Study the diagrams below and answer the questions that follow.

3.3.1

a)
Diagrams that represent analogous structures are:

• Diagram 1 and Diagram 3

b)
Diagrams that represent homologous structures are:

• Diagram 2 and Diagram 3

3.3.2
The butterfly wing (Diagram 1) and bat wing (Diagram 3) are analogous because they have different basic structures and embryonic origins but perform the same function of flight.

3.3.3

a)
The diagram that has a vestigial structure is:

• Diagram 4

b)
It is called a vestigial structure because it is a structure that has lost its original function through evolution and has little or no current use in the organism.

c)
Vestigial structures provide evidence for evolution by indicating that organisms have evolved from ancestors that possessed the fully functional structure. They show common ancestry and how species have changed over time.

2.4.1
The diagram that represents a structure analogous to the structure in Diagram 4 (Bat wing) is:

• Diagram 1

2.4.2
Two diagrams that represent homologous structures are:

• Diagram 2 and Diagram 3 (or Diagram 2 and Diagram 4, or Diagram 3 and Diagram 4)

2.4.3
Analogous structures provide evidence for convergent evolution, showing that different species can evolve similar features independently due to similar environmental pressures. Homologous structures provide evidence for divergent evolution and common ancestry, indicating that species share a common evolutionary origin.