Formation approximately 4.5 bya Early Earth Formation approximately 4.5 bya

Describe the Early Earth

Abiogenesis Living things come from nonliving things Up until the 19th century, (aka: spontaneous generation) Widely accepted explanation for the origins of many organisms, especially ones considered vermin.

Abiogenesis Revisited Could early cells have formed from nonliving matter?

Repeated Experiments The results still showed that organic molecules can form under early Earth’s conditions.

Life History Protobions Prokaryote (Bacteria) Cyanobacteria (Photosynthetic)** Eukaryote (unicellular) Endosymbiotic theory Unicellular to Multicellular Colonial Flagellate Hypothesis Plants Animals (water to land)

What do fossils tell us? 1. help scientists determine the age of the earth Biodiversity

LAW OF SUPERPOSITION the oldest layer is on the bottom and the youngest is on top- fossils are older in the lower layers

Extinctions can be seen in rock layers What conclusion can we draw about extinctions since the beginning of time?

What’s the biggest cause of extinctions today?

What do fossils tell us? 3. provide evidence about past events (asteroids, volcanoes, ice ages) Biodiversity What conclusion can be made about the earths climate since the beginning of time?

What do fossils tell us? 2. give clues about organisms that lived long ago, relationships and how they have changed over time Tree of Life Biodiversity