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EVOLUTION > EXAM 4 FLASHCARDS > Flashcards

EXAM 4 FLASHCARDS

1
Q

How is sexual selection different from natural selection? How is it similar?

A

Similar: sexual selection is a special case of natural selection where both selection favor traits that help increase the reproductive fitness of the individual

Different: Natural selection focuses more on traits that enhance the survival of the individual while sexual selection focuses more on the ability to attract mates and increase reproductive fitness.

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2
Q

male reproductive success is usually limited by availability of few eggs what is the 1ST HYPOTHESIS on how this changes male and female reproductive strategies?

A

Hypothesis 1: Most often, Males will COMPETE for females

  1. Eggs are limited
  2. Sperm is NOT limited
  3. Males who mate with multiple females tend to have higher reproductive success because there is less limitation on the number of gametes that males produce
    • Females ONLY produce CERTAIN number of gametes
  4. Males often compete for access to female
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3
Q

male reproductive success is usually limited by availability of few eggs what is the 2ND HYPOTHESIS on how this changes male and female reproductive strategies?

A

Hypothesis 2: Male reproductive success more strongly tied to NUMBER OF MATES than female reproductive success

  1. Males having more mates = more reproductive success
  2. Females having more mates = do NOT result in more reproductive success
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4
Q

What is an example of the 2nd hypothesis discussed in lecture

A

1948 study on Drosophila
Bateman principle = relates reproductive success to number of mates
- Variability in reproductive success is greater in males than in females (more mates for males = more offspring)

  • Variability in number of mates is greater in males than in females
  • Sexual selection is often more intense in males (resulting in secondary sex characteristic, often time being more elaborate and more selective in males
  • Females use more energy in order to produce and care for offspring than males
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5
Q

male reproductive success is usually limited by availability of few eggs what is the 3RD HYPOTHESIS on how this changes male and female reproductive strategies?

A

Hypothesis 3: Females tend to be the “choosy sex”

  1. Eggs are expensive to produce
  2. Eggs require more energy to produce than sperm
  3. Females are under selection to CHOOSE GOOD MATE so resources to produce (and develop and rear, in some cases) aren’t WASTED
  4. Form of “intersexual selection”
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6
Q

T/F: Females are always the choosy sex (if false give an example)

A

FALSE

Sygnathidae: seahorses, pipefishes, sea dragons
1. Males may incubate developing embryos one eggs are fertilized
2. Males are the choosy sex in this case because they put in the energy into rearing the offspring (don’t want to waste their time)

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7
Q

what is the difference between intersexual selection and intrasexual selection

A
  1. Intersexual selection occurs when individuals of one sex (usually females) choose mates of opposite sex based on certain desirable traits.
    • Traits that are attractive to the opposite sex are selected.
    • EX: Bright plumage in birds, elaborate courtship displays, and complex mating calls.
  2. Intrasexual selection when members of the same sex (usually males) compete for mates
    • Traits that enhance an individual’s ability to compete with others of the same sex are selected.
    • EX: Large body size, antlers in deer, and aggressive behaviors.
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8
Q

what is REASON 1 for the explanations for female mate choice

A

Reason 1: Direct Benefits

  1. Females choose mates that provide something to increase their chances of mating success
    • Protection from predators
    • Increased parental care
    • Access to food/nuptial gifts
    • Access to better territory/resources
  2. Increased resources to females
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9
Q

what is are the 2 examples of direct benefits

A
  1. Male bush katydid provides nuptial gift to female (provides protein and lipid rich material for females to eat when delivering sperm to her)
  2. Male lions help rear young and protect females
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10
Q

what is REASON 2 for the explanations for female mate choice

A

Reason 2: Good genes

  1. Differences among males provide information to female about the genetic qualities that can be inherited by offspring
  2. Males display “honest advertisement” of good genes
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11
Q

what is an example of good genes hypothesis

A

EXAMPLE: PEACOCK EYE SPOTS

  1. Females prefer males with elaborate tails and large eye spots
  2. More elaborate tails and eye spots get larger = increased weight in male offspring chicks and higher survival rates in offspring
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12
Q

what is the handicap principle

A

traits that REDUCE SURVIVAL CHANCES (handicap/costly signals) are preferred by females because they indicate heritable viability (tradeoff)
- Trait is making it so hard for that male to survive that the fact he’s even here indicates he must be high quality
- Signals underlying health/strength viability
- “good genes” may be indicated by a costly trait

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13
Q

what is the first example of the handicap principle

A

EXAMPLES: PEACOCK FEATHER

  1. Longer and more elaborate tails cost more to make and maintain = less fitness cost for higher quality males (high quality males survive much better)
  2. Low quality male = high fitness cost as tail length increases (could potentially die)
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14
Q

what is the second example of the handicap principle

A

EXAMPLE 2: SWORDTAIL FISH
1. Females prefer males with longer sword

  1. Fitness cost for low quality males because they are going to struggle to survive with long sword making it more difficult to swim
  2. Males that do have long sword indicates “i’m very healthy, very viable, and i will provide those strong genes to your offspring” = high quality
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15
Q

“good genes” may be indicated by traits that signal ___________. give an example of this

A

Resistance to Disease
EXAMPLE: RED DISPLAY IN DIFF BIRDS (ZEBRA FINCHES)
reddish/orange coloration in the beaks of zebra finches conferred by carotenoid pigments which are found in the diet of the birds. Red coloration means that they were able to procure these foods. Birds with bright red displays must have a healthy immune system because they are able to “waste their red pigments on frivolous displays, and do NOT have to use it for the immune system”.

Carotenoid: plant pigments that can NOT be synthesized de novo in birds/animals
NOT just reddish/orange but helpful to the immune system (important for good immune function).

