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the Big Bang Theory
the universe began in a single instant 13 to 15 billion years ago. all existing matter and energy suddenly appeared and spread outward, gas condenses to form stars, planets formed from build up of dust and debris.
Precambrian Era
from Earth’s formation through about 90% of its history
Hadeon eon
hell-like, little to no oxygen
evidence of early water
zircon crystals 4.4 billion years ago provide the earliest of this…
Earth’s early atmosphere
was oxygen free
the organic subunits of life
amino acids, fatty acids, nucleotides, simple sugars
hypothesis of lightning fueled atmospheric reactions
fill a chamber with gases and zap with electricity, organic molecules formed
delivery from space hypothesis
meteorites that fell to earth held the molecules of life
reactions at hydrothermal vents hypothesis
the anaerobic environment of hydrothermal vents produced molecules of life
polymers to protocells
hypothesis of the earliest cells formed in a stepwise process beginning with inorganic materials
iron sulfur world hypothesis
life originated at deep-sea hydrothermal vents
RNA world hypothesis
RNA may have been first molecule to store genetic information
ribozyme
RNA can function like an enzyme in protein synthesis
protocell
Membrane-enclosed collection of interacting molecules that can take up material and replicate. permeability very well.
LUCA
last common universal ancestor, prokaryotic. Not the first cellular life, but the last shared ancestor of modern life
oldest cell microfossils
from canadian rocks ~3.77 billion years old
cyanobacteria
Oxygenation of Earth’s atmosphere was due to oxygen-releasing photosynthesis in
Oldest agreed-upon eukaryotic fossils are about
1.8 billion years old
protists
first eukaryotes
endosymbiont hypothesis
origin of mitochondria
endosymbiont
any organism that lives within the body or cells of another organism most often, though not always, in a mutualistic relationship
Nearly all eukaryotes have mitochondria, but only some have chloroplasts
so they were acquired independently
pathogen
cellular organism or virus that causes disease in its host.
virus
Noncellular, infectious particle that can replicate only in a living cell (its host), genome may be DNA or RNA
bacteriophages
Viruses that infect bacteria and inject their DNA
naked virus
are spherical viruses with protein coat having spikes.
enveloped virus
DNA or RNA Virus with an envelope made of lipid membrane derived from host cells. AIDS
retrovirus
a virus whose RNA genome is used as a template to produce
emerging viral diseases
those that have been only recently detected in humans or are now expanding their range. HIV,Zika, Ebola
prokaryotes
cells without a nucleus
bacteria cell shapes
rod, sphere, spiral
flagellum
Rotates like a propeller; does not contain microtubules, does not bend side to side
pili
hairlike filaments used to stick to surfaces and move
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