BIO EXAM 2 - PRE/POST lecture questions

true or false: All else being equal, species that have a greater overlap in resource utilization curves are more likely to be stronger competitors than species that have little overlap in resource utilization curves.

True

true/false: A virus is likely not spreading if R0 (R nought) is much greater than 1.

false; when r nought is greater than 0 the infection will spread

true/false: all microparsites and endoparasites

false; something like a fungal infection is on the outside of the body

what does a realized niche contain?

(biotic components)

what are possible reasons why we see the existing trend in species diversity in terrestrial systems?

- Lower latitudes lack seasonality and have greater species specialization - The tropics have existed for longer uninterrupted periods.

Experiments performed in the rocky intertidal zone by Robert Paine showed that the experimental removal of a predator had dramatic consequences to the structure of the community. What was the ultimate conclusion of this study?

- predators mediate coexistence & reduces number of individuals that dominant - increases species richness

When looking at a simple model of species richness based on a single resource, species richness may be determined by:

- range of available resources - level pf specialization of species on resources - level of overlap pof the usage of resource by species - level of interspecific competition

Plants can produce chemical defenses against herbivores for what reasons and how

- response to herbivory - deter species of herbivores - at an energetic cost - not in response to mechanical damage

Competition between individuals of the same species can have effects on their ________.

- survival - growth - reproduction - access to mates

If one were to plot species numbers in a community after a major disturbance over a long time period...

1. Species numbers would be low right after a significant disturbance. 2. Species numbers would be highest midway through the time toward climax community. 3. Species numbers would decrease some time after the disturbance when strong competitors colonized. 4. Species numbers would theoretically be hump shaped with time.

Parasites are like predators in that they

1. can reduce the competitive impacts of otherwise dominant competitors 2. can reduce the fitness of the organism on which they are preying upon or parasitizing

There is a species of sparrow in the forest. One day a new species of sparrow is introduced from another continent. Both species eat nearly the same size of seeds. What are possible outcomes of their interaction?

1. character displacements results in sparrows eating slightly different sized seeds and species coexist 2. resource partitioning results in sparrows eating slightly different sized seeds and species coexist 3. Competitive exclusion results in one species driving the other locally extinct

A pathogen would spread less quickly if...

1. small host population 2. many individuals were immune 3. unfavourable conditions 4. strong host immune system

Which of the following gerbils is most likely to have the strongest behavioral response (measured by the amount of time hiding rather than foraging) in response to the risk of predation from a fox?

A gerbil that is not good at out running fox's and will die of of old age in 5 years (unless it is killed by a fox).

What is an example of a trophic cascade?

A mountain lion preys upon deer and as a result the abundance of a grass species dramatically increases.

what type of interaction is a gopher who digs a hole in a patch of grass?

Amensalism

Which of the following is the correct sequence of dominant vegetation in a community undergoing succession? 1. annual weed 2. early successional trees 3. shrubs 4. late successional trees 5. herbaceous perennials

Annual weed -> herbaceous perennials -> shrubs -> early successional trees -> late successional trees

What might be considered primary succession:

Colonization of a newly formed volcanic island. Colonization of exposed land after glaciation retreat.

A single algal species competes for a required resource, silicate. As the number of individuals increases, there is less silicate available for the original individuals. This is an example of:

Exploitation (competition)

True/False: Ponds with high levels of nutrients (such as nitrogen or phosphorous) tend to be more diverse than ponds with moderate levels of nutrients.

False; eutrophication -- Very high levels of nutrients tend to result in r-strategists dominating which leads to lower biodiversity.

true/false: Because exploitation interactions involve a +,- relationship, the + and the - balance each other out, such that exploitation interactions do not have ecosystem level impacts.

False; the +/- do not balance each other, the minus indicates a negative impact on a certain species, so exploitation affects the species with the -

The Competitive Exclusion Principle states that:

If two competing species coexist in a stable environment, then they do so as a result of niche differentiation.

You have been studying a plant species for the last three years. On a trip to the Isle of Deerlessness you notice that the same plant species has a different leaf morphology compared to individuals on the mainland. Specifically, the island plants do not have sharp points around the perimeter of each leaf and are instead very smooth. You also learn that this island is devoid of deer, which specialize on this plant. Which hypothesis regarding the morphological differences between these plants is most reasonable?

Leaves have little need on the island for morphological defenses because their primary predator is not found there.

Which of the following behaviours is most likely to be observed in a predator exhibiting optimal foraging: ________

Leaving a patch of prey when encounter rates get low

Who challenged the ideas of Hairston et al. and what did they contend?

Murdoch - the world is green because herbivores are limited by the defences plants have evolved.

If prey are experimentally protected from predators then, all else being equal:

Prey numbers may increase but then potentially decrease when resources become limiting

What term characterizes the equilibrium point for species richness of an island?

