Explain how the trunk of an elephant evolved using Darwin's theory of natural selection, and then Lamarck's theory.

According to Darwin's theory, genetic variation within the population means that some elephants are born with longer noses. Longer noses are better suited to the environment, so longer-nosed elephants are more likely to be able to get food. They are therefore more likely to survive and reproduce. The genes responsible for the longer nose are passed on to their offspring, and across many generations this developed into the modern elephant trunk. According to Lamarck's theory, early elephants stretched their noses to reach more food during their lifetime. The stretched nose is then passed on their offspring.