Exam I

Question 1

Identify the three scientists who were the founding fathers of behavioral ecology.

Answer 1

Nikolaas Tinbergen – Known for his work on the four questions of animal behavior.

Konrad Lorenz – Recognized for his work in animal behavior, particularly imprinting and instincts.

Karl von Frisch – Known for his research on the communication of bees.

Question 2

Proximal vs Ultimate

Answer 2

Proximal questions focus on the immediate mechanisms and development of behavior.

Ultimate questions address the evolutionary and adaptive significance of behavior.

Question 3

The Four ‘Why’ Questions in Behavioral Ecology:

Answer 3

Causation (Proximal):
What causes the behavior?
- such as hormonal, neural, or environmental) that trigger a behavior.
- Example: A bird sings because of hormonal changes triggered by the breeding season.

Development (Proximal):
-How does the behavior develop over the individual’s life?
It looks at the ontogeny of the behavior, or how it is learned or genetically programmed through development.
-Example: A young bird learns the song by mimicking adult birds.

Function (Ultimate):
What is the function of the behavior in terms of survival or reproduction?
This is the adaptive significance of the behavior, such as how it contributes to the individual’s fitness.
-Example: Birds sing to attract mates and establish territory, enhancing reproductive success.

Evolution (Ultimate):
How did the behavior evolve over time?
This question focuses on the evolutionary history of the behavior and how natural selection shaped it. Example: Birds’ singing behavior evolved because it provides a reproductive advantage.

Question 4

LOOK THORUGH SLIDES FOR QUESTION 3

Answer 4

LOOK THROUGH SLIDES

Question 5

Answer all four why questions using the example of lions and all the implications of
infanticide

Answer 5

Causation (Proximal): Male lions engage in infanticide when they take over a pride. This behavior is driven by hormonal changes in the male lion after defeating a rival, which results in an increased testosterone level.

Development (Proximal): Infanticide in lions is not immediately apparent in all males. It is learned over time through interactions with rival males and the experience of competing for mates.

Function (Ultimate): The function of infanticide in lions is to increase the male’s reproductive success. By killing offspring of rival males, he accelerates the female’s return to estrus, allowing him to sire his own offspring sooner.

Evolution (Ultimate): Infanticide evolved because it increases the male lion’s fitness by reducing the time a female spends raising another male’s offspring and by ensuring his genes are passed on.

Question 6

Define the four criteria that must be met in a population for natural selection to occur,
and evolution

Answer 6

Variation: There must be variation in traits within a population.

Heritability: Traits must be heritable, meaning they can be passed on to offspring.

Differential Reproductive Success: Some individuals must have greater reproductive success than others based on their traits.

Fitness: The traits that lead to greater reproductive success are those that increase the individual’s fitness in the environment.

Question 7

Define both natural selection and evolution

Answer 7

Natural Selection: The process by which certain traits become more common in a population because they increase an individual’s chances of survival and reproduction.

Evolution: The change in the genetic composition of a population over successive generations, driven by mechanisms such as natural selection, mutation, gene flow, and genetic drift.

Question 8

Explain how negative frequency dependency in fruit fly foraging gene serves as an
example of how genetics plays a role in the evolution of behavior

Answer 8

In fruit flies, negative frequency dependence occurs when a foraging gene produces two alternative foraging strategies (e.g., “rovers” and “sitters”). The fitness of one strategy depends on its relative rarity in the population:

When one strategy becomes more common, its fitness decreases, and the rarer strategy has higher fitness.
This helps maintain genetic diversity and prevents either strategy from becoming fixed in the population.

Question 9

Explain how genetic variation in blackcaps allowed for evolutionary changes in migration
behavior. Refer to costs and benefits of different migration patterns under different
ecological conditions.

Answer 9

Blackcaps exhibit genetic variation in their migration patterns. Some populations migrate to southern Europe, while others remain in northern areas. The genetic variation in migration is influenced by ecological conditions:

Costs: Migrating involves energy expenditure, exposure to predation, and the risk of bad weather.
Benefits: Migration avoids harsh winter conditions and ensures food availability.
Under different environmental conditions, natural selection favors either migration or staying put, depending on the trade-off between survival and reproduction.

Question 10

Explain the controversy between schools of thought regarding selection on the
individual vs selection on the group (individual vs group selection).

