#predator-prey dynamics

Species Control

Control involving predators controlling prey:

“Top-down control” for control involving predators controlling prey. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Species management must identify the demographic stage and ecological process that most strongly limits population growth. Prevention, early detection, removal, habitat manipulation, and biological control act at different points in an invasion or recovery trajectory. The remaining alternatives—“Bottom-up control”, “Wasp-waist control”, “Abiotic control”—refer to different states, p

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 21

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Species Control

Example of top-down control:

“Removing predators” for example of top-down control. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Effective control reduces propagule pressure or population growth without causing unacceptable non-target effects. Repeated monitoring is necessary because seed banks, dormant stages, recolonization, and density-dependent compensation can reverse short-term gains. The remaining alternatives—“Nutrient addition”, “Herbivore increase biomass”, “Plants controlling animals”—refer to different states, p

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 21

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Species Control

Top-down ecosystem control focuses on:

“Higher levels controlling lower levels” for top-down ecosystem control focuses on. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Effective control reduces propagule pressure or population growth without causing unacceptable non-target effects. Repeated monitoring is necessary because seed banks, dormant stages, recolonization, and density-dependent compensation can reverse short-term gains. The remaining alternatives—“Lower levels controlling higher levels”, “Abiotic factors”, “Vegetation”—refe

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 21

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Lotka Volterra Model

In Lotka–Volterra equations, what does β represent?

“Effect of species 1 on species 2” for in lotka–volterra equations, what does β represent. This relationship follows from the ecological mechanism represented by the terms in the item, not merely from an association between their names. Species interactions are classified by their net effects on the fitness of each participant, but those effects can change with density, resource supply, life stage, and environmental stress. Competition reduces access to shared limiting factors, whereas predation and parasitism transfer resources from victim to consumer. The remaining alternatives—“Effect of sp

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 13-14

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Predator Prey Model

Which of the following best represents predator-prey co-evolution?

Predator–prey coevolution involves reciprocal genetic change: adaptation in one species alters selection acting on the other. Improved prey escape traits, such as faster acceleration, vigilance, armor, toxins, or better camouflage, can reduce capture success. Predators may then be favored to evolve greater speed, enhanced sensory systems, detoxification, cooperative hunting, or altered tactics. This reciprocal escalation or counteradaptation is often called an evolutionary arms race, although trade-offs and ecological context can prevent indefinite improvement. Prey change alone demonstrates a

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14

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Predator Prey Model

Which ecological factor leads to unstable equilibrium?

Alternative prey with uncorrelated abundance do not generally lead to unstable equilibrium. They can buffer a generalist predator’s food supply because one prey may be abundant when another is scarce, and predator switching toward common prey can stabilize dynamics. They can also generate apparent competition or sustain predators that overexploit a rare prey, so the outcome depends on functional responses, switching, and interaction strengths; uncorrelated abundance alone has no fixed destabilizing sign. Predator saturation, by contrast, is a recognized destabilizing mechanism in many predator

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14

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Predator Prey Model

In the Lotka-Volterra model, oscillations in predator and prey numbers are:

Classical Lotka–Volterra predator–prey equations generate coupled cycles because each population changes the growth rate of the other. Prey increase when predators are scarce, creating more food and allowing predator numbers to rise after a lag. Increased predation then drives prey downward; food shortage subsequently reduces predators, permitting prey recovery. In the ideal deterministic model, trajectories form closed orbits around a neutrally stable equilibrium, and cycle amplitude depends on initial conditions. The oscillations are therefore linked rather than independent or random. They a

Ref: Ecology: Concepts and Applications, Molles, 9th Ed., Ch. 14

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PREDATOR

From predator-prey interaction figure, which statements are correct?

The reported figure supports statements (i) and (iii), meaning those claims are the ones consistent with the plotted predator-prey responses. Predator-prey data are usually read by comparing timing, direction, and magnitude of changes: prey often increase before predators, predator growth follows greater food availability, and rising predation can subsequently depress prey. Valid statements must follow the axes, treatment labels, and temporal lags rather than assume that correlation alone proves causation. Statements (ii) and (iv) evidently conflict with at least one of those graphical feature

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 10

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PREDATOR

According to optimal diet theory, a predator should eat prey2 only if:

Optimal diet theory ranks prey by profitability, commonly energy obtained per unit handling time, E/h. A lower-ranked prey type should be accepted only when its profitability exceeds the expected rate of gain from rejecting it and searching for the preferred prey. The expression E2/h2 > E1/(h1 + S1) states precisely that condition: prey 2 yields energy fast enough to outperform the combined search and handling return associated with prey 1. As preferred prey becomes scarce, S1 rises and the right-hand rate falls, making prey 2 more acceptable. Energy alone or handling time alone cannot determi

Ref: Ecology: From Individuals to Ecosystems, Begon et al., 5th Ed., Ch. 10

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