Bio Test 3
• Describe the experiment that showed senescence in bacteria
page 751-753 textbook
Hamilton's rule
* Allele X for helping a relative increases in frequency through natural selection if: r b > c Where: r is the coefficient of relatedness b is the benefit from helping kin c is the cost of helping kin At the individual level if b > c, natural selection will always favor allele X * However, in this case one individual is benefitting and another is paying the cost. * Therefore, the benefit must be discounted by relatedness.
The genus Homo
* Approximately 2.3 million years ago * Homo habilis and Homo rudolfensis had greater cranial capacity than archaeic hominins that preceded them - transitional hominins * Also appear to have greater use of tools Homo habilis, rudolfensis * Homo ergaster (working man, Africa & Europe) * Homo erectus (Asia) appeared about 1.9 million years ago * Considered premodern hominins * More complex tools (chipped on both sides) appeared in Africa (mode 2) Homo ergaster, erectus * Homo heidelbergensis is the presumed link between Neanderthals, denisovans, and Homo sapiens * More elaborate mode 3 tools, sometimes attached to handles * Use of fire to cook food and for warmth 400,000 years ago at the very latest - evidence found inside caves * Reduced nutritional challenge: decrease in sizes of jaw, molars, and digestive tract; increased female body mass * Increased brain size, which required more energy Homo heidelbergensis, neanderthalensis, Denisovan hominin * Two recently discovered Homo species - Homo floresiensis, island of Flores extant until 12,000 years ago - Homo naledi, South Africa Fossils dated to 335,000 and 236,000 years ago
ch 20 example
* Both the 'mutation accumulation' and 'antagonistic pleiotropy' hypotheses predict that: the higher the rate of extrinsic mortality in a population the more rapidly its members should senesce Field experiment with opossum populations Mainland: high predation by birds and mammals Sapelo Island, GA: no large predators on the island, low predation * Monitored mortality (radio collars) and physiological decline (breaking of collagen in tail)
• Explain the smoke detector principle
* For fever and other defensive responses, some kinds of mistakes are more costly than others False positive: No infection, but develop fever Energetic cost: high Risk of harm? small False negative: Infection, but no fever Energetic cost: small Risk of harm? High, possibly fatal * If this is true: 1. fever should be relatively common and most are unnecessary 2. Taking antipyretics to reduce a fever should be safe, especially given the advances in modern medicine
• Explain the physiology of a fever
* Higher fevers are associated with more severe infections * The presence of fever is correlated with better disease outcomes * Human patients that receive fever suppressing (antipyretic) drugs recover less quickly from viral infections * Animals experimentally infected with bacterial pathogens and then treated with fever-reducing drugs have higher bacterial proliferation and higher mortality rates than those allowed a normal expression of fever COST * Maintaining high temperatures can lead to 20% increase in metabolic rate * Shivering can increase metabolic rate over six times the baseline DANGER * Fever may cause tissue damage, and when too high, fever can even cause death The catch: Compromise between advantage and harm "trade-off"
• Describe physical changes that have occurred in the anatomy of humans through evolution
* Humans walk upright and have brains that are large for their body size * Large canines have been lost in the hominin ligeage
• Compare the two models for modern human expansion
* Multiregional hypothesis - hominins left Africa and colonized the rest of the old world as H. ergaster -> modern humans * Out-of-Africa - three waves of colonization - 3rd wave eventually evolved into H. sapiens When moving out of Africa, Homo sapiens encountered and were limited by Neanderthals, strong competitors who occupied a large part of Europe. This delayed the expansion into Europe as compared to other areas.