Answer 10

natural selection: organisms with better traits are more likely to survive & reproduce
natural selection: acts on an individual
group: type of natural selection that acts on entire groups of organisms

Question 11

Explain the meaning of the Lack Clutch. Why does natural selection not favor females
laying as many eggs per clutch as they are able to provide for? Be able to explain the graphs that provide evidence for optimality vs maximum.

Answer 11

Lack Clutch refers to the optimal number of eggs a female bird should lay to maximize her reproductive success. It’s the number of eggs that maximizes the chances of offspring survival.
Natural selection does not favor females laying as many eggs as they can provide for because each additional egg increases the cost of parental investment, potentially leading to fewer surviving offspring due to resource limitations.
The optimality theory suggests that organisms will choose behaviors that maximize their fitness under given constraints. Graphs of optimality vs maximum show that there is a trade-off between the number of eggs laid and the survival of those eggs.
STILL ANSWER THE GRAPHS

Question 12

Explain what phenotypic plasticity and reaction norm are. Explain how they allow for
adaptation in a changing environment. Explain the conditions that favor phenotypic
plasticity. Compare reaction norm and reaction bundle.

Answer 12

Phenotypic Plasticity refers to the ability of an organism to change its phenotype in response to environmental variation.
Reaction Norm is the pattern of phenotypic expression of a single genotype across a range of environments.
Phenotypic plasticity allows organisms to adapt to changing environments. It is favored when environmental variability is high and predictable, as it provides flexibility in coping with different conditions.

Reaction Bundle refers to a group of traits that may change together in response to environmental factors.

Question 13

Explain the example of the great tit in Wytham Park, and how the study provided an
example of reaction norm. Describe the graphs and the ecological conditions leading to
shifts in egg laying dates.

Answer 13

In Wytham Park, a study of great tits showed that egg-laying dates varied in response to environmental conditions, such as the availability of food. The reaction norm was demonstrated through shifts in egg-laying timing based on these ecological conditions.

Graph Explanation: The graphs typically show how changes in the timing of egg-laying correspond with changes in environmental variables, illustrating how phenotypic plasticity allows the species to adapt to different environmental conditions.

Question 14

Understand how and why asking specific questions about observed behaviors leads to formulation of testable hypotheses

Answer 14

Asking specific questions about observed behaviors helps to narrow the focus of a study and generates hypotheses that can be tested experimentally. For example, if an animal species is observed to engage in a particular mating behavior, asking “Why does this species display this behavior?” can lead to hypotheses like “This behavior increases mating success by attracting more mates” or “This behavior functions as a deterrent to predators.” A testable hypothesis must make predictions that can be confirmed or refuted through observation or experimentation. These predictions guide the collection of data and the design of experiments or comparative studies.

Question 15

Demonstrate how use of the comparative method can answer questions about
behavioral differences within populations, between populations and between species.

Answer 15

The comparative method involves comparing behaviors across different species, populations, or environments to understand the underlying causes and evolutionary patterns. It helps answer questions like:

Within populations: Why do individuals in some populations perform a specific behavior while others do not?

Between populations: What environmental or ecological factors cause behavioral differences between populations of the same species?

Between species: What evolutionary or ecological factors shape the behaviors of different species?
By examining behavioral patterns across different contexts, the comparative method provides insight into how natural selection and ecological pressures influence behavior.

Question 16

Provide examples of the comparative method as used to answer questions about
behavior.

Answer 16

LOOK IN NOTES

Question 17

Explain how the comparative method was used to explain why different species of gulls
have different nesting patterns (black headed vs kittiwake gulls).

Answer 17

The comparative method was used to explain differences in nesting patterns between black-headed gulls and kittiwake gulls. Researchers compared the nesting behavior of the two species, which differ in the type of environment they occupy:

Black-headed gulls nest on the ground, while kittiwakes nest on cliff ledges.
The hypothesis was that cliff nesting, observed in kittiwakes, offers a better defense against ground predators, while ground nesting in black-headed gulls allows for easier access to food sources.
By comparing the nesting behavior of these two species in relation to environmental factors (predation pressure and food availability), the comparative method showed how ecological pressures shape nesting behaviors.

Question 18

Explain what can and can not be tested using the comparative method alone. What
types of questions can be asked?

