[Campbell Biology P.556] Figure 24.2 illustrates the biological species concept. Based on th... | Practice Question

Figure 24.2 illustrates the biological species concept. Based on the figure and text, which statement correctly explains why Eastern and Western meadowlarks are considered distinct species, while all humans are considered a single species?

  • A: Meadowlarks are different species due to significant physical dissimilarities, whereas humans, despite diversity, have identical DNA.
  • B: Meadowlarks are reproductively isolated by their differing songs and behaviors, while humans, despite appearance variations, can interbreed successfully.
  • C: The definition of species applies only to animals like birds, not to humans due to their high genetic diversity.
  • D: Meadowlarks are geographically isolated, while humans are globally distributed, preventing distinct species formation.

Explanation

Figure 24.2 a states that Eastern and Western meadowlarks are distinct species because their 'songs and other behaviors are different enough to prevent interbreeding should they meet in the wild.' Figure 24.2 b explains that 'all humans belong to a single biological species Homo sapiens , defined by our capacity to interbreed successfully.' This directly supports the idea that reproductive isolation, not physical similarity, defines a species.