BISC208 Mastering Biology Exam 2 (University of Delaware, Dr. DeVito)

Deer are hosts of ticks but are not reservoirs of B. burgdorferi −− their immune systems detect and kill the bacterium. But a tick with a prior bacterial infection can consume a blood meal from a deer and then bite and infect a human. The fitness effects of a deer on B. burgdorferi can be summarized as:

+ or - depending on whether the deer is the tick's last host.

Assume there are 200 MendAliens living on an island in my back yard. If my island has an area of 20 hectares, what is the population density of MendAliens in terms of MendAliens per hectare?

10 MendAliens per hectare Population density is calculated as population size divided by area: 200 MendAliens / 20 hectares = 10 MendAliens per hectare.

A population is growing exponentially and its instantaneous growth rate (r) is 0.02. Would the number of individuals added to the population (rN) be greatest at a population size (N) of 20, 500 or 1000?

1000

Suppose researchers marked 800 turtles and later were able to trap a total of 300 individuals in that population, of which 150 were marked. What is the estimate for total population size?

1600

You are doing a mark-recapture experiment to determine the population size of the MendAliens living on an island in my back yard. Initially, you catch and mark 130 MendAliens, which you then release. Next, you capture 90 MendAliens, of which 20 are marked. What is your estimate of the population size of MendAliens living on the island in my back yard?

585 To get the population size N, multiply the number marked in the first catch, M1, by the total number caught in the second catch, C, and divide that by the number of marked recaptures in the second catch, M2: N = (M1 x C) / M2 Or: (130 x 90) / 20 = 585.

Estimate total population size in a mark-recapture study in which 200 individuals were initially marked, and you recaptured 150 of which 50 were marked.

600 This is a simple method for field biologists to determine rough population estimates.

What is the combination of resources used and conditions tolerated in the absence of competitors called?

A fundamental niche

In the accompanying figure, which of the lines represents exponential growth?

All of the lines represent exponential growth.

White-footed mice occupy a broad ecological niche−−they occur in most communities regardless of habitat quality. Many other species, like the opossum, are absent from low-quality forest fragments. Based on this information and the graph, propose a hypothesis to explain the observed relationship between increased forest fragmentation and increased incidence of Lyme disease. As forest fragmentation increases, species richness will .... As species richness ... white-footed mice will still ... in the population (due to the species' ... niche), but species like opossums will ...(due to their niches). Since mice ... huge reservoirs of the Lyme bacterium and species like opossums ... a greater percentage of animals present in forest fragments ... host the Lyme bacterium. Thus, the incidence of Lyme disease will ...

As forest fragmentation increases, species richness will decline. As species richness declines, white-footed mice will still be present in the population (due to the species' broad niche), but species like opossums will be absent (due to their narrow niches). Since mice are huge reservoirs of the Lyme bacterium and species like opossums are not, a greater percentage of animals present in forest fragments will host the Lyme bacterium. Thus, the incidence of Lyme disease will increase.

In the accompanying figure, what can be stated about species diversity and latitude?

As latitude increases, diversity decreases.

How do Hadley cells affect temperature

As warm air rises, air at the top of the atmosphere is pushed poleward and cools. This cool air causes the cooler climates away from the equator.

assimillation

Assimilation is the uptake of nutrients into an organism

The movement of nutrients through an ecosystem are called...

Carbon cycles between the atmosphere and living biomass

How does carbon move from the biota to the atmosphere?

Carbon dioxide is released during cellular respiration

How have humans altered the global carbon cycle?

Carbon inputs into the atmosphere have risen

Will this population of lizards stay the same, increase, or decrease over time?

Declining, since R0 < 1

Why do populations grow more slowly as they approach their carrying capacity?

Density-dependent factors lead to fewer births and increased mortality.

Summarize evolution by natural selection as it is viewed today?

Evolution by natural selection is the differential survival and reproduction of the most-fit phenotypes.

True or false? Weather is defined as the prevailing long-term atmospheric conditions in a particular region

False Climate is defined as the prevailing long-term weather conditions in a particular region; weather is defined as the short-term atmospheric conditions of temperature, sunlight, moisture, and wind.

True or false? Local biogeochemical cycles are isolated within their particular ecosystem and all ions and molecules remain in that ecosystem permanently

False Local biogeochemical cycles are linked into one global system by the movement of ions and molecules from one ecosystem to another.

True or false? In the global carbon cycle, rivers link the terrestrial and marine reservoirs of carbon, whereas carbon exchange between the atmosphere and the ocean is achieved by active transport

False Rivers do indeed link the terrestrial and marine reservoirs of carbon on Earth, but carbon is exchanged between the atmosphere and the ocean by diffusion, which depends on the concentration gradient between the two reservoirs.

