Theme 5C Flashcards
What was in the early earth atmosphere
the was little oxygen.
oxidation was prevented due to the small amount of it and other gases like methane ammonia, etc.
An input of energy (lighting) would transform these gasses to primordial soup
What was the Urey miller experiment
It was used to simulate the early conditions of earth and the chemical origins of life
Recreated what they thought were the gases in early earth and oceans (water vapour)
Provided energy source (lightning) to catalyze chemical reactions
They found that 50 percent of carbon in their experiment was found in more complex molecules than what they started with an 2 percent was in amino acids
What did the Urey miller experiment help with
You can recreate organic molecules through this
How do deep sea organisms get energy if they aren’t exposed to light
Hydrogen sulphide, a reducing molecule, makes atp
What happened through the arches to preteozoic eras
Went from prokaryotes to eukaryotes to multicellularity
When and where were the first prokaryotes seen
3.2 to 3.4 billion years ago from Canada South Africa and Australia
Found in stromatolites (thing that forms when Cyanobacteria form a biofilm that traps layers of sediment)
How do Cyanobacteria get energy, was was the effect of this
Through photosynthesis
The byproduct of their photosynthesis was gaseous oxygen which converted the earths reducing atmosphere to an oxidizing one
What was the great oxygenation event
Due to photosynthetic organisms, oxygen accumulates in atmosphere
This lead to a change in the number of rock types, more hydrated and oxidized minerals
What was there a long gap before the atmosphere became O2
Because there was a long period of anoxygenic photosynthesis, not using oxygen
The oxygen that they do release reacted with the ocean chemistry, not into the atmosphere
Oxygen was also reacting with iron and sulphur to form these rocks
Then the environment gets oxygen rich
How did the first eukaryotes come about
As more and more oxygen shows up in atmosphere, eukaryotes start to form
What is endosymbiosis
Origin of eukaryotes is symbiosis between archaea and bacteria
What is the evidence for endosymbiosis
Eukaryotic organelles are bound by membranes
Organelles have own dna separate from dna in nucleus
Similar dna sequences
Reproduction is the same: replicate by pinching cells
What was the ediacarian fauna
A region of time when there was lots growth in Multicellular life, happened after eukaryotes were formed
First animals forming during this period
What was the Cambrian explosion
Rapid appearance of many different organisms
Appearance of soft shelled organisms
Many midterm feature appear like heads mouths eyes legs
Why was there so much more life in the Cambrian explosion?
The increasing O2 levels (from algae) allowed higher metabolic rates and larger body size
Evolved the algae and made algal mats on ocean floor. Now the thing have mouths they can eat this algae and make new niches for themselves
More production of calcium carbonate allow the synthesis of shells and bones
