NEET Biology Organisms and Populations MCQs Set 07

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Multiple Choice Questions

Question 1: Match the interactions with their effects on the two species: 1. Commensalism, 2. Amensalism, 3. Competition, 4. Predation, 5. Mutualism with a. (+,-), b. (0,-), c. (0,+), d. (-,-), e. (+,+).
(a) 1-b, 2-c, 3-d, 4-a, 5-e
(b) 1-c, 2-b, 3-d, 4-a, 5-e
(c) 1-c, 2-b, 3-a, 4-d, 5-e
(d) 1-e, 2-b, 3-d, 4-a, 5-c
Show Answer & Explanation

Answer: (b) 1-c, 2-b, 3-d, 4-a, 5-e

Explanation:
1. Commensalism is 0,+ and amensalism is 0,-.
2. Competition is -,-, predation is +,- and mutualism is +,+.

Teacher's Note:
1. In the signs the first is for one species and the second for the other.
2. Zero means unaffected.

Question 2: Mutualism is an ___ relationship whereas proto-cooperation is a ___ relationship in which both interacting species are benefited.
(a) obligatory; obligatory
(b) non-obligatory; non-obligatory
(c) obligatory; non-obligatory
(d) non-obligatory; obligatory
Show Answer & Explanation

Answer: (c) obligatory; non-obligatory

Explanation:
1. In mutualism the species cannot live without each other.
2. In proto-cooperation the association is not obligatory.

Teacher's Note:
1. Lichen shows mutualism.
2. Sea anemone and hermit crab show proto-cooperation.

Question 3: Interactions in which either one or both participating species are harmed are called
(a) commensalism
(b) proto-cooperation
(c) mutualism
(d) detrimental or negative interactions
Show Answer & Explanation

Answer: (d) detrimental or negative interactions

Explanation:
1. Competition, predation, parasitism and amensalism are negative interactions.
2. At least one species is harmed.

Teacher's Note:
1. Mutualism and commensalism are positive or neutral.
2. Remember the effect signs.

Question 4: Which organisms act as conduits of energy transfer, maintain species diversity in a community and regulate the population of prey species?
(a) Decomposers
(b) Parasites
(c) Predators
(d) Producers
Show Answer & Explanation

Answer: (c) Predators

Explanation:
1. Predators transfer energy from one trophic level to the next.
2. They keep prey populations in check and prevent a single species from dominating.

Teacher's Note:
1. Predators are prudent in nature.
2. They do not over-exploit prey.

Question 5: More than 10 species of invertebrates became extinct within a year when the starfish Pisaster was removed from the American Pacific coast. This extinction was due to
(a) mutualism
(b) intraspecific competition
(c) parasitism
(d) interspecific competition
Show Answer & Explanation

Answer: (d) interspecific competition

Explanation:
1. Pisaster was a keystone predator.
2. Without it, competition among prey species rose and weaker competitors were eliminated.

Teacher's Note:
1. This is Paine's classic experiment.
2. It shows competitive exclusion.

Question 6: Match the defence mechanisms: A. Cardiac glycosides, B. Distasteful due to a special chemical, C. Thorns, D. Camouflage with i. Acacia and cactus, ii. Insects, iii. Calotropis, iv. Monarch butterfly.
(a) A-iii, B-iv, C-i, D-ii
(b) A-iv, B-iii, C-i, D-ii
(c) A-i, B-iv, C-iii, D-ii
(d) A-iii, B-iv, C-ii, D-i
Show Answer & Explanation

Answer: (a) A-iii, B-iv, C-i, D-ii

Explanation:
1. Calotropis produces cardiac glycosides.
2. Monarch butterfly is distasteful, acacia and cactus have thorns and insects use camouflage.

Teacher's Note:
1. The monarch butterfly acquires the chemical from its food plant.
2. Birds learn to avoid it.

Question 7: A species introduced into a new geographical area becomes invasive and spreads rapidly mainly due to
(a) unsuitable climate
(b) presence of many predators
(c) absence of its natural predator
(d) lack of food
Show Answer & Explanation

Answer: (c) absence of its natural predator

Explanation:
1. With no natural enemies, the introduced species multiplies rapidly.
2. It harms native species.

Teacher's Note:
1. Prickly pear in Australia is an example.
2. It was controlled by a moth.

Question 8: When the feeding efficiency of one species is reduced in the presence of another species even if resources are abundant, it is called
(a) interference competition
(b) resource partitioning
(c) mutualism
(d) competitive release
Show Answer & Explanation

Answer: (a) interference competition

Explanation:
1. This is interference competition.
2. The competitor interferes even when food is abundant.

Teacher's Note:
1. Gause's principle deals with resource-limited competition.
2. Interference does not need limited resources.

Question 9: Match: 1. Resource partitioning, 2. Competitive exclusion, 3. Struggle for existence with A. Gause, B. Darwin, C. MacArthur.
(a) 1-A, 2-C, 3-B
(b) 1-C, 2-A, 3-B
(c) 1-C, 2-B, 3-A
(d) 1-B, 2-A, 3-C
Show Answer & Explanation

Answer: (b) 1-C, 2-A, 3-B

Explanation:
1. MacArthur studied warblers and resource partitioning.
2. Gause gave the competitive exclusion principle and Darwin spoke of the struggle for existence.

