Question

regular assignments and regular section: answer these questions in red font. 1. explain how the anatomy of whales supports the idea that they evolved from land mammals. 2. describe the significance of embryology in understanding evolutionary relationships. 3. how does the fossil record contribute to our knowledge of whale evolution? 4. compare and contrast the dna of whales and hippos. what does this comparison suggest about their evolutionary relationship? 5. what evidence do the tiny bones found in modern whales provide regarding their evolutionary history?

Explanation:

1. Whales have vestigial hind - limb bones, which are remnants of when their ancestors walked on land. Their flippers have similar bone structures to the forelimbs of land mammals, indicating homology.
2. Embryology shows similar developmental stages across different species. In whales, early - stage embryos have features like limb buds and gill slits, similar to land - mammal embryos, suggesting a common ancestry.
3. Fossil record provides transitional forms between land mammals and modern whales. Fossils like Ambulocetus and Basilosaurus show intermediate stages in the evolution of whales, with features adapted for both land and water.
4. Whales and hippos have similar DNA sequences, which suggests they share a relatively recent common ancestor. This genetic similarity is evidence of their close evolutionary relationship.
5. The tiny bones in modern whales are vestigial structures. They are remnants of the pelvic and hind - limb bones of their land - dwelling ancestors, indicating that whales evolved from land mammals.

Answer:

1. Whales have vestigial hind - limb bones and flippers with homologous bone structures to land - mammal forelimbs.
2. Embryos of whales have features similar to land - mammal embryos, showing common ancestry.
3. Fossils provide transitional forms between land mammals and whales.
4. Similar DNA suggests a close evolutionary relationship between whales and hippos.
5. Tiny bones are vestigial remnants of land - dwelling ancestors' bones.