Chapter 22: Descent with Modification (2)

Question 1

Define vestigial structures.

Answer 1

These vestigial structures are remnants of features that served a function in the organism’s ancestors.

For instance, the skeletons of some snakes retain vestiges of the pelvis and leg bones of walking ancestors.

Question 2

Define an evolutionary tree.

Answer 2

An evolutionary tree is a diagram that reflects evolutionary relationships among groups of organisms.

Question 3

What are the types of data that could be used to make an evolutionary tree?

Answer 3

Evolutionary trees can be made using different types of data, for example,

– anatomical and
– DNA sequence data

Question 4

define convergent evolution.

Answer 4

Convergent evolution is the independent evolution of similar features in different lineages.

ex: marsupial mammals, many of which live in Australia.

Question 5

What do fossils provide information about?

Answer 5

Fossils provide evidence of:

– the extinction of species
– the origin of new groups
– changes within groups over time

Question 6

Define biogeography.

Answer 6

Biogeography is the scientific study of the geographic distributions of species.

Question 7

The geographic distributions of organisms are influenced by many factors, including _______.

Answer 7

The geographic distributions of organisms are influenced by many factors, including plate tectonics, the slow movement of Earth’s continents over time.

Question 8

About 250 million years ago, these movements united all of Earth’s landmasses into a single large continent called _______.

Answer 8

About 250 million years ago, these movements united all of Earth’s landmasses into a single large continent called Pangaea.