Answer 18

What can be tested:
Evolutionary patterns (e.g., why certain behaviors evolved in some species but not others).
Behavioral differences between species or populations.
Correlations between behavior and ecological or evolutionary factors (e.g., how habitat influences mating systems).
What cannot be tested:
Causality in a specific context (e.g., the exact mechanisms behind a behavior).
Experiments that require manipulation of variables (since the comparative method relies on observing existing patterns rather than manipulating conditions).
Comparative studies ask questions about why behaviors vary across species, but how those behaviors are enacted must often be studied using experimental methods.

Question 19

Explain how hypotheses about the social systems of the weaver birds were tested using
the comparative method

Answer 19

The social systems of weaver birds were studied using the comparative method by comparing different species’ nesting behaviors and social structures. Some species of weaver birds build large communal nests, while others build solitary nests. By comparing the species, researchers tested hypotheses about the relationship between the size of the group, resource availability, and the cost/benefit trade-offs of cooperative vs solitary nesting. The comparative method helped understand how social organization in weaver birds evolved in response to ecological pressures, such as food availability and predation risk.

Question 20

Explain the limitations of the comparative method

Answer 20

Correlation vs causation: The comparative method can show relationships between behavior and environmental variables but cannot establish direct cause-and-effect relationships.
Confounding variables: It’s challenging to control for all the factors that might influence behavior, which makes it difficult to isolate the effect of a single variable.
Lack of experimental control: Unlike experimental methods, the comparative method doesn’t allow for manipulation of variables to directly test hypotheses.
Limited to existing patterns: It relies on natural variation and historical data, which may not always be sufficient to test all hypotheses.

Question 21

Explain the differences (advantages/disadvantages) of using comparative vs
experimental method to answer questions in behavioral ecology

Answer 21

Advantages of the Comparative Method:
Useful for answering broad questions about behavior and evolution across species or populations.
Can provide insights into evolutionary history and ecological adaptations.

Disadvantages:
Limited by the inability to manipulate variables directly.
Can only show correlations, not causal mechanisms.

Advantages of the Experimental Method:
Allows researchers to manipulate variables and test hypotheses in controlled environments.
Can establish cause-and-effect relationships.

Disadvantages:
May not always reflect natural conditions, reducing ecological validity.
Difficult to apply to certain types of behaviors that are hard to replicate in controlled settings.

Question 22

Explain how hypotheses about social organization in primates were tested using the comparative method

Answer 22

The social organization of primates, including their group structure and mating systems, was tested using the comparative method by comparing different species’ social behaviors:

Species with high levels of sexual dimorphism (e.g., gorillas) were compared to those with low levels (e.g., gibbons).
By looking at factors like mating competition, group size, and resource availability, researchers hypothesized that sexual dimorphism might correlate with the degree of male-male competition and the mating system (e.g., polygyny vs monogamy).
The comparative method helped determine how evolutionary pressures shaped social structures and reproductive strategies across different primate species.

Question 23

Explain how the comparative method was used to explain differences in rates of sexual
dimorphism (body weight and canine tooth size) in primates and bush crickets (testes
size) and chimpanzees (sexual swelings)

Answer 23

The comparative method was used to explain differences in sexual dimorphism across species:
GO OVER THIS IN MORE DETAIL
Primates: Sexual dimorphism in body size (e.g., gorillas vs gibbons) and canine tooth size (e.g., chimpanzees) was studied to understand its relation to mating systems and male competition.
Bush Crickets: Researchers compared testes size across species to investigate the relationship between sperm competition and mating behavior.
Chimpanzees: The presence of sexual swellings in female chimpanzees was studied to understand how this trait is related to mate competition and mating strategies.

Question 24

Explain how experimentation can be combined with comparative studies to further
support hypotheses tested (put chicken eggshells near gull nest to test impact of
parental behavior of removing eggshells)

Answer 24

Chicken eggshells near gull nests: Researchers might hypothesize that the presence of eggshells near the nest leads to increased predation risk or affects parental behavior. By placing eggshells near a gull nest and observing parental response, the researchers can test the effects of eggshell removal behavior in the context of natural predation risk.
Complementing comparative findings with experiments allows researchers to directly test predictions made from comparative studies.

