'Proof' for Evolution Flashcards
What is some evidence from Fossils (Paleontology)?
Fossils appear in chronological order; probable ancestors appear in older rocks
For vertebrates, fish appear first followed by amphibians, reptiles, birds and mammals
the deeper the fossils found in sedimentary rock, the simpler the life form
fossils show how individual species have evolved (changed) over time
all organisms do not appear together throughout the fossil record; supports the idea that organisms change slowly over time
What’s Radiometric Dating?
Half-life: the time it takes for half of a sample (50%) to decay
As the number of parent isotope atoms decreases, the number of daughter isotope atoms increases. So by measuring the amounts of these isotopes and using the half-life, it is possible to determine absolute time
What are Homologous Structures?
body parts in different species have the same evolutionary origin but serve different functions in modern species
a result of divergent evolution.
an example is the arm and legs of humans, cats, dogs etc. We are all from Phylum Chordata yet they have a different function.
What are Analogous Structures?
unrelated species develop similar traits due to similar environments
a result of convergent evolution
example: wing of a butterfly, a bat and a bird.
Different ancestors, but same function for all three.
What are Vestigial Structures?
Vestigial Structures are organs in a living being that had a purpose during the life of our ancestors, but the modern beings have no need for them.
Example of a Vestigial Structure?
The Appendix. It’s thought that it was meant to store antibodies and act as a method of breaking down raw meats in the immune system safely without contracting a nasty infection.
Another instance is where whales have pelvic bones. They cant walk, hence it’s obsolete.
What does Embryology say?
It says that all fetuses that involve mammals of the Chordata flavor develop in a similar fetal form.
