How many years ago was earth formed?
4.6 billion years ago.
What has resulted in the physical changes to the earth?
Heating, cooling and movement of continents(tectonic plates).
What was the super continent called?
Gondwana
What does radiometric dating measure?
The radioactive decay of isotopes(Carbon and uranium).
What are the names of the 3 eons and when did they occur?
- Archean (4.6 - 2.5 Billion Years Ago)
- Proterozoic (2.5 - 0.54 Billion Years Ago)
- Phanerozoic ( 542 Million Years Ago - Present
When was the first fossil found?
3.5 Billion years ago.
What was the “Oxygen Revolution”? and when did it occur?
The “Oxygen Revolution” occurred roughly 2.7 billion years ago when cyanobacteria started creating oxygen through photosynthesis. This allowed for aerobic metabolism meaning more energy could be produced and more complex organisms began to form.
What is the Endosymbiont Theory?
- Mitochondria and chloroplasts derived from prokaryotes
- Ingested but not digested
- Reproduced along with host cell
What is the Cambrian explosion?
A massive speciation event that occured 500 million years ago and started the paleozoic era.
What happened in the Paleozoic era that allowed for the colonisation of the land?
- Dessication
- UV radiation
- Gravity
- Thermal fluctuations
What is a mass extinction?
When more than 75% of species go extinct within a (geologically) short period of time.
