ecology exam 1
What are the four basic areas of ecological research
Population Organismal Community Ecosystem
What are two examples of species that show little or no signs of senescence?
Rockfish Naked mole rats
What is the climatic factor that most strongly influences the phenology of tree swallows in Alaska? Has this aspect of climate changed over the last 30 years?
-The wind affects their ability to feed because they feed on insects in the air and the wind makes it harder to capture these birds.This --Aspect of climate has changed over the last 30 years. It's becoming less windy with climate change, wind and temperature affects their lay and hatch dates. Hatching earlier each year
Be able to draw versions of figures 8.6 and 8.8, and describe the main predictions about foraging decisions that these figures summarize. Be able to describe how researchers have tested the predictions made by optimal foraging theory.
8.6 Looks at cost vs benefit when choosing prey The model can be used to test whether animals forage in a manner that results in the maximum benefit, based on estimates for the total energy obtained and the cumulative energy invested. 8.8 When animals have a long time to travel they will deplete the food source, when they have a short time they will not Long: wolf, short: small birds The marginal value theorem assumes that a foraging animal will encounter patches containing varying amounts of food. The animal's rate of energy gain in a patch is initially high but decreases as the animal depletes the food supply in the patch. The time the animal spends in a patch should optimize its rate of energy gain.
Adult male lazuli buntings could be said to cooperate with dull yearling males, or could be said to exploit them. Explain what their interaction is, and why either term is reasonable.
Adult males cooperate with the dull yearlings by allowing they to have a nice place to live, which allows them to possibly mate with females, but they do this for selfish reasons Adult males exploit dull yearlings because allowing dull males to live near them, they make themselves look incredibly attractive by comparison and end up mating much more.
The differences between autotrophs and heterotrophs determines many ecological adaptations. What do these terms mean?
Autotroph- Autotrophs make food for their own use, but they make enough to support other life as well. Almost all other organisms depend absolutely on these three groups for the food they produce. Heterotrophs- cannot make their own food, so they must eat or absorb it. For this reason, heterotrophs are also known as consumers. Consumers include all animals (except symbiotic species) and fungi and many protists and bacteria. They consume either autotrophs or other heterotrophs.
you are crossing a frozen river with a relative, and you both fall through the ice. She pushes you back onto the firm ice, but as a result is so wet and cold she will surely die. Her last words to you are, "I know that we have always said we each wanted only one child before we die. But to make my sacrifice worth it, so I can die happily, please have at least 6 children."She then slips into the inky depths... how related are you and she?
B*r-C>0 6*r-1>0 6 * 1/6 1>0 **in these equations you can solve for "r" and make life a lot easier
What is Hamilton's rule? Describe what each of the 3 terms in this equation mean. Using this equation, answer the following questions:
B*r-C>0 B= benefit to relative C= Cost R= relatedness
let's say that your future expected number of offspring is 2. For you to give your life for your sister, how many more offspring do you expect her to produce, as a result of your sacrifice?
B*r-C>0 B*½-2>0 5*½-2>0
Is most speciation thought to occur because of disruptive selection? If not, what process does cause speciation?
Barriers of geographic isolation cause speciation because the barriers cause forced selection.
Draw a figure that describes how the balance of costs and benefits of eating different sized prey determines the most favored prey size.
Benefits plateau while costs increase exponentially.
Outline the logic that would suggest that smaller birds can't live in conditions as cold as those that bigger species can tolerate. Also, describe why this pattern doesn't hold up in nature.
Body mass theory: large creatures fare the cold better than small creatures because their metabolic rate increases less rapidly — it takes them longer use their stored energy Counter: Chickadees in CO will huddle together for warmth, find an enclosure (in snow), or hibernate (torpor)
What are some of the most important factors that can limit the ranges of species?
Climate Food sources Predation
What is the difference between conduction and convection? What is a major way that plants cool their leaves?
Conduction = direct transfer of energy from warmer (rapid) molecules to cooler (slower) molecules Plants cool themselves when the surrounding atmosphere heats up, plants will often release excess water into the air from their leaves. By releasing evaporated water, plants cool themselves and the surrounding environment.
Give an example from the lecture of evidence that species have evolved to have peak physiological performance at the environmental conditions they experience in nature. Similarly, is there evidence of evolution of physiological flexibility? Also, give an example for each of these patterns from the text.
Crossbills have peak physiological performance due to the fact that their beak of different sizes create a specialization for different kinds of pinecones. The ones with small beaks are the best at obtaining energy from a certain kind of pinecone, while the ones with large beaks are the best at obtaining energy from another kind. Physiological flexibility is seen in the form of social monogamy and extra-pair mating. Although birds socially have a partner, they mate with others in the hopes that their offspring will be more fit. An example of this is the Lazuli bird.