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16
Q

what is REASON 3 for the explanations for female mate choice

A

Reason 3: Fisherian Sexual Selection OR “Arbitrary Choice”

  1. Females prefer arbitrary trait that provides NO information about male’s quality
  2. Sexy Sons Hypothesis (1979) - females benefit from mating with males that have trait because they are more likely to produce sons with desired trait who will also be preferred and be more fit and then pass trait on and on
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17
Q

what is the Fisherian Runaway Sexual Selection

A
  1. Can occur when genetic correlation between preference for trait and trait is high
  2. Over generation, preferred trait becomes exaggerated (runaway)
    • EX: sword in fish get longer and longer; peacock tails get bigger and brighter (exaggeration over time)
  3. Natural selection will curve when fitness cost outweighs benefit
    • EX: Antlers on a deer can only get so large
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18
Q

what is sexual conflict

A
  1. “Sexually antagonistic coevolution”
    • When males increase their reproductive success via an adaptation that is detrimental to females, there is selection for a counter-adaptation in females to regain lost fitness
  2. Traits can evolve in one sex that are detrimental to the other sex
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19
Q

what is the first example for sexual conflict

A

EXAMPLE: GERRIDAE (WATER STRIDERS)
1. Female: possess “genital shield” and spines around vulvar opening
- In order to mate with her male needs to get her to open shield

  1. Male: grasps female with spiky legs from above when attempting to mate and drums water which brings in predators. As predators come in, females are at high risk of being killed. Male will NOT let go until she is dead or allows him access to mate and copulate with her
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20
Q

what is the 2nd example of sexual conflict

A

EXAMPLE: ELASMOBRANCHS
1. Mating involves male biting and grasping pectoral fins of female (she gets injured)

  1. Females have relatively thicker skin than males
  2. Males have developed larger teeth than females
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21
Q

what is the 3rd example of sexual conflict

A

EXAMPLE: Hermaphroditic Land Snails (individuals have the ability to produce both male and female gametes)
1. Reciprocal exchange of sperm during mating; each individual wants to fertilize as many of recipient’s eggs as possible
2. In copulatory canal the sperm may be digested
3. Love dart: sharp calcium carbonate structure coated in mucus with hormones/chemicals
- Increases uptake of sperm
- Reduced willingness to mate
- Those who receive love dart potentially have reduced lifespans after they’ve received it

EXAMPLE: Hummingbird and Hyena Hermaphroditic
1. Female hummingbirds evolved to look like males (apparently to evade aggression)
2. Hyenas: females have pseudo penis to look like male, but often times baby hyenas die during childbirth because of that narrow canal

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22
Q

what is sexual selection

A

selection that favors traits that increase reproductive success (as opposed to survival)

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23
Q

what are 3 examples of sexual selection discussed in lecture

A
  1. Females favor male peacocks with large tails and many large eye spots
  2. Peacock spider dances to attract mates
  3. Elephant seal often have very large and dominant so they can fight off males and over time develop large proboscis on their face that gets larger and larger over time
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24
Q

what are 3 key points for sexual selection

A
  1. Often favors DIFFERENT traits in males and females (what is attractive in a male may be different than that in female)
    • Different size / different color / etc.
  2. Is a type of intraspecific (within the species) competition
  3. Is often associated with secondary sexual characteristics (develop once animal reaches maturity and signals they are ready for reproduction)
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25
Q

what is anisogamy

A

root of sexual selection; introduces opportunity for selection to operate differently in sexes

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26
Q

what are 4 key points of anisogamy

A
  1. Male and female gametes have different morphology
  2. Females produce LARGER/FEWER gametes than male
  3. Males produce SMALLER/MANY gametes than female
  4. Male reproductive success is limited by relatively few eggs that are available to fertilize (only one sperm is successful to fertilize egg = extreme competition)
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27
Q

what is the Bateman gradient

A

a statistical measurement of the relationship between reproductive success (# of offspring) and mating success (# of mates)

  • In females there is a limit to how many offspring they can have
  • Males there is no limit, more mates = more offspring
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28
Q

what is intersexual selection

A

one sex chooses which members of the opposite sex to mate with

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29
Q

what is intrasexual selection and 2 examples

A

often competition between members of the same sex for the opportunity to mate with members of the opposite sex

EXAMPLES
1. Male kangaroos fight intensely for female mates
2. Elephant seal dominant males will fight for females until bloody

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30
Q

what is an alternative tactic for intrasexual selection

A

Female Mimics/Sneaker Males

  1. Morphology that closely resembles females and causes the dominant males to NOT detect those males. Sneakers are able to sneak in and mate with females without big dominant males recognizing them
  2. Can end up selecting for different phenotypes of males that can have strong contrast
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31
Q

what is the good genes hypothesis

A

differences among males provide information to female about the genetic qualities that can be inherited by offspring
1. Males display “honest advertisement” of good genes
2. “Good genes” may be indicated by a costly trait
3. “Good genes” may be indicated by traits that signal resistance to disease

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32
Q

what is the Fisherian sexual selection

A

“Arbitrary Choice” - females prefer arbitrary trait that provide NO information about male’s quality

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33
Q

what is the sexy sons hypothesis

A

females benefit from mating with males that have trait because they are more likely to produce sons with desired trait (son will also be preferred and be more fit, and then pass trait on and on)

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34
Q

what is sexually antagonistic coevolution

A

often occurs when males increase their reproductive success through an adaptation that is simultaneously detrimental to females, creating selection for a counter-adaptation in females to regain their lost fitness.

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35
Q

what were the findings for Fig 1 in the reading (shows bill color rank and female preferance)

A
  1. carotenoid-supplemented males had a significant increase in bill color rank over the first 4 weeks
  2. females preferred carotenoid-supplemented males
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36
Q

what were the findings for Fig 2 for the reading (shows total carotenoids and PHA response)

A
  1. carotenoid-supplemented males had significantly higher plasma carotenoid concentrations compared to controls (higher levels of circulating carotenoids).
  2. carotenoid-supplemented males had significantly larger PHA responses, indicating better immune function
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37
Q

What is the cost of having a bright red beak for zebra finches?

A
  1. carotenoids may be toxic so bright beak display may come with a health risk
  2. display may come at a physiological cost as the carotenoids are diverted for ornamental purposes.
  3. Carotenoid availability in the environment may be limited
  4. Carotenoid displays may cause the male to be stand out more (conspicuous) to predators
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38
Q

What can be determined from Figure 2? in the reading
A. Males in the control group had fewer circulating carotenoids than the experimental group.
B. Males in the experimental group had stronger immune responses than the control group.
C. Males in the experimental group will pass along stronger immune systems to their progeny.
D. A and B
E. All of the above

A

D. A and B

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39
Q

Which of the following is not true of carotenoids?