Teacher's Note:
1. Gause worked on Paramecium.
2. MacArthur on warblers.

Question 10: Which organisms are more adversely affected by competition than carnivores?
(a) Parasites
(b) Carnivores
(c) Fungi and bacteria
(d) Plants and herbivores
Show Answer & Explanation

Answer: (d) Plants and herbivores

Explanation:
1. Plants and herbivores are more affected by competition.
2. Carnivores are less affected.

Teacher's Note:
1. Resource limits matter more for them.
2. Carnivores have lower numbers.

Question 11: When species avoid competition by choosing different feeding times and different foraging patterns, it is called
(a) predation
(b) resource partitioning
(c) interference
(d) competitive exclusion
Show Answer & Explanation

Answer: (b) resource partitioning

Explanation:
1. Species divide resources to coexist.
2. MacArthur showed this in warblers.

Teacher's Note:
1. Five warblers feed in different zones of a tree.
2. They coexist.

Question 12: Which of the following are NOT characteristics of parasites? (A) Unnecessary sense organs, (B) Adhesive organs and suckers, (C) Well-developed digestive system, (D) High biotic potential.
(a) B and D only
(b) A and B only
(c) C and D only
(d) A and C only
Show Answer & Explanation

Answer: (d) A and C only

Explanation:
1. Parasites lose unnecessary sense organs and the digestive system is reduced.
2. Adhesive organs and a high biotic potential are present.

Teacher's Note:
1. Parasites are adapted to host life.
2. Loss of organs is an adaptation.

Question 13: The human liver fluke depends on two intermediate hosts, which are
(a) a fish and a frog
(b) a snail and a mosquito
(c) a snail and a fish
(d) a cow and a pig
Show Answer & Explanation

Answer: (c) a snail and a fish

Explanation:
1. The liver fluke is a trematode parasite.
2. It uses a snail and a fish as intermediate hosts.

Teacher's Note:
1. Fasciola has a snail as its host.
2. Clonorchis has a snail and a fish.

Question 14: Among lice, ticks, copepods, Cuscuta, Taenia, Ascaris and liver fluke, how many are ectoparasites?
(a) Three
(b) Two
(c) Six
(d) Four
Show Answer & Explanation

Answer: (d) Four

Explanation:
1. Lice, ticks, copepods and Cuscuta live on the outside of the host.
2. So four are ectoparasites.

Teacher's Note:
1. Endoparasites live inside.
2. Taenia, Ascaris and liver fluke are endoparasites.

Question 15: Match the commensal relationships: 1. Mango branch, 2. Clown fish, 3. Egret bird, 4. Whale with A. Sea anemone, B. Barnacles, C. Cattle, D. Orchid.
(a) 1-D, 2-A, 3-B, 4-C
(b) 1-D, 2-A, 3-C, 4-B
(c) 1-C, 2-A, 3-D, 4-B
(d) 1-A, 2-D, 3-C, 4-B
Show Answer & Explanation

Answer: (b) 1-D, 2-A, 3-C, 4-B

Explanation:
1. The orchid grows on a mango branch.
2. Clown fish live among sea anemone tentacles, egrets feed near cattle and barnacles grow on whales.

Teacher's Note:
1. Commensals benefit while the host is not affected.
2. These are +,0 relations.

Question 16: The mutualistic relationship between a fungus and a cyanobacterium (or alga) is called
(a) mycorrhiza
(b) root nodule
(c) coral
(d) lichen
Show Answer & Explanation

Answer: (d) lichen

Explanation:
1. Lichens are fungus plus alga or cyanobacterium.
2. Both partners benefit.

Teacher's Note:
1. The alga makes food.
2. The fungus gives water and minerals.

Question 17: A filamentous eukaryotic organism that absorbs nutrients from the soil for a higher plant and gets carbohydrates in return forms
(a) root nodule
(b) gall
(c) lichen
(d) mycorrhiza
Show Answer & Explanation

Answer: (d) mycorrhiza

Explanation:
1. Fungus plus roots of higher plants form mycorrhiza.
2. The fungus absorbs phosphorus from soil.

Teacher's Note:
1. This is mutualism.
2. The plant provides carbohydrates.

Question 18: In which interaction do the two species show co-evolution, co-extinction and co-existence?
(a) Competition
(b) Commensalism
(c) Predation
(d) Mutualism
Show Answer & Explanation

Answer: (d) Mutualism

Explanation:
1. In mutualism the evolution of one affects the other.
2. They can go extinct together.

Teacher's Note:
1. Fig and wasp are an example.
2. They depend on each other.

Question 19: In the fig and wasp relationship, the wasp uses the fig fruit for egg laying and the developing seeds for nourishing its larvae. In turn, this favours
(a) pollination of the fig
(b) flowering
(c) seed dispersal of fig
(d) fruit ripening
Show Answer & Explanation

Answer: (a) pollination of the fig

Explanation:
1. The wasp pollinates the fig while laying eggs.
2. The fig gets pollinated and the wasp gets a place for its larvae.

