unit 4
When a plant photosynthesizes, the carbon used by the plant to construct organic molecules comes from
CO2 in the atmosphere
Greenhouse gases include:
Carbon dioxide, methane and nitrous oxide
Which of the following is TRUE about Island Biogeography
Extinction rate is expected to increase with the number of species on the island
What is the LEAST likely way that phosphorus might enter a lake?
Fixation of atmospheric phosphorus gas
What is the biological significance of genetic diversity in wildlife populations?
Genetic diversity reduces the probability of extinction.
If the sex ratio in a population is significantly different from 50:50, then which of the following statements will always be accurate?
The effective population size will be less than the actual population size.
The map below shows the distribution of three species of anole lizards in the genus Norops. Which of the following distribution shift might be expected for these species in light of climate change?
The mainland species probably will expand its range, to the north and south. The species in Cuba and Jamaica are unlikely to see a substantial range shift.
What does a negative per capita population growth rate tell you about a population?
The population size is decreasing instead of increasing.
Which of the following statements is correct?
There are birds on Antarctica but no snakes, largely because snakes are ectotherms and can't survive at the low temperatures found there.
Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects, birds follow and pick off any insects that fly or jump out of the way of the ants. This situation is an example of what kind of species interaction between the birds and the ants?
commensalism
The interaction between dolphins and birds as they both eat mackerel is an example of...
competition
Which of the following is a biotic factor that can limit the distribution and abundance of a species?
competition
A population of flamingoes in Florida grows according to a logistic model, with r = 0.17 and K = 10,000. Which of the following statements are correct? Check all that apply.
dN/dt is lower at N=200 than it is at N=5000 dN/dt is lower at N=9000 than it is at N=5000 dN/dt will be negative if N = 12,000
Which of the following outcomes is caused by excessive nutrient runoff into aquatic ecosystems?
eutrophication
If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to _____.
expand its realized niche
One reason that deserts tend to be found at 30°N and S latitude is that
global wind and pressure patterns affect where rain falls.
The current mass extinction is caused by
human activities
The carrying capacity for creole wrasses on a reef is limited by the amount of zooplankton prey available. On one reef, there is an increase in zooplankton over a 10-year period. Over this period, the reef's carrying capacity for creole wrasses will...
increase
Globally, primary production in terrestrial ecosystems tends to
increase with increasing rainfall
A population of snails has an annual per capita birth rate of 0.055 and an annual per capita death rate of 0.015. Calculate an estimate of the change in population size over one year, for a given starting population of 1,000 individuals. Assume that the population grows exponentially according to the equation
increases by 40 individuals
Consider the global nitrogen cycle depicted in the figure. How are humans altering this cycle?
industrial nitrogen fixation
Which of the following criteria have to be met for a species to qualify as invasive?
introduced to a new area, spreads rapidly, and displaces native species
Non-native species that are introduced in new environments, spread far beyond the point of introduction, and cause damage are called
invasive species
The population growth seen here...
is exponential and can only occur this way while resources are not limiting
When a mouse dies and is left to decompose in a field, the nitrogen that is contained in its tissues
may be used by nearby plants
This shrimp is climbing into the mouth of a predator to eat the parasites that are in it, and will get back out unharmed. This is an example of:
mutualism
A population of deer in Florida grows according to a logistic model, with r = 0.17 and K = 10,000. At what population size is the per capita population growth rate the highest?
n=1000
In logistic growth, population growth will be 0 when...
n=k
Eighty percent of our atmosphere is nitrogen gas, yet every year farmers spray ammonia on their fields as a fertilizer. This is because the only way to convert nitrogen from a gas into an biologically-available form is by
nitrogen fixing bacteria
In which marine zone would you find the majority of plankton?
pelagic
Based on this food web, identify the correct term for each organism:
photoplankton- 1st trophic level zooplankton -- 2nd trophic level threadfish shad: 3rd trophic level
Based on this food web, identify the correct term for each organism:
photoplankton- primary producer zooplankton -- primary consumer threadfish shad: secondary consumer
Scientists have studied how quickly lionfish abundance has increased in the Bahamas since they first invaded. This is an example of...
population ecology
In the logistic population growth model,
population growth rate is slow when N is small and when N is close to carrying capacity
Compared to exponential growth, what happens as the population size grows and approaches nears carrying capacity?
population growth rate slows down
Based on the following equation of population growth: d N d t = r N a population will be stable over time when...
r=0
Sardines display life history traits of an r-selected species. Therefore, compared to other fish species you'd expect sardines to...
