Conflict
-Mothers begin to ignore or push young away near end of weaning period
-Offspring will scream or attack mother
-Fitness interests are not symmetrical
Parent harassment
In birds some fathers can coerce (force) their young adult sons to help them raise their siblings by harassing them while they are raising their own offspring.
Siblings of some species can fight or kill each other to retain food resources for themselves.
A. True
Siblicide
In some species of birds and mammals, some young siblings will kill each other while parents watch passively.
. Siblicide - Hypothesis: Is this behavior (higher aggressiveness between siblings) learned or innate?
Chicks were more likely to die if they had a masked booby as a nestmate and a masked booby as a parent.
Consider a harsh environment where food is scarce and hard to obtain, predators kill many individuals and survival by oneself is unlikely.
Could social behaviors of group living evolve on unrelated organisms through Natural Selection?
A.yes
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