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CER. Mammals did not descend directly from dinosaurs, but mammals embryos have placodes, as show in Figure 3. Use the information about scales and feathers to explain why mammal embryos and dinosaur embryos each have placodes. Identify the information that can be used as evidence to support your explanation, and then explain why this information can be used as evidence.

User Markita
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The presence of placodes in both mammal and dinosaur embryos suggests a shared evolutionary ancestry, supported by the information about the development of scales and feathers, as these structures originate from similar genetic pathways, providing evidence of a common developmental origin.

The presence of placodes in both mammal and dinosaur embryos points to a shared developmental ancestry despite the fact that mammals did not directly descend from dinosaurs. Placodes are specialized regions in embryos that give rise to various structures such as scales, feathers, and hair. The information about the development of scales and feathers becomes crucial evidence in this context. Scales, feathers, and hair share a common genetic origin, as they are derived from similar ectodermal placodes during embryonic development.

This shared genetic pathway indicates a common evolutionary ancestor for both mammals and dinosaurs, providing compelling evidence for their interconnected evolutionary history. The presence of placodes in both lineages serves as a developmental link, supporting the idea of a shared ancestry and reinforcing the evolutionary connection between mammals and dinosaurs.

User Donovan
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