Ch. 26

Part 1: Haedon Eon

13.7bya: Universe 4.6bya: Earth

~10 million species inhabit Earth today

4.6bya: Geologic/Atmospheric Conditions No Water No Oxygen No Fun

3.9 – 3.5bya: Simple life formed Prokaryote Genetic Material Cell Metabolism Replication But How?

Miller-Urey Experiment Simulate early Earth Amino acids formed

John Sutherland Experiment Simulate early Earth Nucleic acids formed

Liposomes: Lipids form a bilayer in water (cell) Protobionts: Enzymes break down glucose (energy) Divide in response to osmosis (reproduction)

RNA became awesome at: Surviving Reproducing (self replicating) Mutating

Part 2: Archean eon through Cambrian Period

~3.5bya: Stromatolites (Cyanobacteria) Produced Oxygen

~2.1bya: Complex cells with organelles But How?

Prokaryotic mitochondria & plastids were engulfed DNA (small, circular chromosome) Double membrane

~1.5bya: Protists

~530mya: Cambrian Explosion

Part 3: Ordovician Period through Quaternary Period

~450 mya: Ordovician Extinction 90% of all species died Major glacial event

~ mya: Land Plants, Fungi, & Insects ~375mya: Tiktaalik 1 st terrestrial tetrapod Amphibians & Reptiles

~250mya: The Great Dying 96% of all species died Asteroids & Volcanoes

~200mya: Mammals & Dinosaurs ~150mya: Birds

~65mya: K/T Extinction 75% of all species died Giant asteroid slammed into Mexico

TODAY!!! Up to 140,000 species go extinct each year Habitat Destruction, Hunting, Pollution…

Earth will be hit by another asteroid in the future! Apophis 2036?

The diversity of life today is a result of evolution through natural selection over the course of 3.5by.

What does that mean?