History of Life on Earth Evolutionary TIMELINE Ms. Herrera
Earth is 4.6 billions years old • 1 billion= 1000 million • 1 trillion= 1000 billion • How many millions of years old is earth? • 4600 million years
Directions • For each ERA, create drawings that represent the animals featured during that time. • Take your time to draw out animals, plants or bacteria. • Use the book (pages 427 – 440) for samples of pictures.
Vocabulary Extinct- When a species dies out.
Fossil- the preserved or mineralized remains or imprint of an organism that lived long ago
How do fossils form? • 1. Death
Relative dating: • Top layers are younger than bottom layers this also applies to the fossils found within that layer • determining the age of a fossil by comparing its placement with that of fossils in other layers of rock.
Half-life radioactive dating Some of the elements found in rocks are radioactive. Radioactive elements decay at a steady rate. A half life is the time required for half of the radioactive atoms in a sample to decay. Age of a sample can be calculated based on the remaining atoms.
Fossil Record- Provides evidence about the history of life on earth.