Researchers have measured a positive correlation between forest fragmentation and incidence of Lyme disease. According to the theory of island biogeography, how do you predict fragmentation will affect species richness?

Forest fragmentation will subdivide large areas of habitat into many small islands of habitat, causing species richness to decline.

How might genotype frequencies of alleles for body size change under directional selection?

Genotypes that represent larger individuals become more prevalent.

https://media.pearsoncmg.com/bc/bc_0media_bio/spp_redir/hhmi/sicklecell.html How did Dr. Allison test his hypothesis that sickle cell disease was connected to malaria?

He evaluated blood samples for malaria parasites and the presence of sickle cells & He expanded his study area beyond Kenya to the rest of East Africa to see if malaria and sickle disease were connected. Dr. Allison gathered blood samples from more than 5,000 children in East Africa. He analyzed the samples to identify malaria parasites and sickle cells. He found that children carrying the sickle cell character (or trait) had a lower parasite count, as if they were partially protected against malaria.

https://media.pearsoncmg.com/bc/bc_0media_bio/spp_redir/hhmi/sicklecell.html In 1949, Dr. Tony Allison observed a high frequency of Kenyans carrying the sickle cell allele in coastal areas and near Lake Victoria, but a lower frequency in the highlands. What did he hypothesize?

He hypothesized that there was a connection between malaria and sickle cell disease. On the basis of this hypothesis, Dr. Allison predicted high frequencies of sickle cell disease only in areas where malaria is common.

How does inbreeding alter genotype and allele frequencies?

Homozygotes increase in frequency in the population over generations.

A population is correctly defined as having which of the following characteristics? I. inhabiting the same general area II. belonging to the same species III. possessing a constant and uniform density and dispersion

I and II only

Looking at the data in the accompanying figure from the hare/lynx experiment, what conclusion can you draw? I. Food is a factor in controlling hare population size. II. Excluding lynx is a factor in controlling hare population size. III. The effect of excluding predators and adding food in the same experiment is greater than the sum of excluding lynx alone plus adding food alone.

I, II, and III

https://media.pearsoncmg.com/bc/bc_0media_bio/spp_redir/hhmi/sicklecell.html How does Dr. Allison's work provide an example of natural selection in humans?

In areas without malaria, individuals with two sickle cell alleles reproduced at lower rates than those without sickle cell disease & In areas with malaria, individuals with one sickle cell allele reproduced at higher rates than those with no sickle cell alleles. In different environments, natural selection favors different characteristics. In areas with malaria, the reproductive advantages of having one sickle cell allele (and some protection from malaria) kept the allele at high frequencies in the population. In areas without malaria, the reproductive disadvantages from sickle cell disease reduced the allele in populations.

https://media.pearsoncmg.com/bc/bc_0media_bio/spp_redir/hhmi/sicklecell.html In some populations, 1 in 500 people have sickle cell disease. What reason does the film give for why a potentially deadly, inherited disease is found at such high frequencies?

Individuals with one sickle cell allele are protected from malaria and do not have sickle cell disease, thus keeping the allele in the population. People with one sickle cell allele are protected from malaria, but do not have sickle cell disease. Protection from malaria comes at the cost of more sickle cell disease in the population.

Which statement best describes the evolutionary significance of mutualism?

Interaction increases the survival and/or population growth rate(s) of mutualistic species.

How might genetic drift be important in a small population.

It decreases genetic diversity via sampling error during mating. Genetic drift is of large concern with populations of a small size because you are more likely to have mating between close relatives.

How might gene flow be important in managing an endangered population?

It increases genetic diversity by introducing alleles from one population into another. Gene flow is the movement of alleles between populations.

How would the species richness curves on an island be affected if mainland habitats were wiped out by urbanization?

It would lower the rate of immigration and increase the rate of extinction.

nitrate example and nitrite example

NO3 - and NO2 -

Which evolutionary mechanism results in adaptation?

Natural selection

What removes nitrogen from the atmosphere?

Nitrogen fixation

For a gene suspected of causing hypertension in humans, you observe the following genotype frequencies: A1A1 0.574; A1A2 0.339; A2A2 0.087. Is this gene in Hardy-Weinberg equilibrium? Why or why not? (Assume that a difference of three percent or more in any of the observed versus expected frequencies is statistically significant.)

No. The expected genotype frequencies are A1A1 0.553; A1A2 0.381; A2A2 0.066. The expected genotype frequencies are significantly different from those expected from the Hardy-Weinberg Principle.

