Introducing Evolution

Objectives: SOL BIO.8a-d

TSW investigate and understand how populations change through time, including:– Examining fossil records

Fossils

Any evidence of an organism that lived long ago.

Types of Fossils

Cast Mold Trace fossils Imprints Petrified fossils Frozen or Amber

Dating Fossils

Relative Dating– Rock layers are put down in order– Oldest on bottom, youngest layers on top

Radiometric Dating– Carbon-14 (50,000 years or less)– Potassium-40 (1.3 billion years – 50,000

years)

Why Use Fossils?

Scientists have used the fossil record to construct a history of life on Earth.– Earth’s life forms appeared 3.5 billion years

ago– Fossil record is not complete, but pretty

good for general information

The Origin of Life on Earth

Abiogenesis – life from non-living things– Disproven by Redi and Pasteur

Primordial Soup – natural processes formed early organic compounds– Miller-Urey experiment

Bubble Theory – formed protocells– Stanley Fox

Redi & Pasteur

The Origin of Cells

Prokaryotes – Archaebacteria (1st cells) Eukaryotes – endosymbiont hypothesis

– Separate DNA in chloroplasts and mitochondria

– Both organelles the same size and shape of bacteria