📝 Model mice predation experiment (7 MCQs)
📖 From Campbell Biology • 1. Evolution and the theme of Biology and Scientific Inquiry • 7 questions available
What is Model mice predation experiment?
Definition:
A model mice predation experiment is a field experiment where artificial models (clay or plastic models) resembling mice are placed in different habitats to measure predation rates, testing hypotheses about the adaptive value of color patterns, and this approach allows researchers to quantify predation pressure without harming live animals, providing controlled and repeatable data on selective pressures.
Working:
In this experiment, models of different colors (e.g., light and dark) are placed on different backgrounds (sand and dark soil), and after a set time, the models are collected and examined for bite or scratch marks from predators (birds, mammals), and the number of damaged models is counted; if the camouflage hypothesis is true, models that match their background should have fewer marks, and statistical comparisons (e.g., chi-square test) are used to test for significant differences, providing evidence for natural selection.
Example:
A simple example is placing light-colored and dark-colored clay mouse models on a sandy beach and on dark soil, and after 48 hours, 60% of light models on sand are damaged, but 90% of dark models on sand are damaged, suggesting that lighter mice have a survival advantage on sand, supporting the camouflage hypothesis.
Reason:
Model predation experiments are valuable because they allow hypothesis testing without harming real animals, control for variables, and provide direct evidence of selective pressure, and they are widely used in ecology and evolutionary biology to study predation and adaptation.
📝 All Model mice predation experiment MCQs
Q1. Researchers place equal numbers of light-colored and dark-colored model mice in two habitats: one with pale soil and one with dark soil. After several days, predators have removed more light models from the dark habitat. Which conclusion is best supported?
📖 Explanation: The experiment supports a relationship between environmental background and predation risk. More light models being removed on dark soil suggests they were easier for predators to detect, while the result does not show that soil changes inherited coloration or that dark coloration is universally advantageous.
Q2. A student argues that if predators remove more dark models from pale ground, this proves predators consciously choose the less-camouflaged color. What is the strongest evaluation of this reasoning?
📖 Explanation: Differential removal of models can indicate differences in visibility and predation risk, but it does not establish what predators perceive or whether they make conscious choices. The student has extended the evidence beyond what the experiment directly tests.
Q3. Two habitats are tested using identical model mice, equal placement densities, and similar exposure times. Habitat X produces 18 removed models out of 60, while Habitat Y produces 6 removed models out of 60. If X has much less visual contrast between the models and background, what interpretation is most justified?
📖 Explanation: The proportions removed are in X and in Y. Because the models and exposure conditions were controlled, the lower removal where contrast is reduced is consistent with camouflage lowering detection, although it does not prove camouflage is the only factor.
Q4. A researcher finds that dark models are removed more frequently on pale ground, but light models are removed more frequently on dark ground. Which follow-up experiment would most directly test whether background matching explains this pattern?
📖 Explanation: Testing multiple background colors while systematically varying model coloration creates a stronger comparison of visibility and predation. If removal consistently increases when model color contrasts with the background, the evidence for background matching becomes more convincing.
Q5. A graph shows the percentage of model mice removed: pale habitat: light , dark ; dark habitat: light , dark . Which statement best explains the interaction shown by the data?
📖 Explanation: The graph shows that light models have lower removal on pale habitat, whereas dark models have lower removal on dark habitat. Therefore, the apparent advantage of a coloration depends on environmental background rather than being universally superior.
Q6. A researcher places models only on dark soil and observes that dark models are removed less often than light models. Another researcher says, 'Therefore, dark coloration evolved because predators selected it during this experiment.' What is the main flaw?
📖 Explanation: The experiment provides evidence about differential survival or predation risk associated with coloration. Evolution requires changes in inherited characteristics or allele frequencies across generations, so one short-term model experiment cannot alone demonstrate that an evolutionary change occurred.
Q7. A team wants to determine whether the location of model mice affects predation independently of color. They place equal numbers of each color in several habitat locations and rotate colors among locations between trials. Why is this design stronger than using one fixed location for each color?
📖 Explanation: Rotating colors among locations helps separate the effect of coloration from local differences such as predator activity, vegetation, lighting, or microhabitat. Repeated trials further reduce the likelihood that an unusual location produces a misleading apparent color effect.