• Explain the current evidence that homo sapiens interbreed with other hominin species
* Neanderthal genome sequenced * Humans from many areas also sequenced * Humans from Europe and Asia share more alleles with Neanderthals than with humans from Africa - interbreeding was not extensive - Africans have no Neanderthal DNA - non African 1% - 4% * Genetic evidence suggests that humans also interbred with Denisovans as they migrated through Asia - Denisovans also interbreed with a mystery hominin
• Explain what the term means phylogenetic constraint
* Phylogenetic history may impose constraints on structural evolution * There is a close anatomical relationship between the respiratory and digestive system in tetrapods * This anatomy leads to an increased risk of choking A phylogenetic constraint limits further evolution and results in suboptimal structures * Lungs are derivatives of "pouches" derived from the esophagus or gut of fish
• Explain why selection acts more strongly on early-age mutations
* Selection operates more strongly on traits that appear at young ages because of extrinsic mortality causes of death other than senescence * Traits that appear late in life are only subject to selection if individuals live that long
The Hominin Clade
* The hominin lineage split from the chimpanzees lineage 6 million years ago *Hominin evolution has not been linear but more of a branching tree * Most species on the tree are now extinct * Multiple hominin species coexisted from about 4 million years ago until 30,000 years ago * The rise of hominin lineage coincided with environmental changes in Africa about 6 million years ago * Cooling temperatures and seasonal rainfall led to reduction of forest and establishment of savanna * Chimp and gorilla lineages remained in the forest, but early hominins colonized the savanna
Describe the 3 types of antagonistic coevolution
* predator-prey interactions and the idea of an coevolutionary arms race * host-parasite- the reciprocal adaptive genetic change of a host and a parasite through reciprocal selective pressures * Batesian mimicry- a form of mimicry where a harmless species has evolved to imitate the warning signals of a harmful species directed at a predator of them both.
• Explain the rate-of-living hypothesis for senescence
* wear and tear (senescence) is unavoidable * Two testable predictions: 1.If selection has done everything possible to slow the pace of senescence, then there should be little or no genetic variation in the rate of senescence ● 2.There should be a strong negative correlation between metabolic rate and life-span because the faster the metabolism, the higher the wear and tear
Explain the 2 potential issues with cooperation
1) The problem of altruism • Why would an individual perform an action that reduces it own fitness, in the short-term? 2) The free-rider problem • Why would natural selection favor individuals who cooperate when they can free-ride on the effort of others?
• Explain the 6 explanations for our vulnerability to disease
1. Humans are locked in a coevolutionary arms race with their pathogens, most of which evolve much faster then human * There might be heritable genetic variation for vulnerability in populations, in which case natural selection can operate. BUT pathogens are a moving target (coevolutionary arms race) 2. Natural selection has not had time to catch up with rapid changes in the environment * Recent environmental changes create a mismatch between our bodies and our current environment 3. The laws of physics and nature of biology impose trade-offs on what organisms can do * A higher metabolic rate might improve physiological functions, but it has a cost (energy used) - trade-off 4. Natural selection lacks foresight, so that sometimes we are stuck with historical contingent relics of our past * Evolution of four limbs did not "predict" bi-pedal walking in humans. Weight of torso is supported entirely by the lower back, causing strain and pain 5. Natural selection favors reproductive success even at the expense of vulnerability to disease * Natural selection operates on life-time reproductive success, which does not necessarily "go together" with health at age 70 6. Some defenses may be unpleasant, but they are beneficial adaptations rather than maladies * Vomiting be unpleasant, but it is an adaptation to disease as it helps us "fight" pathogens
Explain under what circumstances an evolutionarily stable strategy might emerge in a population
A strategy such that, if all members of a population adopt it, no mutant strategy can invade.
