Class 12 Organisms and Populations MCQs with Answers

Class 12 biology MCQs with answers. organism is a continuous biological system that exists in a given environment and can adapt and maintain a specific structure and behavior. Fungi, bacteria, plants, animals, and humans are all included in this group. A population is formed when a group of organisms band together. The population forms a community that is responsible for the operation of the ecosystem. A population is defined as a collection of individuals or organisms of any species that are found in a well–defined geographical area at a certain moment and can interbreed with other individuals or organisms of that species. For example, the deer population in a woodland.

Class 12 Biology Organisms and Populations MCQs with Answers

Q1. It natality is balanced by mortality in a population at a given time, there will be a/ an:

1. Decrease in the population size.
2. Increase in the population size.
3. Zero population growth.
4. Population explosion.

Q2. According to Allen’s Rule, the mammals from colder climates have:

1. Shorter ears and longer limbs.
2. Longer ears and shorter limbs.
3. Longer ears and longer limbs.
4. Shorter ears and shorter limbs.

Q3. A population has more young individuals compared to the older individuals. What would be the status of the
population after some years?

1. It will decline.
2. It will stabilise.
3. It will increase.
4. It will first decline and then stabilise.

Q4. Niche overlap indicates:

1. Mutualism between two species.
2. Active cooperation between two species.
3. Sharing of one or more resources between the two species.
4. Two different parasites on the same host.

Q5. When species area relationship is considered for a larger area, slope of the line Become:

1. More steeper.
2. Less steeper.
3. Remain unchanged.
4. Form a straight line.

Q7. What will happen to a well growing herbaceous plant in the forest if it is transplanted outside the forest in a
park?

1. It will grow normally.
2. It will grow well because it is planted in the same locality.
3. It may not survive because of change in its micro climate.
4. It grows very well because the plant gets more sunlight.

Q8. Niche is defined as:

1. A component of an ecosystem
2. An ecologically adapted zone of a species
3. The physical position and functional role of a species within the community.
4. All plants and animals living at the bottom of a water body.

Q9. Which of the following forest plants controls the light conditions at the ground?

1. Lianas and climbers.
2. Shrubs.
3. Tall trees.
4. Herbs.

Q10. The equation log A is based on the principle put forward by:

1. Alexander von Humboldt.
2. Edward Wilson.
3. David Tilman.
4. Robert May.

Q11. Formation of tropical forests needs mean annual temperature and mean annual precipitation as:

1. 18–25°C and 150–400cm.
2. 5–15°C and 50–100cm.
3. 30–50°C and 100–150cm.
4. 5–15°C and 100–200cm

Q12. Species diversity is least in:

1. Tundra biome.
2. Desert biome.
3. Grassland biome.
4. Coniferous forest tiome.

Q13. Which of the following would necessarily decrease the density of a population in a given habitat?

1. Natality > mortality.
2. Immigration > emigration.
3. Mortality and emigration.
4. Natality and immigration.

Q14. Which of the following is a partial root parasite?

1. Sandal wood.
2. Mistletoe.
3. Orobanche.
4. Ganoderma.

Q15. A protozoan reproduces by binary fission. What will be the number of protozoans in its population after six
generations?

1. 128.
2. 24.
3. 64.
4. 32.

Q16. Amensalism is an association between two species where:

1. One species is harmed and other is benefitted.
2. One species is harmed and other is unaffected.
3. One species is benefitted and other is unaffected.
4. Both the species are harmed.

Q17. Which one of the following organisms reproduces sexually only once in its life time?

1. Banana plant.
2. Mango.
3. Tomato.
4. Eucalyptus.

Q18. Biosphere is:

1. A component in the ecosystem.
2. Composed of the plants present in the soil.
3. Life in the outer space.
4. Composed of all living organisms present on earth which interact with the physical environment.

Q19. What parameters are used for tiger census in our country’s national parks and sanctuaries?

1. Pug marks only.
2. Pug marks and faecal pellets.
3. Faecal pellets only.
4. Actual head counts.

Q20. Animals from colder climates generally have shorter limbs. This is called:

1. Allen’s rule.
2. Johnson’s rule.
3. Arber’s rule.
4. Niche rule.