Topic 11 Flashcards
The earliest fossils (~3.5 BYO) are of what cells?
Cyanobacteria and Stromatolites
-not just physical structures, but also chemical ones
What kind o fossils are there still today?
Cyanobacteria
Most of these fossil genera are recognizable in early rocks
Stomatolite
Are still alive today
Microfossils and Stromatolite
- Shark Bay, Australia
- Hot springs in yellowstone
Wasn’t the only organism alive, was a population that gave rise to all life and represents a phylogenetic point
Last Universal Common ancestor (LUCA)
we can not peer beyond it and see what life was like before it
phylogenetic end point ( event horizon)
ability to adjust the internal environment to maintain a stable equilibrium
Homeostasis
ability to maintain distinct part and the connections between them
Structural organization
the control of chemical reactions
Metabolism
producing life individuals
growth and reproduction
response to environmental conditions and stimuli and has to be able to evolve by NS, at least this planet
-growth and reproduction
-Stimulate the early atmosphere in a small scale in the lab
-Electricity and gasses (methane, hydrogen, ammonia, and water)
-Thought best to represent early atmosphere ~4 BYA
-Depending on starting gasses, numerous common amino acids formed
late the early atmosphere in a small scale in the lab
Miller-Urey Experiment
Problems with this
-Not much ribose (sugar) -produced – critically important
-And the amino acids weren’t linked together as in proteins
present via previous experiments or came on meteors, existed in the prebiotic environment
Phosphate,purines, pyrimidines
-if they bound together a primitive RNA organisms could have formed.
Early ‘80’s – Cecg and Altman independently
Enzymes need not be proteins
RNA can act as an enzyme
- Much less stable an efficient than proteins
Ribozymes
allows for specialization, acts as the storage molecule
DNA