A. Carotenoids can be synthesized de novo (anew) by animals, plants, bacteria, and most other organisms on Earth.

B. Carotenoids can be used by animals as Vitamin A precursors.

C. Carotenoids are associated with enhanced immune function in some animals.

D. Carotenoids are pigments that convey red, orange, and yellow coloration.

A

A. Carotenoids can be synthesized de novo (anew) by animals, plants, bacteria, and most other organisms on Earth.

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40
Q

What can be determined from Figure 1? from the reading
A. Males who were fed carotenoid-enriched diets had significantly brighter beaks than the control group after 8 weeks.
B. Females preferred males from the carotenoid-enriched group over the control group in most cases
C. Males in the control group were less likely to choose to perch next to females.
D. A. and B
E. All of the above

A

D. A. and B

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41
Q

The hypothesis which states that honest sexual signals which come at a cost to the individual will be attractive to the opposite sex because they reliably indicate quality of mate is known as the? __________

A

handicap principle

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42
Q

Which hypothesis was investigated in the zebra finch study?

A. Red beaks signal that offspring will be healthy.

B. Red beaks signal that the male is able to withstand and metabolize toxic levels of carotenoids in diet.

C. Red beaks signal that the male is able to effectively attain rare carotenoids from environment.

D. Red beaks signal that the male has superior underlying immune function.

A

D. Red beaks signal that the male has superior underlying immune function.

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43
Q

T/F: In studies of house finches, guppies, pupfish, and sticklebacks females have been found to prefer males with brighter carotenoid-based features.

A

TRUE

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44
Q

What variable was measured to determine male zebra finch attractiveness to females in the zebra finch study?
A. the number of successful matings of males in experimental vs. control groups

B. the number of offspring from males in experimental vs. control groups

C. the PHA response in males in experimental vs. control groups

D. the time that female birds spent perched next to the males in the experimental vs. control groups

A

D. the time that female birds spent perched next to the males in the experimental vs. control groups

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45
Q

Which of the following is a way that carotenoid displays (e.g., red feathers) could be “costly” to males? Check all that apply.

A. Carotenoids may be toxic to organisms and so a display may come with a health risk.

B. Carotenoids may have many physiological benefits, and a display may come at a physiological cost as the carotenoids are diverted for ornamental purposes.

C. Carotenoids reduce attractiveness to the opposite sex, and so a display may come at a fitness cost.

D. Carotenoid availability in the environment may be limited, requiring time and defense of food sources by males who utilize these for displays.

E. Carotenoid displays may cause the male to be more conspicuous to predators.

A

A. Carotenoids may be toxic to organisms and so a display may come with a health risk.

B. Carotenoids may have many physiological benefits, and a display may come at a physiological cost as the carotenoids are diverted for ornamental purposes.

D. Carotenoid availability in the environment may be limited, requiring time and defense of food sources by males who utilize these for displays.

E. Carotenoid displays may cause the male to be more conspicuous to predators.

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46
Q

Why is male reproductive success limited by the number of eggs?

A. Eggs are much larger and scarcer than sperm, limiting the number of opportunities for reproductive success for males

B. Sperm are short lived compared to eggs, and it is more expensive for males to reproduce because males produce a much greater number of gametes than there are eggs available to fertilize

C. Although eggs are not metabolically expensive to produce, most female organisms will only produce a small number of eggs during their life span

D. Eggs are smaller than sperm and short, lived, limiting the number of opportunities for reproductive success for males

A

A. Eggs are much larger and scarcer than sperm, limiting the number of opportunities for reproductive success for males

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47
Q

The Bateman principle – which suggests that males will have greater reproductive success if they have more mates, while the same is not true for females – relies on what underlying assumption(s)? CHECK ALL THAT APPLY
A. Males are limited in the number of gametes they produce

B. Females are limited in the number of gametes they produce

C. Females utilize more energy in order to produce, and subsequently care for, offspring than males

A

B. Females are limited in the number of gametes they produce

C. Females utilize more energy in order to produce, and subsequently care for, offspring than males

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48
Q

Direct benefits may include

A. Protection from predators
B. Increased parental care
C. Access to food / nuptial gifts
D. Access to better territory / resources
E. All of the above

A

E. All of the above

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49
Q

Based on the data in this slide, we see that peacock eyespot size is positively correlated with (CHECK ALL THAT APPLY)
PEACOCK FEATHER AND EYE SPOT STUDY IN MALE CHICKS

A. Male offspring weight
B. Chick survival rates
C. Number of mates
D. Health of male

A

A. Male offspring weight
B. Chick survival rates

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50
Q

According to the handicap principle, why are certain traits that reduce survival chances preferred by females?

A. They signify that the offspring will inherit a strong immune system

B. They suggest that the male has greater aggression

C. They are associated with superior hunting skills

D. They indicate the male’s ability to survive despite the handicaps

A

D. They indicate the male’s ability to survive despite the handicaps

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51
Q

Carotenoids (CHECK ALL THAT APPLY)

A. Can be used to confer red coloration to beaks and feather

B. Are used for immune function

C. Confer a fitness cost to males

D. Can be synthesized (produced) by animals

A

A. Can be used to confer red coloration to beaks and feather

B. Are used for immune function

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52
Q

According to the ‘Arbitrary Choice’ model, why do female organisms benefit from selecting mates with certain traits?

A. Because the traits provide a direct benefit to the survival of the females

B. Because they produce offspring that are more likely to survive in various environments

C. Because their offspring are more likely to inherit and exhibit these traits, making them attractive to mates

D. Because the traits may be linked to genetic benefits unrelated to the trait itself

A

C. Because their offspring are more likely to inherit and exhibit these traits, making them attractive to mates

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53
Q

Males of the hanging fly species Hylobittacus apicalis bring the female large prey during courtship. Which model of female mate choice does this describe?

