Organisms and Populations Test

Question 1
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The population size of a species over time is shown in the graph. The growth pattern demonstrated by the population at time 1 is

A
Gradual

B
Declining

C
Continual

D
Oscillating

E
Exponential

Question 2
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Which one of the following pair of animals is an example of commensalism?

A
Sacculina- Crab

B
Plasmodium- Anopheles

C
Golden Jackal- Tiger

D
Ascaris- Man

Question 3
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Which of the following could not cause a large number of density-dependent deaths in a population?

A
Winter storms

B
Disease carrying insects

C
Predators

D
Limited resources

E
Small forest fire

Question 4
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Read the passage and answer the following question.
Students carry out an experiment to explore the effect of different environments on blood flow using small, freshwater fish. Each fish is placed into a petri dish. A wet cotton ball is placed over its gills to allow for the diffusion of oxygen, which will keep the fish alive. The students then place the petri dish onto the stage of a light microscope so that the thinnest part of the tail is directly under the objective lens and blood can be seen flowing in blood vessels. While focusing on a capillary, students count the number of red blood cells flowing through the vessel at 5-second intervals. After monitoring the normal flow of blood for 30 seconds, the environment in the petri dish is altered in one of five different ways. Students observe and record the change in blood flow if any. After the experiment, each fish is returned to the fish tank.

Experiment 1 - Nothing is added to this petri dish.
Experiment 2 - Water at a temperature of $$\displaystyle { 5 }^{ \circ }C$$ is added.
Experiment 3 - Water at a temperature of $$\displaystyle { 30 }^{ \circ }C$$ is added.
Experiment 4 - Ethyl alcohol is added.
Experiment 5 - Nicotine extracted from cigarette tobacco is added.

Experiment Initial average rate of blood flow Final average rate of blood flow
1 9 9
2 8 4
3 9 13
4 8 5
5 9 12

Which of the following statement is incorrect about this experiment?

A
Alcohol is a central nervous system depressant and decreases the blood flow in the capillary.

B
Nicotine is a central nervous system that stimulates and increases blood flow in the capillary.

C
Increasing the temperature increases the blood flow in the capillary.

D
The changes in blood flow in experiments 2 and 3 are temporary because a fish can adjust its body temperature.

E
Experiment 1 is the control.

Question 5
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The interspecific relationship which benefits one species and harms the other includes
I. Commensalism
II. Competition
III. Parasitism
IV. Predation

A
III only

B
III and IV

C
I, II, and III

D
II, III, and IV

E
I, II, III, and IV

Question 6
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The point of time in the graph when the population size reaches the carrying capacity for ecosystem is

A
3

B
4

C
6

D
9

E
12

Question 7
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In what way a plant growing on a forest floor is adapted for its survival?

A
Has shallow roots

B
Requires low light

C
Has a deep ta root

D
Requires strong light

E
Requires moist soil

Question 8
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Based on the given figure, find out the incorrect statement?

A
Rodent density is dependent on food-species diversity

B
Food- species diversity is dependent on rodent density

C
Grazing pressure maintains food-species diversity

D
Rodents are selective in their food choices

E
Rodents help prevent food-species mono cultures from developing

Question 9
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Which of the following will be fewer in number for an invasive species in a new ecosystem?
I. Ecological niches
II. Predators
III. Suitable food sources

A
I only

B
II only

C
III only

D
I and II

E
II and III

Question 10
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The given graph represents the fastest multiplication rate of bacteria when they are added to rich broth.
The following graphs represent bacterial growth under different conditions, with increasing numbers of bacteria on the $$y$$-axis and increasing time on the $$x$$-axis.
Which graph describes the result of introduction of minimal nutrients for the first six hours and then addition of surplus nutrients?

A
1

B
2

C
3

D
4

E
5