Chap 13 Evidence of Evolution Flashcards
What is paleontology?
the study of past life
What provided the original evidence for evolution?
fossils
What are fossils?
the remains of ancient organisms
What are transition fossils?
links that demonstrate common ancestry
Transition fossils can reveal what>\?
step-by-step, the evolution of one species into another
What does relative dating do?
estimates fossil age using rock layers (it puts fossils in order from oldest to most recent)
What does relative dating assume?
that lower rock layers have older fossils than newer layers
What does absolute dating do?
estimates fossil age using chemistry
How does absolute dating work?
measuring using radioactive isotopes as a “clock”, since they decay at a steady, known rate
Fossils are dated by measuring which isotope?
carbon 14
What does carbon 14 decay into?
N14
What is the half-life of carbon 14?
5,730 years
What do scientists measure when using isotopes for dating?
the ratio of C14 to C12
What sheds light on evolutionary events?
biogeography
What is Wallace’s line?
a deep trench separating animals, for millions of years, allowing them to evolve independently
What is the result of Wallace’s line?
a unique variety of organisms on each side of the line
What can anatomical relationships reveal?
common descent
What is homologous structures?
structures inherited from a common ancestor
What are vestigial structures?
structures that have lost their function
What are analogous structures?
structures that evolved independently
When are anatomical structures analogous?
if they are superficially similar but did not derive from a common ancestor
What does embryonic development patterns do?
provide evolutionary clues
How do early vertebrate embryos appear?
they appear alike
What controls embryonic development?
homeotic genes
What are needed for body structures to develop normally?
homeotic genes
Small differences in what might make the difference between a limbed and limbless organism?
gene expression
What reveals relatedness?
molecules
What determines evolutionary relationships in unprecedented detail?
comparing DNA and protein sequences
What are inherited from common ancestors?
sequence similarities
What are based on random DNA mutations?
molecular clocks
Does DNA accumulate random mutations at a regular rate, as long there is no selection for or against the mutation?
yes
Are there more and more random mutations over time?
yes
Is it more likely that two unrelated species would evolve the same DNA of that the similarities were inherited from a common ancestor?
that they were inherited
