Biol Exam 4
Which of the following is an important aspect of studying biogeochemical cycles?
How quickly atoms or molecules move from one compartment to another., The sinks or reservoirs where atoms or molecules get "locked up" for a period of time., How humans impact the rate of movement among compartments., How the cycles for different atoms or molecules interact.
Why would a sampling effect lead to higher productivity in an experimental plot?
If a few highly productive species are present in a community, biomass production will be a function of whether or not they are present.
What is the difference between an herbivore and a carnivore?
Herbivores eat plants; carnivores eat animals.
What does it mean to say that parasitism is a "+/- interaction?"
Parasites gain increased fitness; hosts suffer a fitness loss.
What is a metapopulation?
a group of small, geographically isolated populations
What is the natural logarithm of 6.5?
1.87
What is the natural log of 150?
5
What is the natural logarithm of e^6.5?
6.5
What is a wildlife corridor?
A strip of habitat that connects two preserved areas.
What is a coevolutionary arms race?
Adaptations and counter-adaptations that occur over time in +/- species interactions.
What is a biodiversity "hotspot?"
An area where species richness is extremely high.
What is replacement rate?
An average fertility rate that leads to an r of 0.
What is "genetic restoration" of endangered species?
Artificial gene flow that counteracts the effect of inbreeding and drift.
"Diversity leads to stability." This slogan claims that ecosystems with a large number of species present are more stable than ecosystems with a low number of species. Which of the following lines of evidence support this claim?
As the number of plant species increases, resistance and resilience increases
What is asymmetric about asymmetric competition?
One species is a stronger competitor and has a lower reduction in fitness.
What is the difference between weather and climate?
Both are defined by temperature, precipitation, sunlight, and wind conditions. Climate consists of long-term trends while weather consists of short-term events.
What does it mean to say that mutualism is a +/+ interaction?
Both species in the interaction receive a fitness benefit.
What is the outcome of competitive exclusion?
One species is wiped out in that habitat.
Which of the following is an example of commensalism? (sorry for the typo in the syllabus--find this on p1093)
Cattle egrets walk beside cattle, eating insects disturbed by the movements of the cows.
Which of the following is a common cause of density independent growth? a) Colonizing a new habitat. b) Lack of food or other resources. c) Increases in predation or parasitism rate. d) An extremely high rmax (intrinsic rate of increase)
Colonizing a new habitat.
In response to recent climate change, how is overall (global) NPP changing?
Decreasing on land; decreasing in the oceans.
You want to study the fitness effects of competition between two grass species. Which of the following would be the best approach?
Grow each species by itself and in the presence of each other, under identical conditions.
What is ecological restoration?
Efforts by humans to increase biodiversity and biomass in degraded habitats.
How are the frequency and severity of a disturbance measured?
Events per unit time; amount of biomass removed.
What is the nature of the fungal-plant mutualism mentioned in the text?
Fungi provide key nutrients to the plant; the plant provides photosynthetic products.
In most cases, what is the fitness advantage for parasites that manipulate their host's behavior?
Increasing the liklihood of transmission to a new host.
Why is "greenhouse gas" an accurate way to describe CO2's behavior in the atmosphere?
It absorbs (i.e. "traps") energy from infrared radiation reflected from the Earth's surface.
What does it mean to say that a species has a wide niche breadth?
It can use a wide array of values of a particular resource or tolerate an array of conditions.
Why is the U.S. considered a particularly important country in terms of lowering CO2 emissions?
It combines large population size with large per capita emissions.
Why is the geographic structure of a population important? a) It allows you to calculate how much gene flow is occurring. b) It allows you to calculate the impact of genetic drift on the population. c) It helps you predict how the overall population size and distribution will change through time. d) It allows you to calculate the degree of inbreeding.
It helps you predict how the overall population size and distribution will change through time.
Why is age structure important? a) It can be diagrammed as a population pyramid. b) Without it, you can't calculate r. c) It helps you understand the history and predict the future of the population. d) Without it, you can't calculate lambda.
It helps you understand the history and predict the future of the population.
What does it mean to say that a plant community provides ecosystem services? (please look back at p. 1154)
It improves the ability of the abiotic environment to support life
Net primary productivity is a small fraction (often ~10%) of primary productivity. What happens to all of the energy that is "lost?"
