Tag: population ecology

Questions Related to population ecology

When the population reaches carrying capacity, which of the following equation can be related to it?

zoology human population population ecology population size population and how it changes

  1. Mortality Rate=Birth Rate

  2. Mortality Rate > Birth Rate

  3. Mortality Rate < Birth Rate

  4. None of the above

Show answer
Correct Option: A
Explanation:

Carrying capacity is the maximum number of population species that the particular environment can survive. In this case, the number of individuals that are mortal and the number of new births will be equal. SO, the mortality rate will be equal to birth rate. 

So, option A is the correct answer.

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 

zoology human population population ecology population size population and how it changes

  1. 400

  2. 200

  3. 100

  4. 50

Show answer
Correct Option: B
Explanation:
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'.

Increase in number of individuals in a population represents

zoology human population population ecology population size population and how it changes

  1. Natality

  2. Mortality

  3. Density

  4. Diversity

Show answer
Correct Option: C
Explanation:

In a population, if the number of individuals are more..the population density will be more. And if the population density is less..the number of individuals will be less. Density of a population is determined by the number of individuals residing in a particular area. 

So, option C is the correct answer.

Population density of terrestrial organisms is measured in terms of individuals per _____________. 

zoology human population population ecology population size population and how it changes

  1. Metre

  2. $Metre^2$

  3. $Metre^3$

  4. $Metre^4$

Show answer
Correct Option: B
Explanation:

  • How many organisms there are per unit area is referred to as density.
Population density is a measurement of population size per unit area, i.e., population size divided by total land area.
  • and we normally measure the area in meter square. so option B is the correct answer 

Each environment can support a limited population depending upon its 

zoology human population population ecology population size population and how it changes

  1. Biotic potential

  2. Carrying capacity

  3. Natality

  4. Reproductive potential

Show answer
Correct Option: B
Explanation:
  • Biotic potential is the maximum reproductive capacity of an organism under optimum environmental conditions.
  • Natality is the ratio of the number of births to the size of the population; birth rate.
  • The carrying capacity of a biological species in an environment is the maximum population size of the species that the environment can sustain indefinitely, given the food, habitat, water, and other necessities available in the environment.

So, the correct answer is 'Carrying capacity'.

Carrying capacity of an environment for a given population is

zoology human population population ecology population size population and how it changes

  1. $\dfrac{dN}{dt}=rN(1-\dfrac{N}{K})$

  2. $dN=rN-\dfrac{N}{K}$

  3. $\dfrac{dN}{dt}=rN-\dfrac{N}{K}$

  4. $\dfrac{dN}{dt}=rN-\dfrac{1}{k}$

Show answer
Correct Option: A

The two basic processes which contribute to a decrease in population density are 

zoology human population population ecology population size population and how it changes

  1. Natality and emigration

  2. Mortality and immigration

  3. Natality and immigration

  4. Mortality and emigration

  5. Emigration and immigration

Show answer
Correct Option: D
Explanation:
The size of a population for any species is not a static parameter. It keeps changing in time, depending on various factors including food availability, predation pressure and reduces weather. In fact, it is these changes in population density that give us some idea of what is happening to the population - whether it is flourishing or declining. Whatever might be the ultimate reasons, the density of a population in a given habitat during a given period fluctuates due to changes in four basic processes, two of which (natality and immigration) contribute an increase in population density and two (mortality and emigration) to a decrease.
(i) Natality in population ecology is the scientific term for birth rate.
(ii) Mortality is the number of deaths in the population during a given period.
(iii) Immigration is the number of individuals of the same species that have come into the habitat from elsewhere during the time period under consideration.
(iv) Emigration is the number of individuals of the population who left the habitat and gone elsewhere during the time period under consideration.

So, the correct answer is 'D'.

"Verhulst-Pearl" logistic growth is described using the equation $\dfrac{dN}{dt}=rN(\dfrac{K-N}{K})$. In this K stands for

zoology human population population ecology population size population and how it changes

  1. Temperature in degree Kelvin

  2. Intrinsic rate of natural increase

  3. Carrying capacity

  4. Population density

Show answer
Correct Option: C
Explanation:
The population growth rate is measured in number of individuals in a population (N) over time (t). The term for population growth rate is written as (dN/dt). The d just means change. K represents the carrying capacity, and r is the maximum per capita growth rate for a population. Per capita means per individual, and the per capita growth rate involves the number of births and deaths in a population. The logistic growth equation assumes that K and r do not change over time in a population.

So, the correct answer is 'C'.

A high density of elephant population in an area can result in :-

zoology human population population ecology population size population and how it changes

  1. Predation on one another

  2. Mutualism

  3. Intra specific competition

  4. Inter specific competition

Show answer
Correct Option: C
Explanation:
A high density of elephant population in an area can result in intra specific competition as elephants as a species will require the same resources or will be surviving in the same niche and with greater density of population the resources will be limited as compared to the number of individuals
So, the correct answer is 'Intra specific competition'

For which of the following cases, population density can be easily determined by utilizing non-biological parameter?

zoology human population population ecology population size population and how it changes

  1. Fish density

  2. Density of bacteria in culture plate

  3. Siberian cranes at Bharatpur wetlands

  4. Tiger census

Show answer
Correct Option: A
Explanation:

Non biological parameters of water can be easily used to determine the population density of the fishes.

Bacteria, Siberian cranes and Tigers are impacted heavily by biological parameters and their population cannot be just estimated on the basis of non biological parameters.
These parameters include :

  1. Presence of heavy metals
  2. pH of water
  3. Mineral content like nitrates and phosphorus
  4. Temperature
  5. Dissolved oxygen
  6. Turbidity
So the correct answer is 'Fish'.