A symbiotic relationship is A) A close relationship between two species B) A close relationship between two species where both benefit C) A close relationship between two species where one causes harm
A) A close relationship between two species
Which of the following is an abiotic factor? A) Average temperature B) Number of species in an area C) Amount of food D) Number of mates
A) Average temperature
A mutualistic relationship A) Benefits both partners B) Benefits only one partner C) Benefits one and harms the other
A) Benefits both partners
Natural selection operates directly on A) Individuals B) Populations C) Species
A) Individuals
What about when the coefficient of relatedness when individuals share two common ancestors? A) It will be higher B) It will be lower C) It will be the same
A) It will be higher
The Red Queen hypothesis supports? A)Sexual reproduction B)A sexual reproduction C)Both
A)Sexual reproduction
List the assumptions of the basic optimal foraging model
Animals seek to acquire energy, rather than some nutrient * Animals can't seek new foods while they are handling an existing one * Food items are encountered sequentially * Items are instantly recognized and assessed * Fitness depends on energy intake
An example of intraspecific competition would be A.Wolves eating more rabbits as the size of the rabbit population increases B.Kelp perch competing for hiding places in a kelp forest C.Two different plants species growing near each other competing for resources
B.Kelp perch competing for hiding places in a kelp forest
• Describe the coevolutionary arms race between the host immune system and pathogen virulence
Binary fission (a sexual reproduction) => new mutations => selection favors beneficial mutations High reproductive rate = high fitness => selection favors increased virulence * Fortunately for us, there are some aspects of their biology that pathogens cannot change
In large populations which mutations are more likely to become fixed in the population? A)Random deleterious mutations B)Mutations with a small selective advantage C)Mutations with a large selective advantage D)Both B and C
C)Mutations with a large selective advantage
We can get an MMR vaccination that will confer lifelong immunity but we have to get a new flu shot every year. Why? A) the flu vaccine is of lower quality B) The pharmaceutical industry is trying to make more money C) The flu virus is more contagious D) The flu virus mutates faster
D) The flu virus mutates faster
Which of the following is the best definition of a niche? A.The habitat where an organism lives B.The food an organism eats C.The way an organism reproduces D.An organisms role in its environment ●
D.An organisms role in its environment
Explain how mutualistic interactions between species can increase the fitness of both species through coevolution
Definition: An association between species that are usually distantly related, and that is beneficial for both partners
Describe diffuse coevolution
Diffuse (guild) coevolution involves interactions between more than two species. Example: mutualistic coevolution between panic grass (Dichanthelium lanuginosum), a fungus (Curvularia protuberate), and a virus in geothermally heated soils of Yellowstone Park.
A forager should stay longer in a patch if A. the distance between patches is long B. if the quality of the patch is low C. the rate of food intake is high across all patches D. all of the above E. A and B only
E. A and B only
Describe eusociality
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.
Explain the difference between facultative and obligate mutualism
Facultative (optional) mutualisms: partners benefit from, but do not require, one another. Obligate mutualism: partners have an absolute requirement for each other for survival and reproduction.
Explain why cooperation is more likely between female worker bees than between female workers and male drones
Female workers are 3 times more related to each other than to brothers so this should favor a 3:1 sex ratio. The more closely related you are the more cooperation.
• Describe the different types of phylogenies that can develop due to immune response
Figure 20.6 Phylogenies of measles and influenza. (A) The measles virus generates lifelong immunity, so there is no immune selection for escape variants. Shown here is a gene tree for the measles nucleocapsid gene. (B) The influenza virus can evolve escape variants that get around immunological memory, reinfecting hosts that have previously had the disease. Such escape variants are strongly favored by immune selection; this process gives rise to the characteristic cactus-shaped phylogeny of the influenza hemagglutinin gene shown here. Adapted from Grenfell et al. (2004).
• Describe some of the way pathogen subvert the host immune system
HIV: * suppresses the expression of host MHC (major histocompatibility complex), which recognizes infected cells * induces programmed death in uninfected immune cells Poxviruses (smallpoxs and chickenpoxs): * Produce enzymes that degrade the chemokine signals responsible for replication and migration of cells to fight infection * Produce molecules that block the host's chemokine signal receptors * Produce false chemokine to lure immune response away from infected areas
• Explain the "trade-off" that human experience as result of the structure of the epiglottis
Imaginary "fix" to the choking problem * no air in the mouth, no talking...! Trade-off between choking risk and communication ability
• Explain the difference between intraspecific and interspecific competition
Intraspecific competition causes population growth rate to slow as populations reach K Interspecific competition occurs between individuals of different species that share the use of resource that limits, reproduction, growth, or survival
Symbiosis: Interaction in which partners live "together"
MUTUALISM AND SYMBIOSIS ARE NOT SYNOMYMS! • Some mutualisms are not symbiotic • Many facultative mutualism, are incompatible with symbiosis • Most symbioses are parasitic
Give the Nash's equilibrium for 1 time interactions, known number of interactions, unknown number of interactions
Nash equilibrium applies if all players know all possible payoffs and neither player can benefit by changing only his own strategy. Play game only once both defect, do the best for themselves = Nash equilibrium
Explain how natural selection acts of foraging behavior
Natural selection can operate on foraging behavior if - there is variation in the behavior - the behavior has a genetic basis
Explain the optimal foraging model
OFT is a set of mathematical models that aims to examine the ecological and evolutionary balance among various elements involved in animal foraging behavior. The central idea: natural selection should improve animal foraging efficiency
• Explain the disposable soma hypothesis
Originally: tradeoff between growth and repair * But things become more interesting as we condider organisms that have separate 'germ cell' lines and 'somatic cell' lines * Germ cells are selected to avoid degradation and decay (faithful transmission of alleles) * Somatic cells are selected for growth at the expense of repair * Today: the DSH focuses on the tradeoff between reproduction and investment in repair that is: early fecundityandlater survival * Why not invest in both? Because organisms cannot eliminate extrinsic mortality There is no selective benefit to invest in repairs organisms may not live enough to need
Explain how between-group selection and with-in group selection operates in ants
Seed harvester ants form multiple queen colonies Founding queens are unrelated, but cooperate to build their quarters and lay about the same number of eggs Members of other colonies raid new nests and steal brood When workers start to emerge, they protect brood and queens start to fight
• Describe the pattern seen in humans and other animals as organisms age.