S*

Which accurately defines species richness?

Species richness is the total number of species in a community

When considering ecological models one must keep in mind...

That ecological interactions in nature are typically more complex than a given model provides for

You are assigned the task of determining species richness in a given area. The lead researcher has told you that the number of samples you have to take is not limited. As you collect data, what pattern should you expect to see?

The most common species in this space will likely be identified first, followed by more rare species.

According to the theory of island biogeography, how would the number of species found on a small island far from mainland compare to a larger island or a similar sized island that is closer to mainland?

The number of species on the small, far island will be less than on the near, larger island.

If a plant were grazed upon by individuals of a snail population, and the plant produced compounds to deter further feeding, then what might occur?

The plant may experiences a trade-off of some sort, because there is likely a cost to producing the compounds that deter grazers.

what is an accurate definition of primary productivity?

The rate at which biomass is produced per unit area or volume through photosynthesis

Think of a scenario where wolves are introduced to an island where elk live. This elk population has not been in contact with wolves for thousands of years. What will most likely happen?

There is an evolutionary arms race, where elk evolve defenses as wolves continue to evolve to overcome those defenses.

True/False: Biodiversity generally tends to be high in low latitudes, and low in high latitudes.

True; higher evolutionary rates due to shorter generation times in the tropics have caused higher speciation rates and thus increased diversity at low latitudes.

true/false: Predation and grazing typically have a negative impact on the fitness of the organism being consumed.

True; it is typically a +/- interaction where the organism being consumed has its fitness negatively impacted

Which scientists are credited with the theory of island biogeography?

Wilson & MacArthur

A niche for a species of salamander is determined by the density of individuals in the area, soil temperature, amounts of precipitation, and food availability. Thus, the niche would be modeled as a:

a four dimensional niche

What term describes structured analyses that use large numbers of data sets to discern consistent trends?

a meta-analysis

what is true about a realized niche?

a realized niche is typically smaller than a fundamental niche

A spider that spins a web to capture prey would be considered...

a sit and wait predator

what does a fundamental niche contain?

abiotic components (temp, moisture)

what refers to the mass of organisms per unit area?

biomass

If all trophic levels are being controlled by the abundance of resources available to plants it would be called _____________.

bottom up control

What do you call a series of similar communities that are in different stages of succession all in order?

chronosequence

You determine that two species of birds coexist in the same tree, but that they have different feeding behaviors that prevents them from competing with one another for resources. One bird species feeds on insects found in the bark of this tree, while the other bird species feeds on insects at the branch tips. One explanation of your observation could be that:

coexistence is due to niche differntiation

what type of interaction happens when a beaver makes a dam which creates a habitat for a species of fish?

commensalism

what type of interaction happens when a raccoon and a crow fight over some edible garbage?

competition

what type of interaction happens when a cow eats grass?

exploitation

true/false: "Optimally foraging" children, seeking to sell water, should all stand on the same side of the road.

false

true/false: The tragedy of the commons is a pervasive phenomenon that cannot be overcome.

false: Elenor Ostrom talks about how communities overcoming the tragedy of the commons.

true/false: Most parasites are lethal to their hosts.

false: there would be an impact on the parasite's own fitness if it was very lethal to host species.

True/False: According to the intermediate disturbance hypothesis we should expect the lowest levels of diversity at intermediate levels of disturbance and the highest levels of diversity when disturbances are frequent or rare. This is because when disturbances are frequent we get many r type species, and when disturbances are rare we get many K type species.

false; The intermediate disturbance hypothesis predicts the highest levels of diversity at intermediate disturbance rates, because there is a mix of r and K species.

True/False: Game Theory typically considers games with only one player.

false; applies to situations with more than one player. Decisions depend on what other players are doing.

true/false: K - selected species tend to be pioneer species (those that show up early in the process of succession) and r -selected species tend to be climax species (those that are common in late succession).

false; opposite is true -- r type are pioneer and k type are climax

true/false: Predators kill individuals, and therefor always tend to reduce biodiversity.

false; predator mediated coexistence

An optimally foraging organism is trying to maximize it's_______

fitness

Which type of organism typically does not kill their prey, but consumes part of each prey item, and does not need a host?

grazer

Snowy plovers, a coastal bird species, are found to live only on sandy beaches. Where snowy plovers live is referred to as their:

habitat

characteristics of microparasites?

includes bacteria, protozoans, viruses and some fungi multiply directly in host many intracellular can often regulate host populations

In theory, the number of plant species _____________ as the size of islands increases.

increases

If the Ro of a pathogen was 10 the prevalence of this disease in a population would be...

increasing

If a plant produces chemical defenses in response to grazers this could be called

induced response

Competition between individuals of the same species is which type of competition?

intraspecific competition

In a two-species interaction, one species is a better competitor than the other. The weaker competitor may be able to persist if...

