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