CHAPTER 13 Flashcards
How do scientists collect data on what earth was like 2
gas bubbles trapped in rocks
data gathered from other planets and their moons
what was the first phase in the evolution of the atmosphere
the surface was covered in volcanoes which released co2 and oxygen
then nitrogen water vapour and methane and ammonia were released by volcanoes
what gases would the early atmosphere be made from
mostly carbon dioxide and a little oxygen
how were oceans formed
water vapour in the atmosphere condensed as the planet cooled
icy comets melted and released water
what happened to the co2 in the atmosphere once oceans were formed
it dissolved into the water and formed carbon precipitates that formed sediments on the sea floor
what happened once algae had evolved
they absorbed the co2 from the oceans to photosynthesis and produce o2 as a waste product
how are sedimentary rocks formed
when organisms die they sink to the sea bed and are covered in layers of sediment
they then become compressed and form rocks with clear layers
what is coal made from
compressed plant deposits
what is crude oil made from
compressed plankton
what is limestone made from
calcium carbonate
what happened once more plants evolved to photosynthesis
they absorbed much of the co2 and released more o2 into the atmosphere more complex animals could now evolve
overall process of the evolving atmosphere
volcanoes produced gases like co2 and nitrogen oceans were formed
green plants started to photosynthesis co2 was removed and o2 released more complex animals could survive
what happens when animals eat plants
the co2 in the plant is transferred to the animals tissues
how was coal formed
plant material deposited into swaps they were bused in aerobic conditions and compressed for millions of years
how was limestone formed
animals ingested co2 through plants they die build up of skeletons on seabeds
pressure of other sediments forms this sedimentary rocks
how were crude oil and natural gases formed
remains of plankton were deposited into the mud on the sea bed these were covered in sediments they were compressed gas and oil are found in this rocks
what are the main 2 ways in which co2 was removed from the atmosphere
photosynthesising in to plants dissolving in oceans
how was methane and ammonia removed from the atmosphere
they reacted with o2
equation for ammonia + o2
ammonia + o2 -> nitrogen and water
equation for methane + o2
methane + o2 -> carbon dioxide + water
what are the main 4 gases in the current atmosphere
nitrogen
oxygen
argon
co2
percentage of nitrogen in atmosphere
78
percentage of o2 in atmosphere
21
percentage of argon in atmosphere
0.9
percentage of co2 in atmosphere
0.04
evidence against global warming
natural flutactions in earth temperature
one way of measuring the link between co2 levels and climate
ice cores are drilled from glaciers which have co2 gases inside
how does deforestation impact on co2 levels
carbon sinks like rainforests are cut down
less co2 is removed from air by these trees co2 is also released
how do rising oceans temperatures affect co2 levels
co2 is less soluble in warm water
oceans less effective
what are methane levels rising 2
increased cattle farming
landfill sites = more methane released by decomposition
what is the greenhouse effect
sun emits short length radiation this passes through the greenhouse gases in the atmosphere
the earth heats up it emits infrared radiation to cool down this is absorbed by the gases
re radiated towards earth and heats it up
