Tag: variation

Questions Related to variation

Read the passage and answer the following question.

A total of 12 bird species having distinct diets, behavior, coloration and beak shapes inhabit a large volcanic island in the South Atlantic 500 miles from the Coast of Africa not found on the mainland. Two species are flightless herbivores. A bird found on the mainland is related to these bird species but it does not fly over water but can occasionally survive at sea in a storm. There are no reptiles, mammals or amphibians on the island, although there are many insect and plant species.

The evolution of two flightless bird species on the island indicates

zoology variation examples of natural selection selection natural selection

  1. Flight improved the ability of the species to escape predators, but impaired food gathering on the ground.

  2. Flight originally evolved only to escape predators.

  3. Mimicry is a highly effective evolutionary strategy.

  4. The species had greater fitness without the ability to fly.

  5. Flight is not an effective means to escape predators.

Show answer
Correct Option: D
Explanation:

According to Charles Darwin, Natural selection is a tool of nature to impose the survival of the fittest. As some species fight to become the fittest, they adapt. Many organisms due to this, evolved, got adapted as they chose to survive in that habitat. Adaptation is the biggest drive to evolution and the pinpointed conclusion of the natural selection. 

So, the correct option is 'The species had greater fitness without the ability to fly'.

Read the passage and answer the following question.

A total of 12 bird species having distinct diets, behavior, coloration and beak shapes inhabit a large volcanic island in the South Atlantic 500 miles from the Coast of Africa not found on the mainland. Two species are flightless herbivores. A bird found on the mainland is related to these bird species but it does not fly over water but can occasionally survive at sea in a storm. There are no reptiles, mammals or amphibians on the island, although there are many insect and plant species.

Two of the bird species on the island are herbivores that both inhabit the same species of tree and eat the fruit the tree produces year-round. Which of the following helps both species to inhabit the tree without competing for resources?

zoology variation examples of natural selection selection natural selection

  1. One species lives in the top 30 percent of the tree and the other species lives in the lower 70 percent.

  2. One species is nocturnal and the other is active during the day.

  3. Reproductive isolation exists.

  4. The species have differing beak shapes.

  5. One species must become extinct.

Show answer
Correct Option: A
Explanation:

This phenomenon is called Resource partitioning. When the resources in a niche are limited, so as to avoid the competition species divide the resources accordingly.

According to R* rule of limited resources of ecology, If two species are living in a resource limiting space, the species which can survive in the lowest equilibrium of resource will only resist the extinction. Coexistence is only possible if each species have the low R* on that resource.
So, the answer is 'One species lives in the top 30 percent of the tree and the other species lives in the lower 70 percent'.

Replacement of the lighter-coloured variety of peppered moth (Biston betularia) to its darker variety (Biston carbonaria) in England is the example of

zoology variation examples of natural selection selection natural selection

  1. Natural selection

  2. Regeneration

  3. Genetic isolation

  4. Temporal isolation

Show answer
Correct Option: A
Explanation:
In England, before industrialisation in $1860$, it was observed that there were more white-winged moths on tree trunks than dark-winged or melanised moths. But after industrialisation in $1920$, there were more dark-winged moths in the same area. Before industrialisation, the tree trunks were covered by white-coloured lichens. In that background, the white-winged moths survived but the dark-winged moths were eaten by predators. During post industrialisation period, the tree trunks became dark due to industrial smoke and soot. Therefore, the white winged moths could not survive due to predators but dark-winged moths survived, i.e., the moths that were hidden in background survived. Thus, industrial melanism supports evolution by natural selection.

So, the correct answer is 'Natural selection'.


The adaptation shown by the bacterium Pseudomonas for metabolization of nylon is an example of

zoology variation examples of natural selection selection natural selection

  1. Genetic variation

  2. Natural selection

  3. Neo-Lamarckism

  4. None of the above

Show answer
Correct Option: B
Explanation:

Pseudomonas is the genus of a bacterium. This bacterium was placed in the medium where only nylon was present. This resulted in the development of the bacterial species which was able to metabolize the nylon. The nylon was the only source of food available so, the organism adapted itself to feed on the nylon. This is an example of natural selection.

Thus, the correct answer is option B. 

Read the following statements and select the correct option.
(i) Increase in melanised moths after industrialisation in Great Britain is a proof for natural selection.
(ii) When more individuals of a population acquire a mean character value, it is called disruption
(iii) Changes in allelic frequency in a population will lead to Hardy-Weinberg equilibrium.
(iv) Genetic drift changes the existing gene or allelic frequency in future generations.

zoology variation examples of natural selection selection natural selection

  1. Only (ii) is correct

  2. Only (iv) is correct

  3. Both (i) and (iv) are correct

  4. Both (i) and (iii) are correct

Show answer
Correct Option: C
Explanation:

When more individuals of a population acquire a mean character value, it is called stabilising selection. No change in allelic frequency in a population will lead to Hardy-Weinberg equilibrium.

So, the correct option is 'Option C'.

State whether the following statements are true or false .
Boiled potato tuber cannot be used for potato osmoscope experiment

zoology variation examples of natural selection selection natural selection

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

On boiling, most of the cells of the potato become dead. Due to this the cells become inactive and cannot undergo the process of osmosis. When there is no osmosis the water level inside the cavity of potato shows no change.

So, the given statement is true. 

Choose the correct answers from the alternatives given.
Fitness is an important concept in natural selection. Fitness is most properly a property of

zoology variation examples of natural selection selection natural selection

  1. an individual

  2. a genotype

  3. a species

  4. a phenotype

Show answer
Correct Option: B
Explanation:

Natural selection, the process that results in the adaptation of an organism to its environment by means of selectively reproducing changes in its genotype or genetic constitution.

So correct answer is B, a genotype

Choose the correct answers from the alternatives given.
The offspring of better-adapted individuals are expected to make up a larger proportion of the next generation. The.most likely explanation is

zoology variation examples of natural selection selection natural selection

  1. genetic drift

  2. mutation

  3. natural selection

  4. gene flow

Show answer
Correct Option: C
Explanation:

As the natural selection a process in which organisms with certain inherited traits are more likely to survive and reproduce than are individuals with other traits. So correct answer is C, natural selection.

The peppered moth used to be a light colour with black spots. When the atmosphere in London became filled with soot because of the Industrial Revolution, the white trees became darker and light coloured moths were eaten by birds more readily. Within months, moths became darker and lighter moths were rare. After the Industrial revolution, light coloured moths were found in greater numbers. The given example can be related to 

zoology variation examples of natural selection selection natural selection

  1. Adaptive radiation

  2. Natural selection

  3. Convergent evolution

  4. None of the above

Show answer
Correct Option: B
Explanation:

The given example is of natural selection. According to the theory of natural selection, nature supports the survival of the fittest. It means, only those individuals will survive who adapt themselves to the change in the environment. In the given case, moths changed their colour to adapt themselves according to the change in the environment. They were selected by the nature as fittest. So, the correct option is B.

Which of the following traits accounts for natural selection?

zoology variation examples of natural selection selection natural selection

  1. Skeletal Adaptations

  2. Coloration

  3. Physiological traits

  4. All of the bove

Show answer
Correct Option: D
Explanation:
Natural selection is the one of the most accepted theory of evolution of species. According to this theory, nature supports the survival of the fittest who adapts according to the change in the environment. It was given by Darwin. He also said that a population will show change in genetic traits over many generations, that help it remain best suited to the environment. For example, skeletal adaptations of long neck in giraffe, change in colouration in peppered moth, physiological changes in humans to digest the cow's milk (lactose tolerance). So, the correct option is D.