Organisms and Populations Test

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Organisms and Populations Test - 24

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Weekly Quiz Competition

Question 1
1 / -0

The formula for exponential population growth is

A
$$rN / dN=dt$$

B
$$dN / dt=rN$$

C
$$dt / dN=rN$$

D
$$dN / rN=dt$$

Solution

Exponential growth occurs when the increase in the population becomes rapid and soon attains its full potential rate due to constant requirements (with respect to the availability of food and other requirements).
The equation is represented as,
dN/dt = (b-d)xN
let (b-d) = r, then
dN/dt = rN
Here,
N = population size
b = birth rate
d = death rate
r = intrinsic rate of natural increase
So, the correct answer is option B.
Question 2
1 / -0

Human population growth is

A
Lag

B
Stationary

C
Exponential

D
None of these

Solution

Population growth curve is the graphic representation of population growth by plotting number of individuals at different time intervals. The human population growth curve is S-shaped or sigmoid. It has three phases:
(a) Lag phase is slow in the beginning due to small size of population, lack of adaptation to new environment and slow development
(b) Log phase or exponential phase is the geometric increase in population size due to abundance of food, space and natural resources.
(c) Stationary phase or zero growth phase is the stability of population, i.e., birth and death rates are equal, so that there is no growth in population size.

So, the correct answer is 'Exponential'.
Question 3
1 / -0

The aggregate of process that determine the size and composition of any population
is called

A
Population dispersal

B
Population dynamics

C
Population explosion

D
Population density
Question 4
1 / -0

If in a population, natality is balanced by mortality then there will be?

A
Decrease in population growth

B
Zero population growth

C
Increase in population growth

D
Over population
Solution
- Natality stands for the number of births in a particular place at a given time.
- And mortality is the number of deaths that takes place in a particular region at a particular time.
- If the number of death is equal to the number of births then it is seen that there is no increase in the population of that area.
Hence the correct answer is (B)
Question 5
1 / -0

When environmental conditions are favorable, then the population growth curve will be?

A
'L' shaped

B
'J' Shaped

C
'S' Shaped

D
'U' Shaped
Solution
- The J-shaped growth curve describes a situation, in which after the initial established phase(lag phase), population growth continues in an exponential form until stopped abruptly, as the environment resistance becomes suddenly effective.
- Growth is density-independent, regulation of growth rate is not tied to the population density until the final crash.
Thus, the correct answer is option B.
Question 6
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Population termed r-strategists have

A
J-shaped growth curves

B
Type III survivorship curves

C
Are usually pioneer species

D
All of these

Solution

During a short period of time, some population produce many offsprings which require little care. Therefore, these populations usually have a survivorship curve similar to type III. These tend to have J-shaped growth curves until some environmental change causes them to decline usually within a short time. From an evolutionary point of view, such species have undergone selection to maximize their rate of natural increase and for this reason, they are termed as r-strategies.
So the correct answer is 'J-shaped growth curves'.
Question 7
1 / -0

Which of the following is not a controlling factor of
population density

A
Psychological factor

B
Geographical factor

C
Socioeconomic factor

D
Demographic factor
Question 8
1 / -0

Morphallaxis is reported in

A
Porifers

B
Coelentrates and flatworms

C
Nemarteans and some ascidians

D
All the above

Solution

Morphallaxis means restorative regeneration. In this type of regeneration, each body part is capable of developing into a complete individual. It is observed in many lower animals following severe injuries. It is seen in Porifers, coelenterates, Platyhelminthes, nematodes and some ascidians.
So, the correct answer is 'Option D- All of the above'.
Question 9
1 / -0

Number of death and birth in the last stage of plateau
growth curve of a population will be

A
Equal unlike of middle stage

B
Unequal with more deaths

C
Unequal with less deaths

D
Equal like of middle stage

Solution

In middle stage growth rate is very high due to lack of environmental resistance, but in last stage growth rate is very low due to high environmental resistance. In this phase both natality and mortality is equal to each other.
Question 10
1 / -0

High growth at the time of exponential phase of human
population growth curve is due to

A
High birth and death rates

B
High birth and low death rate

C
Low birth and high death rate

D
Low birth and death rates

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Re-Attempt Weekly Quiz Competition

Organisms and Populations Test - 24

Result

Organisms and Populations Test - 24

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SHARING IS CARING

Question 1

$$rN / dN=dt$$

$$dN / dt=rN$$

$$dt / dN=rN$$

$$dN / rN=dt$$

Solution

Question 2

Lag

Stationary

Exponential

None of these

Solution

Question 3

Population dispersal

Population dynamics

Population explosion

Population density

Question 4

Decrease in population growth

Zero population growth

Increase in population growth

Over population

Solution

Question 5

'L' shaped

'J' Shaped

'S' Shaped

'U' Shaped

Solution

Question 6

J-shaped growth curves

Type III survivorship curves

Are usually pioneer species

All of these

Solution

Question 7

Psychological factor

Geographical factor

Socioeconomic factor

Demographic factor

Question 8

Porifers

Coelentrates and flatworms

Nemarteans and some ascidians

All the above

Solution

Question 9

Equal unlike of middle stage

Unequal with more deaths

Unequal with less deaths

Equal like of middle stage

Solution

Question 10

High birth and death rates

High birth and low death rate

Low birth and high death rate

Low birth and death rates

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