A. Arbitrary choice
B. Sexy sons
C. Direct benefits
D. Good genes
E. Handicap principle

A

C. Direct benefits

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54
Q

Morphological or behavioral characteristics used to attract a mate can also have the consequence of drawing a predator’s attention to the individual who possesses that trait, yet these so-called expensive traits persist in many species. This describes

A. Direct benefits
B. The handicap principle
C. Sensory bias
D. Runaway sexual selection

A

B. The handicap principle

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55
Q

When a trait experiences the effects of
Fisherian runaway selection, what is likely to happen when the fitness cost of the trait outweighs its benefit?

A. The genetic preference for the trait will become more widespread

B. Natural selection will act to prevent further exaggeration of the trait

C. The trait will be removed from the population completely

D. The trait will continue to become more exaggerated over generation

A

B. Natural selection will act to prevent further exaggeration of the trait

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56
Q

When populations include two or male phenotypes that are all successful at passing on genes to the next generation, the population has likely experienced

A. Disruptive selection
B. Stabilizing selection
C. Directional selection
D. Convergent selection

A

A. Disruptive selection

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57
Q

The male water strider’s behavior of drumming the water is detrimental to the female because

A. It attracts predators
B. It attracts other males
C. It makes it harder for the female to stay on top of the water
D. All of the above

A

A. It attracts predators

58
Q

what are the three models proposed to explain reason traits are favored

A
  1. direct benefits
  2. good genes and costly signals
  3. fisherian sexual selection

(caveat = warning): much speculation…so take explanation with gran of salt (cum grano salis)

59
Q

what is the sensory bias model

A

Model for the evolution of elaborate traits by sexual selection, in which a preexisting bias in the perceptual system of one sex favors members of the other sex who display a particular trait.

  1. proposes that female mating preferences evolve as a by-product of natural selection on their sensory systems.
  2. Females may prefer certain male traits because they are pre-existing biases in their sensory system, rather than because those traits directly indicate male quality.
60
Q

what are the 4 different levels of sociality

A
  1. subsocial
  2. parasocial
  3. quasisocial
  4. eusocial
61
Q

what is subsocial level of sociality

A

Subsocial: aggregations; or parental care of young for some length of time
- EX: monarch butterflies

62
Q

what is parasocial level of sociality

A

communal living, but everyone takes care of their own need/young
- EX: weaver bird nests

63
Q

what is quasisocial level of sociality

A

community works together to care for young
EX: meerkats

64
Q

what is eusocial level of sociality

A

“true” social
- MOST COMPLEX
- Primarily insects (bees, termites, and ants) = MAJOR

65
Q

What is eusociality?

A

highest level of sociality and extreme altruism (individual sacrifices their own fitness for the benefit of the group)

66
Q

What three criteria are used to define a eusocial group?

A
  1. Division of Labor with a caste system
    • Sterile worker class(es) assist reproductive class
    • Only a FRACTION of a population reproduces
  2. Cooperation among group members in rearing offspring
  3. Overlap of generation capable of contributing to colony function and living in single group
67
Q

What organisms are eusocial?

A

primarily insects
- bees, termites, wasps, and ants
- ALL ANTS ARE EUSOCIAL (many bee and wasp species that are solitary and do not live in groups)

68
Q

what is an example of advanced eusociality

A

HONEYBEES
Queen with enlarged abdomen (does all the reproducing)
- Maintains control via pheromones
Caste (workers who do all the duties of the hive; sterile NOT reproducing at all) are determined by cell size, and mainly, quality of diet (trophogenic determination)
- “Royal jelly”

69
Q

what is cooperation and its relation to social behavior

A

Two or more individuals interact in a way that leads to mutual net benefits from joint actions (minimizing conflict)

70
Q

what is altruism and its relation to social behavior

A

Behavior that benefits others at cost of fitness of the altruist
- There is at least an indirect fitness benefit to the individual
EX: honey pot ant

71
Q

Describe the three evolutionary paths to eusociality. Explain how natural selection would favor social behavior in each of these paths.

A
  1. Kinship: individuals who are related behave altruistically to each other
    - Natural selection favors traits that pass on genes; related individuals have similar genes
  2. Reciprocity: individuals benefit by exchanging acts of altruism
    • Natural selection favors reciprocal exchange wherein costs are paid back
  3. Group Selection: natural selection acts at the level of the group
    • Natural selection favors (altruistic) traits in the individual that are advantageous to the group
    • HIGHLY DEBATED (PHILOSOPHICAL IDEA)
72
Q

How has kin selection been used to explain the evolution of eusociality in Hymenoptera?

A

Haplodiploidy: sex determination system in Hymenoptera (bees, wasps, and ants)

Males are HAPLOID (all of their genes go to every single offspring = unfertilized egg); females are DIPLOID (offspring share ½ of mom’s genes = fertilized egg)

Assuming one mating by queen
- Female Hymenoptera workers, on average, share 75% of alleles (vs. genetic relatedness in human siblings = 50%)
- Workers (females) within a hive are even more closely related to each other than siblings

73
Q

Explain how “free riders” (cheaters) could lead to selection against social behaviors.

A

If individuals continually bear the costs of helping while cheaters exploit the system and don’t give anything in return, trust within the group can break down, reducing the willingness to cooperate.

74
Q

what is sociality

A

the tendency of individuals of the same species to live in groups and display reciprocal, cooperative behavior

75
Q

what is kin selection and key points

A

natural selection that favors behaviors by individual that increase survival of kin (and may decrease individual’s survival); (propsed by RA Fisher and JBS Haldane in 1930s)

Fitness measured in terms of inclusive fitness
- Not only your own offspring, but also those you help to rear that are related to you

76
Q

what does fitness equal in kin selection

A

genetic contribution of an individual to the next generation’s gene pool relative to the average for the population

- Classically measured as number of offspring
 - Can also include offspring of closely related individuals = inclusive fitness (direct + indirect fitness)
 - “I would gladly give up my life for two brothers or eight cousins”
77
Q

what is reciprocity/reciprocal altruism

A

altruism between individuals (even unrelated ones) occurs when there will be repayment/promise of repayment
- Potential for free riders (cheaters who take and don’t give back)

78
Q

what is an example of reciprocal altruism

A

Mobbing behavior (work together to chase predator): antipredator tactic; common in birds

Costly to mobbers (using energy and putting themselves at risk by engaging with predators), but once a predator is driven away everyone benefits (even those not involved in mobbing)

79
Q

what was an experiment conducted to examine reciprocal altruism? what were the findings?

