Chapter 15 - key topics Flashcards
1
Q
What is a fossil, how are they formed?
A
fossil: the preserved remains or impressions of once-living organisms
formed: sediment protects the remans from other animals, erosion, and decay.
1
Q
How are fossils dated?
A
relative dating: age of fossils based on layers of surrounding rocks
radiometric dating: uses radioactive isotopes to measure age of fossils or surrounding rocks.
2
Q
What are homologous and vestigial structures?
A
homologous structure: similar structure due to inheritance from a common ancestor
vestigial structure: inherited from an ancestor and no longer serves a clear function in the organism that posses it
3
Q
How similar is the genetic code between organisms? What does this mean?
A
- the genetic code is nearly identical among all organisms
- closely related organisms share similar DNA sequences
