Organisms and Populations Test

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Organisms and Populations Test - 86

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Weekly Quiz Competition

Question 1
1 / -0

Scholars caught, marked and released 80 fishes in a pound. Later 100 fishes were caught at random. 40 of them were marked. The number of fishes in the pond is

A
400

B
200

C
100

D
50

Solution

Let's take the total number of fishes in the pond be x.
When 80 fishes are marked, then the ratio of tagged fishes to total fishes is 80/x
When 100 fishes were caught out of which 40 were marked, then the ratio of tagged fishes to total fishes is 40/100
Taking the distribution of fishes in the pond to be uniform, the ratio of tagged fishes to the total fishes will be same in both the situations.
Hence, the equation can be shown as:
80/x = 40/100
This comes out to be 200
So, the correct answer is '200'.
Question 2
1 / -0

Density of population (D) is

A
$$D=\dfrac{S(size)}{W (weight)}$$

B
$$D=\dfrac{S(space)}{N (Number)}$$

C
$$D=\dfrac{N(number)}{S (space)}$$

D
None of the above

Solution

The population density of a place is a number that defines the crowd in that place. It is calculated by dividing the population by the given area.
D = N/S = Number/Space
Question 3
1 / -0

An intimate relationship between two species in which co-evolution and adaptation occur is

A
competition

B
a community

C
predation

D
symbiosis

Solution

Symbiosis refers to a close, long-term interaction between two different species. But, there are many different types of symbiosis relationships. Mutualism is a type of symbiosis where both species benefit from the interaction. And co-evolution and adaptation occur in symbiosis.
So, the correct option is 'symbiosis'
Question 4
1 / -0

A single bacterium is actively growing in a medium that supports its growth up to $$100$$ million. Assuming the division time of the bacterium as $$3$$ hours and the life span of non-dividing bacteria as $$5$$hours, which one of the following represents the maximum number of bacteria that would be present at the end of $$15$$ hours?

A
$$10$$

B
$$64$$

C
$$24$$

D
$$32$$

Solution

In the given problem, the medium supports the growth of up to 100 million bacteria. It means, till the population reaches 100 million, bacteria will keep on dividing and there will be no non-dividing bacteria. Generation time of the bacteria is 3 hours. It means, it takes 3 hours to divide. At the end of 15 hours, there will be total 5 generation time.
Number of bacteria at the end = 2$$^n$$ where n is number of generation time.
Hence, number of bacteria present at the end of 15 hours = 2$$^5$$ = 2 x 2 x 2 x 2 x 2 = 32.
Thus, the correct answer is option D.
Question 5
1 / -0

In a population of predator and prey it was seen that when the prey population was numerically high the predator population consumed more and more prey. This is because the predator population

A
can digest any quantity of food

B
responds functionally

C
responds numerically

D
is a voracious feeder

Solution

A predator is an organism which gets its food from the host after killing. It does not live in constant association with the host and this is known as predation.
The predator population works according to the prey and help in keeping the prey population in a check. In absence of predators, the population will increase immensely and will affect the normal ecological balance.
So, the correct option is 'responds functionally'
Question 6
1 / -0

Competitive exclusion principle stating that inferior species is eliminated eventually after prolonged competition was given by

A
Allen

B
Pearl-Verhulst

C
Gause

D
Darwin

Solution

Two or more species with close niche requirements cannot exist indefinitely in the same area as sooner or later they come into competition for possession of it. This is called as Gause's competitive exclusion principle, which state that an ecological niche cannot be simultaneously and completly occupied by established populations of more than one species. Two species can live in same habitat but not in the same niche. More siimilar the two niches are, severe the competition is.
So, the correct answer is 'Gause'.
Question 7
1 / -0

_________ rule states that mammals from colder climates generally have shorter ears and limbs to minimize heat loss.

A
Allen's

B
Berger's

C
Borg's

D
Powell's

Solution

According to Allen's rule, in endothermal animals of colder areas, the extremities like feet, tail, ears, etc. tend to be smaller as compared to their relatives in warmer regions. This minimizes heat loss.
Question 8
1 / -0

What does the shape of the given age pyramids (A to C) reflect about the growth status of populations?

A B C

A
Declining Stable Expanding

B
Stable Expanding Declining

C
Expanding Stable Declining

D
Declining Expanding stable

Solution

Triangular age pyramid has high proportion of preoperative
individuals, moderate number of reproductive individuals and fewer post-reproductive individuals. It represents young or rapidly growing population.
In urn-shaped age pyramid, the number of reproductive individuals is higher than the number of pre-reproductive individuals. It represents declining or diminishing population with negative growth.
In bell-shaped age pyramid, the number of pre-reproductive and reproductive individuals is almost equal. Post reproductive individuals are comparatively fewer. It represents stable or stationary population, neither growing nor diminishing.
Question 9
1 / -0

Island bio geography theory states that the number of species on an island is determined by immigration rates of new species to the island and extinction rates of species on the island immigration rates to an island decline as its distance froooom the mainland increases and extinction rates decrease with increasing island size when the immigration and extinction rates on an island are equal, the number of species on the island reaches equilibrium.
Which of the following gives the correct combination oof distance (near and far) and area (small and rage )of island where species (s-s) occur?

A
$$S_1$$ - near island, small island

B
$$S_2$$ - near island, large island

C
$$S_3$$ - near island, far island

D
$$S_4$$ - near island, large island

Solution

If the island is near the mainland, a number of species will reach the island. So, the competition between them will increase. As the distance of the island from the mainland increases, the immigration rate will also decrease.
So, option D is the correct answer.
Question 10
1 / -0

Which is correctly labelled with respect to the given diagram?

A
B : Logistic curve

B
C : Carrying capacity

C
C : Exponential curve

D
A : Carrying capacity

Solution

In exponential growth, a population's per capita (per individual) growth rate stays the same regardless of population size, making the population grow faster and faster as it gets larger. Exponential growth is not a very sustainable state of affairs, since it depends on infinite amounts of resources (which tend not to exist in the real world). Exponential growth may happen for a while, if there are few individuals and many resources. But when the number of individuals gets large enough, resources start to get used up, slowing the growth rate. Eventually, the growth rate will plateau, or level off, making an S-shaped curve. The population size at which it levels off, which represents the maximum population size a particular environment can support, is called the carrying capacity, or KK.
So the correct option is 'C: Exponential curve'.

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Re-Attempt Weekly Quiz Competition

Organisms and Populations Test - 86

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Organisms and Populations Test - 86

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SHARING IS CARING

Question 1

400

200

100

50

Solution

Question 2

$$D=\dfrac{S(size)}{W (weight)}$$

$$D=\dfrac{S(space)}{N (Number)}$$

$$D=\dfrac{N(number)}{S (space)}$$

None of the above

Solution

Question 3

competition

a community

predation

symbiosis

Solution

Question 4

$$10$$

$$64$$

$$24$$

$$32$$

Solution

Question 5

can digest any quantity of food

responds functionally

responds numerically

is a voracious feeder

Solution

Question 6

Allen

Pearl-Verhulst

Gause

Darwin

Solution

Question 7

Allen's

Berger's

Borg's

Powell's

Solution

Question 8

Declining Stable Expanding

Stable Expanding Declining

Expanding Stable Declining

Declining Expanding stable

Solution

Question 9

$$S_1$$ - near island, small island

$$S_2$$ - near island, large island

$$S_3$$ - near island, far island

$$S_4$$ - near island, large island

Solution

Question 10

B : Logistic curve

C : Carrying capacity

C : Exponential curve

A : Carrying capacity

Solution

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