A

PIED FLYCATCHERS EXPERIMENT - will birds be more likely to assist others who have helped in the past?

Phase 1: stuffed owl in front of nest box 1; nest box 2 is locked (not allowed to help with mobbing)
- Birds from 1 and 3 mob stuffed owl

Phase 2: stuffed owl in front of nest box 2 and 3; all cages unlocked
- Birds from nest box 1 joined mobbing when owl was in front of nest box 3
- Birds from nest box 1 DID NOT join when owl at nest box 2

Evidence for reciprocal altruism because when the individuals were NOT helping, the birds remembered it and did NOT help

80
Q

what is group selection

A

natural selection favors traits that promote survival and reproduction of groups
- Natural selection operating at GROUP level as opposed to individual level

Darwin 1st suggested; observed that social adaptations are not always (perhaps often?) beneficial to the individual

This hypothesis has been LARGELY DISPUTED as simply NATURAL SELECTION or better-explained KIN SELECTION
- As we look at the behaviors more carefully and perform empirical research to gauge whether or not group selection is occurring, it is often discovered that either kin selection is operating or there’s actually individual fitness benefits to the behavior that just appears to be altruistic

81
Q

what is hamilton’s rule

A

W.D. Hamilton suggested: level of sacrifice an individual makes for a relative is directly proportional to the relatedness

Altruism is favored by natural selection when (benefits x relatedness is greater than the cost = altruism favored)
- rB > C

82
Q

what does each letter in rB > C stand for in Hamilton’s rule

A

r = relatedness of altruist to beneficiary (proportion of shared genes) -> full siblings share 50% of genes

B = benefit of altruist’s action to beneficiary (in number of offspring equivalents) -> measure of benefits

C = cost to altruist (in number of offspring equivalents)

83
Q

what is a sentinel

A

a soldier or guard whose job is to stand and keep watch

84
Q

In the research study for meerkats what did Figure 3 (meerkats fed with 25g of hard-boiled egg) show

A
  1. meerkats fed with 25 g of hard-boiled egg spent more time on raised guard
  2. Fed individuals were more likely to go on guard before starting to forage in the morning (engaged in sentinel behavior more)
85
Q

The research by Clutton-Brock et al. (1999) showed that sentinel behavior is costly to the sentinel because

A. the sentinel experiences reduced foraging time.
B. the sentinel experiences increased risk of predation.
C. the sentinels produce fewer offspring than those that do not engage in sentinel behavior.
D. The research showed all of the above.

A

A. the sentinel experiences reduced foraging time.

86
Q

Which of the following is correct regarding the data displayed in the following figure for meerkat study? FIGURE SHOWS MEERKATS WHO WERE FED VS. THOSE WHO WEREN’T CHECK ALL THAT APPLY

A. Fed meerkats (experimental group) gained more weight during the 30-day experimental period than those who had not been fed (control group).

B. Fed meerkats (experimental group) engaged in sentinel behavior on more occasions during the 30-day experimental period than those who had not been fed (control group).

C. Fed meerkats (experimental group) engaged in sentinel behavior for a longer total amount of time during the 30-day experimental period than those who had not been fed (control group).

D. Female meerkats who had been fed engaged in sentinel behavior more often than male meerkats who had been fed.

E. Fed meerkats (experimental group) foraged more during the 30-day experimental period than those who had not been fed (control group).

A

B. Fed meerkats (experimental group) engaged in sentinel behavior on more occasions during the 30-day experimental period than those who had not been fed (control group).

C. Fed meerkats (experimental group) engaged in sentinel behavior for a longer total amount of time during the 30-day experimental period than those who had not been fed (control group).

87
Q

The researchers concluded that their data supported which of the following underlying evolutionary explanations for sentinel behavior in meerkats?

A. individual benefits
B. reciprocal altruism / reciprocity
C. kin selection
D. group selection

A

A. individual benefits

88
Q

Which of the following is a likely benefit of engaging in raised guarding to the individual on sentinel duty?

A. Individuals who are on sentinel duty do not engage in the job of babysitting younger meerkats, which allows for more time foraging.

B. Individuals who are on sentinel duty locate more food than those that are not (and so are healthier).

C. Individuals who are on sentinel duty are, on average, closer to the safety of the burrow than those that are foraging (and so avoid predation more easily).

D. Individuals who are on sentinel duty are more likely to find a mate than those who are not.

A

C. Individuals who are on sentinel duty are, on average, closer to the safety of the burrow than those that are foraging (and so avoid predation more easily).

89
Q

Match each hypothesis for the evolution of sentinel behavior to its theoretical basis.
Reciprocity, individual selection, group selection, kin selection

A. Sentinel behavior is costly to the sentinel due to reduced foraging time, but the sentinel will later benefit as other individuals rotate into the sentinel role

B. Sentinel behavior reduces the fitness of the individual sentinel because it reduces foraging time, but has been selected for because it increases the indirect fitness of the sentinel by helping relatives avoid predation

C. Sentinel behavior is selected for because it benefits the sentinel more than any other individuals; sentinels are the first to detect and avoid predators and this benefit outweighs the cost of reduced foraging time

D. Sentinel behavior is costly to the sentinel, but has been selected for because the whole group benefits due to predator avoidance

A

A = RECIPROCITY. Sentinel behavior is costly to the sentinel due to reduced foraging time, but the sentinel will later benefit as other individuals rotate into the sentinel role

B = KIN SELECTION. Sentinel behavior reduces the fitness of the individual sentinel because it reduces foraging time, but has been selected for because it increases the indirect fitness of the sentinel by helping relatives avoid predation

C = INDIVIDUAL BENEFITS. Sentinel behavior is selected for because it benefits the sentinel more than any other individuals; sentinels are the first to detect and avoid predators and this benefit outweighs the cost of reduced foraging time

D = GROUP SELECTION. Sentinel behavior is costly to the sentinel, but has been selected for because the whole group benefits due to predator avoidance

90
Q

In meerkats, another behavior that they exhibit is helping care for young. Adult helpers remain in the colony for a few years, feeding and caring for the young of the dominant female before having any of their own offspring. Which of the following hypotheses use the construct group selection to explain this helping behavior?