What does the graph in the accompanying figure tell you about the definition of a keystone species?

Removing a keystone species from the community drastically reduces diversity.

The mark-recapture method would be best for sampling a population of _____. The

Shark The mark-recapture method works best for active species whose individuals tend to be highly mobile.

https://media.pearsoncmg.com/bc/bc_0media_bio/spp_redir/hhmi/sicklecell.html Compare sickle cell disease and malaria.

Sickle cell disease and malaria are both potentially lethal diseases. Though malaria is an infectious disease and sickle cell disease is inherited, both can cause life-threatening conditions.

Pythons are generalist predators, consuming a wide variety of prey including birds, mammals ranging from rodents to deer, and alligators. A road survey showed a 99 percent decrease in the frequency of raccoon and opossum observations within python areas from 2003 to 2011. Rabbits and foxes have also disappeared from the area. Do you think food availability limits, or could limit, the carrying capacity of Burmese pythons in the Everglades? Since pythons are ... , it would seem that food availability ... be a primary factor in determining the carrying capacity. However, the dramatic disappearance of raccoons and opossums indicates that predation rates are very ... and at least some food sources are disappearing. In the long run, the size of the python population will be ... (the population cannot increase ... forever).

Since pythons are generalists, it would seem that food availability would not be a primary factor in determining the carrying capacity. However, the dramatic disappearance of raccoons and opossums indicates that predation rates are very high and at least some food sources are disappearing. In the long run, the size of the python population will be food-limited (the population cannot increase exponentially forever).

What aspect of a region's climate has the most impact on plants and animals?

Temperature and moisture

What are the three major reservoirs of the global carbon cycle

Terrestrial ecosystems, oceans, and the atmosphere

DNA studies suggest that the lionfish invasion began with just a few females released off the coast of Florida, probably from a fish tank. Based on your knowledge of ocean currents, predict the direction in which the lionfish dispersed most quickly.

The North Atlantic Gyre flows in a clockwise direction, so the prevailing current on the Florida coast would be south to north, and it would disperse lionfish up the coast

Which desert is caused by a Hadley cell?

The Sahara Desert in Africa not the result of topography, since there are no extensive North-South mountain ranges in Africa

Nitrification

The conversion of organic nitrogen-containing compounds to nitrites and nitrates.

What location on Earth receives the most solar radiation per unit area?

The equator because sunlight arrives almost perpendicular to Earth's surface there.

How would the addition of a plant in which nitrogen fixation occurs alter succession?

The following community would change drastically. With nutrients more readily available, the species of plants would be much different than before.

As N approaches K for a certain population, what can be predicted by the logistic equation?

The growth rate will approach zero.

Why can't a female lizard have both high fecundity and high survival?

The more energy the female devotes to offspring, the less that can be devoted to her survival.

https://media.pearsoncmg.com/bc/bc_0media_bio/spp_redir/hhmi/sicklecell.html If a person has two normal copies of the hemoglobin allele, which statements are true? a. The person is homozygous at the hemoglobin locus. b. The person is susceptible to malaria. c. The person is protected against malaria. d. The person is heterozygous at the hemoglobin locus.

The person is homozygous at the hemoglobin locus & The person is susceptible to malaria. A person with two copies of any allele is homozygous. A person with two normal copies of the hemoglobin allele is more susceptible to malaria than someone with a sickle cell hemoglobin allele.

What conclusion can you draw from the accompanying figure?

The relationship between the populations cannot be determined only from this graph.

https://media.pearsoncmg.com/bc/bc_0media_bio/spp_redir/hhmi/sicklecell.html Predict what will happen to the frequency of the sickle cell allele in areas where malaria has been eradicated.

The sickle cell allele will decrease in frequency. Without malaria, selection for the sickle cell allele decreases. As a result, the frequency will likely decrease.

How do greenhouse gases contribute to global warming?

They prevent infrared light from leaving Earth's atmosphere

How do early successional species alter the environment in ways that make growing conditions more difficult for their own species?

They reduce the disturbed nature of the soil, making it harder for their seeds to become established.

Why are species like the lionfish considered "invasive"?

They spread aggressively and displace native species

Which survivorship curve does Lacerta viviparta best resemble?

Type II There is a steady decline in survivorship over time.

What can influence the abiotic components of an organism's environment?