It is used to keep the organisms alive (defense, movement, transport of fluids and nutrients, digestion, replacing damaged molecules and cells, sexual display, etc.)
What does it mean to say that an individual has acclimatized to a particular environment? a) It has adapted (has high fitness alleles). b) It has adapted (changed behavior or physiology). c) It has survived and produced offspring. d) Its phenotype has changed.
Its phenotype has changed.
In the experiment on mussels and blue crabs, what hypothesis do the data suggest, but not test? a) Mussels can sense the presence of one or more water-born chemicals from crabs. b) Mussels can hear crabs preying on other mussels (sound of shells being broken). c) Mussels can sense the presence of one or more water-born chemicals released from fish that are being eaten. d) Mussels in the tank "downstream" from the crab experienced higher water flows
Mussels can sense the presence of one or more water-born chemicals from crabs.
What is the key difference between primary productivity and net primary productivity?
Net primary productivity represents just the energy used to build biomass.
How is exponential growth defined? a) Density-dependent growth. b) Continuous growth. c) Extremely rapid growth. d) No change in r through time.
No change in r through time.
Plants that grow near plant species that host nitrogen-fixing bacteria benefit, because the plant with the nitrogen-fixing bacteria contributes nitrogen-rich leaves and roots to the soil. Is the relationship between the two plant species a mutualism?
No--the plant that benefits but doesn't host its own bacteria is commensal (it is facilitated).
Some beetles that visit flowers to harvest nectar get into the flower by chewing through the sides of the petals. As a result, they do not become dusted with pollen. Is this a mutualistic interaction?
No--these beetles are acting as consumers, not mutualists.
Extensive and unusual cold snaps have occurred here recently. Is this evidence that global warming is lessening or not occurring?
No—although the long-term trend is for warming, short-term weather patterns can still be variable.
Which of the following statements is correct?
Nutrients cycle through ecosystems; energy flows through trophic levels and dissipates through ecosystems.
With respect to climate change, what is the difference between positive feedback and negative feedback?
Positive feedback increases CO2 levels in the atmosphere and ocean; negative feedback reduces CO2 levels in the atmosphere and ocean.
How is primary succession different from secondary succession?
Primary succession takes place in the absence of soil.
Which is likely to be more intense: fires that occur in the same location frequently, or rarely?
Rarely, because so much more fuel will build up over time.
What defines sustainability in resource use?
Rate of production = rate of use
Where is the main reservoir of phosphorus?
Rock in the Earth's crust
What is the most important difference between species richness and species diversity?
Species diversity takes species number AND relative frequency into account.
What's the difference between a standing defense and an induced defense? a) Induced defenses are just augmented versions of standing defenses. b) Standing defenses are based on confronting danger; induced defenses are based on crypsis (hiding). c) Standing defenses are always present; induced defenses develop in response to a threat. d) Standing defenses are used by juveniles; induced defenses are used by adults.
Standing defenses are always present; induced defenses develop in response to a threat.
Some antibiotics kill many of the bacteria that live in the human gut, in addition to killing the bacteria that are actually causing disease. Patients often suffer indigestion, as a result. Does this observation support or conflict with they hypothesis that gut bacteria are mutualistic?
Support--if illness results from eliminating the bacteria, it suggests that they are beneficial.
Gary Larson drew a cartoon with an alligator lying on a psychiatrist's couch. The alligator is saying, "You know those little birds that clean our teeth*? I been eating them like popcorn." Explain the joke. *This is similar to the cleaner shrimp mutualism explained in the text.
The alligator has guilt because it hasn't been acting as a mutualist.
What is fecundity?
The average number of female offspring produced by a female, over her lifetime.
How long is a generation?
The average time between a female's first offspring and her daughter's first offspring.
What is the nature of the bacteria-plant mutualism mentioned in the text?
The bacteria "fix" atmospheric nitrogen; the plant provides protection and nutrients.
What does it mean to say that one species facilitates another species?
The facilitated species grows better in the presence versus absence of the other species.
Why is it accurate to claim that the ant-treehopper mutualism described in the text is "contingent?"
