Ecology Flashcards
When was the earth formed
4.6 billion years ago
What was the original state of the earth
Molten balk of rock and minerals
What is one theory about the earth structure
That volcanoes released carbon dioxide,water vapour and nitrogen and these gases formed the early atmosphere
How did the earth cool down
Water vapour in the atmosphere condensed as the earth gradually cooled down,and feel as rain
How were oceans formed
Water collected on the hollows in the crust as the rock solidified and the first oceans were formed
What was the atmosphere like as the earth began to stabilise
The atmosphere was mainly carbon dioxide there could of also been some water vapour and nitrogen gas as well as traces of methane and ammonia
When did life begin on earth
3.4 billion years ago when first simple organisms,similar to bacteria appeared
When did algae evolve
2.7 billion years ago
When algae evolved what could it do
It could use energy from the sun to make its own food(photosynthesis)
How was oxygen gas produced
As a waste product of photosynthesis
What is the word equation for photosynthesis
Carbon dioxide+water——>glucose+oxygen
How were animals formed
When the atmosphere become richer in oxygen and they relied on algae and plants for their food and oxygen to respire.
