Biological Evidence of Evolution
A. Evidence for Evolution
1.Evolution does not occur in a straight line with one species
another in a series of orderly steps.
a. Living species that are closely related share a common .
b. How closely related two species are depends when they
, or split, from their common ancestor.
2.The study of similarities and differences among structures of living species is called .
a. Body parts of organisms that are similar in position but different in function are
called . The forelimbs of different mammals are examples.
b. If species have homologous structures, this suggests that the species are .
c. The more similar two structures are to each other, the more likely it is that the species have evolved from a recent .
d. are body parts that perform a similar function but differ in structure. The wings of flies and birds are examples.
e. The existence of analogous structures indicates that the species are not related.
3.Body parts that have lost their original function through evolution are called
. The of flightless birds are an example.
a. The best explanation for is that the species that have
vestigial structures are to ancestral species that still use the structures for a specific purpose.
b. Whales have a tiny bone, which is a vestigial structure for walking on land.