📝 Beach mice vs inland mice coloration (7 MCQs)
📖 From Campbell Biology • 1. Evolution and the theme of Biology and Scientific Inquiry • 7 questions available
What is Beach mice vs inland mice coloration?
Definition:
Beach mice and inland mice coloration refers to the phenotypic difference in coat color between populations of mice living in coastal sandy habitats (light-colored) and inland darker habitats (dark-colored), and this variation is a classic example of local adaptation, where natural selection favors coat colors that provide camouflage against the background, reducing predation risk.
Working:
This coloration difference works because the light-colored beach substrate selects for lighter mice, as predators (like owls and hawks) are less likely to spot them, while the darker inland substrate selects for darker mice, and these differences are due to both genetic and environmental factors, with the genetic basis involving pigmentation genes such as Mc1r, and field experiments have shown that mice mismatched to their background are predated more heavily, providing evidence for the adaptive significance of coloration.
Example:
A simple example is the Gulf Coast beach mouse, which is pale with a white belly, versus the inland oldfield mouse, which is dark brown; when model mice of contrasting colors are placed on beaches and inland habitats, the mismatched models (dark on beach, light on inland) are attacked more often by predators, demonstrating the selective advantage of matching coloration.
Reason:
Understanding beach vs inland mouse coloration is important for studying evolutionary processes, as it provides a clear case of natural selection in action, and it helps illustrate how environmental pressures shape traits, contributing to the study of adaptation, speciation, and conservation.
📝 All Beach mice vs inland mice coloration MCQs
Q1. Researchers observe that mice on a dark beach tend to have darker coats, while mice farther inland tend to have lighter coats. Which conclusion is most scientifically justified from this observation alone?
📖 Explanation: The observation establishes an association between location and coat color, but it does not establish causation. Additional evidence is needed to determine whether inheritance, environmental effects, selection, or another factor explains the pattern.
Q2. Two populations differ consistently in coat color. A student argues that the difference proves that living on the beach causes individual mice to become darker during their lifetime. What is the strongest criticism of this reasoning?
📖 Explanation: A population-level difference cannot by itself reveal whether traits are inherited or acquired. Comparing offspring, controlling environmental conditions, or conducting breeding experiments would help distinguish genetic effects from environmental influences.
Q3. Suppose a researcher finds that dark-coated mice are more common on the beach and light-coated mice are more common inland. Which follow-up investigation would best test whether the observed pattern has a genetic basis?
📖 Explanation: Moving mice between environments while controlling rearing conditions helps separate environmental effects from inherited differences. If offspring retain population-associated coat tendencies despite similar conditions, genetic differences become more plausible.
Q4. A student states, 'Because beach mice are darker, natural selection must have caused the difference.' Which reasoning error is present?
📖 Explanation: The observation is compatible with natural selection, but it does not prove that mechanism. Other explanations, such as migration, genetic drift, environmental effects, or historical differences, must be considered and tested.
Q5. A survey produces the following proportions of dark-coated mice: Beach: 80%, Edge: 55%, Inland: 20%. Which interpretation is best supported by these data?
📖 Explanation: The data show a spatial association: dark coats are most frequent near the beach and least frequent inland. However, the pattern alone cannot establish that distance itself causes the difference or identify the mechanism.
Q6. Researchers want to determine whether the observed color difference could affect survival. They place equal numbers of dark and light mice in beach-like and inland habitats and monitor survival. Which result would provide the strongest evidence for habitat-dependent selection?
📖 Explanation: Differential survival that consistently matches habitat conditions provides stronger evidence that coat color can influence fitness. The other results either show no difference or merely repeat the original observation without testing its consequences.
Q7. A researcher models coat-color frequency across locations and notices that dark coloration is highest where the ground is darkest. Another study finds that predators detect contrasting mice more often. Which conclusion best integrates both findings?
📖 Explanation: The two findings together support a plausible model in which background matching reduces predator detection and can influence survival. However, demonstrating evolutionary change still requires evidence connecting survival differences with reproduction and inheritance.