Water pollution

In 1983, a population of dark-eyed junco birds became established on the campus of the University of California, San Diego (UCSD), which is located many miles from the junco's normal habitat in the mixed-coniferous temperate forests in the mountains. Juncos have white outer tail feathers that the males display during aggressive interactions and during courtship displays. Males with more white in their tail are more likely to win aggressive interactions, and females prefer to mate with males with more white in their tails. Females have less white in their tails than do males and display it less often. (Pamela J. Yeh. 2004. Rapid evolution of a sexually selected trait following population establishment in a novel habitat. Evolution 58[1]:16674.) ]The UCSD campus male junco population tails were, on average, 36% white, whereas the tails of males from nearby mountain populations averaged 40—45% white. If this observed trait difference were due to a difference in the original colonizing population, it would most likely be due to __________.

a founder effect

The range of Burmese pythons in Florida is expanding rapidly. List abiotic factors and biotic factors that might limit the range of pythons. a. occurrence of parasites b. competition for food c. occurrence of deep seawater (Atlantic Ocean and the Gluf of Mexico) surrounding Florida d. increased predation on eggs or juveniles e. cold temperatures to the north f. spread of disease

a. Biotic Factor b. Biotic Factor c. Abiotic Factor d. Biotic Factor e. Abiotic Factor f. Biotic Factor

Newly hatched ticks do not harbor B. burgdorferi. Rather, they pick it up from certain hosts that are reservoirs of the bacterium. When a larval tick crawls onto a host, it may get groomed off and killed by the host, or it may feed successfully, in which case it may or may not then become infected with B. burgdorferi. Felicia Keesing and others measured the rate of tick feeding and infection on different hosts. a. What percentage of ticks on mice were infected with B. burgdorferi? b. What percentage of ticks on opossums were groomed off and killed?

a. about 45% b. about 95%

Burmese pythons were first found in the wetlands of Everglades National Park in the 1980s, but only rarely. The graph shows what happened next. Most of the data are derived from chance encounters of pythons on roads (pythons are notoriously difficult to find). a. How would you describe the type of population growth in pythons from 2000 to 2008? Researchers hypothesize that the severe winter of 2010 caused the decline in the number of pythons encountered that year. Is cold weather typically a density-dependent factor or a density-independent factor? Explain the difference. b. ... is typically a ... factor because it affects the pythons the same way no matter whether there are few or many pythons. A ... factor, such as ..., increases with increasing python density.

a. exponential b. Cold weather is typically a density-independent factor because it affects the pythons the same way no matter whether there are a few or many pythons. A density-dependent factor, such as competition for food, increases with increasing python density.

a. What information is presented on the y-axis? b. What does the top red graph line represent? c. What kind of island has the highest rate of extinction? d. On what kind of island would new species be most likely to arrive? e. The number of species on an island is at equilibrium when the rate of immigration is equal to the rate of extinction. This is shown on the graph by the points where each green and red line cross. What kind of island is likely to have the highest number of species? f. The equilibrium theory of island biogeography predicts that large islands close to the mainland will have more species than small islands that are distant from the mainland. Which of the following factors does not contribute to that prediction?

a. the rate of immigration or extinction b. the rate at which new species immigrate to an island that is close to the mainland c. a small island d. an island that is close to the mainland e. a large island close to the mainland f. Evolution occurs more rapidly on large islands, thereby increasing species diversity.

Which of the following would be most significant in understanding the structure of an ecological community? I. determining how many species are present overall II. determining which particular species are present III. determining the kinds of interactions that occur among organisms of different species IV. determining the relative abundance of species

all of the above

Nitrifying bacteria convert _____ to _____

ammonium ... nitrites

In the accompanying figure, which of the arrows represents the carrying capacity?

arrow C

Looking at the data in the accompanying figure, what can be said about survival and clutch size? a. Probability of survivorship does not correlate with clutch size. b. Large clutch size correlates with low survival. c. Animals with low survival tend to have smaller clutch sizes. d. Animals with high survival tend to have larger clutch sizes.

b. Large clutch size correlates with low survival.

Suppose you trap some fish in a lake, mark them, and release them. Every month for a year you re-trap a similar number of the fish and release them. You notice each month that the proportion of marked fish trapped is declining. Which of the following is a reasonable explanation for this observation? a. The fish do not have long lifespans so some of the marked fish are dying each month. b. The marking of the fish increases their fitness. c. The fish population is decreasing. d. The marked fish are more susceptible to being trapped than unmarked fish.

b. The fish do not have long lifespans so some of the marked fish are dying each month.

Which assumption must be correct for a population to be in Hardy-Weinberg equilibrium for a specific gene? a. The number of immigrants must equal the number of organisms emigrating. b. Mating must be nonrandom with respect to the gene. c. No genetic drift can affect allele frequencies for the gene. d. Natural selection must favor one phenotype.

c. No genetic drift can affect allele frequencies for the gene.