Senescence General decline in the physical functioning or performance of living organisms with age, ending in death. -Increase in mortality rate -Decrease in fecundity * Why do we age? * Why is it that natural selection cannot drive organisms to an eternal life and infinite number of offspring?
• Describe the factors that can influences the amplitude of oscillations
Some of the most notable examples of population changes occur in species that experience large, cyclic swings in population size. Quite often, these cycles co-occur with population cycles of other species in the same location. For example, red foxes (Vulpes vulpes) in northern Sweden prey on voles, grouse, and hares. Studies of these species have demonstrated linked population cycles in each of the prey species, with population peaks every 3-4 years (Figure 1). What drives these cycles? Grouse, hares, and voles feed on vegetation, and the availability of their preferred foods will influence the population size of each. The availability of food acts as a bottom-up control that affects population size. In years when their preferred food items are abundant, populations will grow. When preferred foods are scarce, individuals must turn to less desirable foods to prevent starvation. They grow more slowly, reproduce less, and populations decline. When vole populations peak and competition for food is strongest, they turn to bark as a marginal food, and this shift in foraging behavior coincides with a population decline (Figure 1a). Grouse and hare populations cycle in a manner comparable to those of voles, which suggests that food availability plays a role in regulating populations of these herbivores.Foxes prefer to consume voles and other small rodents, but will occasionally eat grouse and hares when voles are less abundant. We would expect that the number of foxes in the population would increase as availability of their preferred food increases, and studies have demonstrated that this does, in fact, occur (Figure 1b). Owl populations cycle in a similar manner, closely following the abundance of voles.As predator populations increase, they put greater strain on the prey populations and act as a top-down control, pushing them toward a state of decline. Thus both availability of resources and predation pressure affect the size of prey populations. We cannot easily determine the extent to which each of these controls drives population cycles in the Swedish boreal forest, because this system is not amenable to caging experiments, but studies show that food and predation work together to regulate population sizes
Hamilton's interpretation of fitness
The fitness of an individual is the sum of its: direct fitness -- the number of viable offspring it produces and its indirect fitness -- the incremental effect that the individual's behavior has on the direct fitness of its genetic relatives
Explain what factors might influence a forager to remain in a single patch longer
The forager should stay longer if the distance between patches is great. Individual should stay longer if the habitat quality is low to make up for the cost of travel time between patches
Describe the prisoner's dilemma
The prisoner's dilemma is a standard example of a game analyzed in game theory that shows why two completely rational individuals might not cooperate, even if it appears that it is in their best interests to do so.
Explain why the level of kinship between individuals influences cooperation
There are strong evolutionary reasons why we might expect to see cooperation and altruism among close relatives of any species. The basic reason is that genetic relatives share alleles that they have inherited from common ancestors- parents, grandparents, and so on. "Blood is thicker than water"
•Competitive exclusion principle
Two species with identical niches cannot coexist •One species will be a more effective competitor and will eventually exclude the other species
Which of the following relationships is NOT an example of coevolution? a. A male prairie dog barking a warning call in the presence of predators. b.Monarch butterfly larvae that feed only on milkweed plants that are not toxic to the monarch larvae but toxic to other animals; the butterflies provide pollination for the milkweed plants. c.The mutualism between fungi and algae that form lichen species. d.Ants that live in the thorns of Acacia trees; the trees provide a home for the ants while the ants protect the trees from other predators.
a. A male prairie dog barking a warning call in the presence of predators. Coevolution occurs when the action of natural selection on one species causes natural selection to operate in new ways on the other species. This is a result of a deep, integrated relationship between the two species. In the example of the prairie dog, the warning call will help alert other prairie dogs to the presence of the predator, but there is not a direct change in how natural selection operates on the coyote, therefore this is not an example of coevolution. Read the chapter introduction to learn more about the different types of coevolution discussed in the chapter.
