Answer:
Origin of whales
Natural selection
Modern understanding
Step-by-step explanation:
Origin of whales - In the first edition of "On the Origin of Species" in 1859, Charles Darwin speculated about how natural selection could cause a land mammal to turn into a whale.
Natural selection - To understand the origin of whales, it's necessary to have a basic understanding of how natural selection works. Natural selection can change a species in small ways, causing a population to change color or size over the course of several generations. This is called "micro-evolution."
Modern understanding - Darwin didn't know anything about genetics, Pobiner said. "He observed the pattern of evolution, but he didn't really know about the mechanism." That came later, with the discovery of how genes encode different biological or behavioral traits, and how genes are passed down from parents to offspring.