What is an advantage to female birds in engaging in extra-pair copulations? What is the main cost to a male or female bird in having a mate who engages in extra-pair copulations (these are different for males and females).
Extra pair copulations allows the species best and most favorable traits are passed down while other fathers care of the younge Male costs Birds are defending kids that are not theirs, not good evolutionarily Male benefits Increasing fitness if you are doing it Female costs She gets less help from the dad who is getting it on Female benefits More genetic variation Females can try and mate with the most impressive males but have a father for kids
What is cross-adaptation (or pre-adaptation)?
Faster adaptation to things that are more similar EX: DDT and an insect
Describe Why fishing pressures will alter the optimal life history traits for fish. What are examples for cod and silversides of traits that can be shifted by fishing pressure?
Fisheries go after the biggest fish and because of this fish are adapting to not grow as large.
What is genetic drift, and how is it different from gene flow? For what kinds of populations is genetic drift typically most important? How can gene flow slow evolution?
Genetic Drift: variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce. In the absence of strong selection, it is very random Gene Flow: Species travel between populations and genes are shared, it keeps populations from drifting too far apart. Most important for small populations because random consequence can make it that those who carry unpopular genes will not mate and die off
What is the different lines of evidence from the Darwin's finches studies that show that evolution occurred?
He started to understand, after noticing a variety of similarly related species with slight adaptations as he went from island to island. He began to realize that island isolation resulted in their varying adaptations to that island's environment. Saw that there were changes is phenotypes in reaction to food changes
What are the 4 prerequisites for evolution by natural selection to occur? Think of why each of these is necessary for evolution by natural selection to occur. In other words, how would the lack of each of these features prevent evolution from occurring?
Heritable variation Not clones of parents More offspring are produced than survive (selection) Heritable differences determine who survives and reproduces
What factors determine the extent of parental investment in their offspring?
How many offspring they have, how big they are, resource availability
If an animal has to travel long distances between food patches, will it spend more time or less time in each patch than if patches are close together? Both give your answer and describe why this pattern exists.
If an animal has to travel a large distance it will spend more time at a patch of food, if an animal is traveling a short distance, it will spend less time at a patch of food. They stay long because of the high energy 'cost' of travel and stay for a short time because they can quickly get the easiest, most profitable food Predation causes potential deviation from this pattern and thus suboptimal behavior in terms of food acquisition
What two attributes of cane toads have showed directional evolution in Australia. Describe where these changes have occurred in the toad's range and why they are adaptive.
Longer legs, hop faster, and are more hyperactive. Frogs have these traits when they are located on the boundary of invasion, which therefore speeds up rate of invasion.
Why do most birds lay far fewer eggs than they could rear?
More eggs decreases the egg quality
Two different genetic processes make offspring different than their parents. What are these?
Mutation and recombination
What are niche models and what do they seek to predict?
Niche model - Tool that predicts a species' geographic distribution based on the environmental conditions at locations the species is known to occupy.
What are the factors that make being an annual seem clearly beneficial, rather than having delayed reproduction? In contrast, what are two of the primary reasons that can favor surviving for more than one year and reproducing repeatedly?
One of the reasons reproducing repeatedly was seen as beneficial was because you get like "multiple rolls at the dice" in case conditions are not favorable one year not all your eggs were in one basket.
What is a "complex life history"?
Patterns of growth, survival, and reproduction over your life. (your life cycle) Eg. Survivorship patterns Age at first reproduction Total number vs. size of offspring Mature individual size As with physiological and behavioral ecology, the balance of costs and benefits of different strategies At least two distinct stages that differ in their habitat, physiology, or morphology metamorphosis
What is a complex life history? What is the general explanation for why complex life cycles have evolved?
Patterns of growth, survival, and reproduction over your life. (your life cycle) Is one which there are at least 2 distinct stages that differ in their habitat, physiology or morphology. There Is an abrupt transition between habitats or forms. Ex. caterpillar to butterfly Typically outliers Different animals in different environments and at varying levels of the food chain have adapted complex life histories depending on what is best for that species survival Stage specific selection pressures
What is physiological Stress? What is a definition of acclimatization? Ecotypes?
Physiological Stress → stress coming from an outside source that affects the organisms biological function Acclimatization → a type of adaptation but is short term and reversible in order to reduce physiological stress Ecotypes → populations with adaptations to a specific, unique extreme environments.
Give at least 3 examples of life history trade offs [from either the book or lecture]. For each, explain what functions or traits the tradeoff is between and what determines the balance of the two or more traits.