Question 25

Understand how tests of optimality can provide evidence in support of hypotheses (crows dropping whelks from various heights).

Answer 25

Optimality theory predicts that animals will behave in ways that maximize their fitness under certain constraints. For example, crows dropping whelks: Crows were observed dropping whelks from different heights to determine the height at which the shells would break open, maximizing energy expenditure while minimizing effort. By testing different heights, the researchers showed that crows drop the whelks from an optimal height to maximize the success of their foraging efforts, supporting the hypothesis that animals engage in behaviors that maximize benefits (energy gain) relative to costs (effort).

Question 26

Explain they types of information that can be provided by experimental vs comparative studies.

Answer 26

Experimental studies provide specific, controlled tests of hypotheses, often focusing on causality. They allow researchers to manipulate one or more variables and observe the effects. Comparative studies offer insights into evolutionary patterns, correlations between behavior and ecological conditions, and how behaviors differ across species or populations.

Question 27

Use foraging models (starlings and bees) to explain how behaviors that allow for maximum gain in a parameter evolve as optimal foraging strategies

Answer 27

Foraging models, like the ones used for starlings and bees, are grounded in the idea of optimal foraging, which suggests that animals will evolve to behave in ways that maximize their net energy gain. Starlings: A classic foraging model by Kacelnik (1984) studied how starlings forage for leatherjackets (larvae). The model assumes that the optimal strategy maximizes energy intake per unit of time spent foraging. Starlings were observed choosing patches with the highest energy yield. As they foraged, they encountered diminishing returns (finding fewer and fewer leatherjackets), which led them to switch patches. The model explains how foragers optimize energy intake by balancing the time spent in a patch (where resources are being depleted) and traveling to new patches. Bees: Bees foraging for nectar also follow optimal foraging strategies. In models of honey bee foraging, bees are assumed to maximize the rate of nectar intake. They assess flower quality, the distance to flowers, and energy expenditure. Optimal foraging theory predicts that bees should focus on the flowers that provide the most nectar for the least effort, leading to the evolution of behaviors that maximize gain.

Question 28

Understand that the currencies being maximized are not always obvious, and must be tested

Answer 28

The currencies being maximized in foraging are not always immediately obvious, and they depend on the ecological context. For example: The currency could be energy intake, but it could also be time (how much time an animal spends foraging), predation risk, or reproductive success. To determine the correct currency, researchers need to test hypotheses. For instance, starlings may appear to maximize energy intake, but in certain contexts, time efficiency may be more important if the bird faces high predation risk. Understanding the currency being maximized is crucial, as different currencies lead to different optimal foraging strategies. Researchers must carefully consider the ecological and physiological context to identify which currency is being optimized.

Question 29

Explain how models can be used to test hypotheses about how different conditions, constraints and currencies affect optimal behavior using the example from Kacelnik’s 1984 study with starlings and leatherjackets

Answer 29

In Kacelnik's 1984 study on starlings and leatherjackets, he tested how foraging behavior changes when animals face different conditions and constraints, such as: Patch quality (the abundance of leatherjackets in a patch). Diminishing returns (the decreasing abundance of leatherjackets as they are consumed). The study showed that starlings switch patches when the rate of energy intake in a patch decreases, reflecting a strategy of maximizing energy intake per unit of time. This study demonstrated how optimal foraging theory can be used to test hypotheses about how conditions like diminishing returns, time constraints, and resource availability influence foraging behavior.

Question 30

Explain the Marginal Value Theorem (diminishing returns) using the honey bee example from the 1985 study by Schmid-Hempel. Understand how it was demonstrated that there is a fixed program determining behavior.

Answer 30

The Marginal Value Theorem (MVT) explains how an animal should behave when resources are patchily distributed. The MVT predicts that an animal should leave a patch when the rate of resource gain (e.g., nectar in flowers) decreases, reflecting diminishing returns. Honey bee example (Schmid-Hempel, 1985): In this study, bees were observed foraging from flower patches. As bees deplete nectar from a patch, their rate of nectar collection decreases. According to MVT, the bee should leave the patch when the rate of nectar collection drops below the average rate for the entire environment (i.e., diminishing returns). This concept is crucial in understanding how animals should allocate time between different patches to maximize their energy intake. The study showed that honey bees exhibit a fixed program for foraging, in which they follow a predictable pattern of patch leaving when the marginal gain (nectar intake rate) falls below the average.