reach sexual maturity early
Global warming is the result of
rising concentration of greenhouse gases
On a tropical Pacific island, warm temperatures lead to extensive bleaching and mortality of coral. A year later, much of the area previously occupied by coral is now covered in sponges and coral larvae have little available substrate to settle on. Five years later, the reef is still dominated by sponges. This situation would be an example of...
secondary succession and inhibition
An ecosystem has a carrying capacity of 1,000 individuals for a given species, and 2,000 individuals of that species are present. The population...
size will decrease
Resource partitioning would be most likely to occur between _____.
sympatric populations of species with similar ecological niches
Which of the following is thought to be the most important abiotic factor in determining species geographic distributions?
temperature
On your first day as a wildlife biologist for a national park, you are told that yearly changes in the size of the wolf population in the park can be modeled with the following equation, where N is 120 and r is -0.05. d N d t = r N You conclude that:
the population is declining, and you expect to have ~114 wolves in the park next year
Population ecologists are primarily interested in
understanding how biotic and abiotic factors influence the size of groups of interbreeding individuals.
Which two abiotic factors are most important in influencing the distribution and abundance of organisms in terrestrial environments?
water and temperatures
Which of the following would you LEAST expect in a desert angiosperm?
wide, thin leaves with no stomata
Where do you expect to find the driest, sunniest conditions?
30 degrees north and south
A population of 3000 starfish has a yearly per capita population growth rate of 0.012. A year from now, how big will the population be? Assume that the population grows exponentially according to the equation
3036
In July 2008, the United States had a population of approximately 302,000,000 people. How many Americans were there in July 2009, if the estimated 2008 growth rate was 0.88% (per capita growth rate (r) of 0.0088)?
304,657,600
Now with your starting population at 100, change your per capita population growth rate r to 0.6. Now what is your population size at time 7? Note how even small changes in r can have profound effects on growth rate. You Answered
6,669 (with margin: 0)
If there are 30 kcal of energy contained in a mouse, how much energy will likely be obtained by a cat that eats this mouse?
<30 kcal
What is the carrying capacity for this population of whooping cranes?
>325
Use the following diagram of five islands formed at around the same time near a particular mainland, as well as MacArthur and Wilson's island equilibrium model principles to answer the question. Which island would likely have the lowest extinction rate?
A
Which of these would be expected to have the highest species richness?
A
Which of these is NOT a likely consequence of global warming?
A cactus population is found at lower latitudes than it was 50 years ago
For populations that grow exponentially (d N d t = r N): which of the following populations will experience the fastest population growth rate?
A population of 1000 rabbits that has a yearly death rate of 0.01 and a yearly birth rate of 0.11
Inbreeding...
can lead to low genetic diversity
A population of E. coli within a person's gut with a population size of two million and a net reproductive rate (R0) of 0.9 would be expected to have how many individuals in the next generation?
1.8 million
There are 30 kcal in a mouse which dies of a disease and decomposes into a field of grass. How much of those 30 kcal will be reused by the grass growing near this mouse?
0 kal
Which of the following describes commensalism? (each side of the dash represents one species involved in the interaction; whether it benefit (+), is harmed (-), or is neither harmed nor helped by the interaction (0)) -/-
0/+
A population of snails is located in a lake that has a carrying capacity of 20,000 snails. The intrinsic capacity for increase for these snails is 0.15 and the current population is 12,000. In a year, how big do you expect the snail population to be?
12720
We expect that a human population should be roughly stable in size when the total fertility rate (number of children per woman) is around _______, and the net reproductive rate (R0) is around ______.
2 1
Note how quickly populations can grow even with per capita growth rates that are less than 1. Once you've set different parameters for starting population size and per capita growth rate, set your starting population size to 100 and your per capita growth rate to 0.5. What is your population size at time 7?
3,312 (with margin: 0)
northern coniferous forest./taiga
Annual precipitation ranges from 30 - 70cm with periodic droughts. Some may receive 300 cm of precipitation. Cold winters (can be as cold as -50C in some areas) and hot summers (over 20C).
Temperature in terrestrial ecosystems is highest...
At the equator, because there sunlight hits the earth at a 90 degree angle on average
You're trying to conserve a small population of 100, mostly male birds. Which of these strategies would increase a population's effective size most quickly?
Building a habitat corridor to connect the population to another population of 10 female birds
Which of these islands do you expect has the greatest extinction rate?
