Test: Population Interactions - NEET MCQ

It is an association between members of two species in which members of one species capture, kill and eat up members of other species. The former is called predator and later is called prey.

Topic in NCERT: Predation

Line in NCERT: "In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (host and prey, respectively)."

Predation is an interaction between members of two species in which members of one species capture, kill and eat up members of other species. The former are called predators and the latter are called preys.

Topic in NCERT: Population Interactions

Line in NCERT: "Predation, parasitism and commensalism share a common characteristic, the interacting species live closely together."

The evolution of complementary adaptations in two species caused by the selection pressures that each exerts on the other is called co-evolution. It is common in symbiotic associations e.g., many insect-pollinated plants have evolved flowers whose shapes, colours, etc., make them attractive to particular insects, at the same time the pollinating insects have evolved sense organs and mouth parts specialised for quickly locating and extracting nectar from particular species of plants.

Topic in NCERT: Plant-Animal Interactions

Line in NCERT: "the evolutions of the flower and its pollinator species are tightly linked with one another."

In competition, both species are harmed. In predation and parasitism, one species derives benefit and the other one is harmed. Commensalism is an interaction in which one species is benefitted and other one remains unaffected.

Topic in NCERT: Population Interactions

Line in NCERT: "Even in minimal communities, many interactive linkages exist, although all may not be readily apparent. Interspecific interactions arise from the interaction of populations of two different species. They could be beneficial, detrimental or neutral (neither harm nor benefit) to one of the species or both."

The correct option is:

2. Both statements 1 and 2 are correct and statement 2 is the correct explanation of statement 1

Explanation:

- Statement 1 is correct: Brood parasitism in birds involves a parasitic bird laying its eggs in the nest of a host bird, and the host bird then incubates these eggs.

- Statement 2 is correct: During the course of evolution, the eggs of parasitic birds have evolved to resemble the host's eggs in size and color. This adaptation reduces the chances of the host bird detecting the foreign eggs and removing them from the nest.

Therefore, statement 2 provides the correct explanation for statement 1.

Topic in NCERT: Parasitism

Line in NCERT: "Brood parasitism in birds is a fascinating example of parasitism in which the parasitic bird lays its eggs in the nest of its host and lets the host incubate them. During the course of evolution, the eggs of the parasitic bird have evolved to resemble the host's egg in size and colour to reduce the chances of the host detecting the foreign eggs and ejecting them from the nest."

A can be either predation or parasitism since one species is harmed and the other is benefitted. B is commensalism since one species is benefitted and other has no effect on it. C can be amensalism since one species is harmed and the other has no effect on it.

Topic in NCERT: Interspecific interactions

Line in NCERT: "Both the species benefit in mutualism and both lose in competition in their interactions with each other. In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (host and prey, respectively). The interaction where one species is benefitted and the other is neither benefitted nor harmed is called commensalism. In amensalism on the other hand one species is harmed whereas the other is unaffected."

Resource partitioning is a strategy where species share the same resources but divide them in a way that reduces competition, allowing them to coexist. This can be through spatial or temporal division of resources.

Topic in NCERT: Competition and Co-existence

Line in NCERT: "One such mechanism is ‘resource partitioning'. If two species compete for the same resource, they could avoid competition by choosing, for instance, different times for feeding or different foraging patterns."

In ammensalism one component (population) is harmed and the other remains unaffected. The alga Microcystis release hydroxyl amine that kills the surrounding fauna but the alga itself remain unaffected. Parasitism is generally considered to deal with any small organism that live on or in another organism regardless of whether its effect is negative, positive or neutral. In predation one population adversaly affects the other by direct attack but nevertheless depends on other. In exploitation one species harms the other by making its direct or indirect use for support, shelter or food.

Topic in NCERT: Amensalism

Line in NCERT: "In amensalism on the other hand one species is harmed whereas the other is unaffected."

Predators help control prey populations, often preventing prey from reaching excessively high densities. This is a natural ecological balance.

Topic in NCERT: Predation and its Ecological Role

Line in NCERT: "Some predators help in controlling their prey populations."

A nutrient depletion zone can develop when there is rapid soil solution uptake, low nutrient concentration, low diffusion rate, or low soil moisture. These conditions are very common; therefore, most plants rely on fungi to facilitate the uptake of minerals from the soil. Mycorrhizae, known as root fungi, form symbiotic associations with plant roots. In these associations, the fungi are actually integrated into the physical structure of the root. The fungi colonize the living root tissue during active plant growth.

Topic in NCERT: Mutualism

Line in NCERT: "Similarly, the mycorrhizae are associations between fungi and the roots of higher plants."

CominensaHsm is the relationship between two living individuals of different species in which one is benefitted while other is neither harmed nor benefined, e.g., Small fish (sucker fish) gets stuck near the bottom of a shark with the help of it's hold fast (modified dorsal fin) and is dispersed to distant areas. It also gets protection and derives its nutrition also and shark does not get any benefit or harm. Predation is an association between members of two species in which members of one species capture, kill and eat up members of other species, e.g.. Insectivorous plants like Drosera. Antibiosis : in this one organism inhibit growth of other organism through the secretion of antibiotics. This is based on biological antagonism and also known as allelopathy, e.g.. Smoother crops e.g.. Barley rye, millets are those which do not allow weeds to grow near by. Parasitism: in this type of association one member is benefitted. (parasite) and other is harmed (host), e.g.. Parasitic bacteria, viruses.

Topic in NCERT: Commensalism

Line in NCERT: "The interaction in which one species benefits and the other is neither harmed nor benefited is called commensalism."

Monarch butterflies (a) have cryptic coloration to avoid being preyed upon, making them (iii) prey with cryptic coloration.
Cactus-feeding moths (b) are predators of the prickly pear cactus, making them (i) predator.
Starfish Pisaster (c) is a predator that regulates prey populations, so it's (iv) a predator.
Herbivorous insects (d) are prey species in an ecosystem, making them (ii) prey.

• Thorns on Acacia trees are a direct defense mechanism in plants to deter herbivores from feeding on their leaves or branches.
• High reproductive rate of a parasitic plant is not a defense mechanism; it's an adaptation for survival and spread, unrelated to protecting against herbivory.
• Camouflage in insects like the Monarch butterfly is an adaptation for insects, not plants, so it does not qualify as a plant defense.

Topic in NCERT: Defenses Against Herbivory

Line in NCERT: "Plants therefore have evolved an astonishing variety of morphological and chemical defences against herbivores. Thorns (Acacia, Cactus) are the most common morphological means of defence. Many plants produce and store chemicals that make the herbivore sick when they are eaten, inhibit feeding or digestion, disrupt its reproduction or even kill it."

 the human liver fluke’s life cycle (D) is an  example of parasitism, where one species benefits at the expense of another. The other options describe mutualistic or commensal relationships.

Topic in NCERT: Life Cycles of Parasites

Line in NCERT: "The human liver fluke (a trematode parasite) depends on two intermediate hosts (a snail and a fish) to complete its life cycle."

A carnivore population increases due to an increase in the population of herbivores. In this, an organism i.e. carnivore (predator) is benefited by killing and eating another organism i.e. herbivore (prey).