Organisms and Populations Test

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Organisms and Populations Test - 63

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Weekly Quiz Competition

Question 1
1 / -0

Which of the following equation correct represents the exponential population growth curve?

A
dN/dt = rN

B
dN/dt = rN $$(\dfrac{K-N}{K})$$

C
$$N_t = N_0e^rt $$

D
Both A and C
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.
- When resources are unlimited, populations exhibit exponential growth, resulting in a J-shaped curve.
- Exponential growth is represented by the equation dN/dt = rN. In this equation, dN/dt is the growth rate of the population in a given instant, N is population size, t is time, and r is the per capita rate of increase –that is, how quickly the population grows per individual already in the population.
- The integral equation for exponential growth is $$N_t = N_0e^rt $$.Where $$N_t$$=Population density after time t,$$N_o$$ =Population density at time zero,r=intrinsic rate of natural increase,e=the base of natural logarithms (2.71828),
- So, the correct answer is 'Both A and C'.
Question 2
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Which of the following statements is/are correct?

A
Geometric growth produces J-shaped population growth curve.

B
Logistic occurs when resources are limiting.

C
Equation for exponential growth is $$N_t = N_0^{rt}$$.

D
All of these.
Solution
- In the case of J-shaped growth form, the population grows exponentially, and after attaining the peak value, the population may abruptly crash. It is also called geometric growth.
- The integral form of the exponential growth can be represented by the equation as N$$_t$$ = N$$_0$$e$$^r$$$$^t$$.
where,
N$$_t$$ = Population density after time t
N$$_0$$ = Population density at time zero
r = intrinsic rate of natural increase
e = the base of natural logarithms.
- Logistic growth of a population size occurs when resources are limited while exponential growth is possible only when infinite natural resources are available.
So, the correct answer is option D.
Question 3
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Which of the following statement is/are incorrect?

A
A population has certain attributes which an individual does not have

B
Tiger census in our National parks and tiger reserves is often based on pug marks

C
If a new habitat is being colonized birth rate may contribute more significantly to population growth

D
Both (A) and (B)
Solution
Correct Option: C
Explanation:
A population can be defined as a group of individuals of the same species that reside in the same region.
Birth rate, mortality rate, age distribution pattern, sex ratio, and population density are all characteristics of a population, not an individual.
Pug markings are animal footprints, while fecal pellets are animal excrement.
Pug prints (footsteps) and faecal pellets are frequently used to count tigers in our national parks and tiger reserves. (Waste from animals.)
It also aids in detecting the presence of other wild animals.
For example, if a new habitat is only being colonized, immigration may contribute to population increase more than birth rates.
Hence, the incorrect statement is if a new habitat is being colonized birth rate may contribute more significantly to population growth.
Question 4
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The population growth is generally described by the following equation:
$$\dfrac{dN}{dt} = rN \dfrac({K-N}{K})$$
What does'r' represent in the given equation ___________________.

A
Population density at time 't'

B
Intrinsic rate of natural increase

C
Carrying capacity

D
The base of natural logarithm

Solution

A population growing in habitat with limited resources shows a sigmoid growth curve. This type of population growth is called verhuladt-pearl logistic growth as given by the equation:
$$\dfrac{dN}{{dt} = rN\dfrac ({K-N}{K})$$
When, N = population density at time t; r = Intrinsic rate of natural increase and K = caring capacity
Question 5
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In a population per capital birth rate is 0.15 and per capital death rate is 0.08 during a unit time period. What is the value of r (intrinsic rate of natural increase ) for the given population?

A
0.23

B
0.07

C
0.05

D
0.25

Solution

Intrinsic rate of natural increase (r)
= Birth rate - death rate
= 0.15 -- 0.8 = 0.07
Question 6
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Study the population growth curves (A and B) in the given graph and select the incorrect option

A
Curve 'A' shows exponential growth, represented by equation $$\dfrac{dN}{dr} = rN$$

B
Curve 'B' shows logistic growth, represented by equation

$$\dfrac{dN}{dr} = rN(\dfrac{K-N}{K})$$

C
Exponential growth curve is considered as more realistic than the logistic growth curve

