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