The fitness benefit to treehoppers depends on the presence of spiders (a predator).
Why do metapopulations exist in nature? a) Some populations go extinct over time; others are founded by colonization. b) Distinct populations are found in different islands, as in the Galapagos or Aland islands. c) The habitats that are available or occupied are patchy. d) Most species consist of large, contiguous population
The habitats that are available or occupied are patchy.
What is carrying capacity? a) The balance between emigration rate and immigration rate. b) The maximum number of individuals that can be supported by the resources in a habitat. c) The predation rate in a population. d) The maximum population size in a population that cycles over time.
The maximum number of individuals that can be supported by the resources in a habitat.
What does it mean to say that parasitism and other species interactions are dynamic?
The nature of the relationship can change over time, depending on changes in the environment.
What does age structure refer to? a) Changes in the size of the population through time. b) The average number of offspring produced per female. c) The relative number of individuals in various age classes. d) The number of individuals in the youngest age class known (i.e. newly born/hatched/germinated).
The relative number of individuals in various age classes.
What does it mean to say that history plays a role in community structure?
The species present now depend on what disturbances occurred in the past, and which species happened to arrive.
What is demography? a) The study of changes in population size and structure. b) A measure of a species' range (geographic location of individuals). c) A measurement of population density (number of individuals per unit area). d) The use of mark-recapture studies in natural populations.
The study of changes in population size and structure.
Why is "fossil fuels" an appropriate term?
They are derived from fossilized organisms.
Why are ectotherms much more efficient at converting primary production to biomass than endotherms?
They spend much less energy maintaining body temperature.
What are researchers referring to when they talk about "primary, secondary, tertiary" consumers or detritivores?
Trophic level, meaning position in a food chain (e.g. secondary eat primary).
When biologists study life history, what is the central issue they are trying to address? a) Variiation in egg size versus egg number. b) Variation in how early development occurs (events right after fertilization, cleavage, and gastrulation). c) Variation in the allocation of resources to growth and reproduction versus survival/longevity. d) In a life table, what is the combination of survival and fecundity?
Variation in the allocation of resources to growth and reproduction versus survival/longevity.
Is it possible that a coevolutionary arms race is still going on between Cephalotes ants and their nematode parasites?
Yes, because Cephalotes should be under intense selection to avoid parasitism.
Examine the data in Figure 53.17. Do they support the hypothesis that humans are causing increased CO2 concentrations?
Yes, because fossil-fuel burning and forest destruction release CO2.
Think of the number of different parasites (species of bacteria, viruses, fungi, flatworm, apicomplexan, etc.) that can attack humans. Is it reasonable to expect that every other organism faces a similar array of parasites? a) Yes--every species represents a resource that may be exploited by an array of parasites b) Yes, humans are a relatively young species so should have a relatively low number of parasites. c) No--most species should have a single, generalist parasite. (Generalists can exploit more than 1 species.) d) No--most species should have a single, specialist parasite.
Yes--every species represents a resource that may be exploited by an array of parasites
Can a standing defense also be an inducible defense? (Hint: think about the mussel shell experiment.) a) No--they are mutually exclusive. b) No--inducibility requires specific signals from a predator or herbivore (often these signals are not known). c) Yes--the amount of a standing defence can increase in response to presence of a threat. d) No--standing defenses can't be modified.
Yes--the amount of a standing defence can increase in response to presence of a threat.
In biology, how is a 'weed' defined?
a species that is adapted to growing in disturbed soils
In biological communities, what is "resilience?"
ability to "bounce back" after a disturbance, to the pre-disturbance conditiion
On the graphs called a population pyramid, what does the vertical axis represent?
an age class
What is a fitness trade-off? a) when two or more traits affect fitness at the same time--for example, choosing "good genes" and resources provided by a mate b) an exchange of benefits between individuals, that results in fitness increases for both c) traits that lead to acclimation, but not adaptation d) an inevitable compromise between competing demands on different aspects of fitness
an inevitable compromise between competing demands on different aspects of fitness
What is a "natural experiment?"
an unplanned/unmanipulated change in environmental conditions that can be exploited to answer a question
Stochastic processes are random and/or unpredictable. Which of the following represents a stochastic process that can have a disproportionately large impact on small populations?
