1. Evolution of Life on Earth
Melissa Harker

2. Prokaryotes-first life form
We are closer to archaea than prokaryota (16s rRNA)
3.8 billion years ago bacteria emerged, then oxygen-producing bacteria
Stromatolites and cyanobacteria evolved later
After 2.5 bya, increase in oxygen changed life forms...algae, etc.

5. Primitive eukaryotes
After protista, primitive worm-like creatures appeared
Sponges, cnidaria appreared, trilobites-first arthropod

6. Edicaran Fauna
Similar to jellyfish, no hard parts to make good fossils Ma

7. Cambrian explosion (540 Ma)
A result of the rise of oxygen?
Chordates (will explain later)
Most organisms from this period, trilobites, etc. died off
First vascular plants from algae, then ferns, then seed plants, gymnosperms, finally angiosperms
Ferns do not evolve into seed plants—they are an evolutionary dead end!

8. Primary Chordates Jawless fish-most primitive
Hagfish have no backbone, lampreys do
Lungfish actually were not well-adapted, “advanced” fish
The Coelacanth is not the ancestor of amphibians

11. Amphibians Evolved from a relative of the coelacanth
Key structure to life on land is the amniotic egg that reptiles, birds, and mammals have

12. Reptiles Turtles closest to crocodiles genetically
Birds evolved from dinosaurs

13. Mammals
Did not evolve from birds, even though the first mammals laid eggs.
They are a separate spin off
Marsupials evolved before placentals