Lake Victoria, in Africa, is home to a group of related fishes known as cichlids. Many of these fishes are similar in appearance but have different feeding habits. What is the best method for scientists to determine conclusively whether the fish are members of a population that has a lot of variation or members of entirely different species?

• A. Study the fossil record.
• B. Compare DNA sequences because the DNA of members of the same species should be identical.
• C. Do studies on comparative anatomy, especially looking for homologous structures.
• D. All of the listed responses are correct.
• E. Observe the fish in their natural environment for possible instances of interbreeding leading to several generations of fertile offspring.

Answer: (E)

Verified step by step guidance

1. Step 1: Understand the concept of species and population variation. A species is a group of organisms that can interbreed and produce fertile offspring, while population variation refers to differences within a species.
2. Step 2: Consider the importance of observing interbreeding in the natural environment. If the fish can interbreed and produce fertile offspring, they are likely members of the same species.
3. Step 3: Evaluate the role of DNA sequence comparison. While DNA comparisons can provide insights, identical DNA is not necessary for species classification due to genetic variation within a species.
4. Step 4: Analyze the significance of comparative anatomy. Homologous structures can indicate common ancestry but may not conclusively determine species boundaries.
5. Step 5: Recognize the limitations of fossil records. Fossil records can provide historical context but may not reflect current species interactions and interbreeding capabilities.