Population Questions
1. Which is TRUE if a population is at the carrying capacity?
a) the environment cannot support a larger population (b) the birthrate is about equal to the death rate
c) the population size is steady (d) all of the above
2. An increase in the population of a herbivore is generally _______ the populations of its natural predators
a) preceded by an increase in (b) matched by an increase in (c) followed by an increase in
d) independent of
3. If natural predators are removed, herbivore populations will most likely
a) increase (b) remain constant because births always balance deaths (c) increase, overgraze, and die back due to starvation (d) change in unpredictable ways
4. In a natural, balanced ecosystem herbivores do NOT overgraze vegetation because
a) natural predators keep the herbivore populations in check (b) natural herbivores control their own populations (c) natural vegetation grows fast enough so that there is always more than the herbivores can eat (d) herbivores quit eating when they get full and therefore do not overgraze vegetation
5. Which of the following would NOT be a factor in environmental resistance?
a) parasites (b) birth rate (c) availability of food (d) predators
6. In a natural, balanced ecosystem predators do not eliminate their prey because
a) they know that if they do they will starve (b) some prey always escape and reproduce (c) there is just enough prey to feed all the predators (d) there is an unlimited amount of prey for the predator
7. Territoriality limits population because
a) many individuals are killed fighting for territory (b) many individuals become sterile in certain habitats (c) individuals that cannot defend a territory usually don’t breed (d) territoriality does NOT limit population
8. Which of the following can cause a DECREASE in the population in an area where no individuals can enter or leave?
a) lack of food (b) accumulation of wastes (c) overcrowding (d) lack of available shelter
e) all of the above
9. The number of offspring that can be produced in a population under ideal conditions is defined as
a) biotic potential (b) recruitment (c) birth rate (d) natality (e) survival rate
10. Assume that a population of hamsters could enter a cage but none could leave. Any decrease in population would probably be due to
a) immigration (b) mortality (c) natality (d) emigration (e) impossible to say
11. Which of the following will result in the DECREASE in the size of a population?
a) emigration (b) immigration (c) natality (d) births (e) all of the above
12. The combination of biotic and abiotic factors which limit population growth are collectively called
a) biotic potential (b) growth factors (c) environmental resistance (d) S-curve factors
e) recruitment factors
13. The population density is the
a) number of organisms in an ecosystem (b) number of organisms in a biome (c) growth rate of an organism (d) number of organisms in a given area (e) none of the above
14. A population consists of
a) all the organisms living in a specified area (b) one species of organism found in a specified area (c) all of one kind of organism living in a specified area at a given time (d) the number of species of organisms inhabiting an area (e) the number of people in an area
15. Which is the best example of a population?
a) the number of people living in Quispamsis (b) the variety of species in a specified area (c) the number of tree species in a forest (d) the number of different birds at a backyard feeder in winter (e) the number of species feeding in an area
16. Explain the difference between open and closed populations and provide an example of each.
17. Name two ways humans cause extinctions.
18. Describe, using a specific example, how carnivores can control the size of plant populations.
19. To be healthy, a population must maintain a balance between what two opposing forces?
20. Ideal conditions for population growth could be thought of as a good thing. How can they be negative for the population and for the ecosystem as a whole?
21. Give an example of an organism with high biotic potential and one with low biotic potential.
22. Imagine a pride of lions on an African savanna. Describe what would happen to the lion, zebra and plant populations if the lions killed too many zebra.
23. How would you describe the general health of our environment? Why should we be concerned about the health of the environment?
24. After a day at the beach, your dog is home to 2000 sand fleas. Over the next few days, 250 new fleas are born, 200 jump off your dog, you squish 150, and 300 more jump onto the dog when you go to the beach again. Calculate the population growth.