A. Caring for the young of the dominant female ensures that more young survive, improving the genetic quality and size of the colony.

B. Helping allows the non-breeding adults to learn how to care for young before having their own.

C. Non-breeding adults spend more time foraging if they are collecting food for young, and occasionally when the young are full the helpers get to eat the excess food themselves.

D. Adult helpers are treated less aggressively than non-helpers by the dominant breeders in the colony.

A

A. Caring for the young of the dominant female ensures that more young survive, improving the genetic quality and size of the colony.

91
Q

True or False? The researchers concluded that an individual’s choice to engage in sentinel behavior was likely a result of optimization of individual benefits related to two factors: individual nutritional status and current presence/absence of another guard.

A

TRUE

92
Q

Assuming that alleles confer the behaviors of altruism and selfishness, and that these alleles are both present in populations,

A. group selection cannot explain the evolution of altruism because selfish alleles confer more benefits to the individual and, over time, would become more common than altruistic ones.

B. group selection can explain the evolution of altruism because altruistic alleles confer more benefits to the individual and, over time, would become more common.

A

A. group selection cannot explain the evolution of altruism because selfish alleles confer more benefits to the individual and, over time, would become more common than altruistic ones.

93
Q

T/F: Evidence suggests that meerkat sentinel behavior is not altruistic. Instead, selection has favored this behavior because the fitness benefit (reduced predation) outweighs the fitness cost (reduced foraging time).

A

TRUE

94
Q

Vocabulary word bank:
ants , parrots, crows, elephants, flamingos, hyenas, baboons, cheetahs, starling

Definition
cackle
murder
colony
pandemonium
parade
flamboyance
Murmuration
Troop
coalition

A

A. cackle = HYENAS
B. murder = CROWS
C. colony = ANTS
D. pandemonium = PARROTS
E. parade = ELEPHANTS
F flamboyance = FLAMINGOS
G. Murmuration = starlings
H. Troop = baboons
I. coalition = cheetahs

95
Q

True or False? Cooperation was a key feature of the development of sociality.

A

TRUE

96
Q

Which of the following is NOT TRUE of eusocial groups?

A. Only one or small number of the individuals reproduce
B. Generations overlap and live and work together
C. A sterile worker class exists
D. Group members cooperate to rear young
E. All Hymenoptera (wasps, bess, and ants) are eusocial

A

E. All Hymenoptera (wasps, bess, and ants) are eusocial ((While all ants are eusocial, there are many bee and wasp species that are solitary and do not live in groups)

97
Q

Charles Darwin was initially puzzled by the observation that worker honeybees die when they sting an intruder to their hive (the bee’s stinger is ripped from the bee’s abdomen, causing a fatal injury). Based on what you know about natural selection, why did this observation complicate Darwin’s theory?

A. Defensive behaviors are uncommon in the animal world

B. Natural selection favors traits that increase the survival and reproductive success of the individual, but a defending worker bee’s chance of survival is zero

C. The stinging apparatus appeared to be too complex to have evolved

D. The shape of the stinger is NOT heritable since the defender dies

A

B. Natural selection favors traits that increase the survival and reproductive success of the individual, but a defending worker bee’s chance of survival is zero

98
Q

Which of the following equations illustrates the correct relationship?

A. Inclusive fitness + direct fitness = indirect fitness

B. Indirect fitness + direct fitness = inclusive fitness

C. Direct fitness - indirect fitness = inclusive fitness

D. Indirect fitness + inclusive fitness = direct fitness

A

B. Indirect fitness + direct fitness = inclusive fitness

99
Q

On average, what portion of your genes would you share with a full sibling (i.e., y’all share the same biological mother and father)?
A. 25%
B. 50%
C. 75%
D. 100%

A

B. 50%

100
Q

Kin selection suggests that natural selection favors altruistic traits when

A. The inclusive fitness benefits of helping relatives outweighs costs

B. The entire social group benefits

C. Indirect fitness is greater than direct fitness

D. The individual receives fitness benefits through reciprocal exchange of favors

A

A. The inclusive fitness benefits of helping relatives outweighs costs

101
Q

Reciprocal altruism is characterized by

A. Individuals that are closely related to each other displaying altruism towards each other

B. A sterile worker caste helping with the rearing of others’ offspring

C. Individuals that are altruistic toward each other when there is promise of repayment

D. The cost to the beneficiary is always greater than the benefit to the altruist

A

C. Individuals that are altruistic toward each other when there is promise of repayment

102
Q

What behavior did the pied flycatchers display in the experiment that suggests evidence for reciprocal altruism?

A. Birds from nest boxes 2 and 3 did NOT participate in the mobbing at any phase

B. Birds from all nestboxes mobbed the predator regardless of its location

C. Birds from nestbox 1 joined the mob at nestbox 3, but not at nestbox 2 in the second part of the experiment

D. Birds from nestbox 2 mobbed when the owl was at their nestbox in the second phase of the experiment

A

C. Birds from nestbox 1 joined the mob at nestbox 3, but not at nestbox 2 in the second part of the experiment

103
Q

According to the research article and case study on meerkats, what is the most likely evolutionary explanation for sentinel behavior? Explain how natural selection would favor this trait.

A

Natural selection favors sentinel behavior in meerkats because it directly enhances the individual’s chances of survival and reproduction. By acting as sentinels, meerkats can detect predators early, stay close to safety, and forage more efficiently when not on guard. These benefits outweigh the costs of reduced foraging time and energy expenditure on vigilance, leading to the propagation of genes associated with sentinel behavior.