Question 31

Explain the economics of prey choice (size) factors into foraging behavior, using the shore crab/mussel study and the starling/mealworm study

Answer 31

Foraging behavior often involves trade-offs between energy intake and the costs of acquiring food. Two examples that illustrate this: Shore crab/mussel study: Shore crabs forage for mussels of different sizes. The study found that crabs prefer larger mussels because they provide more energy, but larger mussels are harder to crack open. As a result, crabs will often balance the energy reward (larger mussels) with the cost (effort to open the shell). The optimal prey size is one that maximizes energy gain per unit of effort. Starling/mealworm study: In this case, starlings foraged for mealworms. A model showed that starlings should select larger mealworms because they provide a greater energy gain, but only if the time cost of finding them is not too high. When smaller mealworms are easier to find and eat, they may be more optimal under certain conditions.

Question 32

Understand the roles of experience (learning, Downy woodpecker) and predictability of environment, as well as currencies (food supply, temperature; yellow-eyed junco and great tit vs marsh < two are examples of risk prone vs risk averse> in foraging strategies

Answer 32

Experience: In the case of Downy woodpeckers, the birds learn to forage more efficiently over time. Birds that have experience with foraging can optimize their search strategies, increasing their energy gain per unit of time. Predictability of the environment: Foraging strategies are also shaped by how predictable the environment is. For example: Yellow-eyed juncos and great tits are risk-prone species that will forage in unpredictable environments even if it means a higher chance of failure. In contrast, marsh tits are more risk-averse, foraging in environments that are more stable and predictable. Currencies: In these examples, animals are often optimizing energy gain, but they may also be considering time, effort, or predation risk depending on the environmental conditions.

Question 33

Explain the role of memory in foraging strategies (using examples such as Clark’s nutcracker, marsh tits, black-capped chickadees)

Answer 33

Memory plays a crucial role in foraging behavior by helping animals remember the location of food sources or patterns of resource availability. Clark’s nutcracker: Known for its ability to store large quantities of seeds, this bird uses spatial memory to remember the locations of its caches. This memory is key to surviving in winter when food is scarce. Marsh tits and black-capped chickadees also use spatial memory to recall where they have hidden food. These birds rely on their ability to remember multiple food caches in a variety of locations.

Question 34

Explain how the hippocampus is used for spatial memory in birds and mammals, and that it is larger in food storing birds and mammals that need intense spatial skills

Answer 34

The hippocampus plays a crucial role in spatial memory, which is essential for animals that store food. In birds like Clark’s nutcracker and mammals like squirrels, the hippocampus is larger in individuals that rely heavily on food caching. This adaptation allows them to remember the locations of stored food and optimize future foraging efforts.

Question 35

Explain how episodic memory, social learning and mental time travel are used by scrub foraging jays

Answer 35

Scrub jays demonstrate episodic memory, which allows them to recall specific events, such as where and when they hid food. This ability allows them to plan for future food needs by remembering past experiences. Social learning also plays a role, as scrub jays can learn foraging behaviors by observing others. Mental time travel refers to the ability to mentally simulate future events (e.g., remembering that food caches might spoil and planning to retrieve them in time). This capacity for future planning helps scrub jays make adaptive foraging decisions.

Question 36

Explain and provide example of the dynamic vs static model of foraging (bluegill sunfish).

Answer 36

The dynamic model of foraging suggests that animals adjust their behavior based on changes in the environment, such as varying prey availability. Bluegill sunfish were studied in a dynamic foraging context, where the fish adjusted their foraging behavior based on the availability of prey size and energy gain. Static models assume a constant environment where animals don’t change their strategies, and decisions are made in a fixed way. The dynamic model emphasizes flexibility, whereas the static model assumes fixed behaviors.

Question 37

Explain and provide examples of social learning (sticklebacks, scrub jays) and the role of ‘local experts’ (chimpanzees, Temnothorax ant and meerkats) in skill acquisition

Answer 37

Social learning: Some animals learn foraging behaviors by observing others. For example: Sticklebacks can learn to forage for certain food items by watching conspecifics. Scrub jays learn caching behaviors from watching others hide food. Local experts: Certain individuals within a group may have more experience or better skills at foraging and can act as “local experts”: Chimpanzees and Temnothorax ants have individuals who are particularly skilled at foraging and can lead others in the group to food sources. Meerkats also rely on local experts to teach younger or less experienced group members how to forage effectively.

