Question

on the galapagos islands, darwin observed tortoises with domed and saddle - shaped shells. how did darwins observations of these tortoises help him form the theory of evolution by natural selection?
a. the tortoises provided evidence that the galapagos had been colonized by tortoises multiple independent times.
b. the tortoises helped to confirm that environmental changes cannot affect the characteristics of a species.
c. the tortoises helped to confirm that two similar species do not necessarily share a common ancestor.
d. the tortoises provided evidence that different species have adaptations suited to their particular environments.

Explanation:

Darwin's theory of evolution by natural selection posits that organisms adapt to their environments over time. The tortoises with different shell shapes (domed and saddle - shaped) would have adaptations suited to their specific environments on the Galapagos Islands. For example, a saddle - shaped shell might be an adaptation that allows a tortoise to reach higher vegetation in a particular habitat. This shows that different species (or in this case, different forms within a group of tortoises) have adaptations that are beneficial for their particular environments, which is a key aspect of natural selection.

Answer:

D. The tortoises provided evidence that different species have adaptations suited to their particular environments.