104
Q

what are the three key ingredients needed for natural selection to occur

A
  1. variation
  2. hereditary (at least some variation needs to be inherited)
  3. differential reproductive success
105
Q

what traits does natural selection favor

A

traits that enables genes to be passed on

106
Q

what is coevolution

A

two (or more) species reciprocally affect each other’s evolution (as one changes over time, so does the other)

107
Q

what is pairwise coevolution

A

two species involved

Close interactions between two species such as mutualisms, predator/prey, competitive, parasite/host

108
Q

what is diffuse coevolution

A

MORE than two species involved

Variety of interactions; the more species, the more difficult to ascertain relationships between observed changes

109
Q

what is a symbiotic relationship

A

relationship when BOTH species are benefiting from the engagement

110
Q

what is mutualism

A

symbiotic relationship between two species wherein both species experience net benefits

111
Q

what is mimicry

A

when an organism evolves to resemble another organism or object to gain a survival advantage

112
Q

what is antagonistic coevolution

A

when two (diff) species have negative effects on each other’s fitness as they evolve
- E.g., interactions between predators/prey and host/parasites

  - We also talked about sexually antagonistic evolution (sexual conflict), which is an intraspecific (within SAME species) analog to this idea

 - May lead to evolutionary arms race
113
Q

what is evolutionary arms race

A

continuous pattern of adaptation and counter adaptations between competing sets of genes (predator/prey; host/parasite) observed in antagonistic coevolution

- May also be seen within species, as in sexually antagonistic coevolution (sexual conflict)

- Constant effort to try to outsmart/outpace the other species

 - Predator/prey: predator gets faster and better at catching prey; prey now has to get faster and better at avoiding predation

  - Host/parasite: host evolves defense mechanisms to fight parasite; parasite gets better at becoming more toxic to defeat defense mechanisms
114
Q

what is cospeciation

A

when association between two species is very close (as in host and parasite), speciation may happen in parallel

 - As these two species are evolving together, they might both speciate together
115
Q

what were the 4 simple mutualism examples discussed in lecture

A
  1. Clownfish and anemone
    Clownfish = garner protection from anemone
    Anemone = gets food from clownfish crumbs
  2. You and your gut bacteria
    You = warm/perfect temperature home for bacteria (you are feeding gut bacteria)
    Gut bacteria = help you digest food
  3. Oxpecker and large mammals
    Oxpecker = picks out bugs from a variety of different mammals’ ears
    Large mammals = provide food source (bugs) for the oxpecker to feed on
  4. Nile Crocodile and plover bird
    Plover bird = “little toothbrush” cleans the teeth of the Nile crocodile and removing bits of food
    Nile crocodile = allows bird to work on cleaning teeth instead of eating them
116
Q

what is predator/prey coevolution and an example

A

type of antagonistic coevolution;the process where a predator species evolves adaptations to better catch its prey, which in turn forces the prey species to evolve defenses to avoid capture

EXAMPLE:
Lion and a zebra where lion evolves adaptations to catch zebra and zebra then evolves adaptation to be better and avoiding capture from the lion

117
Q

what is host/parasite coevolution and an example

A

type of antagonistic coevolution; the process where a host organism and its parasite both evolve in response to each other, where the host develops defenses against the parasite, and the parasite evolves mechanisms to overcome those defenses

EXAMPLE: HornWorm Larva
Type of caterpillar that results in a sphinx moth, technically a pest species (eats tomatoes); the white things sticking out of them are the pupa of parasitoid wasps = BAD NEWS for caterpillar

118
Q

how can coevolution lead to cospeciation

A

when two species that have a close, interdependent relationship, like a host and parasite, evolve alongside each other in such a way that when one species undergoes a speciation event the other species also speciate simultaneously

119
Q

how does a fig wasp and fig show mutualism

A

Female Wasps = climb into fig through ostiole and lay their eggs within the fig fruit, and in doing so, she ends up carrying pollen and pollinating the flower
- She is eventually going to die in there
- Eggs that hatch will be new generation of males(makes hole for female to escape) and females (carry pollen to another fig and continues the cycle)

Fig = provides a safe environment for wasp larvae to develop (nursery for next generation of wasps)
THIS EXAMPLE IS ALSO EVIDENCE FOR COSPECIATION

120
Q

how do leafcutter ants and lepiotaceae fungus show mutualism

A

Ants = farm fungus in their nests; keep fungus alive (they tend to it / cut leaves in order to feed fungus) and might even bring in antimicrobial bacteria to keep fungi healthy

Fungus = provides food source indirectly to ant colony; fungus is breaking down materials, like leaves, into sugar and other things that is digestible by ants

121
Q

how do phasmatodea eggs and plant seeds show mutualism

A
  1. Phasmatodea eggs often mimic the morphology of plant seeds
  2. Many seeds of the elaiosomes that are rich in lipids and proteins (attract ants); ants collect seeds to eat these nutrients, meanwhile dispersing seeds
    • Ants eat the capitula/elaiosomes only
  3. Phasmatodea eggs often have similar structure on capitulum
  4. Benefit: ants disperse and protect eggs
  5. First instar may mimic ant (after egg hatches, the nymph phasmatodea looks a lot like the ant so it avoids detection long enough to get out
  6. Mutualism present because benefit of dispersal and protection of the eggs/mimicry of seeds and ants
    (DIFFUSE COEVOLUTION EXAMPLE)
122
Q

what is a tradeoff

A

cost and benefits associated with a trait/adaptation/behavior

123
Q

how do common imperial hairstreak butterfly and the asian meat ant show mutualism can have tradeoffs

A

BENEFIT:
1. Butterfly larvae and pupae (immature stages) secrete sugary nectar for ants to feed on

  1. Ants aggressively defend the larvae and pupae (they get protection 😀)
    • Ants present = larvae and pupae experienced less predation (increased survival)
    • Ants excluded (absent) = larvae and pupae decreased survival

TRADEOFF:
1. High energetic cost to butterfly in producing the sugary substance for ants which results in lower pupal and adult weight
- With ants = pupae and adult weight lower
- Without ants = pupae and adult weight higher