R selected have as many offspring as possible, the trade off is only a few will survive. While K selected species will have few children and raise them Trade offs between lifespan and reproduction time Humans can take care of their young but diseases that come later in life may pass down through genetics and hurt your offspring Lots of eggs= maturity faster and greater sprint speeds Molerat Yellow rockfish Tradeoff between the number of seeds per plant and the size of each seed
.Describe why species that are 'r' vs 'K' selected differ in their life history traits. Also, give at least 4 examples of traits that differ between these groups.
R-selected is selection for high population growth rates (r is for growth rates) K-selected is slower rates of increase, for when approaching K, or carrying capacity. (Don't really remember examples)
What are the two factors that control the speed of evolutionary change, as shown in the breeder's equation? Be able to explain what each term in this equation means with words or a figure.
Response to Selection = Heritability of a trait x The strength of selection
Why in at least some lizard populations do the fastest runners not have the highest fitness? What evidence is there that a tradeoff with other Important Traits exists for fast running?
Running fast is not always an indicator of fitness Lizards trade off speed for endurance and clumsiness Trade-offs for tree-living creatures are between speed, size, and falling
What is a semelparous vs. an iteroparous species? What are two examples of each kind of species?
Semelparous: reproduce once over lifetime (like annual flowers) Iteroparous: multiple bouts of reproduction
Describe Why fishing pressures will alter the optimal life history traits for fish. What are examples for cod and silversides of traits that can be shifted by fishing pressure?
Since the largest fish are being hunted for, only the smaller fish are left to breed, since being small is giving them a better chance at survival and reproduction, the population shifts to grow smaller with generations time.
Similarly, what are two attributes of a predator of cane toads have showed directional evolution in Australia. Describe where these changes have occurred in the toad's range and why they are adaptive.
Snakes that were not local to the cane toads would eat them not knowing they were venomous and would not be able to digest the toad whereas the snakes that did live around the cane toads would eat them and be adapted to their poison so they could digest them.
Snowshoe hares are an excellent example of a species with an excellent adaptation that becomes extremely bad with changing climate. Explain what this adaptation is and why climate change has rapidly altered its value to these bunnies.
Snowshoe hares turn white (from its brown) in the winter to blend in with snow. But since climate change has been making winter start later and end earlier, when the warm melts the snow early, the round is no longer white but the snowshoe hares are.
Why do Venus fly traps let go of many insects that they have trapped?
Some of them are too small and are not worth the energy so they will wait until they can get a full meal. It would be a waste of energy to try and keep the small fly when they could let it go and catch bigger flies while saving energy. → opportunity costs
What are the two general explanations for why natural selection can't easily select for traits that favor continued health into old age? Make sure to describe the reasoning behind each idea.
Species would die sooner with testosterone in their body (why though) Sometimes you have to consider the tradeoffs. Even if you have longevity you might not find a mate. Natural selection will select traits to get you to reproductive age but stops after that.
Describe the differences between stabilizing, disruptive, and directional selection.Stabilizing selection is the hardest type of evolution to describe to people unfamiliar with how evolution works- how is stabilizing selection a form of "evolution by natural selection"?
Stabilizing What will physically successful reproducing adults children look like when they are ready to reproduce Bell curve widens before selection Ex. siberian foxes Disruptive The mean is broken up and the species ends up having either extreme Ex. african finch Directional When the mean is unsuccessful, the bell curve shifts in a direction to benefit the species Ex. wild dogs
What is one example from the text or lecture for each of stabilizing, directional, or disruptive selection?
Stabilizing : siberian foxes Directional: african finch Disruptive: wild dogs Bulldogs & Foxes= directional, street dogs & giraffes=stabilizing, african finches=disruptive
What Is similar about the ways that temperature Influences ectotherms and endotherms?
Temperature causes both to modify their energy balance by either transpiration (terrestrial plants) or behavior (animals). Behavioral or morphological adjustments. Shivering to warm up/sweating to cool down (endotherm) Seeking sun warmth (ectotherm)
Describe how the crossbill studies of Craig Benkman show evidence of natural selection. What is a possible cost of being a crossbill that is well-adapted to feeding on one kind of cone?
The crossbill birds have beaks that are specialized for pine nuts. Since these beaks allowed them to specialize in this beak size determines feeding efficiency. This leads to picking mates based on their feeding efficiency therefore influencing sexual selection. A possible cost to being a crossbill that is well-adapted to feeding on one kind of cone is that with the earth getting warmer, less of the trees they feed on are available.
Phenotype
The physical appearance
What are the assumptions that are made in turning mark-recapture data into a population size estimate?
The proportion of marked individuals found in the second capture is used to estimate the total population size.
What is the thermoneutral zone? What happens to a species when it is outside this zone?
