How did Kenneth Roeder use the command center theory to examine decision making in the praying mantis?
Roeder used the command center theory to show that different brain areas control different behaviors in the praying mantis. He found that after cutting nerve connections, mantises could still attack prey even while mating — proving that separate neural “command centers” coordinate behaviors and can inhibit or release one another.
What is a free running cycle? Do most animals run on a daily cycle based on environmental conditions, a free-running cycle, or both? Discuss an example.
A free-running cycle is an organism’s internal biological cycle that continues without external cues. Most animals run on both daily (circadian) cycles tied to environmental cues and free-running rhythms.
Example: Hamsters kept in constant darkness still show ~24-hour activity cycles, though they slowly drift in timing.
In Class we discussed the infanticidal tendencies of the male house mouse. What type of cycle are these mice on that prevent them from killing their own offspring? What hormone is the likely controller of this Jekyll and Hyde behavior?
Male house mice are on a reproductive (hormonal) cycle tied to mating. After mating, a hormonal timer prevents them from killing their own pups for about three weeks—the same length as gestation.
The hormone prolactin likely regulates this behavioral switch from infanticidal to parental.
Define what an associated reproductive pattern and a dissociated reproductive pattern are, and give an example of an organism that displays each.
Associated is where mating occurs when gonads are active and hormones are high (example: songbirds breeding in spring)
Dissociated is where mating occurs when hormone levels are low often after hibernation. (Example: garter snakes)
Explain with exmaples, some roles of testosterone on animal behavior. Provide examples.
Testosterone influences aggression, territoriality, sexual behavior, and parental care.
Example: Male deer grow antlers and fight during the breeding season due to high testosterone.
Example: In songbirds, testosterone triggers singing to attract mates and defend territory.
How do red-sided garter snakes wake up from hibernation and are able to mate immediately, despite having very low levels of testosterone?
These snakes mate immediately after hibernation because sperm is stored before dormancy and their neural circuits for mating are activated by temperature cues, not current testosterone levels. Their behavior is dissociated from hormone levels.
Do you think mobbing behavior by gulls is due to natural selection? Why or why not?
Yes. Mobbing behavior evolved through natural selection because gulls that defend their nests deter predators and increase chick survival — enhancing reproductive success.
Why can adaptive perfection likely never happen?
Because of trade-offs, genetic constraints, and changing environments. No trait can be optimal for every situation.
How can we use the comparative method to demonstrate that mobbing behavior is adaptive?
Researchers compare related species that do or do not mob. If mobbing species have higher chick survival in predator-rich environments, it suggests the behavior is adaptive.
Many people think that an adaptation is a trait that improves the survival chances of an organism. Under what circumstances would such a trait be an adaptation? Under what other circumstances would a survival-enhancing attribute actually be selected against?
A trait is an adaptation if it increases reproductive success.
However, if it improves survival but reduces reproduction (e.g., avoiding all risks so never mating), it can be selected against.
Why do some butterflies “mud-puddle” in large groups? Explain using the cost-benefit approach.
Male butterflies gather in mud to obtain salts and minerals needed for sperm and reproduction.
Benefit: Nutrient gain for mating success.
Cost: Exposure to predators and dehydration.
This is explained using the cost-benefit approach.
What are the costs and benefits to camouflage?
Costs: less visibility to mates or group members, and often it exerts energy to maintain camouflage.
Benefits: reduced predation and increased survival
What is a Darwinian puzzle? Discuss an example
A Darwinian puzzle is a trait that seems maladaptive but has hidden advantages.
Example: Peacock’s tail — costly to grow and makes males more visible, but attracts females, improving reproductive success
Why do gazelles and other related members stot? Explain as it relates to truth in advertising.
Gazelles stot (leap high) to signal strength and fitness to predators. It’s “truth in advertising”—showing they’re too healthy to catch, discouraging pursuit
Mother bob-white quail live in small groups called coveys over the winter. Using the optimality theory, explain why there is an optimal size of coveys.
Using optimality theory, covey size balances predation risk and food competition.
Small groups: less protection.
Large groups: more competition.
There’s an optimal middle size that maximizes survival and feeding efficiency
How can some groups of organisms develop into a “selfish herd”? Provide an example.
Animals group together to reduce individual predation risk—each tries to be in the center.
Example: Penguins or fish schools, where individuals use others as “shields.”
Explain how Reto Zach used the optimality theory to analyze foraging decisions in the beachcombing northeastern crow
Zach studied northwestern crows dropping whelks to open them. Crows optimized height and size to maximize energy gained versus effort — a test of optimal foraging theory
How to do math to figure out optimal foraging for caloric gain.
Rate = Energy gain / search time + handling time
What are some criticisms of the optimal foraging theory? What are some other factors that need to be considered when applying this? Give an example that was discussed in class.
It ignores risk, competition, learning, and nutrient balance.
Example: Animals may choose safer but less profitable food when predators are nearby.
Ex: Skinks in the enclosure with snake scent spent more time hidden in dark areas compared to the skinks in the enclosure with no snake scent which lead them to eat more and gain weight.
When should game theory be applied to studying the adaptive value of feeding behavior instead of optimal foraging theory? Give an example that was discussed in class.
Use game theory when behavior depends on interactions with others (competitors).
Example: Fish-stealing Terns. Some Terns fish and hunt for their food, and some
Terns steal the fish from the hunters.
What is frequency-dependent selection?
The success of a trait depends on how common it is in the population.
Example: If too many animals
use one feeding strategy, alternative strategies become more successful.
Many non-human primates are attracted to the smell of ethanol. Why would this be adaptive? Do you think humans drinking alcohol is an adaptive trait? Why or why not.
Some primates eat fermenting fruit because ethanol signals ripe, energy-rich food.
For humans, alcohol consumption may have been adaptive historically, but today it’s largely maladaptive due to social and health costs.
Discuss the possible evolutionary steps that explain the adaptation of the complex waggle dance done by honeybees.
Likely evolved from simpler orientation dances that indicated flower scent and direction. Over time, these signals became more precise, encoding distance and angle to food sources, making foraging highly efficient.