Question 38

Explain the premise of van Valen’s Red Queen Hypothesis, define what is meant by ‘Coevolutionary Arms Race’

Answer 38

The Red Queen Hypothesis, proposed by evolutionary biologist Van Valen in 1973, posits that organisms must constantly adapt and evolve not necessarily to gain an advantage but to maintain their current fitness relative to other evolving organisms. The term comes from the Red Queen in Alice in Wonderland, who says, "It takes all the running you can do, to keep in the same place." This highlights the ongoing struggle where evolutionary progress is required just to survive in a competitive environment, rather than improving in absolute terms. A Coevolutionary Arms Race refers to the process of reciprocal adaptation between two interacting species. Each species evolves traits that counteract the evolutionary strategies of the other. This leads to an escalating cycle of adaptation and counter-adaptation. For example, predators may evolve better hunting strategies, while prey evolve better defense mechanisms, and vice versa.

Question 39

Describein detail how daphnia and their pathogenic bacteria have been used to test the hypothesis of coevolutionary arms race.

Answer 39

The Daphnia (a type of water flea) and its pathogenic bacteria provide a classic example to test the coevolutionary arms race hypothesis. In this system: Daphnia are prey to various predators, but they are also infected by a pathogenic bacterium. Over time, Daphnia evolve immune defenses to better resist infection from the bacteria. In response, the bacteria evolve strategies to overcome Daphnia's immune defenses. Through experiments where different generations of Daphnia are exposed to bacteria, scientists observe how host resistance and pathogen virulence evolve in parallel. This arms race between the host and pathogen highlights the coevolutionary dynamic, where each evolves in response to the other's changes.

Question 40

Explain with examples the activities engaged in by predators (or parasites) that involve adaptations acquired over evolutionary time and the counter adaptations acquired over evolutionary time by the prey (or hosts) to mitigate efforts by the predator (parasite) to exploit them.

Answer 40

Predators and parasites engage in long-term evolutionary battles with their prey or hosts, resulting in adaptations and counter-adaptations. Here are examples: Predator/Parasite Adaptations: Venom: Many predators, like snakes or spiders, have evolved venom to immobilize or kill prey quickly. Parasitism: Parasites like tapeworms have evolved mechanisms to invade and reproduce inside hosts without killing them immediately. Prey/Host Counter-Adaptations: Prey Escape Behaviors: Prey species like gazelles use fast running speeds or evasive maneuvers to avoid predators. Host Immune Responses: Hosts like humans or mice evolve immune systems to resist parasitic infections, such as the development of antibodies to fight off specific parasites.

Question 41

Distinguish between, and provide example of these predator/prey adaptations: camouflage, masquerade, aposematic coloration, startle effect.

Answer 41

Camouflage: Animals, like stick insects, blend into their environment, making it difficult for predators to spot them. This strategy helps avoid predation by hiding in plain sight. Masquerade: Some species, like leaf-tailed geckos, mimic objects such as leaves or tree bark. This mimicking of inanimate objects can confuse predators and prevent detection. Aposematic Coloration: Bright, conspicuous coloration (such as in poison dart frogs) signals to predators that an animal is toxic or dangerous. This serves as a warning to predators. Startle Effect: Some animals, like caterpillars, have patterns or behaviors that suddenly startle predators (e.g., a sudden puffing up or revealing bright colors), causing them to hesitate and avoid attacking.

Question 42

Describe the details of the study investigating how blue jays were used in a laboratory study to test hypotheses (and define the hypotheses) explaining why multiple closely related species of underwing moth inhabit forests

Answer 42

A laboratory study investigated why multiple closely related species of underwing moths (genus Catocala) inhabit forests. The hypothesis was that blue jays, known predators of moths, could help explain the differences in moth coloration patterns and their success in avoiding predation. The hypothesis: Moths with more cryptic (camouflaged) coloration should have lower predation rates by blue jays. Blue jays were trained to attack underwing moths. The moths with more cryptic underwing patterns were harder for blue jays to spot, supporting the idea that cryptic coloration helps moths avoid predation. This study provided evidence for the role of cryptic coloration in avoiding predators and explained why moths with more conspicuous color patterns are less successful in forest habitats.