Teacher's Note:
1. Each fig species has its own wasp.
2. This is co-evolution.

Question 20: Match the interaction with its example: A. Mutualism, B. Predation, C. Parasitism, D. Competition, E. Commensalism with 1. Sparrow and seed, 2. Goat and Abingdon tortoise, 3. Flamingoes and fishes, 4. Monarch butterfly and bird, 5. Hedge plant and Cuscuta, 6. Orchid and mango tree, 7. Human and Ascaris, 8. Orchid and bee, 9. Balanus and Chthamalus.
(a) A-8, B-2 and 3, C-5 and 7, D-1, 4 and 9, E-6
(b) A-8, B-1 and 4, C-5 and 7, D-2, 3 and 9, E-6
(c) A-8, B-1 and 4, C-6 and 7, D-2, 3 and 9, E-5
(d) A-6, B-1 and 4, C-5 and 7, D-2, 3 and 9, E-8
Show Answer & Explanation

Answer: (b) A-8, B-1 and 4, C-5 and 7, D-2, 3 and 9, E-6

Explanation:
1. Orchid and bee is mutualism (pollination).
2. Seed eating and bird eating monarch are predation, Cuscuta and Ascaris are parasites, competition is shown by goat and tortoise, flamingoes and fishes, Balanus and Chthamalus, and orchid on mango is commensalism.

Teacher's Note:
1. Know a standard example for each type of interaction.
2. Flamingoes compete with fishes for zooplankton.

Question 21: Which of the following statements is NOT true?
(a) Heat loss or heat gain is a function of surface area
(b) Thermoregulation is energetically expensive for many organisms
(c) All birds and mammals are regulators
(d) 99 percent of animals and nearly all plants are regulators
Show Answer & Explanation

Answer: (d) 99 percent of animals and nearly all plants are regulators

Explanation:
1. Ninety-nine percent of animals and nearly all plants are conformers.
2. So the first statement is wrong.

Teacher's Note:
1. Regulators maintain constant internal conditions.
2. Conformers change with the environment.

Question 22: People living at high altitude in the Himalayas have a ___ red blood cell count than people living in the plains.
(a) the same
(b) negligible
(c) lower
(d) higher
Show Answer & Explanation

Answer: (d) higher

Explanation:
1. Low oxygen at high altitude leads to more RBCs.
2. This compensates for the low availability of oxygen.

Teacher's Note:
1. Altitude sickness is due to low oxygen.
2. The body acclimatises.

Question 23: Which of the following are symptoms of altitude sickness?
(a) Skin rashes
(b) Hair loss
(c) Fever and cough
(d) Nausea, fatigue and heart palpitations
Show Answer & Explanation

Answer: (d) Nausea, fatigue and heart palpitations

Explanation:
1. Low atmospheric pressure at altitude causes nausea, fatigue and palpitations.
2. These are altitude sickness symptoms.

Teacher's Note:
1. The body acclimatises over days.
2. It makes more RBCs.

Question 24: How does the human body compensate for altitude sickness?
(a) By increasing the binding affinity of haemoglobin
(b) By decreasing the breathing rate
(c) By increasing RBC production, increasing the breathing rate and decreasing the binding affinity of haemoglobin
(d) By decreasing RBC production
Show Answer & Explanation

Answer: (c) By increasing RBC production, increasing the breathing rate and decreasing the binding affinity of haemoglobin

Explanation:
1. The body makes more RBCs and breathes faster.
2. Haemoglobin binding to oxygen is decreased so that it releases it to tissues.

Teacher's Note:
1. These are physiological adjustments.
2. They occur within days.

Question 25: Antarctic fish keep their body fluids from freezing because they
(a) hibernate
(b) have thick fur
(c) migrate
(d) have antifreeze proteins
Show Answer & Explanation

Answer: (d) have antifreeze proteins

Explanation:
1. Antifreeze proteins lower the freezing point of body fluids.
2. This keeps the fluids liquid.

Teacher's Note:
1. Such adaptations are physiological.
2. Cold water is below zero.

Question 26: Under normal conditions, which two factors are the most important in influencing population density?
(a) Birth and migration only
(b) Immigration and emigration only
(c) Temperature and rainfall
(d) Natality and mortality
Show Answer & Explanation

Answer: (d) Natality and mortality

Explanation:
1. Population density depends on natality, mortality, immigration and emigration.
2. Under normal conditions birth and death rates matter most.

Teacher's Note:
1. Natality and immigration increase density.
2. Mortality and emigration decrease it.

Question 27: The logistic growth equation is
(a) dN/dt = rN (K - N) / K
(b) dN/dt = r / N
(c) dN/dt = rN
(d) Nt = N0 e^(rt)
Show Answer & Explanation

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

Explanation:
1. The logistic equation includes the carrying capacity K.
2. Growth slows as N approaches K.

Teacher's Note:
1. The logistic curve is S-shaped.
2. It levels off at K.

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