Organisms and Populations is a pivotal chapter for NEET aspirants, requiring a thorough understanding of ecological principles and environmental adaptations. This guide presents 25 MCQs, covering all essential topics to ensure you are well-equipped for the upcoming NEET examination. Let’s delve into the questions, answers, and their comprehensive explanations.
1. Which ecological pyramid is always upright?
Answer:
Explanation:
The Pyramid of Energy is always upright as it represents the flow of energy through different trophic levels, decreasing at each subsequent level due to energy losses, mainly through metabolic processes.
2. What type of interaction occurs when a cattle egret feeds on insects disturbed by cattle?
Answer:
Explanation:
In this interaction, the cattle egret benefits by getting food, while the cattle is neither harmed nor benefited, indicating a commensal relationship.
3. Identifying the geometric representation of age structure is a feature attributed to _______.
Answer:
Explanation:
The geometric representation of age structure is a characteristic feature of a population. It helps in understanding the distribution of various age groups within a population, which is crucial for studying population dynamics and predicting future growth trends.
4. Which of the following adaptations are found in plants living in deserts?
Answer:
Explanation:
Desert plants, or xerophytes, have adaptations like mesophylls for storing water and sunken stomata to reduce water loss through transpiration, enabling them to survive in arid conditions.
5. Which type of population dispersion results from the availability of resources?
Answer:
Explanation:
Clumped dispersion results from the availability of resources as individuals are attracted to areas with abundant resources, leading to groups or “clumps” of population.
6. The carrying capacity of a habitat is determined by the
Answer:
Explanation:
Carrying capacity refers to the maximum population size that an environment can sustain indefinitely. It is determined by the availability of limiting resources like food, water, and shelter.
7. The insect, Praying Mantis, serves as a prime illustration of _______.
Answer:
Explanation:
The Praying Mantis is renowned for its ability to blend in with its surroundings through camouflage. This adaptation allows it to evade predators and ambush prey effectively.
8. In which type of population growth is the rate of population growth proportional to the current population size?
Answer:
Explanation:
In exponential growth, the population increases rapidly as each individual produces more offspring, leading to a J-shaped curve. The growth rate is proportional to the current population size.
9. Which of the following is an example of a K-strategist species?
Answer:
Explanation:
K-strategists like elephants have lower reproductive rates, produce fewer offspring, invest more in parental care, and are generally larger and longer-lived compared to r-strategists such as bacteria and insects.
10. In a food chain, the 10% energy transfer law is due to:
Answer:
Explanation:
The 10% energy transfer law in a food chain is due to energy losses from entropy (disorder) and respiration at each trophic level, which means only about 10% of the energy is transferred to the next level.
11. Which adaptation helps organisms living in polar regions to reduce heat loss?
Answer:
Explanation:
Organisms in polar regions adapt by having a large body size and a smaller surface area to volume ratio, which helps in reducing heat loss and conserving body heat.
12. Natality refers to:
Answer:
Explanation:
Natality refers to the birth rate of a population, indicating the number of offspring born in a given time period. It is a crucial factor determining population growth.
13. Which of the following best describes r-selection?
Answer:
Explanation:
r-selection is characterized by a short lifespan, high reproduction rate, and little to no parental care. Species that exhibit r-selection often inhabit unstable environments and produce many offspring.
14. Identify the correct formula representing exponential population growth.
Answer:
Explanation:
The formula for exponential population growth is represented as dN/dt = rN, where dN/dt is the rate of population growth, r is the per capita growth rate, and N is the population size. This formula signifies that the growth rate of the population is proportional to the current population size.
15. In which type of symbiotic relationship do both partners benefit?
Answer:
Explanation:
In mutualism, both partners benefit from the relationship, such as bees pollinating flowers while obtaining nectar.
16. How do decomposers contribute to an ecosystem?
Answer:
Explanation:
Decomposers break down dead organic material and waste, recycling nutrients back into the ecosystem, which can then be used by producers.
17. What type of survivorship curve is represented by humans?
Answer:
Explanation:
Humans exhibit a Type I survivorship curve, characterized by high survival rates for the young and a higher probability of dying as they age.
18. An area with a high concentration of elephant population can lead to:
Answer:
Explanation:
When the density of elephants in an area is high, it can lead to intraspecific competition, as the individuals of the same species (elephants) compete with each other for the limited available resources, such as food and water.
19. Which factor is NOT abiotic?
Answer:
Explanation:
Bacteria are living organisms and therefore are considered biotic. The other options – temperature, soil, and light – are non-living and classified as abiotic factors.
20. What is the primary source of energy in an ecosystem?
Answer:
Explanation:
The Sun is the primary source of energy in an ecosystem. It provides energy to producers (like plants) which is then transferred through the food chain.
21. Which adaptation is NOT seen in desert plants?
Answer:
Explanation:
Desert plants typically have small leaves or spines to reduce transpiration and water loss. Large leaves are not an adaptation to arid environments.
22. What is the role of pioneer species in ecological succession?
Answer:
Explanation:
Pioneer species are the first to colonize bare substrates or disturbed ecosystems. They modify the environment, making it suitable for other species to inhabit.
23. Which of the following species does not exhibit the phenomenon of annual migration?
Answer:
Explanation:
Salamanders do not partake in annual migration, unlike the Arctic Tern, Salmon, and Siberian Crane, which migrate to exploit seasonal resources and for breeding purposes.
24. A sea anemone, which is sedentary, adheres to the shell lining of a hermit crab. This type of association is known as _____
Answer:
Explanation:
The relationship between a sedentary sea anemone and a hermit crab is an example of commensalism. In this association, the sea anemone benefits by getting better access to food, while the hermit crab neither benefits nor is harmed.