Thermoneutral zone: the range of environmental temperatures over which endothermic animals maintain a constant basal (resting) metabolic rate If the temperature gets below this zone, the animal's body temperature drop which triggers an increase in metabolic heat generation
Why does pesticide and antibiotic resistance increase so rapidly? Also, describe a strategy to use pesticides to control pest species that would slow the spread of resistance
They are able to adapt quickly with many generations and they don't turn over crop pesticide so they get used to it
Explain why at aspects of their biology make tree swallows highly sensitive to the climatic factor you list in the question above.
They feed in the air and faster winds make it harder to catch these insects. Have difficulty thermoregulating in the first 10 days of life, so have to hatch while its warmer
Are the "frozen frogs" of Chapter 4 really frozen? Explain.
They hibernate. Climate change can rapidly affect them by having smaller children, not knowing when to unthaw and not freezing at all The area around the cells freeze, so when the thaw, they do it very quickly to avoid the sharp ice cutting them and to prevent other cells from dying Yes. The water outside of their cells are freezing, not inside their cells, but they have ice-nucleating proteins that slows the process of freezing. They then produce solutes in order to lower the freezing point inside the cells, maintaining a liquid interior. The thawing process is extremely rapid as compared to the freezing process due to the fact that thawing could potentially result in ice crystals penetrating cells. They don't completely freeze: just 35-65% of the water in their bodies; they freeze either underneath leaf litter or under the water so they still have some warmth (this is from Rayna from recitation)
Why do small bodied species [such as insects] often show faster evolution to pesticides than to large-bodied species [such as birds and mammals]?
They reproduce more often and small bodies are able to change their cells quicker than large bodies because they are small
What are two distinct ways in which mosquitoes have evolved resistance to DDT?
They will fly far away from wall that have DDT instead of resting on them
What is the difference between transpiration and evapotranspiration?
Transpiration is the evaporation of moisture from plants, This process helps to lift needed water to the tops of plants, Transpiration affects the climate of the surrounding environment cooling the atmosphere nearby. Transpiration is also an important part of the water cycle. Evapotranspiration includes the transpiration that occurs in plants. The term is more inclusive as it also includes evaporation of lakes, streams and oceans. All transpiration is part of the evapotranspiration of the water cycle. However not all evaporation is transpiration, only the evaporation from plants is transpiration.
Speculate about the costs of using tools to help acquire food-are there clear costs to these behaviors? What are the main benefits? What do these costs and benefits imply about the kinds of species that should and should not evolve to use tools?
Use of tools requires you have to have the intelligence in the first place. This requires a larger brain (which requires more energy) and a brain takes up a ton of space. Sometimes there are animals that are not smart, and that can be the result of having no space for those brains to be stored in their bodies.
What is runaway selection?
a sexual selection mechanism to account for the evolution of exaggerated male ornamentation by persistent, directional female choice.
Adaptation
any alteration in the structure or function of an organism or any of its parts that results from natural selection and by which the organism becomes better fitted to survive and multiply in its environment
What are two examples from the lecture of traits that are governed by simple Mendelian inheritance? What does this mean?
genes and alleles -examples: Sickle cell anemia and favism
Population
group of organisms of a species that interbreed and live in the same place at a same time
Locus
is a fixed position on a chromosome, like the position of a gene or a marker
Why are marine species that live in deeper waters generally longer live
less disturbances
.Describe what reproductive value means. Draw a curve of reproductive values vs age for human females.
measure of. the relative reproductive potential of. an individual at any age Reaches an apex of optimum reproductive capacity around age 20? and then declines steadily until age 55?
Abiotic
non-living chemical and physical parts of the environment
Allele
one of the possible forms of a gene (dominant and recessive)
What aspects of the environment can make speciation more or less likely to Occur?
predation
What are the main selective forces influencing the color of male guppies? Under what circumstances will males be colorful, and when will they be dull?
predators
What is a one sentence definition of phenotypic plasticity?
the ability of one genotype to produce more than one phenotype when exposed to different environments
Why do kiwis invest in a small number of big offspring, vs many birds that have many small ones?
the kiwis don't really have any predators. So they don't need to have a lot of kids (like some birds do to make up for many dying). They just raise a small amount and invest a lot in them in order to carry on their gene pool. Because they have no predators and a high carrying capacity, their biggest limiting factor if food so its worth to invest more in one youth than risk losing more due to lack of food
What are opportunity costs?
the loss of potential gain from other alternatives when one alternative is chosen. Example: when a lion choses to kill a zebra or a gazelle, what energy are you losing, gaining
nutrient cycle
unidirectional and noncyclic pathways, whereas the movement of mineral nutrients is cyclic that continually recycle along with other mineral nutrients into productive ecological nutrition.