50 terms

Ecology Exam 2


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The mark-recapture method would be best for sampling a population?
Sharks. It is best for active species whose individuals tend to be highly mobile.
Environmental heterogeneity often causes a population to be divided into?
In populations of animals that defend an area for their own exclusive use or in plants that compete intensively for below ground resources such as water or nutrients, the spatial distribution of individuals is usually what?
Which of the following sampling techniques represents an index of abundance rather than an estimate of density?
Number of bear droppings along a trail.
The demographic age pyramid of a rapidly growing population is?
Wide at the base, narrow at the top.
Which of the following statements about the movement of organisms is FALSE?
Many plants use active dispersal mechanisms, like wind, for dispersal.

TRUE answers
1) In animal populations, it is usually the young adult age classes that disperse.
2) Some seeds must pass through animal digestive systems to germinate.
3) The movement of individuals among subpopulations is a key process in maintaining gene flow.
4) In the oceans, many organisms disperse passively on the tides and currents.
Leaving the native country.
Which of the following statements about population distributions and densities is true?
Dispersal plays a major role in range expansion for populations that have been introduced into a new region.

1) dispersal has little effect on local population densities.
2) Temporal variation in environmental conditions stabilizes population ranges.
3) Dispersal is not a factor in range expansion for introduced specifies, such a the gypsy moth.
4) The distribution of tree species in North America has been fairly constant for the past 20,000 years.
How might a species' range be extended?
Through climate change.
Why do we classify lionfish populations near the eastern US as an invasive species?
Lionfish are native to the tropical Pacific. There are no natural water routes of warm water between the Pacific and Atlantic oceans.
The California newt is found only in California. This is an example of what kind of species?
Which of the following best represents a measure of ecological density?
The number of frogs per meter of pond shoreline.
Which of the following best describes the distribution of corn in an agricultural field?
Which method is commonly used to estimate population sizes of mobile animals?
One of the most basic models of population growth is exponential growth. Which of the following statements about exponential growth is FALSE?
The population levels off at carrying capacity because of density independent factors.
Exponential model of population growth
N(t) = N(0)e^rt
The age-specific mortality rate is represented by?
Coyotes care for their young and are relatively long-lived. Please choose the accurate description of the likely survivorship curve for this species.
The curve is convex with a steep decline for older age classes.
The gross reproductive rate is?
The average number of female offspring born to her over her lifetime.
Demographic stochasticity refers to?
Random year-to-year variations in a population's birth and death rates.
The leading cause of current species extinctions is?
Habitat destruction.
According to Clinton Jenkins, the real reasons humans choose to protect biodiversity include:
Attachment to places or animals that have emotional appeal.
David Suzuki promotes the idea of protecting "latent hotspots." His justification is that "latent hotspots"
Contain species that are currently stable but face high risks in the near future.
As human impacts in an area increase, these species are more likely to suffer. Which of the following hypothetical species might be most at risk?
A large mammal that lives only in alpine areas.
A human eats a deer. Which of these terms applies to the relationship between the human and the deer?
Predation. The human is the predator and the deer is the prey.
Humans and sharks both eat fish. Which of these terms applies to the relationship between the human and the shark?
Competition. The human and the shark are both competing for a resource.
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. Both members of the species pair benefit.
Which of these terms applies to the relationship between a dog and a blood-sucking tick?
Parasitism. The tick benefits at the expense of the dog; the dog is the host and the tick is the parasite.
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. One member of the species pair benefits and the other is unaffected.
Termites rely on protozoa in their guts to help them digest their primary food, cellulose. The protozoa rely on bacteria to secrete the digestive enzymes necessary for digesting the cellulose. The relationship of the termites to the protozoa is a ________, While the relationship of the protozoa to the bacteria is a _________.
Mutualism; mutualism.
Oxypeckers are birds native to Africa. They have been observed feeding on ticks on the backs of large mammals and were thought to reduce the number of ticks. Recent studies indicate that the tick load is unaffected by the oxpeckers, and the oxpeckers usually reopen old tick wounds and consume the mammals' blood. Ecologist are considering reclassifying the relationship between oxpeckers and large African mammals from _____ to ______.
Mutualism; parasitism.
As predators feed on prey, prey abundances decrease over time. This is predicted to result in a(n).
Decrease in predator abundance.
If there is a single species present with the carrying capacity of 500, and another competing species with the same limiting resource becomes established in the area and has a population 200 it will effectively change the carrying capacity for species 1 to ________
Which of the following is true of coevolution?
In coevolution, adaptations are in response to another species rather than the environment.
The elaborate courtship ritual and flower development both act to enhance reproductive success of the insect and orchid, respectively. This is an example of ___.
What might happen over time if two bird species competed for the same seed resource and one preferred larger seeds while the other species preferred smaller ones?
Beak sizes might shift over time.
Species having wide geographic distributions generally encounter a broader range of physical environmental conditions than species whose distribution is more restricted.
Which of the follow is an exception to diffuse coevolution?
In most species of euglossine bees, a single bee species is specialized to pollinate a single species of orchid.
A flower is not ideally matched with a pollinator that visits it daily. Why might that be?
The flower has several other pollinators with differing traits.
The range of physical and chemical conditions under which a species can persist and the array of essential resources it utilizes constitute the species'
Ecological niche
An organism's realized niche is always smaller than its fundamental niche
The process whereby one species gives rise to several others that exploit different features of the environment is known as?
Adaptive radiation.
Which of the following is an example of species interaction leading to adaptive radiation?
A flower is pollinated by different members of the same genus of insect during different times of day.
Where are the Galapagos Islands located?
600 miles west of Ecuador, near the equator.
Which of the following sets of animals are likely to be found on the Galapagos?
Tortoises, finches, blue- footed boobies
Urbanization impacts?
Most species negatively, but a few positively.
The gradual replacement of regionally distinct ecological communities with cosmopolitan communities that reflect the increasing global activity of humans is referred to as?
Biotic homogenization.