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44 Cards in this Set

  • Front
  • Back
What did the first life on Earth breathe?
CO2
What was the first life on Earth?
cyanobacteria
Water and other volatiles came from...
comet impacts
Did we have the right elements?
yes
blank + blank make amino acids
these elements plus lightning
DNA may have originated from these acids in a _______
clay matrix
Reproduction occurs via.....
DNA
Evolution with a capital
E
3 causes of mutation
1. Radiation (all those rock decays; cosmic rays)
2. Chemical contamination
3. “Transcription errors”
Define Senescence
Biological Aging
Define Apoptosis
Programmed Cell Death
Define Unregulated Cell Division
leads to a tumor or cancer
Define natural selection
those with competitive “edge” more likely to succeed in reproducing; those without are less likely
examples of natural selection
1. TB bacteria and antibiotics
2. cockroaches and insecticide
3. light/dark pepper moths in England
Requirements for Mutational Evolution
MANY INDIVIDUALS (AT LEAST ONE QUADRILLION)
SMALL BODY SIZE (LESS THAN TWO CM.)
SHORT GESTATION PERIOD (LESS THAN THREE MONTHS)
LARGE NUMBER OF PROGENY
Hoyle - what did he think?
the probability of cellular life evolving were about one-in-1040000. He commented: The chance that higher life forms might have emerged in this way is comparable to the chance that a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials therein.
Talk to me about Shapiro and Genomes
not really the static "beads on a string" Rather, they are fluid and complex.now seen as multipurpose elements that turn on and off as required for the survival and well-being of the organism they belong to
Stromatolites
Large agglomerations of single-celled organisms
Stromatolites first form
microbial mats

(produces layered fossils)
Do Stromatolites still exist today?
yes
Why at 2.5 GYA did the O2 level jump?
LOTS of cyanobacteria and other CO2 breathers
How did this work chemically?
liberated O2 from CO2
Prokaryotes
simple structure, no nucleus
Endosymbiotic theory
Idea that complex eukaryotes formed from symbiotic relationship between simpler prokaryotic cells
In other words, big cell “encapsulates” smaller specialized prokaryotes which form mitochondria, chloroplasts, etc.
4 examples of evidence of endosymbiotic theory
1. Mitochondria have their own DNA, which is unlike nuclear DNA but similar to prokaryote DNA
2. Chloroplasts actually resemble cyanobacteria
3. “Main cell” offered nucleus which stores most of the mitochondria/plastid DNA in a more “protected” environment
4.Laboratory observations of endosymbiotic relationships developing between some algaes and prokaryotes
Single-Celled Evolution
Move from cyanobacteria (simple) to green algae (complex)
From prokaryote to eukaryote
Eukaryotes have 10x to 1,000x more DNA (information for complex structures)
600 MYA
start seeing a range of multi-cellular organisms
The Ediacaran Fauna
Small fossils (typically a few mm to a few cm)
Cyclomedusa
common fossil round symetry
Tribrachidium
3-fold symmetry
Spriggina
bilateral symmetry - shows animal features
Ediacaran Properties
All “soft-bodied” – vaguely reminiscent of jellyfish and anemones
For early ones, not sure if the moved around or not – could be “filter feeders”
the Burgess Shale
fossil deposit in Northern Canada
Trilobites
found in the Cambrian

Armor
Legs
Mouth
Eyes (!!)
The Cambrian Explosion
only in bodies of water
enabled by sudden massive amount of O2
Permian Period
Earth would now have been “recognizable

Land has immense forests of trees and other plants (but no flowers!)
Pangea
new supercontinent formed about one every 500 million years
Permian Extinction (The Great Dying)
Overall mortality of living creatures even for “survivor” species might have been >95-99%
Fungal spike
Why did the Permian Extinction Occur?
Glaciation of Gondwana
Simultaneous glaciation of the poles
Volcanoes
Formation of Pangaea
Mesozoic
follows Permian extinction
Mesozoic period brought us
angiosperms, and mammals
The Cretaceous-Tertiary (K-T) extinction
Alvarez and alvarez came up with the KT theory that a meteor hit and caused dust to come up and kill all life
Chicxulub
Evidence of the crater
Tunguska
airburst in Russia