Organisms and Populations Test

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Organisms and Populations Test - 60

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Weekly Quiz Competition

Question 1
1 / -0

Which of the following pairs contributes to an increase in population?

A
Natality and immigration

B
Mortality and emigration

C
Natality and emigration

D
Mortality and immigration

Solution

Natality is the proportion of births to the total population in a place at a given time, while mortality is the death rate per thousand individuals. Immigration is the movement of individuals into an area and emigration is movement of individuals out of an area. Therefore, natality and immigration will increase population.
Question 2
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Organisms that can tolerate a wide range of salt concentration are termed as

A
stenosaline

B
stenohaline

C
euryhaline

D
eurysaline

Solution

Euryhaline organisms are able to tolerate a wide range of salt concentration (or salinaties). E.g. Poecillia sphenops is a fishasdu that can live fresh water, brackish water or salt water. Hence the correct option is C.
Question 3
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Study the characteristics of a population represented in the graphs below.
Mark the correct graph that represents the type of selection that this population is likely to undergo.
_____ : Past
.......... : Future

A

B

C

D

Solution

It is observed that the individuals with larger body size, in the given population, are lesser in proportion as compared to individuals with smaller or moderate body size. Also, large bodies of individuals have low fitness. When natural selection acts on such a population, it would favour smaller or moderate sized individuals, hence shifting the body size vs. frequency graph to the left.
Question 4
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Which of the following representation shows the pyramid of numbers in a forest ecosystem?

A

B

C

D

Solution

In forest ecosystem, a single large sized producer like tree provide food to several herbivores, e.g., birds, in turn these small sized herbivores birds are usually eaten by falcon or eagle. The number of eagle is, however very small. Thus, the pyramid of number obtained from this kind of relationship is spindle shaped.
Question 5
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Desert, rain forest, tundra, etc, are examples of

A
Community

B
Biome

C
Ecosystem

D
Population
Solution
- A biome is a large regional unit characterized by a major vegetation type and associated fauna found in a specific climatic zone.
- Some examples of terrestrial biomes are desert, temperate deciduous forest, tropical rain forest, tundra, etc.
- So, the correct answer is option B.
Question 6
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Certain characteristic demographic features of developing countries are

A
high fertility, high density, rapidly rising mortality rate and a very young age distribution

B
high infant mortality rate, low fertility, uneven population growth and a very young age distribution

C
high mortality, high density, uneven population growth and a very old age distribution

D
high fertility, low or rapidly falling mortality rate, rapid population growth and a very young age distribution.

Solution

A young growing population is considered as an asset for any developing country as it contributes to the working population.
High fertility rates, low mortality rates along with a young age distribution is an asset to any growing country.
So, the correct option is 'high fertility, low or rapidly falling mortality rate, rapid population growth and very young age distribution.'
Question 7
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In the given figure, identity the temperate forest and coniferous forest respectively from the marking A-F and select the correct option.

A
A and B

B
B and D

C
D and E

D
C and F

Solution

Coniferous forests occur just South of tundra across North America, Europe, Asia and are also found in southern hemisphere. Precipitation in coniferous forests is 10-35 cm in drier parts and over 100 cm in wetter parts. It occurs both as rain as well as now. The average winter temperature does not exceed 60C. Temperate forests are found in both Northern and sou them hemispheres. Their annual precipitation lies between 75-150 cm.
So, the correct answer is 'D and E'.
Question 8
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Which of these interactions has negative effects?
(i) Predation
(ii) Mutualism
(iii) Commensalism
(iv) Parasitism

A
(i) and (iii)

B
(i) and (iv)

C
(ii) and (iii)

D
(i) only
Solution
Predation (+,-):-
In this interaction, one organism, the predator, eats all or part of the body of another organism, the prey.
Mutualism (+,+):-
When the two different population species interact in such a manner that it is beneficial to each other, then this form of interaction is called mutualism.
Commensalism (+,0):-
In this kind of integration, one species population benefits from the other species population. But the other species population does not benefit nor is it harmed in any way. Birds perching on cattle in rural areas are good example of commensalism.
Parasitism (+,-):-
This is an interaction of populations where a parasitic mode of nutrition is clearly seen, with one species being completely dependent on the other host species for all its meals/ nutrient requirements.

So, the correct answer is optio B.
Question 9
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Study the four statements (i - iv) given below and select the two correct ones out of them.
(i) A lion eating a deer and a sparrow feeding on grains are ecologically similar in being consumers.
(ii) Predator star fish helps in maintaining species diversity of some invertebrates.
(iii) Predators ultimately lead to the extinction of prey species.
(iv) Production of chemicals such as nicotine, strychnine by the plants are metabolic disorders.
The two correct statements are

A
(ii) and (iii)

B
(ii) and (iv)

C
(i) and (iv)

D
(i) and (ii)

Solution

(i) A lion eating a deer and a sparrow feeding on grains are ecologically similar in being consumers.
(ii) Predator star fish helps in maintaining species diversity of some invertebrates.
(iii) Predators lead to the control of prey species.
(iv) Production of chemicals such as nicotine, strychnine by the plants are metabolic defence mechanism.
So the correct option is '(i) and (ii)
Question 10
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The fitness of individuals with different phenotypes of the same trait differs in two different situations P and Q. P and Q respectively indicate

A
disruptive and directional selection

B
directional and stabilising selection

C
directional and disruptive selection

D
stabilising and disruptive selection.

Solution

Darwin stated that of fitness of an organism is measured by its ability to survive better than other species in a given surrounding.
Disruptive selection is a type of natural selection which can describe the change in population gene pool where the two extreme values of the population are favoured over the middle values. Here, the population is divided into two distinct groups.
Directional selection is a type of natural selection of species in which the extreme phenotype is preferred over the other phenotype and after a large amount of time the entire frequency of allele shift in that direction.
So, the correct option is 'disruptive and directional selection'