BZ220 Exam Two

In a haplodiploid population of wasps, a female individual can either help her older full-sib sister rear offspring, or set off to rear her own offspring. If she helps her sister, she rears no offspring of her own, but helps her sister to rear 50. If she sets out on her own, she can rear 14 offspring of her own, and without help, her sister only rears 28. Calculate the following values from Hamilton's rule. Relatedness of the haplodiploid sisters, r = ___ Benefit to the recipient, b = ___ Cost to the actor, c = ___ According to Hamilton's rule, would we expect the allele for helping to increase in frequency?

0.75 22 14 Yes

A species of frog has a tough integument (skin) that makes it difficult for predators to pierce and eat them. Analysis of closely-related and ancestral species has shown that the tough integument most probably arose as a response to arid (dry) environments, as a way to decrease desiccation (drying out). Which of the following statements is most strongly supported by this observation?

A tough integument as protection against predators is a pre-adaptation

Which of the following components of experimental designs are necessary to test hypotheses regarding adaptation? Indicate all correct answers.

Control groups Randomization of treatments Repeating experiments

Ampicillin has been used to treat the bacteria that lead to bronchitis. Over the years, researchers have noticed that Amphicilin has been less and less effective in eliminating cases of bronchitis. Using your knowledge of evolution and medicine, what is the most appropriate course of action?

Doctors should only prescribe Ampicillin in the most extreme cases of bronchitis. This will reduce the selective pressure for Ampicillin-resistance and result in an increase in Ampicillin-susceptible bacteria

High levels of relatedness always lead to the development of eusociality in species

False

Researchers found that female orange-crowned warblers preferentially mate with males that have bright feather coloration. A separate study demonstrated that good health and bright feather coloration in male orange-crowned warblers are strongly correlated. In addition, the offspring of males with bright feather coloration have higher survivability compared to offspring from dull-colored males when resources are sparse. Based on these data, what is driving female preference for brightly colored males?

Female choice for good alleles ("genes") in their offspring

Males from the bird species Acrocephalus schoenobaenus (sedge warbler) have a large number of different songs that they can sing. A scientist hypothesizes that the number of songs is under sexual selection such that female sedge warblers prefer to mate with males that sing many different songs. To test their hypothesis, the scientist plays 4-minute song recordings from each of three male sedge warblers to female sedge warblers. Male 1 sings the most number of different songs, male 2 sings the fewest number of different songs, and male 3 sings an intermediate number of different songs. Which of the following findings would most strongly support the scientist's hypothesis?

Females positively respond to the song of male 1 > response to the song of male 3 > response to the song of male 2.

Which of the following statements reflect life history traits in tailed frogs.

Females then lay a clutch of around 60 eggs every other year Tailed frogs can live up to 40 years in the wild Females reach sexual maturity 4 years after metamorphosis; males reach sexual maturity 3 years after metamorphosis

If female variance in reproductive success is greater than male variance in reproductive success, what would we expect?

Females to be competitive Males to be choosy

In spadefoot toads, when occupying densely populated ponds, some individuals may develop cannibalistic morphologies (e.g., enlarged keratinized oral sheath). Cannibalistic individuals have been shown to preferentially predate tadpoles that are more unrelated to them (i.e., eat cousins over siblings). What would you hypothesize this to be an example of?

Kin selection resulting from selfishness

Gene A encodes for claw length (short; long) and body size (big; small) while gene B encodes for dorsal coloration (brown; white). Both of these genes occur close to each other on chromosome 3. This hypothetical species lives in the Arctic, and selection favours white individuals because they can escape predation through camouflage. Selection also favours large body sizes as they have an increased capacity for thermoregulation. A population is sampled and most individuals are found to be white and small. What could explain this?

Linkage

Haplodiploid wasps collect nectar from flowers, and while doing so, they spread pollen. What kind of social interaction is this?

Mutualism

Why might non-synonymous mutations in antigenic sites be favored in strains of influenza?

Non-synonymous mutations will change the proteins in antigenic sites, thus making it less likely host immune systems will recognize the virus

Blind salamanders in the family Proteidae are quite long-lived, with an estimated lifespan up to 102 years! In a study published in July in Biology Letters, researchers found that this species does not have a particularly low metabolic rate. This study is added evidence to the rejection of which hypothesis?