C
CO2 in the atmosphere (choose all that apply)
Has increased in the last 100 years due to burning of fossil fuels Has increased in the last 100 years due to deforestation Has led to an overall increase in temperature on Earth Has led to an increase in the amount of CO2 in the oceans
The following factors are some that control the distribution and abundance of organisms. Match with the appropriate term ("biotic" or "abiotic").
Herbivory- biotic competition- biotic temperature- abiotic predation- biotic sunlight- abiotic water- abiotic disease- biotic nutrients- abiotic pH- abiotic
The following question refers to the figure below, which depicts the age structure populations. In the figure, populations of a plant species labeled I, II, and III are depicted using simplified age structures containing three age classes: young seedlings, middle-aged juveniles, and older adults. Which population(s) appear(s) to have stable growth?
III
Community ecology studies...
Interactions between populations of various species that occupy the same area at a given time
A population of 2000 starfish has a yearly per capita population growth rate of 0.012. By next year, how do you expect population size to have changed? Assume that the population grows exponentially according to the equation d N d t = r N
It will increase by 24 starfish
Which of the following observations gives the LEAST support to the time hypothesis of global diversity patterns?
Lakes that have more recently unglaciated have a higher diversity than lake that unglaciated further in the past.
Small populations are of concern to conservation biologists due to...
Low genetic diversity
Which of the following is a density-independent factor that can limit the size of a population of penguins on an ice shelf in Antarctica?
Melting of the sea ice by global warming.
Which of the followings population is most likely to be able to significantly change its range in response to climate change? The areas shaded in red represent current ranges
Merriam's kangaroo rat
Extinctions
Occur at high rate during catastrophic events (mass extinctions) and lower rate outside of catastrophic events
For populations that grow exponentially (d N d t = r N): given a per capita growth rate of 0.1, which of the following populations will have the most rapid population growth?
One with 1000 individuals
Which population should display the highest growth rate?
One with a high birth rate and a low death rate
Which of the following statements is correct about the graph of exponential population growth shown here?
Over time, the population size gets bigger and the rate of population growth becomes faster.
Carbon cycles between the biotic and abiotic worlds mainly through
Photosynthesis and respiration
For a given species, extinction rate is higher when
Populations are small
desert
Precipitation is usually less than 30 cm per year. Temperature can vary seasonally and daily. In hot areas, temperatures can exceed 50C. In cold areas, temperatures can drop to -50C
tundra
Precipitation ranges from 20 - 100cm annually. Cold winters (-30C) and cool summers (10C). Covers 20% of Earth's land surface.
temperate broadleaf forest
Precipitation varies from 70 - over 200cm annually. Winter temperatures average 0C, with hot and humid summers reaching up to 35C.
tropical forest
Rainfall can be relatively constant or seasonal, from 150 - 400 cm per year. Temperatures are high, with an average of 25 - 29 C with little or no seasonal variation.
CHAPPARAL
Seasonal precipitation averaging 30 - 50cm annually. Average summer temperatures are 30 - 40C, with an average of 10 - 12C for the remainder of the year. Examples include areas of coastal California and the matorral in Spain.
temperate grassland
Seasonal precipitation that can average between 30 and 100 cm with periodic droughts. Cold winters (-10C) and hot summers (30C).
savanna
Seasonally dry with average rainfall of 30 - 50cm. Temperatures are warm, averaging from 24 - 29C.
Which of the following is NOT a reason that only ~10-15% of the energy at one trophic level is transferred to the next trophic level in a wetland foodweb?
Some of the energy is transferred back to a lower trophic level
After the Panama isthmus emerged about three million years ago and connected North and South America, cats of North America began to migrate into South America. Today South America has several cat species descended from these previous migrants. What best explains this biogeographic pattern?
The cats have always been able to live in South America but were previously unable to get there.
A fish swimming into an estuary from a river would have which of the following as its greatest physiological challenge?
The change in water solute content would challenge the osmotic balance of the fish.
What can you say about these communities?
They both have equal richness but "A" has greater diversity
Which of these is a potential reason why tropical communities tend to have greater species diversity than temperate or polar communities?
Tropical communities are generally older than temperate and polar communities.
If the carrying capacity for the North Atlantic cod on the Grand Banks of Newfoundland is 500,000 tons, when do you expect that the rate of population growth would be greatest?
When there are 250,000 tons of cod on the grand banks
Which of the following organisms best illustrates K-selection?
a polar bear producing one or two cubs every three years
Conservation biologists aim to conserve
all the above
Under what conditions would a population grow slower than predicted by exponential growth?
all the above
Which of the following plants is most likely to thrive in a desert environment?
angiosperm
In the figure, which of the arrows represents the carrying capacity?
arrow C