Which of the following is TRUE of species interactions? a. They do little to affect species distributions. b. They cannot affect species abundance. c. They can act as agents of natural selection. d. The outcome of any species interactions is static through time.

c. They can act as agents of natural selection.

An egret eats insects stirred up by grazing animals. Which of these terms applies to the relationship between the egret and the grazing animal?

commensalism

Epiphytic orchids grow harmlessly on their host trees, and derive their resources from the air and from rain, rather than from their host plant. Which of the following is the best description of this species interaction?

commensalism

Humans and sharks both eat fish. Which of these terms applies to the relationship between the human and the shark?

competition

Which species interaction depends on prey density and effectiveness of prey defenses to determine the impact on the prey population?

consumption

Which of the following examples would most accurately measure the density of thepopulation being studied? a. counting the number of prairie dog burrows per hectare b. counting the number of times a 1 kilometer transect is intersected by tracks of redsquirrels after a snowfall c. counting the number of coyote droppings per hectare d. counting the number of moss plants in 1-square-meter quadrants e. counting the number of zebras from airplane census observations.

d. counting the number of moss plants in 1-square-meter quadrants

Cystic fibrosis is a genetic disorder in homozygous recessive (ff) humans that typically significantly reduces life expectancy. Over time, we would expect the f allele frequency to ________ for this trait.

decrease

An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square kilometer in one woodlot and 20 per square kilometer in another woodlot. What was the ecologist comparing?

density

An earthworm that feeds on the remains of plants and animals is acting as a _____

detritivore

What are rain shadows?

dry regions on the leeward side of mountain ranges that result when an air mass releases its moisture on the windward side of the range and then is carried by winds to the leeward side.

Imagine five forest communities, each with one hundred individuals distributed among four different tree species (W, X, Y, and Z). Which forest community would be most diverse? a. 100W, 0X, 0Y, 0Z b. 70W, 10X, 10Y, 10Z c. 40W, 30X, 20Y, 10Z d. 50W, 25X, 15Y, 10Z e. 25W, 25X, 25Y, 25Z

e. 25W, 25X, 25Y, 25Z

Which of the following is the most important assumption for the mark-recapture method to estimate the size of wildlife populations? a. More individuals emigrate from, as opposed to immigrate into, a population. b. All females in the population have the same litter size. c. There is a 50:50 ratio of males to females in the population before and after trapping and recapture. d. Over 50% of the marked individuals need to be trapped during the recapture phase. e. Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.

e. Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.

In relation to humans, B. burgdorferi is a/an ______ and the tick is a/an ______.

endoparasite/ectoparasite

Cystic fibrosis is a genetic disorder in homozygous recessives that causes death during the teenage years. If 9 in 10,000 newborn babies have the disease, what are the expected frequencies of the dominant (A1) and recessive (A2) alleles according to the HardyWeinberg model?

f(A1) = 0.9700, f(A2) = 0.0300

The recessive allele that causes sickle cell anemia is harmful to homozygous individuals. What maintains the presence of this allele in a population's gene pool?

heterozygote advantage

In a tide pool, 15 species of invertebrates were reduced to 8 after one species was removed. The species removed was likely a(n) ________.

keystone species

Humans who have pets tend to be healthier than humans who do not have pets. Which of these terms applies to the relationship between a human and a pet?

mutualism

What is the term used to describe the process shown in the panels in the accompanying figure, assuming Time 2 follows Time 1?

niche differentiation

Denitrifying bacteria convert _____ to _____

nitrates ... nitrogen gas

For biologists studying a large flatworm population in the lab, which HardyWeinberg condition is most difficult to meet?

no mutation

Which of these terms applies to the relationship between a dog and a blood-sucking tick?

parasitism

A human eats a deer. Which of these terms applies to the relationship between the human and the deer?

predation

What is the main advantage of controlled burnings of forested areas? Controlled burnings _____.

prevent the overgrowth of the underbrush

A cow eating grass is an example of a _____

primary consumer

In an ecosystem, phytoplankton are _____

producers Autotrophs, such as phytoplankton, are producers

When a human eats a steak, the human is acting as a _____

secondary consumer

Most Swiss starlings produce four to five eggs in each clutch. Starlings producing fewer or more than this have reduced fitness. What term best describes this situation?

stabilizing selection

A human who just ate a hamburger is eaten by a shark while swimming. The shark is acting as a _____

tertiary consumer

Carrying capacity is ...

the maximum population size that a particular environment can support

Succession in an ecological context refers to ...

the sequence of changes in species composition over time within the community after a disturbance