Question

which of these is an example of a key innovation?

a new flower color morph arises in a plant population, but an associated pollinator does not distinguish flowers by color.

co-occurring diploid species of wheat and goatgrass hybridize to form a viable tetraploid offspring that can no longer breed with its parents.

a founding population of honeycreepers evolves beaks capable of cracking the seed of a tree species in their new habitat.

Explanation:

Define key innovation

A key innovation is a novel phenotypic trait that allows a species to exploit a previously incompatible or inaccessible resource, often triggering Adaptive Radiation by opening up new ecological niches.

Analyze the first option

The first option describes a new flower color morph that is not distinguished by its pollinator. Because this trait does not open up new ecological opportunities or resources, it is not a key innovation.

Analyze the second option

The second option describes hybridization and polyploidy leading to speciation. While this is a mechanism of sympatric speciation, it does not describe the acquisition of a novel functional trait that unlocks new niches.

Analyze the third option

The third option describes a founding population of honeycreepers evolving specialized beaks to crack seeds in a new habitat. This novel morphological adaptation directly allows them to exploit a new food source, facilitating Adaptive Radiation in their new environment. This is a classic example of a key innovation.

Answer:

• (A) A new flower color morph arises in a plant population, but an associated pollinator does not distinguish flowers by color.
• (B) Co-occurring diploid species of wheat and goatgrass hybridize to form a viable tetraploid offspring that can no longer breed with its parents.
• (C) A founding population of honeycreepers evolves beaks capable of cracking the seed of a tree species in their new habitat. (Correct answer)