Exam 3 Flashcards
Optimal Foraging Model Definition
addresses the optimization of food type, patch choice, time spent in different patches, and movement patterns
What do optimal foraging models focus on
they focus on energy as the currency for optimization, specifically energy gain per cost
Optimal foraging theory (OFT)definition
makes predictions about how animals maximize fitness while foraging
what are the 4 points that are significant to OFT
- individuals maximize energy intake per unit of time
- the energy content of a food item is the only determinant of food choice
- the time taken to capture a food item is the only determinant of food choice
- a higher energy item might be less valuable than a lower energy item if it takes too much time to capture it
natural selection favors…
energetically efficient foraging and feeding behaviors
What are the trade offs in optimal foraging
the trade off is between energy expended in searching and energy acquired from food
currency in optimal foraging models is
the unit that animals optimize for
what does currency represent?
it represents the net energy gain per unit of time
Why do animals adopt foraging strategies?
they adopt strategies to provide the most energy for the lowest cost
What is the best strategy?
The optimal decision rule
how can one determine the best model
by identifying the currency and constraints
Constraints in the foraging model can include…
limits to foraging efficiency
What are some hypotheses about the limitations?
feature of the environment, and physiology
optimal diet model is also called…
the prey choice or contingency model
what does the optimal diet model predict
it predicts that foragers should ignore low-profit prey when more profitable prey is available and that there are different diets based on search times
what does profitability depends on
it depends on energy provided by prey, handling time, and search time
functional response curves show…
the rate of prey capture as a function of food density
What theory is used with function response curves to predict foraging behavior
optimal diet theory
type 1 curve shows
rate of prey capture increases linearly with food density (as prey density rises, predators capture prey faster)
at high prey density for type 1 curves, what does the predator choose?
predators choose prey with the highest E/H (energy gain per handling time)
type 2 curves show…
rate of prey capture increases but then levels off due to handling time limitations (as food density increases, handling time also increases)
at high prey density for type 2 curves, predators choose to…
spend more time handling prey. this leads to diminishing returns
type 3 curve shows…
a sigmoid curve with an initial increase and later decrease in prey capture rate (high prey densities lead to selective prey capture)
at low prey densities for type 3 curves, predators do what?
predators capture prey quickly and switch preferences based on E/H
Marginal Value Theorem (MVT) is applied to….
optimal foraging, especially when deciding to leave a food patch
what factors impact MVT?
prey depletion, increased difficulty in catching prey, search time constraints, and traveling time between patches
Starlings optimize net energy gain by…
traveling longer. this results in a larger optimum load of food
What happens overtime with the starlings as they forage within a patch?
they experience diminishing returns. starlings are able to hold so many within their bill making there a tradeoff between handling time and traveling time
Coevolution definition
the reciprocal evolutionary change between interacting species and is driven by natural selection
coevolution requiers what?
reciprocal evolutionary changes between interacting species driven by natural selection
coevolution involves what type of relationships?
mutualistic, commensal, or predatory relationships
What did Darwin predict with the Star Orchid?
the existence of a moth pollinator for the star orchid based on the nectary length
What did Wallace explain in “Creation by Law”?
that pollination requires a struggle by the proboscis to reach the nectary, shorter orchids were not pollinated due to little struggle between the nectary and the moth to release the pollen
who said “good heavens what insect can suck it?”
Darwin
Georgraphic Mosaic Theory of Coevolution states that…
prey impose selection pressure on predators leading to coevolutionary dynamics.
What drives prey evolution
the asymmetry in the “life-dinner principle”
Evolution Definition
a change in allele frequency in a population over time
Allele definition
a version of a gene that can vary
Example of Alleles
human blood types: A, B, and O are alleles for the blood type gene
How may alleles code for water beetles’ different colors
Three
What causes for some water beetles colors to be favored?
predation pressure
natural selection definition
differential survival and reproduction of individuals based on phenotype
what are the 5 selective pressures of natural selection?
- Predation 2. competition 3. reproduction 4. acquiring nutrients 5. abiotic factors
What is a good example of natural selection during the industrial revolution?
White colored moths and dark colored moths
What coloration was favored before the industrial revolution?
White coloraiton
What coloration was favored after the industrial revolution and why
Dark coloration. The blended into the trees/polluted environment more than the white coloration before the industrial revolution. this lead to a shift in allele frequencies
Sexual selection definition
A form of natural selection focused on mating success
What does sexual selection involve
it involves one sex selecting for specific traits in the opposite sex
True or false: sexual selection drives variation in reproductive strategies among animals
True
What is sexual selection like in many species?
Many species are female driven sexual selection due to the fact that females are choosier due to higher parental investment
What are the different reproductive strategies?
Oviparous, ovoviviparous, viviparous
what do males do for female driven sexual selection?
they produce sounds to attract mating
Where is the sound received?
the tympana
what is the type of competition where male provide more parental care?
during male-male competition
during sexual conflict, what usually happens?
the female’s lifespan is reduced
What are pollination syndromes?
a development driven by pollinators in which phylogenetically unrelated flowers match the preference of their pollinators in form, color, and scent
What was the purpose of the study read for class?
the purpose was to provide evidence to support Darwin’s hypothesis that the pollinator and their preferred flower coevolved to match the pollinator, specifically looking at the hawkmoth, and its preferred flower species, which matches its proboscis
Why isn’t it beneficial for moths to simply feed on nectar from the longest flowers, where more nectar might be found?
the amount of nectar does not directly correlated to the energy gained and energy expended to achieve the nectar. The study determined that N. alata was the most energy balanced flower that M. sexta fed from
Describe the flight response of M. sexta when it encounters a desirable floral plume
M. sexta prefers flowers with corolla length matching its proboscis length, with odor encounter rate being highest in the core of the plume. It navigates without bisual cues and responds with casting flights when lost. N. alata and N. sylvestris also guide it by triggering upwind speeds.
What were some of the problems associated with M. sexta feeding on flowers significantly longer and shorter than its proboscis length?
The study found that the energy gained from nectar is unrelated to flower length, and M. sexta receives less energy in shorter flowers due to low handling. Feeding on N. alata results in a significant positive net-energy gain.
