Over millions of years of time, an island's vegetation shifts. The seed-producing plants that dominated the early origins of the island die out in favor of new species of plants that do not produce seeds but provide a good habitat for insects. How is this change likely to affect a species of birds that uses seed as its primary source of food and insects as a secondary food source?
a. The species will maintain its heritable traits while learning to make insects their primary food source.
b. The species will decline and become endangered because its adaptations have reduced utility.
c. The species will split into two: one adapted to eating seeds and a second adapted to eating insects.
d. Over time, a shift in traits will be observed as the species adapts to an insect diet.
D
I agree.
To determine how the change in vegetation is likely to affect the species of birds, we need to consider the options given and assess their likelihood based on the information provided.
a. The species will maintain its heritable traits while learning to make insects their primary food source.
This option suggests that while the birds primarily rely on seeds for food, they will be able to learn and adapt their behavior to make insects their primary food source. However, it is important to note that learning is usually a short-term response, whereas the mention of "over millions of years of time" implies long-term evolutionary changes. Thus, this option is less likely.
b. The species will decline and become endangered because its adaptations have reduced utility.
This option suggests that the birds' adaptations, which were specifically for eating seed-producing plants, have reduced utility in the new vegetation. Given that the new species of plants do not produce seeds, the birds may struggle to find enough food to survive and reproduce. As a result, their population could decline and become endangered. This option seems plausible based on the information provided.
c. The species will split into two: one adapted to eating seeds and a second adapted to eating insects.
This option suggests that the change in vegetation will lead to the divergence of the bird species into two subgroups, one specializing in seed-based diet and the other in an insect-based diet. While speciation can occur due to changes in the environment, there is no mention in the question about reproductive isolation or genetic divergence, so this option is less likely.
d. Over time, a shift in traits will be observed as the species adapts to an insect diet.
This option suggests that the birds will gradually develop new traits that are advantageous for consuming insects rather than seeds. Given that the new species of plants provide a good habitat for insects, it is possible that the birds undergo evolutionary changes to adapt to this new food source. This option aligns with the notion of natural selection and long-term evolutionary processes, making it a plausible answer.
Considering the information provided, option d, "Over time, a shift in traits will be observed as the species adapts to an insect diet," is the most likely answer.
d. Over time, a shift in traits will be observed as the species adapts to an insect diet.
With the shift in vegetation on the island, the primary source of food for the birds, which is seeds, will become less available as the seed-producing plants die out. As a result, the birds will have to rely more on the insects that inhabit the new species of plants growing on the island. Over time, natural selection will favor individuals of the bird species that have traits beneficial for catching and consuming insects. These traits may include changes in beak shape, body size, and behavior that are better suited for insect hunting. Gradually, the population of birds will adapt to their new insect diet, resulting in a shift in traits observed in the species.