Evolution of life on Earth Flashcards
How do we know how life evolved on Earth?
- analysing DNA and fossils directly
- indirect fossils which show evidence of of processes life carries out
What fraction is life on land of Earths history?
1/10
When is the first evidence of eukaryotic life on Earth?
2 billion years ago
What is the most abundant biomass on Earth?
microbial life
When was the late heavy bombardenment?
8.5 billion years ago
What is temperature impacted by?
the albedo and the green house effect
What are the two main reactions on Earth today?
aerobic respiration and oxygenic photosynthesis
What were the metabolisms of early organisms on Earth?
methanogenesis and anoxygeneic photosynthesis
Describe methanogenesis
Use of carbon dioxide and hydrogen to produce methane and water
Describe anoxygenic photosynthesis
Doesn’t produce oxygen, other organisms had to use fermentation to produce energy which produced methane
What did early metabolisms cause?
A methane rich atmosphere which helped maintain the warm temperature and a habitable planet
When did oxygen become rich in the atmosphere?
2.3 billion years ago
What allowed the formation of new organisms?
the great oxidation event
What is the Cambrian explosion?
the introduction of many different phyla of animal
What are the critical steps for life to evolve?
- origin of life
- photosynthesis
- eukaryotic differentiation
- observers evolving