Question 43

Explain what is meant by apostatic, and negative frequency selection.

Answer 43

Apostatic Selection: This occurs when predators preferentially attack the most common phenotype in a population. If a particular color or form becomes too common, predators learn to recognize and target it, allowing less common phenotypes to survive. Negative Frequency Selection: This is a type of apostatic selection where rare phenotypes are selected for because they are less likely to be recognized by predators. In populations of moths, rare color morphs are less likely to be detected by predators, leading to an advantage for the rare phenotype.

Question 44

Explain how cryptic coloration might have evolved (triangle paper on tree that has different patterns leading to different survivorship)

Answer 44

Cryptic coloration, which helps an animal blend into its environment and avoid detection by predators, likely evolved through natural selection. A study on triangular patterns on tree bark showed that moths with color patterns that mimicked the bark had higher survivorship compared to moths with less matching patterns. This suggests that cryptic coloration offers a survival advantage and evolves when individuals that are better camouflaged are less likely to be predated.

Question 45

Describe the relationship between aposematism and crypsis as related to toxicity in frogs

Answer 45

Aposematism is a strategy where toxic or harmful animals exhibit bright colors to warn potential predators of their toxicity (e.g., poison dart frogs). Crypsis refers to the ability to avoid detection through camouflage (e.g., tree frogs). The relationship lies in the fact that many toxic frogs exhibit both aposematic coloration and crypsis. Frogs with bright colors may be toxic, warning predators not to attack, while others may rely on camouflage to avoid detection altogether.

Question 46

Explain how conspicuous coloration in toxic/injurious species can lead to avoidance by predators (chick study)

Answer 46

In a study with chicks, researchers showed that chicks avoid brightly colored toxic/injurious species. This suggests that conspicuous coloration is an effective way for toxic species to avoid predation. Predators quickly learn to associate bright colors with toxicity or danger and subsequently avoid those species.

Question 47

Describe the relationship between gregarious behavior and gregarious lifestyle and aposematism (locust, monarch, etc.)

Answer 47

Gregarious behavior refers to living in groups, and it is linked to aposematism because a group of toxic animals can reinforce the warning signal. For example: Monarch butterflies are toxic and often travel in groups. Their bright orange and black coloration signals danger to predators, and the presence of many individuals amplifies the warning. Locusts also exhibit aposematism, and their gregarious behavior (large swarms) makes them highly conspicuous to predators, deterring attacks.

Question 48

Compare and contrast Mullerian and Batesian mimicry, and provide examples

Answer 48

Müllerian Mimicry: In this form of mimicry, two toxic or dangerous species evolve to resemble each other, reinforcing the warning signal to predators. Example: Heliconius butterflies, all of which are toxic, mimic each other’s coloration. Batesian Mimicry: A non-toxic or harmless species mimics the appearance of a toxic species to avoid predation. Example: The viceroy butterfly mimics the appearance of the monarch butterfly, which is toxic.

Question 49

Explain how conspicuous coloration comes with a cost (expensive to make, expensive to maintain); examples from moths and guppies

Answer 49

Conspicuous coloration, such as that found in moths and guppies, can be costly because: It requires energy to produce bright pigments. Bright coloration can attract not only mates but also predators. For example, guppies with brighter colors may attract more mates but are also more visible to predators. Similarly, moths with bright colors may experience higher predation rates, but if they are toxic, the coloration helps deter predators.

Question 50

Explain how cuckoos manage to parasitize their hosts, and how hosts respond (think about how it happens evolutionarily). Understand egg mimicry by cuckoos, egg discrimination and signature marking by hosts

Answer 50

Cuckoos parasitize their hosts by laying eggs in the nests of other birds. Their eggs are mimicry of the host’s eggs (egg mimicry), which allows the cuckoo to trick the host into raising its young. Hosts respond to parasitism by discriminating against foreign eggs and ejecting them from the nest. Over time, hosts evolve better egg discrimination abilities, while cuckoos evolve to make their eggs more similar to the host’s eggs. Additionally, cuckoos mark their eggs with signature patterns that match the host's eggs, making it harder for the host to detect and reject them.