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Multiple Choice
Why are giraffe necks not perfectly suited for their function, despite their apparent adaptation for reaching high foliage?
A
Because environmental changes always result in perfectly optimized traits.
B
Because natural selection works with existing genetic variation and historical constraints, leading to imperfect adaptations.
C
Because giraffes intentionally evolved longer necks to compete with other animals.
D
Because mutations always produce the most efficient anatomical structures.
Verified step by step guidance
1
Understand the concept of natural selection: Natural selection is a process where organisms with traits that provide a survival or reproductive advantage are more likely to pass those traits to the next generation. However, it works with existing genetic variation and cannot create entirely new traits from scratch.
Recognize the role of historical constraints: Evolutionary adaptations are limited by the traits and structures that organisms already possess. For example, giraffes evolved longer necks from ancestors with shorter necks, but the process is constrained by the anatomy and genetic makeup of those ancestors.
Consider the imperfection of adaptations: Adaptations are not always perfectly optimized for their function. They are shaped by trade-offs and compromises, as well as the limitations of genetic mutations and environmental pressures.
Debunk misconceptions about intentional evolution: Evolution does not occur because organisms intentionally decide to change or compete. It is a gradual process driven by random mutations and selection pressures over time.
Clarify the role of mutations: Mutations are random changes in DNA that can lead to new traits. However, not all mutations are beneficial or efficient. Natural selection filters these mutations, but the resulting adaptations are still influenced by existing genetic variation and constraints.