The leaf-cutter ant (Acromyrmex octospinosus) is one species of ant that participates in a beneficial mutualism with a fungal species. The female workers as well as the reproductive females in the colony are often covered with a thick whitish-gray coating, which turns out to be bacteria that produce antibiotics. Which of the following is TRUE regarding the function of these bacteria? a. They produce antibiotics that kill parasites that grow in the fungal gardens. b.They produce antibiotics that kill both parasites that grow in the fungal gardens and those in the ant eggs and larvae. c.They produce antibiotics that kill parasites in the ant eggs and larvae. d.They produce antibiotics that protect the adult ants, improving their reproduction.
a. They produce antibiotics that kill parasites that grow in the fungal gardens. In the leaf-cutter ant (Acromyrmex octospinosus), which is involved in an ant-fungus mutualism, the thick coating on the worker is composed of bacteria that produce antibiotics that suppress the growth of parasites in the fungal garden. These antibiotics specifically protect the fungi they grow, and there is strong evidence that selection has favored the use of the Streptomyces bacteria by the ants (Mangone and Currie 2007). They do not have an effect on other parasites in the ant colony, and so do not affect ant eggs or larvae directly. Read the subsection titled "Ant-Fungus Mutualisms" in Section 18.1 and see Figure 18.4.
Suppose that an allele is present in pelican offspring that causes a nestling to share its food with its nestmate if it is not particularly hungry. This gene imposes a fitness cost of 0.2 on those who carry it, while conferring a benefit of 0.5 on the sibling who receives the additional food. Will this gene increase in frequency if two nestmates are always full siblings? Remember Hamilton's Rule. a.Yes, because rb > c b.No, because rb < c c.Yes, because rb < c d.No, because rb = c
a.Yes, because rb > c Hamilton's rule shows that the extent to which natural selection favors assisting family members depends on how closely related individuals are to one another and how high or low the associated costs and benefits turn out to be. When the coefficient of relatedness r is high, benefit b to the recipient is high, and cost c to the actor is low, then natural selection should strongly favor individuals who help their kin. In the example, r (between full siblings) = 0.5, c = 0.2, and b = 0.5. Therefore, rb - c > 0 and we would expect the allele to increase in frequency. Read the subsection titled "Inclusive Fitness and Genetic Relatedness" in Section 17.1.
Explain the marginal value theorem
an optimality model that describes the strategy that maximizes gain per unit time in systems where resources, and thus rate of returns, decrease with time. In general, individuals will stay longer if (1) patches are farther apart or (2) current patches are poor in resources.
Archaeic hominins
australopithecus platyops, afarensis, africanus * Approximately 4 million years ago * Use of tools dates back to 3.4 million years - fossil ungulate bone with cut marks presumably from simple stone tools (mode 1) paranthropus boisei, aethiopicus, robustus * Parathropus overlapped in time with Homo * Also known as megadont hominins * Extinct lineage * Approximately 3 million years ago * Large bone ridges for muscle attachment, large teeth * Presumably fed on low quality food items that required grinding
Panic grass (Dichanthelium lanuginosum) can live in geothermally heated soils only when the fungus Curvularia protuberata is present. In order for Curvularia protuberata to colonize the soil, the Curvularia thermal tolerance virus (CThTV) must also be present. This web of coevolutionary interactions between multiple species is referred to as __________. a.cultural coevolution b.diffuse coevolution c.intraspecific coevolution d.antagonistic coevolution
b.diffuse coevolution Mutualistic relationships provide benefits to the species involved. This diffuse coevolutionary relationship involves a web of mutualisms between three species; Dichanthelium lanuginosum depends on Curvularia protuberata, and Curvularia depends on the CThTV virus to live in the geothermally heated soils of Yellowstone National Park. The loss of CThTV would result in the loss of Curvularia, which would result in the loss of Dichanthelium in this highly specialized environment.