124
Q

how does a monarch butterfly and milkweed show evolutionary arms race

A
  1. Milkweed makes toxic chemicals
  2. Monarch caterpillars are able to eat and sequester those chemicals into body tissues (NOT AFFECTING THEM) and in turn become toxic to other things
  3. Plant (milkweed) needs to get more toxic if it doesn’t want caterpillar eating it
125
Q

how does a jumping spider and weaver ant show evolutionary arms race

A
  1. Jumping spider is a predator to the weaver ant
  2. Jumping Spider (Myrmaplata plataleoides) mimics weaver ant to avoid detection (Oecophylla smaragdina) in order to hunt it
  3. Jumping spider evolves mimicry to get better at avoiding detection by ant
  4. Weaver ant must evolve to get better at detecting that spider
126
Q

how does a bacteria and bacteriophage show evolutionary arms race

A
  1. Bacteriophage = virus that infects bacteria
  2. Bacteria evolved different resistance mechanisms to this bacteriophage
    • Prevention of adsorption by alternating surface structures
    • Phage DNA can be degraded via restriction enzymes or mechanisms like CRISPR-Cas9
    • Cell death (last resort) upon infection to protect other bacteria
127
Q

how do bats and moths show evolutionary arms race

A
  1. Bat = bats that hunt at night use sonar (sound waves) to detect prey
  2. Moth = silk moth have long tails on their wings and those tails help them avoid detection by the bat
    - Longer tail = better avoiding of capture by bat (confuse sonar in bats)
  3. Moth evolves tails that get longer and longer while bat’s sonar evolves to get better at detection of moths
128
Q

what can be key to understanding human evolutionary history

A

Parasites (ex: when did humans lose most of their body hair)

129
Q

what are the key points for the origin of human HEAD lice

A
  1. DNA comparisons suggest the most recent common ancestor of chimp lice and human head lice lived ~6 million years ago
  2. Humans and chimpanzees also diverged around this time
  3. Thus, hominins and their head lice co-speciated from ancestral chimps and their lice (as chimps and humans diverged so did their lice)
130
Q

what are the key points for the origin of human BODY lice

A
  1. Human head and body lice are different morphotypes belonging to same species
    • Human head lice remain on the head
  2. Human body lice live on clothing and move onto skin up to 5 times a day
  3. A DNA comparison suggests the most recent common ancestor of human body lice lived less than 72,000 years ago
131
Q

what are the key points for the origin of human PUBIC lice

A
  1. Human pubic lice (Phthirus pubis) belong to the same genus as gorilla lice (Phtrius gorilla)
  2. DNA comparisons show that human pubic lice and gorilla lice last shared a common ancestor 3-4 million years ago
132
Q

what was the hypothesis on why body and head lice diverged

A

As hominins began wearing clothing, a new niche was created, and the body louse diverged from the head louse
- Clothing indicated there was a loss of hair at the same time body and head lice diverged

 - Head + body lice = related to chimp lice; share recent common ancestor 

 - Pubic lice = “crabs”; most closely related to gorilla lice
133
Q

what’s a lichen

A

mutualism (often obligate mutualism) between fungi and photosynthetic organism (algae, cyanobacteria)
- obligate = coevolved to point where they can’t survive without each other
- fungi = provides home for photosynthetic organism
- photosynthetic org = provides sugars to fungus

134
Q

Symbiotic relationships, wherein two species engage in a close association, include all except

A. Mutualism
B. Commensalism
C. Predation
D. Host-parasite
E. All of the above are examples of symbiotic relationship

A

D. Host-parasite

135
Q

Lichens can be observed growing on rocks and trees all over the planet, even helping to build soil in areas where soil has been removed or covered, such as occurs with a lava flow. Lichens are an association between a fungal species and either a photosynthetic algae or cyanobacteria. Each species receives benefits from the other and neither species can survive without the other. What is this type of interaction called?

A. Mutualism
B. Competition
C. Commensalism
D. Parasitism

A

A. Mutualism

136
Q

Why do ants collect both capitulate Phasmatodea eggs and plant seeds with elaiosomes?

A. To eat the eggs/seeds
B. To grow the seeds/eggs for future food sources
C. Because it’s fun
D. To eat the capitula/elaiosomes only

A

D. To eat the capitula/elaiosomes only

137
Q

An evolutionary trade-off is best described as a

A. A relationship wherein evolutionary change in one species negatively affects the fitness of another species

B. A situation in which optimization of one character trait cannot occur without negatively affecting another trait

C. When the evolution of a trait in one species affects the evolution of a trait in another species

D. Traits that are attractive to the opposite sex must be costly

A

B. A situation in which optimization of one character trait cannot occur without negatively affecting another trait

138
Q

Which statement accurately describes the results of an exclusion study that investigated the relationship between the ant Iridomyrmex anceps and the imperial blue butterfly, Jalmenus evagoras?

A. When butterflies were excluded, ant mortality increased at both sites

B. When butterflies were excluded, ant mortality decreased at both sites

C. When ants were excluded, butterfly larvae and pupae mortality increased at both sites

D. When ants were excluded, butterfly larvae and pupae mortality decreased at both sites

A

C. When ants were excluded, butterfly larvae and pupae mortality increased at both sites

139
Q

Which statements describe the coevolutionary relationship between the imperial blue butterfly (Jalmenus evagoras) and the ant Iridomyrmex anceps? CHECK ALL THAT APPLY

A. Presence of butterfly larvae and pupae reduces the survival of ants

B. Butterfly larvae and pupae secrete sugary nectar consumed by ants

C. Ants protect the butterfly larvae and pupae from predators

D. Ants reduce the survival of butterfly larvae and pupae as they reduce the food available to butterflies

E. Butterfly pupae not tended by ants grow larger than larvae tended by ants

A

B. Butterfly larvae and pupae secrete sugary nectar consumed by ants

C. Ants protect the butterfly larvae and pupae from predators

E. Butterfly pupae not tended by ants grow larger than larvae tended by ants

140
Q

Studies of rough-skinned newts have documented their ability to produce toxins in defense against a predator attack. The common garter snake, a predator of rough-skinned newts, exhibits a resistance to the toxin produced by the newt. In response, newts have been observed to produce increasingly potent toxins, which, in turn, results in selection for snakes with even greater resistance to the toxin. What phrase best describes this interaction between rough-skinned newts and garter snakes?

A. Obligate mutualism

B. Evolutionary arms race

C. Mimicry

D. Host-parasite coevolution

E. Diffuse coevolution

A

B. Evolutionary arms race

141
Q

Given the phylogeny of select primates and their lice, what is the closest relative of human pubic lice?

A. Human pubic lice are most closely related to chimp lice

B. Human pubic lice are most closely related to human head lice

C. Human pubic lice are most closely related to gorilla lice

A

C. Human pubic lice are most closely related to gorilla lice

EVOLUTION (5 decks)

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