Rate of Living: Aging rate is correlated with metabolic rate

African long-tailed widowbirds are sexually dimorphic. The males have very long tail feathers, even though those feathers impede their ability to fly away from predators. Research has shown that females preferentially mate with males that have long tail feathers. Which of the following hypotheses is most plausible based on these observations?

Runaway sexual selection

Researchers have discovered that disease outbreaks tend to be higher and are prevalent periodically in cities that are popular tourist destinations compared to small suburban towns. What is the best explanation for this observed pattern?

Seeding

Which of the following show support for the Antagonistic Pleiotropy hypothesis for senescence?

Selection for a gene in mice found to increase fecundity but later cause ovarian cancer

A virus infects a host with a very weak immune system. At present, the virus is highly virulent. Since the immune system of their host is weak, most individuals die within a day of infection! Which of the following is a reasonable prediction for the evolution of this virus, given new mutations?

Selection will favour a mutation leading to lower virulence

Research on some species of passerine birds has indicated that males with larger testes tend to pass on their alleles more than those with smaller testes. What would be a plausible driving force for this observed relationship?

Sperm competition

the reproductive behaviors of the common Suriname toads (Pipa pipa) are quite distinct. During amplexus (i.e., frog mating), female toads will release eggs for external fertilization, which males toads then fertilize. After fertilization, males perform swimming maneuvers until the eggs become embedded onto the females' backs. The mother will then carry the fertilized eggs on her back, protecting her clutch from predators and ensuring that they receive sufficient oxygen, until the eggs hatch. Based on this information and the lecture material, which sex would be expected to be choosy and why?

The female is choosy because she has a greater parental investment.

The mutation that led to the expression of lactase in adults only rose to high frequencies where animals were domesticated. This is an example of:

The fitness of mutations depending on the environment

The salamander species Ensatina eschscholtzii xanthoptica (yellow-eyed Ensatina) has a color pattern that very closely resembles a brightly colored poisonous newt that co-occurs in the same habitat. A scientist hypothesizes that this color pattern of the yellow-eyed Ensatina is an adaptation (because predators will avoid the salamander if it looks poisonous) and performs the following experiment to test his hypothesis. 25 clay models of salamanders are painted to mimic the yellow-eyed Ensatina and another 25 were painted to mimic a drab-colored salamander. These models are then placed within the geographic range of the yellow-eyed Ensatina and left for 25 days. The clay models are then collected and the number of attack marks on each model are recorded. Which of the following results would provide evidence that supports the scientist's hypothesis?

The models that resembled yellow-eyed Ensatina had significantly fewer attack marks than the other models.

Which of these hypotheses have been put forth to explain why birds do not produce theoretically optimal clutch sizes as predicted by Lack?

The parents are saving and investing energy for future reproductive events

Scientists are interested in understanding whether bees respond positively to the scents of flowers that they have never encountered. They decide to measure the behavioral responses of bees after they sprayed the scent (i.e., perfume) of a local flower that the bees have encountered, as well as a foreign flower that the bees have never encountered. What would be an appropriate control for this study?

They also spray an odorless perfume to control for the bees responding to the spraying rather than a flower scent

Parental care in frogs can be found in some species of Dendrobatids (poison dart frogs). For example, in one species, the father guards his eggs until they hatch. Then the mother carries each tadpole one at a time to a different bromeliad (plant). She then deposits the tadpole and 1 unfertilized egg for the tadpole to eat while growing. The number of tadpoles therefore affects the number of trips for the mother and the characteristics of the unfertilized egg she deposits. If the pair have a large clutch (i.e., many tadpoles), what can we hypothesize about the size of the unfertilized egg the mother deposits?

We would hypothesize that she would deposit smaller unfertilized eggs because resource allocation has favored quantity over quality

non synonymous mutation

a nucleotide mutation that alters the amino acid sequence of a protein.

What are the two key points that should be in any definition of adaptation used in this class

the adaptation increases fitness The adaptation is a derived character state rather than a primitive character state

eusociality

the highest level of organization of sociality, is defined by the following characteristics: cooperative brood care, overlapping generations within a colony of adults, and a division of labor into reproductive and non-reproductive groups.

genetic linkage

the way in which two genes that are located close to each other on a chromosome are often inherited together

antagonistic pleiotropy

when one gene controls for more than one trait, where at least one of these traits is beneficial to the organism's fitness early on in life and at least one is detrimental to the organism's fitness later on due to a decline in the force of natural selection