In the case of California salamanders, we can see how traits in one species (coloration of the toxic newts) influence selection on another (coloration of a nontoxic salamander). The figure describes the actions of a predator, the Western scrub jay, on two salamander species. Which of the following is true about the behavior of the Western scrub jays? a. The jays took about the same amount of time to approach E. e. xanthoptica and E. e. oregonensis individuals. b. There was no significant difference in the behavior of the jays after being exposed to either the nontoxic salamander or the toxic newt. c. The jays were very hesitant to approach E. e. xanthoptica (mimic), even though this salamander did not possess the neurotoxin found in the newts. d. E. e. xanthoptica does not benefit from mimicing the toxic California newt.
c. The jays were very hesitant to approach E. e. xanthoptica (mimic), even though this salamander did not possess the neurotoxin found in the newts. Shawn Kuchta and his team of researchers first presented a Western scrub jay with a toxic California newt (Taricha torosa), and then they presented the jay with either the mimic salamander Ensatina eschscholtzii xanthoptica, or an individual from the closely related subspecies Ensatina eschscholtzii oregonensis, which is visibly similar to E. e. xanthoptica except that it lacks orange and yellow coloration (Kuchta et al. 2008). After experience with the toxic California newts, some of which the jays attacked, the jays took more time to approach E. e. xanthoptica than E. e. oregonensis individuals. Read the subsection titled "Mimicry and Coevolution" in Section 18.2 and examine Figure 18.17.
Calculate the coefficient of relatedness (r) between you and your first cousin. a. r = 0.25 b. r = 0.50 c. r = 0.125 d. r = 0.625
c. r = 0.125 To calculate the coefficient of relatedness (often denoted r) between two individuals (you and your first cousin), we must locate your most recent common ancestor or ancestors (assume that those are your common grandparents). Now we calculate the probability that a given allele in that ancestor has been passed on to both of you. Each step is a meiotic division with ½ (0.5) probability that the grandparents' allele is passed to your parent and then to you. There are four such steps in each path. Since you have two common ancestors, we will use the probability rule (adding the individual probabilities of sharing an allele from your grandmother and of sharing an allele from your grandfather). The chance you share an allele through one specific grandparent is 0.54 = 0.0625, but the total probability that you share an allele from either grandparent is r = 0.54 + 0.54 = 0.125. Read the subsection titled "Inclusive Fitness and Genetic Relatedness" in Section 17.1 and examine Figure 17.2 and Box 17.1.
If there are many prey types to choose from, what should a predator do? a. Eat the prey with the highest E b. Eat the prey with the lowest H c. Eat the prey with the highest E/H d. Eat the prey with the lowest S (the most common prey)
c. Eat the prey with the highest E/H
Which of the following terms does NOT apply to the "kinship and cooperation" model? a.coefficient of relatedness b.inclusive fitness c.reciprocal altruism d.Hamilton's rule
c.reciprocal altruism There are strong evolutionary reasons why we might expect to see cooperation and altruism among close relatives of any species. The basic reason is that genetic relatives share alleles that they have inherited from common ancestors. Alleles that are shared because of common ancestry are referred to as identical by descent. The coefficient of relatedness between two individuals is defined as the probability that an allele in one individual has a copy that is identical by descent in the other individual. An individual's total (inclusive) fitness can be viewed as the sum of (1) its direct fitness, which is the number of viable offspring that it produces, and (2) its indirect fitness, which is the incremental effect that the individual's behavior has on the (direct) fitness of its genetic relatives. Read the subsection titled "Path 1: Kinship and Cooperation" in Section 17.1.
Interspecific competition
causes population growth rate to slow as populations reach K •Niche overlap •The greater the overlap the more intense the competition •Outcomes •Resource partitioning •Evolution/ speciation •Competitive exclusion •Local extinction of one species
If the prisoner's dilemma game is played only once, what would we expect to see? a. We would expect to see cooperation. b. It is impossible to predict based on game theory c. We would expect to see one player testify (defect) and one player refuse to testify (cooperate). d. The only Nash equilibrium is defection.
d. The only Nash equilibrium is defection. If both subjects want to minimize the lengths of their prison sentences, each should defect and agree to testify against his codefendant. The seemingly intractable problem that the prisoners face is that once taken to their separate interrogation rooms, each has no way to ensure that the other will cooperate if he does so himself—and in fact by the logic above, each has every reason to suspect the other will defect instead. So, why would we ever see cooperative behavior in games that take the form of the prisoner's dilemma? In one-shot games—that is, in circumstances in which the game is played only once—the answer is that we do not expect to see cooperation. Defection is a Nash equilibrium (neither player can benefit by changing his strategy and cooperating), and it is the only Nash equilibrium. Read the subsection titled "The Prisoner's Dilemma" in Section 17.1.