catastrophic storms or disease/pest outbreaks
Why do chance events play a role succession?
certain species may show up early or late in the process, or not at all
Suppose two species begin competing. Over time, evolution results in key traits in each species changing in a way that reduces competition. What is the term for this event?
character displacement
Which of the following terms describes a situation where two species interact in a way that causes natural selection to act on each other--meaning that allele frequencies change in response to the interaction?
coevolution
Consider the fungi that associate with tree roots and exchange sugars (from the plant) for nitrogen, phosphorus, and water (from the fungus). Recent research shows that these fungi can connect many different tree individuals, often of different species, and distribute nutrients and sugars among them. This has been called the Wood Wide Web. These relationships are:
complicated--contingent and dynamic
In biological communities, what is "resistance?"
degree of change during and after a disturbance
In biology, how is 'disturbance' defined?
disruptions that remove biomass or change abiotic conditions
What is habitat fragmentation?
division of a large, contiguous habitat into many small pockets or fragments
Which of the following is NOT a reason why habitat quality deteriorates when fragmentation occurs?
large predators prefer to hunt in fragmented habitats
Which of these factors is NOT a major factor in determining how fast decomposition occurs?
moisture, temperature and number of detritivores are all important factors
What is the relationship between a service dog and its human handler?
mutualistic
Suppose two species begin competing. Over time, evolution results in the resources exploited by each species changing such that it reduces competition. What is the term for this event?
niche differentiation (aka niche partitioning)
In the context of conservation biology, what does genetic diversity mean?
number and relative frequency of alleles in a population, species, or lineage.
What are the key differences between a parasite and a predator? a) parasites are small relative to the victim and may not consume all of it b) parasties are much more numerous than predators c) parasites are short-lived; predators are long-lived d) predators are animals; parasites are not (parasites are bacteria or viruses)
parasites are small relative to the victim and may not consume all of it
What does it mean to say that a population "cycles?" a) the growth rate (r) is density dependent b) population size is steady through time (at carrying capacity) c) population size goes through a regular high-low fluctuation d) the growth rate (r) is density independent
population size goes through a regular high-low fluctuation
What's the difference between a fundamental niche and a realized niche?
potential vs. actual resources used (or conditions tolerated)
What is the difference between r and lambda? a) r gives the instantaneous growth rate; lambda gives the growth rate over a discrete time interval b) r gives the maximum growth rate; lambda gives the current growth rate c) r is calculated from life tables; lambda is calculated from observed population sizes d) r gives the growth rate for a population; lambda gives the growth rate for a species
r gives the instantaneous growth rate; lambda gives the growth rate over a discrete time interval
In most species that undergo metamorphosis, larvae live in different habitats and use different food sources than adults. Which of the following is the most likely hypothesis to explain the adaptive significance of metamorphosis?
reduce intraspecific competition
What do detritivores eat?
remains of other organisms
What is a functional group?
species that use resources or allocate resources in a similar way
At some point, categories like herbivore/parasite/predator break down. (For example, small insects that eat small amounts of large plants, over a long time, seem to conform to the definition of a parasite.) Why is this? a) scientific knowledge--including categorizations like this--is continuously updated as new data become available b) Herbivory, parasitism, and predation can change over time, in response to natural selection. c) Newly discovered organisms (or viruses) may not fit existing categories. d) the categories are artificial constructs--the organisms don't care
the categories are artificial constructs--the organisms don't care
What is lambda? a) fertility rate b) net reproductive rate c) the finite growth rate d) the per-capita rate of increase e) intrinsic rate of increase
the finite growth rate
On the graphs called a population pyramid, what do the horizontal bars represent?
the number of individuals in a certain age class
What is r? a) the per capita rate of increase b) fertility rate c) the finite growth rate d) net reproductive rate
the per capita rate of increase
Why are animals that eat seeds referred to as "seed predators?" a) they are eating plant tissue b) they are large in size compared to the seed c) they consume all of the seed in a short period of time d) this is an error--they should be referred to as herbivores (seeds are plant structures)
they consume all of the seed in a short period of time
What is phenology?
timing of seasonal events
What is biomass?
total organic matter, usually measured per plant or per square meter
