Evidence of Common Ancestry

Study of embryos of various organisms to show a common ancestor because of similarities in development

• natural selection
• embryology
• speciation
• evolution

How do fossils provide evidence that evolution has happened on Earth?

• Fossils show how the sizes of certain animals has changed drastically over millions of years
• Fossils show that some species have gone extinct
• Fossils show how life forms present today are different than those from the past
• Different sedimentary rock layers provide evidence for how the environment has changed over time

Humans, birds, whales, and lizards all have similar arm bones. What is the reason for this?

• The function of these bones is the same in all animals
• They live in similar environments
• They have a common ancestor
• All organisms resemble humans

Vestigial structures

• structures that perform a similar function but are not similar in origin

• remnants of once-important structures that have slowly lost all or most of their function

• features found in different organisms that share structural similarities but may have very different functions

• preserved remains of an organism

Which layer is the youngest

• 1
• 2
• 3
• 4

The picture shows a/an ___________

• homologous structure

• vestigial structure

What is this an example of?

• Homologous structure

• Analogous structure

• Vestigial organs

• Functional adaption

Scientists compare the limbs of organisms to look for evidence of common ancestry. These limbs provide evidence of common ancestry because they -

• perform the same function
• are the same size
• have the same basic structure
• are parts of the same animal

Using the Data Table 1, which organism is least related to rabbits?

• Fly
• Bat
• Tree
• Bacterium

 Using the cladogram to the right, flies are most closely related to:

• Beetles
• Wasps
• Butterflies
• Ants