A researcher observed that waterbirds developed broader webbed feet over their individual lifetimes through constant stretching while swimming, and asserted that their offspring inherited these enlarged webs directly. Which evaluation best critiques this assertion according to modern biological principles?
- The assertion relies on the inheritance of acquired characteristics, which is invalid because somatic modifications caused by environmental use do not alter germline genetics.Answer
- BThe assertion correctly describes natural selection, where environment-induced somatic changes immediately mutate reproductive genes.
- CThe assertion accurately applies Lamarck's law of use and disuse, proving that somatic hypertrophy directly alters chromosomal allele frequencies.
- DThe assertion is flawed because use and disuse can only cause the complete atrophy and loss of vestigial structures, not morphological enlargement.
Answer
The assertion relies on the inheritance of acquired characteristics, which is invalid because somatic modifications caused by environmental use do not alter germline genetics.
The correct answer highlights the fundamental flaw in Lamarckian evolution. Physical changes occurring in body cells (somatic tissue) due to use or environmental strain are not encoded in gametes (germline tissue), meaning they cannot be inherited by offspring.
Step-by-Step Solution
Key Concept
Lamarck's Theory of Inheritance of Acquired Characteristics vs. Modern Genetics