it is better at something some time, some where, or some how

Any species that has a low abundance but exerts strong effects upon the community through multiple trophic levels would be considered which of the following?

keystone species

Beavers build dams that create flooding that creates abundant aquatic habitat. They might be considered ______________?

keystone species

The connection between food web complexity and stability is more complex than once thought. Currently we think that populations are actually _________ stable when the web is complex and the aggregate whole community might be _________ stable when the web is complex.

less, more

You are conducting a biodiversity survey of all the organisms in a field outside of Ithaca. You record 24 species of plants and 6 species of mammals. Given this data, how many parasites can you expect to find?

many more than 30

In the myxomatosis-rabbit system, the two vectors were...

mosquitos and fleas

what type of interaction happens when a hummingbird pollinates a flower?

mutualism

What reasons explain why Myxomatosis virulence declined in European rabbits outside of their native range?

myxoma virulence was elected against intermediate virulence was selected for there was selection for increased transmissibility

Which of the following is the best measure of effectiveness of optimal foraging.

net rate energy intake

what type of interaction happens when a sparrow and a squirrel forage for different foods in the same forest but do not interact or affect one another

neutralism

Assume that resources for a community of species are available on a continuum. A common species of bird utilizes a particular portion of this continuum. What term defines the length of the portion of resources that this bird uses?

niche breadth

According to the predictions that make up the theory of island biogeography, how long does it take for species to reach equilibrium?

no set time

It would be most difficult for a species to invade a community where the resource utilization of current resident species ________________.

overlaps

Mistletoe is a plant that grows on other plants and is best categorized as a

parasite

What type of organism relies on a host, but it does not usually kill it?

parasite

What is a metapopulation?

patchiness in a population that allows it to function like many connected smaller subpopulations.

Parasitism is most similar to...

predation

An island is newly formed by a volcanic eruption. You want to follow what happens with plant communities on the island. What type of succession is this?

primary succession

For any given species, there is a _______, which describes the niche that occurs under normal circumstances of interspecific competition within a community and typically differs from the hypothetical ______, which describes the niche that the species would inhabit if interspecific competition was removed.

realized niche, fundamental niche

Some marine mussel communities do not change even after strong storms. They might be considered ______________?

resistant

what refers to the rate of production of biomass by heterotrophs?

secondary productivity

Anthropologists have long wondered what happened to the inhabitants of Easter Island. It is clear that part of the island was land used for farming. Which of the following likely occurred after the island was depopulated?

secondary succession

If a plant evolves a defensive chemical to ward off herbivory how do we expect an insect herbivore to evolve?

the insect herbivore may evolve resistance to the chemical.

In which of the two examples of a community is species richness greater: A community with 100 species that can all be found equally within a 25 km radius of the area A community spread across the same area that has 100 species, in which 5% of the individuals are rare species.

the species richness is the same (why? section 10.1 and lecture)

The breeding sites of Virginia's warbler and orange-crowned warblers overlap in central Arizona. When one species was experimentally removed, the remaining species fledged greater percentages of young per nest. The experimental removal of one species indicates that

there is interspecific competition

According to Hairston et al., why is the world green?

top down control on herbivores

True/False: An evolutionary stable strategy (ESS) is one that, when adopted by an entire population, cannot be invaded by an alternative strategy.

true

true/false: Large African herbivores will shift their preferred foraging areas in the presence of predators.

true

Which type of organism attacks their prey, kills it, and then consumes it?

true predator

true/false: In basic models optimally foraging organisms could maximize fitness through energy rate maximization, however this would not work perfectly for many foraging organisms in the real world, because they must also respond additional factors like predation risk.

true; There are important tradeoffs between food and safety. Most models will not be perfect because they cannot account for every factor in the environment.

true/false: Predators can sometimes have little impact on prey populations.

true; - low predator population - prey high rates of growth - predators kill prey that were not reproducing or sick

true/false: When considering the energetic gain of an optimal forager, it is important to consider that there are also energetic costs.

true; All foraging activities will typically have both costs and benefits.

true/false: Dominant species tend to have more of the biomass in a community than keystone species.

true; Dominant species are those that are common in the community and therefore make up a great deal of the biomass.

true/false: Ectoparasites have an easier time spreading than endoparasites.

true; endoparasites have to find ways to leave the host body meanwhile endoparasites are already on the outside of the body.

true/false: Parasite & host populations can fluctuate in ways that are similar to predator-prey population cycles.

true; when the infection threshold is high, many hosts are infected, some may die, reducing the number of hosts for the parasites, therefore affecting the parasite. OR hosts become immune, and are not susceptible to the virus, effecting the parasite.

According to Joseph Connell's theory regarding disturbance, when would communities be expected to contain the most species?

when the frequency of disturbance is at intermediate levels