Ants, bees, and wasps are haplodiploid species. What is the coefficient of relatedness (r) between female workers and their drone brothers? a. 0.50 b. 1.00 c. 0.75 d. 0.25
d. 0.25
The rate of evolutionary change is higher in fungi that experience: a. Free-living conditions b. Aggression c. Cheating d. Mutualism with algae
d. Mutualism with algae
Antagonistic coevolution might include: a. Predator-prey relationships b. Host-parasite relationships c. Mutualism d. a and b
d. a and b
Predator-prey interactions are one type of antagonistic coevolution. Which of the following traits would natural selection favor in these interactions? a.Natural selection will only favor those traits that help prey escape predation. b.Natural selection will only favor those traits that help predators capture their prey, resulting in an end to the evolutionary arms race. c.Natural selection will favor traits that help the prey species and negatively impact the predator species. d.Natural selection will favor traits in prey that increase the chance of escaping predation and traits in predators that increase their chance of capturing and killing prey, resulting in an evolutionary arms race.
d.Natural selection will favor traits in prey that increase the chance of escaping predation and traits in predators that increase their chance of capturing and killing prey, resulting in an evolutionary arms race. In the antagonistic interactions between predator and prey, natural selection favors any trait that increases the chance of getting ahead in the evolutionary arms race. When a new trait facilitating escape evolves in prey, this immediately intensifies selection on predators for traits that increase their probability of capturing and consuming this better-adapted prey. Such a trait in predators will then favor any trait in prey that allows them to escape even better, and so on, in an ongoing coevolutionary dynamic. Read Section 18.2 titled "Antagonistic Coevolution," and examine the example in the textbook on the predatory whelk Sinistrofulgur and its bivalve prey Mercenaria.
Describe evolutionary ecology
examines how interactions between and within species evolve. It explicitly considers the evolutionary effects of competitors, mutualists, predators, prey and pathogens. Integrating Ecology and Evolution allows us to examine fitness consequences of interactions between organisms and their environment.
True or False: Homo sapiens descended from chimpanzees.
false
True or False: Homo sapiens evolved from Neanderthals.
false
Describe some of the costs of foraging
foraging has costs: - energy - time - risk of predation
Calculated coefficient of relatedness between 2 individuals
r, the coefficient of relatedness, can be calculated from a pedigree (family tree) and the fact that the probability of any given allele passing from parent to offspring is 0.5 Count and add up: the number of generations that connect A and B to their shared ancestor
• Explain the mutation accumulation hypothesis
selection may not be strong enough to eliminate deleterious mutations that have a small effect. Deleterious mutations expressed early in life may get eliminated by selection. In contrast, deleterious mutations expressed late in life build up in the genome. Individuals that live long enough will potentially manifest many deleterious mutations of small effect.
Explain how cospeciation occurs
when speciation in one partner lead to speciation in the other
• Explain the two types of growth that a population can have
•Carrying capacity (K) - maximum sustainable size that a population can reach in a particular environment •After reaching K the growth rate of the population typically declines •K is typically set by some resource that individuals are competing for (food, area, nest sites, etc)
• Explain the relationship between humans and other great apes such as chimps and gorillas
•Hominoidea - also known as the great apes •Orangutans, gorillas, chimpanzees, humans, gibbons •Hominini - humans and their sister group Pan •Hominin - all species of humans •Homo, Paranthropus, Australopithecus, Ardipithecus, etc. •At most loci humans are most closely related to chimps
• Explain the two possible outcomes with interspecific competition
•Resource partitioning Evolution/ speciation •Competitive exclusion Local extinction of one species
• Explain why predator-prey interactions sometimes lead to oscillations
•Some predator-prey population cycles are more intense than others •Some predator-prey interaction reach a stable equilibrium
Resource partitioning
•Species become adapted in different ways to subdivide similar resources •Allows competing species to coexist •Reduces the each species niche
