Common Ancestry

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 animal

Preserved parts or traces of animals or plants that lived in the past

• Fossils

• Embryos

• Anatomical homologies

• ancestors

Type of fossil that leaves an imprint of an organism in sediment that eventually hardens to stone

• inclusion fossil

• cast fossil

• mold fossil

• petrification

Which of the following is true based on the law of superposition?

• Fossils buried deeper in the sediment/ rock layers are younger than the ones on the top layer

• Fossils at the top of the sediment/rock layers are younger than the ones on the bottom layer

• The position of fossils in the sediment/rock layers does not determine the fossils' age.

• Fossils at the top of the sediment/rock layers are older than the ones on the bottom.

Similar structures that exist between species and can be identified as a link to a common ancestor.

• Developmental Homologies

• Law of Superposition

• Inclusion Fossils

• Anatomical Homologies

The information in the fossil record diagram supports which of the following conclusions?

• Birds descended directly from trilobites and dinosaurs.

• Trilobites became extinct before dinosaurs appeared on Earth.

• Jellyfish live longer than any other organism on Earth.

• Mammals did not appear on Earth until after the dinosaurs went extinct.

Why do the lines for each organism not extend through the whole chart?

• The species became endangered.

• The species developed into a new species.

• The species became extinct.

• The species never appeared on Earth and it was all a guess from scientists.

What is the most reasonable conclusion that can be drawn from a comparison of these structures

• The common ancestor of birds and bats must have had wings and flown.

• Birds and bats are closely related to each other while humans are unrelated to both.

• Humans live in habitats very different from the habitats of both birds and bats.

• Humans and bats share a closer evolutionary history with each other than with birds.

Which evidence of common ancestry is being studied in the visual?

• Anatomical homology

• Embryonic development

• Molecular homology

• DNA

Which stage of development do the embryos of vertebrates look the most similar?

• early stages

• middle stages

• late stages