Life On Earth Flashcards
What was the earth called when it was one huge land mass
Pangaea
What 2 parts did Pangaea break into
- Laurasia
- Gondwanaland
Define paleontology
The study of plant and animal fossils
What is a paleontologist
A scientist who studies fossils
How old is earth
4,6 billion years old
What are the 4 eras of earth
- Precambrian era
- Palaeozoic era
- Mesozoic era
- Cenozoic era
What happened in the Precambrian era
- Friday unicellular prokaryotes
- unicellular and multicellular eukaryotes developed
What happened in the Paleozoic era
There was a huge increase in biodiversity
- mosses, ferns, oral reefs
- Fish developed lungs and amphibians developed
- Reptiles arose after the amniotic egg
What happened in the Mesozoic era
Dinosaurs were dominant
- Mammals developed
- Flowering plants developed
What happens in the Cenozoic era
CURRENT ERA
- More diverse birds and mammals
- Hominids evolved
What are transition fossils
Between dinosaurs and modern birds
Give an example of a traditional fossil
Archaeopteryx
What are trilobites
They have armoires plates and hard shells with segmented parts
What do indicator species do
Help scientists to identify the age of sedimentary rock
Define extinct
When the last living member of a species on earth dies
What is a mass extinction
When more than 70% of all species become extinct around the world and very quickly
What are the 2 most significant mass extinctions
- 250 million years ago, the end of the Paleozoic era (96% became extinct)
- 65 millions years ago, at the end of the Mesozoic era, Dinosaurs becoming extinct
What are possible causes of mass extinctions
- Large meteorites from space
- Volcanic action
- Continental drifts
- Ice ages
What type of rock are fossils formed in
Sedimentary rock
Define fossilization
When plants and animals become trapped in the layers and become fossils
What are trace fossils
Mark or footprint left in mug or wet sand by living organisms
What is a body fossil
When minerals in hard parts of animals/plants become replaced by rock minerals
What are unaltered fossils
When the entire body of an organism is preserved instantly
What are mound fossils
When all organisms tissue break down, leaving the exact shape impression the the rock
What is a cast fossil
When other substances fill the mound and form a 3D shape of the original organism
What are 2 methods of dating fossils
- Relative dating
- Radiometer is dating
Why do we need to study fossils
- Dating layers of the earth
- Evolution
- Fossile and oil
