Final answer:
Homologous structures are structures shared by related organisms that were inherited from a common ancestor. Examples include the limbs of mammals like bats, lions, whales, and humans. Vestigial structures are residual parts from past ancestors that no longer have a function. These structures provide evidence for the patterns of evolution.
Step-by-step explanation:
Homologous structures are structures shared by related organisms that were inherited from a common ancestor. Examples of homologous structures include the limbs of mammals like bats, lions, whales, and humans, which all have a common ancestor. Although these organisms have different functions for their limbs, the common structure suggests evolutionary relatedness.
Vestigial structures are residual parts from past ancestors that no longer have a function. Examples include pelvic bones in snakes despite having no legs, wings on flightless birds, leaves on some cacti, traces of pelvic bones in whales, and sightless eyes in cave animals.
These homologous and vestigial structures provide evidence for the patterns of evolution by showing that different organisms share common ancestors and have undergone changes over time.