module 5 Flashcards
(35 cards)
how long ago did earth form
4.6 billion years ago
why was it inhospitable?
-too hot
-meterors and lightining
-volcanoe gases
how long ago did earch cool down?
and what were the important changes?
answer 1: about 3.5 billion years ago
answer 2:
-volcanic gases disipated
-no o2 only lots of co2
-cooling allowed water to form and other stuff
what are the 4 main EONS to present day
hayden [precambrian supereon]
-oceans began to form
archean [precambrian supereon]
-land raised up
proterozoic [precambrian supereon]
-more land forming
phanerozoic
what 3 ERAs make up phanerozoic?
- paleozoic
- mesozoic
- cenozoic
what are the key molecules and macromolecules that all living cells contain?
-DNA
-RNA
-protiens
“abiogenesis”
origin of life
where did life begin?
in the oceans
what 4 thing was needed to form a living cell?
- organic molecules
- nucleotides and amino acids polymerized
- polymers became enclosed in membranes
- protobionts evolved cell properites
what are some hypothesis’ that explain the origin of life (step 1 in recipe)
- extraterrestrail
- reducing hypothesis (didnt form life)
-urey and millar - deep sea vents
-pressure bomb experiment
- GUNTER
was the black smoker system or lost city system better for first life
lost city (white smokers) was more suitable
what did Oparin and Haldane propose in 1920’s
organic molecules spontaneously formed
[primordial soup]
(step 2 in recipe) how did nucleotides and amino acids become polymerized?
monomer (nucleic acids) —-> polymerized
*happend using clay cuz no enzymes
(step 3 in recipe) polymers become enclosed in membranes
polymers become enclosed in membranes
examples that could natuarally occur
-coacervates (with water)
- microspheres (protien membranes)
- liposomes (lipid membranes)
what is a photobiont
first non living thing enclosed with organic molecules [precusor to life]
(step 4 in reciepe) membrane bound polymers acquire cellular properties
formation of dna and rna in photobionts
anaerobic heterotrouphs
first prokaryotes 4 billion years ago
metabolized organic molecules by fermentation or methogenesis
anaerobic chemoautotrouphs
uses redox reactions with things like sulfur to reduce CO2
anaerobic photoautotrouphs
uses photons and suflur to reduce CO2
aerobic photoautotrouphs
now that water is available it uses photons and uses H2O as the last electron donor
what is evidence of cyanobacteria dominating the oceans?
- cyanobacteria grow in large mats and create layers of CaCO3 and sediment
- as successive layers are deposited, more cyanobacteria grow beyond each layer to reach sunlight
- STROMATOLITES: found in hyper-saline environements
what are stromatolites
vertically layered mats of cyanobacteria
why is multicelluar an advantge
endosymbyosis
LUCA
last universal common ancestor