NEET Biology Organisms and Populations MCQs Set 06

Answer: (d) Both temperature and precipitation

Explanation:
1. Biomes such as desert, grassland and forest are determined by annual temperature and precipitation.
2. Both factors together decide the biome.

Teacher's Note:
1. Regional and local variations form habitats.

Answer: (c) Habitat

Explanation:
1. Within a biome, local variations create different habitats.
2. Niche is the functional role of a species.

Teacher's Note:
1. A habitat is where an organism lives.

Answer: (d) All of the above

Explanation:
1. Temperature, water, light and soil are the major abiotic factors.
2. They together cause variation among habitats.

Teacher's Note:
1. The four are named in NCERT.

Answer: (d) Both thermal springs and deep-sea hydrothermal vents

Explanation:
1. In thermal springs and deep-sea hydrothermal vents the average temperature may exceed 100 degrees C.
2. Tropical deserts have high temperatures but not above 100 degrees C.

Teacher's Note:
1. Some archaebacteria live in these habitats.

Answer: (d) All of the above

Explanation:
1. Temperature affects enzyme kinetics, basal metabolism and other physiological functions.
2. So all are correct.

Teacher's Note:
1. It also affects the distribution of species.

Answer: (c) More than 100 ppt

Explanation:
1. Inland waters have less than 5 ppt, sea water 30-35 ppt, and some hypersaline lagoons more than 100 ppt.
2. So option (c) is correct.

Teacher's Note:
1. ppt means parts per thousand.

Answer: (b) Surface area to volume ratio

Explanation:
1. Small animals have a large surface area relative to volume, so they lose heat fast.
2. They must spend much energy to maintain body temperature, so they are not found as thermal conformers.

Teacher's Note:
1. Small birds are rare in polar areas.

Answer: (b) Diapause

Explanation:
1. Zooplankton enter diapause, a stage of suspended development, during adverse conditions.
2. Hibernation and aestivation occur in animals like bears and snails.

Teacher's Note:
1. Many species of zooplankton show this.

Answer: (b) Conformers

Explanation:
1. Most animals and nearly all plants cannot maintain a constant internal environment.
2. Hence they are conformers.

Teacher's Note:
1. Only a few organisms are regulators.

Answer: (b) Above 3500 m

Explanation:
1. Altitude sickness is seen above about 3500 m.
2. Symptoms are nausea, fatigue and heart palpitations.

Teacher's Note:
1. Acclimatisation reduces the effects.

Answer: (d) Increased heart palpitations

Explanation:
1. The body compensates for low oxygen by increasing RBC production, decreasing binding of oxygen to haemoglobin and increasing breathing rate.
2. Palpitations are a symptom, not an adaptation.

Teacher's Note:
1. Acclimatisation takes time.

Answer: (c) Desert lizards

Explanation:
1. Desert lizards bask in the sun and move into shade or burrows to regulate body temperature.
2. CAM plants and Opuntia use physiological and anatomical adaptations.

Teacher's Note:
1. Behavioural adaptation involves movement or action.

Answer: (d) Both population genetics and evolution

Explanation:
1. Population ecology links ecology to population genetics and evolution.
2. Physiognomy is not related.

Teacher's Note:
1. Natural selection acts on populations.

Answer: (b) a-iv, b-iii, c-ii, d-i

Explanation:
1. Pacific salmon breeds once in life and most birds breed several times.
2. Oysters produce many small offspring while mammals produce few large offspring.

Teacher's Note:
1. Life history traits evolve in response to selection.

Answer: (c) a-iv, b-iii, c-i, d-ii

Explanation:
1. Both benefit in mutualism (+/+) and both are harmed in competition (-/-).
2. Predation is +/- and amensalism is -/0.

Teacher's Note:
1. Commensalism is +/0.

Answer: (b) Starfish Pisaster

Explanation:
1. Robert Paine's experiment: removal of the starfish Pisaster led to extinction of more than 10 species of invertebrates within a year.
2. Competitive exclusion increased as the predator was removed.

Teacher's Note:
1. Pisaster is a keystone predator.

Answer: (a) Predation

Explanation:
1. Herbivores eating plants are treated as predators in ecology.
2. So phytophagous insects show predation.

Teacher's Note:
1. Herbivory is a +/- interaction.

Answer: (c) Nectar

Explanation:
1. Cardiac glycosides, strychnine and quinine are plant chemicals that deter herbivores.
2. Nectar attracts pollinators and is not a defence.

Teacher's Note:
1. Many plants produce toxic chemicals.

Answer: (c) The Abingdon tortoise became extinct due to the competitor starfish

Explanation:
1. The Abingdon tortoise became extinct due to goats introduced on the island, which were better foragers.
2. The starfish is not involved, so (c) is wrong.

Teacher's Note:
1. Gause's competitive exclusion principle is related.

Answer: (a) Difference in foraging activities

Explanation:
1. MacArthur's warblers divided resources by foraging in different parts of the tree.
2. This is resource partitioning.

Teacher's Note:
1. It allows closely related species to coexist.

Answer: (b) Clown fish only

Explanation:
1. The clown fish gets protection from predators among the stinging tentacles of the anemone.
2. The anemone gets no benefit in this commensal relationship, so only the clown fish benefits.

Teacher's Note:
1. This is an example of commensalism.

Answer: (b) Opuntia and cactophagous moth

Explanation:
1. Orchid-bee, yucca-moth and fig-wasp are classic coevolution examples where flowers and pollinators evolve together.
2. Cactoblastis was introduced as a biological control for Opuntia, so it is not coevolution.

Teacher's Note:
1. Coevolution means reciprocal evolutionary change.