Massachusetts Comprehensive Assessment System (MCAS) Biology Practice Test

What method can scientists use to effectively study differences between closely related species, such as brown and collared lemmings?

1. Observe their physical behavior in different habitats.

2. Determine the genome of each lemming species and look for differences.

3. Analyze their diet and environmental adaptations.

4. Evaluate their reproductive rates in respective environments.

The correct answer is: Determine the genome of each lemming species and look for differences.

Determining the genome of each lemming species and looking for differences is a powerful method for studying closely related species like brown and collared lemmings because it allows scientists to assess genetic variation on a molecular level. This genomic approach can reveal how small genetic differences influence traits, behaviors, and adaptations that define each species. By sequencing the genomes, researchers can identify specific genes that are responsible for physical and behavioral characteristics unique to each species. This level of detail can help clarify their evolutionary relationships and how they have adapted to their respective environments over time. It provides a direct insight into the genetic basis of divergence, which may not be evident through behavioral or ecological observations alone. Observing behavior, analyzing diet, or evaluating reproductive rates might provide valuable information about the species' adaptations and interactions with their environments, but these methods often do not capture the underlying genetic differences that contribute to those traits. Therefore, while those approaches are useful complementary studies, they do not provide the same level of detailed understanding that genomic analysis does.