D
Curve 'A' can also be represented by equation $$N_t = N_0e^rt$$

Solution

Since resources of growth for most animal population are finite and become limiting sooner or later, the logistic growth model is considered as more realistic
Question 7
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Species interaction with negative influence on both is referred to as

A
Amensalism

B
Mutualism

C
Commencialism

D
Competition

Solution

Competition is defined as the active demand by two or more individuals of the same species or members of two or more species at same trophic levels for a common resource. Introspective competition is competition amongst members of the same species for a common resource such as for food, space and mate. Inter specific competition is rivalry amongst members of different species. The severity of competition depends upon similarity in the requirement of food and shelter. So, the correct answer is 'Competition'.
Question 8
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The maximum possible number of individuals that a habitat can support is called its _________________.

A
fecundity

B
surviving ability

C
carrying capacity

D
biotin potential

Solution

In nature, a given habitat has resources to support a certain number of individuals of a population, beyond which no further growth is possible. This limit is called as nature's carrying capacity (K) for that species in that habitat
Question 9
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Which of the following factors influence population density under normal conditions?

A
Deaths

B
Immigration

C
Emigration

D
Both (A) and (B)

Solution

Under normal condition births and deaths influence density of a population the other two factors being only active under special condition
Question 10
1 / -0

Read the following statement and select the correct option :
Statement 1 Brood parasitism in birds is an examples of parasitism in which the parasitic bird lays its eggs in the nest of its host and the host incubates them
Statement 2 During the course of evolution, the eggs of the parasite bird have evolved to resemble the hos's eggs in size and color to reduce the chances of the host bird detecting the feign eggs and removing them from the nest.

A
Both statement 1 and 2 are correct

B
statement 1 is correct but statement 2 is incorrect

C
statement 1 is incorrect but statement 2 is correct

D
both statement 1 and 2 are incorrect

Solution

Brood parasitism in birds is an example of parasitism in which the parasitic birds lays its eggs iin the nest of its host and the host incubates them. Ths way, the bird can save the energy that it would have spent in incubation and can use thaqt energy iin fooraging and other activtiies. During the course of evolution, the eggs of theparasite bird have evolved to resemble the host's eggs in size and colour to reduce the chances of the hose bird detecting the foreign eggs and removing them from the nest .Laying eggs by cuckoo (koel) in crow's nest is brod parasitism. Cowbirds also show brood parasitism

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Organisms and Populations Test - 63

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Organisms and Populations Test - 63

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SHARING IS CARING

Question 1

dN/dt = rN

dN/dt = rN $$(\dfrac{K-N}{K})$$

$$N_t = N_0e^rt $$

Both A and C

Solution

Question 2

Geometric growth produces J-shaped population growth curve.

Logistic occurs when resources are limiting.

Equation for exponential growth is $$N_t = N_0^{rt}$$.

All of these.

Solution

Question 3

A population has certain attributes which an individual does not have

Tiger census in our National parks and tiger reserves is often based on pug marks

If a new habitat is being colonized birth rate may contribute more significantly to population growth

Both (A) and (B)

Solution

Question 4

Population density at time 't'

Intrinsic rate of natural increase

Carrying capacity

The base of natural logarithm

Solution

Question 5

0.23

0.07

0.05

0.25

Solution

Question 6

Curve 'A' shows exponential growth, represented by equation $$\dfrac{dN}{dr} = rN$$

Curve 'B' shows logistic growth, represented by equation $$\dfrac{dN}{dr} = rN(\dfrac{K-N}{K})$$

Exponential growth curve is considered as more realistic than the logistic growth curve

Curve 'A' can also be represented by equation $$N_t = N_0e^rt$$

Solution

Question 7

Amensalism

Mutualism

Commencialism

Competition

Solution

Question 8

fecundity

surviving ability

carrying capacity

biotin potential

Solution

Question 9

Deaths

Immigration

Emigration

Both (A) and (B)

Solution

Question 10

Both statement 1 and 2 are correct

statement 1 is correct but statement 2 is incorrect

statement 1 is incorrect but statement 2 is correct

both statement 1 and 2 are incorrect

Solution

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Curve 'B' shows logistic growth, represented by equation

$$\dfrac{dN}{dr} = rN(\dfrac{K-N}{K})$$