Relate fossil record to age of Earth and the time over which life has been evolving Flashcards
When does a pattern become obvious in fossils?
• When enough fossils studies and placed in relative time order
What were younger and older fossils like?
- Younger fossils were more like modern plants and animals
* Older fossils were different and unlike modern types. Ancient fossils were all small, simple creatures only
What do rocks older than 600 million years contain? What does it indicate?
only the fossils of ‘mats’ of microscopic cell growths and chemicals, indicate activity of living things.
What did palaeontologists began to do in the 19th century?
name period of Earth history according to typical fossils in rock of each time
What did they notice?
certain times in past, there seems to have been sudden mass extinctions of living things, followed by appearance of many new types of life
How old is earth?
4 600 million years old
When was first trace of living found?
about 3 800 million years ago
- Precambrian times ( 1 000 million years ago)
life forms single celled
Palaeozoic Era
First appearance of fossils of jellyfish, wormlike creatures, fish, plants on dry land, land animals. ( Sudden ‘explosion’ of animals with shells and exoskeletons)
Mesozoic Era
Age of Dinosaurs, first mammals and birds. Major mass extinctions before and after era
Cainozoic
Mammals dominant
