📝 Camouflage hypothesis in mice (7 MCQs)
📖 From Campbell Biology • 1. Evolution and the theme of Biology and Scientific Inquiry • 7 questions available
What is Camouflage hypothesis in mice?
Definition:
The camouflage hypothesis in mice proposes that the coat coloration of mice has evolved to match their background environment, thereby reducing the risk of predation through camouflage (crypsis), and this hypothesis predicts that mice with coat colors matching their habitat will have higher survival rates than those that do not, making it a testable explanation for color variation in wild populations.
Working:
This hypothesis works by assuming that predators use vision to locate prey, and that mice with colors that blend in with the substrate (e.g., light sand or dark soil) are less likely to be detected; to test it, researchers can compare survival of mice (or models) with different colors placed in different habitats, and if the camouflage hypothesis is correct, the survival rate will be higher for matching colors, as measured by the proportion of attacks or predation events, and the data support the role of natural selection in maintaining color variation.
Example:
A simple example is an experiment where clay models of mice of different colors (light, dark, and mismatched) are placed on sandy and dark-soil habitats, and after several days, the number of models with tooth or beak marks is recorded; if the light models on sand have fewer marks, the camouflage hypothesis is supported, which was the case in classic studies on beach mice.
Reason:
The camouflage hypothesis is central to understanding natural selection and adaptation, and testing it provides strong evidence for the role of predation in shaping the evolution of traits, and it has implications for conservation, as habitat changes can disrupt camouflage and increase predation risk.
📝 All Camouflage hypothesis in mice MCQs
Q1. A population of mice contains both light- and dark-colored individuals. On pale ground, predators more frequently capture dark mice. Which interpretation most directly supports the proposed camouflage hypothesis?
📖 Explanation: The observation supports camouflage because predation appears related to the visual contrast between mouse coloration and the environment. A stronger camouflage hypothesis predicts that individuals whose color blends with the background should be harder for visually hunting predators to detect.
Q2. Researchers place equal numbers of light and dark mice on two surfaces. On pale sand, light mice survive more often, while on dark soil, dark mice survive more often. What conclusion is best justified?
📖 Explanation: The pattern changes with environmental background, so the strongest explanation is that matching coloration reduces visibility to predators. This does not establish that either coat color is universally superior; its advantage depends on the surrounding environment.
Q3. A researcher releases 50 light mice and 50 dark mice into pale habitat and records survival after several weeks. If camouflage is important, which additional result would most strongly strengthen the hypothesis?
📖 Explanation: Camouflage predicts an environmental interaction: a coat color should provide greater survival when it visually blends with the background. Demonstrating this pattern while controlling other variables gives stronger evidence than differences in weight, feeding, or survival alone.
Q4. A student argues, 'Light mice survived more often on pale ground, so predators must actively avoid eating light mice.' What is the main flaw in this reasoning?
📖 Explanation: The conclusion incorrectly assumes a conscious predator preference when reduced visibility provides a simpler explanation. A camouflage hypothesis concerns detectability and resulting predation risk, not whether predators deliberately choose to avoid a particular color.
Q5. A study reports the following survival percentages after predator exposure: Pale ground—light mice 80%, dark mice 45%; Dark ground—light mice 40%, dark mice 75%. Which inference is best supported by the pattern?
📖 Explanation: The graph pattern shows that each color performs better when it visually matches the habitat: light mice do better on pale ground and dark mice do better on dark ground. This interaction is exactly what a camouflage-based prediction would anticipate.
Q6. Two experiments test the same hypothesis. Experiment 1 compares light and dark mice on only pale ground. Experiment 2 compares both colors on pale and dark ground while keeping predator exposure similar. Why is Experiment 2 more informative?
📖 Explanation: Experiment 2 allows researchers to distinguish a general color effect from an environment-dependent camouflage effect. If each color performs better against its matching background, the result provides more specific support for camouflage than a single-background comparison.
Q7. A researcher models predation risk as increasing with visual contrast. Suppose mouse A has contrast score 2 against its background and mouse B has contrast score 6. If all other factors are equal, which prediction follows most directly from the hypothesis?
📖 Explanation: If visual contrast is used as a model for detectability, the higher-contrast mouse should be easier for predators to detect. Assuming other factors remain equal, this predicts greater predation risk for mouse B, linking the model directly to the camouflage hypothesis.