NEET Biology Organisms and Populations MCQs Set 18

Answer: (b) Poles to equator region during latitudinal transition

Explanation:
1. Rise in temperature and air humidity can be observed from poles to equator region during latitudinal transition.
2. Hence option (b) is correct: Poles to equator region during latitudinal transition

Teacher's Note:
1. Temperature and humidity both rise as one moves from the poles towards the equator.
2. Moving up a mountain has the opposite effect.

Answer: (a) Homeostasis

Explanation:
1. Statement is related with homeostasis Epistasis – Gene that mask the effect of another gene Heterosis – Hybrid vigour i.e., superior than their parents Antibiosis – Ammensalism (–; 0)
2. Hence option (a) is correct: Homeostasis

Teacher's Note:
1. Homeostasis is the constancy of the internal environment.
2. Epistasis is a gene interaction, heterosis is hybrid vigour and antibiosis is an interaction between species.

Answer: (c) The functional role played by the organism where it lives

Explanation:
1. Ecological niche was termed by J. Grinnel. It refers the functional role played by the organism where it lives.
2. Hence option (c) is correct: The functional role played by the organism where it lives

Teacher's Note:
1. A niche is the functional role of a species in its habitat, while the habitat is only the place where it lives.
2. The term was first used by Grinnell.

Answer: (b) Birth rate

Explanation:
1. Natality refers to birth rate. Death rate – Mortality Number of individual entering a habitat – Immigration Number of individual leaving the habital – Emigration
2. Hence option (b) is correct: Birth rate

Teacher's Note:
1. Natality is birth rate, mortality is death rate, immigration is entry and emigration is exit.
2. These four decide how a population changes in size.

Answer: (d) Mutualism

Explanation:
1. Mycorrhizae is a symbiotic association of fungi with roots of higher plants.
2. Hence option (d) is correct: Mutualism

Teacher's Note:
1. Mycorrhiza is a mutualistic association of a fungus with plant roots.
2. The fungus supplies phosphorus and the plant supplies carbohydrates.

Answer: (b) Halophytes

Explanation:
1. Halophytes growing in saline soils show (i) Vivipary which is in-situ seed germination (ii) Pneumatophores for gaseous exchange
2. Hence option (b) is correct: Halophytes

Teacher's Note:
1. Halophytes of mangrove swamps have pneumatophores and show vivipary.
2. Both features are adaptations to saline, waterlogged soil.

Answer: (a) Large number of progeny with small size

Explanation:
1. r-selected species species whose population growth is function of biotic potential (r). They have large number of progeny with small size.
2. Hence option (a) is correct: Large number of progeny with small size

Teacher's Note:
1. r-selected species have a high biotic potential and produce many small offspring.
2. K-selected species produce few large offspring with parental care.

Answer: (b) When N/K is exactly one

Explanation:
1. dN/dt = rN(1 minus N/K) becomes zero only when N/K = 1, i.e. when N equals the carrying capacity.
2. If N/K were zero the population would still grow at the rate rN.
3. Hence option (b) is correct: When N/K is exactly one

Teacher's Note:
1. In the logistic model growth stops when N reaches K, that is N/K = 1.
2. At that point the term (1 minus N/K) becomes zero.

Answer: (c) Pistia

Explanation:
1. Pistia - roots are poorly developed as it is free floating hydrophyte.
2. Hence option (c) is correct: Pistia

Teacher's Note:
1. Pistia is a free-floating hydrophyte with poorly developed roots.
2. Its leaves and body absorb water directly.

Answer: (b) Competition

Explanation:
1. During competition, both partners are adversely affected.
2. Hence option (b) is correct: Competition

Teacher's Note:
1. In competition both species are harmed (minus, minus).
2. In mutualism both gain, and in predation or parasitism one gains.

Answer: (a) Tropical rain forest

Explanation:
1. Most animals are tree dwellers in tropical rain forest.
2. Hence option (a) is correct: Tropical rain forest

Teacher's Note:
1. Tropical rain forests have tall trees and many layers (stratification), so most animals live in the trees.
2. The dense canopy gives food and shelter at many heights.

Answer: (d) Keoladeo National Park

Explanation:
1. Keolado National Park {Bharatpur Bird Sanctuary}
2. Hence option (d) is correct: Keoladeo National Park

Teacher's Note:
1. Migratory birds from Siberia reach Keoladeo National Park (Bharatpur) in winter.
2. This is like a person moving to a hill station in summer.

Answer: (a) Ectoparasitism

Explanation:
1. Hence option (a) is correct: Ectoparasitism

Teacher's Note:
1. Cuscuta (dodder) is a parasitic climber that stays outside the host and sends haustoria into it.
2. So it is an ectoparasite.

Answer: (d) Tropical rainforests

Explanation:
1. Large woody vines called lianas commonly found in tropical rainforests.
2. Hence option (d) is correct: Tropical rainforests

Teacher's Note:
1. Lianas (woody vines) are typical of tropical rain forests.
2. Dense canopy forces climbers to reach light by climbing.

Answer: (c) (a), (c)

Explanation:
1. Desert lizards burrow in soil to escape high temperature (a) and bask in the sun when it is cold (c).
2. They cannot lose heat rapidly or insulate the body with fat, so (b) and (d) are wrong.
3. Hence option (c) is correct: (a), (c)

Teacher's Note:
1. Desert lizards burrow to escape heat and bask in sun when the temperature is low.
2. They have no thick fatty dermis.

Answer: (c) Predator is an organism that catches and kills other organism for food

Explanation:
1. Predator is an organism that catches and kills other organism for food.
2. Hence option (c) is correct: Predator is an organism that catches and kills other organism for food

Teacher's Note:
1. A predator catches and kills other animals for food.
2. A parasite does not always live inside the host, and a host does not simply give food.

Answer: (b) Temperate deciduous forests

Explanation:
1. Quercus species are the dominant component in temperature deciduous forests.
2. Hence option (b) is correct: Temperate deciduous forests

Teacher's Note:
1. Quercus (oak) is dominant in temperate deciduous forests.
2. These forests lose leaves in autumn.

Answer: (b) A normal distribution

Explanation:
1. In a normal distribution curve both mean and median have same value.
2. Hence option (b) is correct: A normal distribution

Teacher's Note:
1. In a normal distribution mean, median and mode are equal.
2. A skewed curve has unequal mean and median.

Answer: (d) Its population growth curve is of J-type.

Explanation:
1. Its population growth curve is of J-shaped because nutrition is unlimited.
2. Hence option (d) is correct: Its population growth curve is of J-type.

Teacher's Note:
1. A sudden rise and sudden fall in numbers is a J-shaped curve.
2. Sigmoid growth would level off near the carrying capacity.

Answer: (c) Population

Explanation:
1. Geometric representation of age structure is a characteristic of population.
2. Hence option (c) is correct: Population

Teacher's Note:
1. Age pyramids show the age structure of a population.
2. They are drawn as the number of pre-reproductive, reproductive and post-reproductive individuals.

Answer: (c) Intra specific competition

Explanation:
1. Hence option (c) is correct: Intra specific competition

Teacher's Note:
1. A high density of one species increases competition among its own members.
2. This is intraspecific competition.