The pair of embryos that are most alike in later stages of development is amphibian and bird.
Explanation:
Amphibian and bird embryos share several key developmental features due to their evolutionary heritage. Both groups are part of the tetrapods, and during early development, their embryos exhibit similar traits such as development of a notochord, somites, and gill structures at certain stages.
- Similarities in Development: During the embryonic stage, both amphibians and birds show a similar body plan with establishment of dorsal-ventral patterns and the formation of limb buds.
- Evolutionary Lineage: Birds evolved from theropod dinosaurs, which are closely related to some amphibian lineages. This common ancestry contributes to similarities in embryonic development.
- Gill Structures: Both amphibian and bird embryos exhibit pharyngeal arches (which can develop into gills or other structures) in their early stages, emphasizing their evolutionary connections despite being quite different as adults.
In contrast, the comparisons of fish-mammal and fish-amphibian embryos show less similarity in later develop stages, as mammals have quite distinct embryonic development patterns due to their placental nature, while fish and amphibians share some early features but diverge significantly as they develop. Thus, the most similar pair in later stages are amphibians and birds.