Question

with the extinction of the dinosaurs 65 million years ago, multiple niches that the dinosaurs once filled opened up and allowed mammals the opportunity to evolve and exploit those niches. this is an example of sympatric speciation adaptive radiation phylogeny reproductive isolation phylogenetic isolation question 5 (2.5 points) two species of toads have been successfully interbred in a laboratory but do not hybridize in nature because one species mates in summer and the other mates in the fall. this is an example of isolation reproductive

Explanation:

• Sympatric speciation occurs when new species evolve from a single ancestral species while inhabiting the same geographic region. This is not the case here as the focus is on mammals exploiting niches after dinosaur extinction.
• Adaptive radiation is the process by which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available. After the dinosaurs' extinction (a major environmental change), mammals had new niches (resources) and diversified, which fits this concept.
• Phylogeny is the evolutionary history and relationships among individuals or groups of organisms. It is more about the "tree - like" relationships rather than the process of diversification into new niches.
• Reproductive isolation is a mechanism that prevents members of different species from producing viable, fertile offspring. This is not relevant to the mammals - dinosaurs example which is about ecological niche exploitation.
• Phylogenetic isolation is not a standard term in evolutionary biology in the context of this question.

For the second part:

• Reproductive isolation is a broad category. Temporal isolation (a type of reproductive isolation) occurs when two species breed at different times (e.g., one in summer and one in fall). Since the two toad species have non - overlapping mating seasons (temporal difference) which prevent them from hybridizing in nature (even though they can in the lab), this is an example of reproductive (specifically temporal) isolation.

Answer:

First question: B. adaptive radiation
Second question: reproductive (temporal)