Which of the following correctly describes predation?
In predation, the predator benefits while the prey is harmed or killed.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Population Interactions - Predation and Herbivory
#predator-prey
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Which of the following describes a predator-prey relationship?
A predator-prey relationship involves one organism (predator) hunting and consuming another (prey), like a tiger hunting a deer.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Population Interactions - Predation and Herbivory
Which of the following is a correct statement about predator-prey relationships?
Predator and prey populations are interdependent and fluctuate cyclically based on each other's numbers.
Ref: NCERT Class 12 Biology Chapter 11: Organisms and Populations Life History Variations and Population Interactions - Overview
Top-down control exemplifies:
“Trophic cascade” for top-down control exemplifies. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. The relevant inference should follow the pathway from resource supply to organismal uptake and then to ecosystem-level flux. Productivity, trophic transfer, decomposition, and nutrient regeneration are connected, but each measures a different part of that pathway. The remaining alternatives—“Nutrient cycling”, “Abiotic influence”, “Bottom-up model”—refer to different states, processes, or scales and
Ref: Fundamentals of Ecology, Odum & Barrett, 5th Ed., Ch. 4
When a predator uses venom to catch prey, it's an example of:
Venom is a chemical predatory weapon because toxins delivered by a bite, sting, fang, harpoon, or nematocyst disrupt prey physiology. Components may block ion channels, impair neuromuscular transmission, damage membranes, alter coagulation, or initiate rapid tissue injury. Immobilization reduces escape and shortens pursuit or handling time, while digestive enzymes may begin extraoral processing. Calling this “chemical warfare” is informal, but it correctly distinguishes chemical incapacitation from purely mechanical capture. Mimicry relies on resemblance or deceptive signaling, ambush describe
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14
The prey isocline in Lotka-Volterra model represents:
A prey zero-growth isocline contains combinations of prey and predator densities for which the prey population’s instantaneous net growth is zero. In the basic Lotka–Volterra equation dN/dt = rN − aNP, setting the derivative to zero for positive N gives P = r/a. Below that predator density, prey births exceed losses to predation and prey increase; above it, prey decline. The isocline therefore summarizes how prey growth changes with predator density, which is the intended meaning of “prey population growth versus predator density.” It is not itself a predator-mortality relation or merely a pre
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14
In Marginal Value Theorem, longer travel time implies:
Longer travel time between patches increases the optimal residence time within a profitable patch under the marginal value theorem. Travel is an unavoidable period with no food gain, so frequent departures would devote a large fraction of total foraging time to transit. A forager should therefore exploit each reached patch more thoroughly, remaining until its declining marginal gain rate equals the lower habitat-wide average created by the greater travel cost. Graphically, increasing travel time moves the tangent’s origin farther left on the cumulative gain curve and shifts the tangency point
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14
Which situation favors stable coexistence?
A predator with multiple prey can persist by switching toward whichever prey is relatively abundant, reducing pressure on a prey species when it becomes rare. This frequency-dependent switching can provide each prey a low-density refuge and dampen extreme consumer–resource cycles. A broader resource base also prevents immediate predator starvation when one prey declines, although persistent predator subsidy can instead create apparent competition and harm a rare focal prey. Stability therefore depends on switching strength, functional responses, and whether prey fluctuations are synchronized.
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14
Predators are unable to drive prey to extinction if:
A limited predator carrying capacity prevents predator numbers from increasing without bound as prey become rare. If predator survival and reproduction depend strongly on the focal prey, declining prey reduces the resource base, causing predator decline before every prey individual can be removed. Refuges, handling constraints, territoriality, and alternative food webs may further permit persistence. This negative feedback can protect prey from extinction: low prey density supports fewer predators, reducing total predation pressure. Density-independent predator growth would remove that stabili
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14
Which graph type best represents predator-prey oscillations?
Predator and prey time series are often represented by approximately sinusoidal waves because both populations rise and fall repeatedly, with the predator peak lagging behind the prey peak. When predators are scarce, prey increase; abundant prey then supports predator reproduction. The enlarged predator population depresses prey, after which food shortage causes predator decline and allows prey recovery. This negative feedback generates coupled cycles in the classical Lotka–Volterra model. A sine wave is only a visual approximation: actual trajectories need not be mathematically sinusoidal, an
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14
Which of the following reduces the efficiency of a predator?
Long handling time reduces a predator’s feeding efficiency because time spent pursuing, subduing, processing, or digesting one prey item is unavailable for locating and consuming others. Profitability falls as E/h decreases, even if the prey contains substantial energy. At high prey density, handling can become the limiting step and produce a saturating Holling type II functional response: encounter opportunities increase, but consumption approaches a maximum of roughly one item per handling-time unit. Camouflage usually improves approach success for the predator, group hunting can increase ca
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14
Which of these contributes to predator’s carrying capacity besides victim abundance?
Alternative prey can raise a predator population’s effective carrying capacity because they provide energy when the principal victim is scarce. A generalist predator may switch its foraging effort, maintain survival and reproduction, and persist at densities that the focal prey alone could not support. In population models, predator growth depends on the summed contributions of consumable prey, so an additional positive term can keep net growth above mortality. Refuge space generally protects prey and may lower predator intake rather than support more predators. Mutualism and migration can inf
Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14