NEET Biology Organisms and Populations MCQs Set 14

Answer: (a) Autecology, synecology

Explanation:
1. Autecology studies a single species or organism in relation to its environment.
2. Synecology studies the community, or groups of species, in relation to the environment.

Teacher's Note:
1. Auto means self and syn means together.

Answer: (c) How different organisms are adapted to their environments, in terms of not only survival but also reproduction

Explanation:
1. Physiological ecology explains how organisms are adapted to their environment for survival and reproduction.
2. Interactions among organisms belong to population and community ecology.

Teacher's Note:
1. Adaptation is the central idea.

Answer: (d) Both (a) and (c)

Explanation:
1. Local populations, also called demes, are populations of the same species living in an area and are partly separated from each other.

Teacher's Note:
1. So both local population and deme are correct names.

Answer: (a) They have the same species

Explanation:
1. Sister populations are local populations of the same species.
2. Different species would form different populations, not sister populations.

Teacher's Note:
1. Species identity is the criterion.

Answer: (d) Keystone species

Explanation:
1. A keystone species affects the community far more than its numbers would suggest.
2. Fig trees fruit in the lean season and feed many animals.

Teacher's Note:
1. Their removal would affect many other species.

Answer: (c) Vegetation

Explanation:
1. Succession is studied mainly as the gradual change in plant communities, since animals depend on them.
2. Animals and decomposers change as a result.

Teacher's Note:
1. Plants define the structure of the habitat.

Answer: (a) Pioneer species

Explanation:
1. Pioneer species are the first colonisers of a bare area.
2. They reproduce fast and grow quickly.

Teacher's Note:
1. Climax species are long-lived and slow growing.

Answer: (c) Net community productivity

Explanation:
1. As the community matures, species diversity, humus and biomass rise and the net community productivity falls, since most energy is used in respiration.

Teacher's Note:
1. Net production is highest in young stages.

Answer: (a) Only a newly exposed habitat

Explanation:
1. Primary succession begins on a barren area, such as new lava or rock, with no soil.

Teacher's Note:
1. A cleared forest, a harvested field and a refilled pond already have soil or seeds, so they show secondary succession.

Answer: (c) A - kangaroo rat in desert, B - mycorrhizal fungi, C - Metasequoia in a China valley

Explanation:
1. The kangaroo rat is a keystone species of deserts.
2. Mycorrhizal fungi are critical link species for plants.

Teacher's Note:
1. Metasequoia is restricted to a valley in China, so it is endemic.

Answer: (c) A - fig tree and wasp, B - Viscum and oak, C - orchid and mango

Explanation:
1. The fig tree and its wasp is a mutualism.
2. Viscum on oak is a parasite and an orchid on a mango tree is commensalism, since the orchid benefits and the tree is not affected.

Teacher's Note:
1. The other sets contain wrong pairs.

Answer: (d) Hyperparasite - a parasite living on another parasite

Explanation:
1. A hyperparasite lives on another parasite.
2. Brood parasitism is shown by the cuckoo and crow.

Teacher's Note:
1. A hemiparasite has its own chlorophyll, while a holoparasite is totally dependent on the host.

Answer: (c) There is an absence of natural predators

Explanation:
1. In its new home the cactus had no natural predator.
2. It was controlled only after a cactus-feeding moth from its natural habitat was introduced.

Teacher's Note:
1. This shows that predators regulate prey populations.

Answer: (c) Both (a) and (b)

Explanation:
1. Plants use morphological defences like thorns and spines and chemical defences like nicotine, caffeine and strychnine.
2. So both are important.

Teacher's Note:
1. Green colour has no defence function.

Answer: (c) Pisaster starfish

Explanation:
1. Robert Paine removed the starfish Pisaster from a rocky coast.
2. Within a year, 10 species of invertebrates became extinct due to interspecific competition.

Teacher's Note:
1. This shows that a predator can regulate competition.

Answer: (d) Competitive exclusion

Explanation:
1. The goats were better competitors for food and eliminated the tortoise.
2. A superior competitor eliminating an inferior one is competitive exclusion.

Teacher's Note:
1. Resource partitioning allows coexistence.

Answer: (b) Proto-cooperation

Explanation:
1. In proto-cooperation both species benefit, but neither is dependent on the other.
2. Hence it is not obligatory.

Teacher's Note:
1. In mutualism proper the partners depend on each other.

Answer: (c) Lichen

Explanation:
1. In helotism the fungus controls the alga in a lichen, in a master-slave type of relationship.
2. The alga makes food but is held captive.

Teacher's Note:
1. It is a special type of mutualism.

Answer: (b) 1-c-iv, 2-d-i, 3-a-ii, 4-b-iii

Explanation:
1. Mutualism is (+,+) as in lichens, competition is (-,-) as in flamingoes and fishes, predation is (+,-) as in Pisaster, and commensalism is (+,0) as in the cattle egret and cattle.

Teacher's Note:
1. Revise this point from the NCERT chapter and link it with the related terms.

Answer: (a) The population grows in an exponential or geometric fashion

Explanation:
1. With unlimited resources the population grows exponentially, giving a J-shaped curve.
2. Logistic growth is seen when resources are limited.

Teacher's Note:
1. Growth is dN/dt = rN.

Answer: (c) dN/dt = rN (K - N)/K

Explanation:
1. The logistic equation is dN/dt = rN ((K - N)/K), where K is the carrying capacity.
2. The simple dN/dt = rN is for exponential growth.

Teacher's Note:
1. The population levels off as N approaches K.

Answer: (a) Polar areas, temperate areas, subtropical areas, tropical areas

Explanation:
1. Temperature increases from the poles to the equator.
2. Polar regions are coldest, then come temperate, subtropical and tropical areas.

Teacher's Note:
1. The other sequences are not in correct order.

Answer: (d) a, b, c and d

Explanation:
1. Temperature, rainfall, vegetation and species diversity all change with altitude and latitude.

Teacher's Note:
1. As we go up a mountain or towards the poles, temperature falls and communities change.

Answer: (b) Warm-area animals are small in size, with large surface area and low volume

Explanation:
1. Animals of warm areas tend to be small and have a large surface area relative to volume, so they lose heat easily.

Teacher's Note:
1. Cold-area animals are larger, with a smaller surface to volume ratio (Bergmann's rule).