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Bio 1215-Chapter 1
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what is the best evidence about how our universe began?
began with a
"big bang" 13.7 billion
years ago
How old is the earth and the solar system?
more than
4.5 billion
years old
How did the earth and solar system form?
from the coming together of
pre-existing debris
joined by gravity
How did the elements settle in the earth?
settled by
density
in early earth
How old are the oldest rocks and how were they discovered?
oldest rocks over
4 billions
years old and discovered by
radioactive isotopes
when did surface water stabilize into oceans?
about
4 billion
years ago
what were the 5 major elements found in the surface and atmosphere?
N2
CO2
HCN
NH3
H2O
Very little O2
when did the origin of life begin?
more than 3 billion years ago
O2 is destructive to bonds in ____________ .
organic molecules
what are some things that define a living thing? List at least 7.
order
cells
reproduction
evolution
metabolism
ability to grow
transforms energy
homeostasis
respond to stimuli
How old are the oldest fossils?
3.1-3.7 billion
years
what are some evidence that life may have began earlier, before atmosphere stabilized? (2)
old fossils
ambiguous chemicals
why did the first organisms use a process other than cellular respiration to transform energy? what was the alternative?
because there was
very little oxygen
in the atmosphere
may have
released methane
how does methane and the green house effect relate?
methane
may have warmed the climate
via the green house effect
when did photosynthesis evolve?
more than 2.5 billion
years ago
which organism might have been the first to use photosynthesis?
cyanobacteria
what are stromatolites?
photosynthetic prokaryotes
what did photosynthetic bacteria add to the atmosphere and water bodies? what is the proof?
added
oxygen
rust
is evidence b/c oxygen was not present therefore no rust formed on metals
how did rising oxygen levels affect early life? why?
probably
poisoned
many kinds of early life because oxygen
very reactive
when did eukaryotes first appear?
about
2 billion
years ago
when did the first animals appear?
about
600 million
years ago
A great diversification of animals occurred in which period?
the Cambrian explosion
(all these animal groups were aquatic)
when did the first plants and fungi appear?
about 500 million
years ago
how old are humans?
about 200 000
years olds
what are 2 ways the earth is still changing?
climate is changing
(global warming)
species are
evolving
and going
extinct
what does the chemical origin of life suggest?
theory suggest that life began
abiotically
(ex. chemicals)
why is it unlikely that new forms of life are forming from simple chemicals today? (2)
lots of reactive oxygen around
(prevents molecules from combining into organic molecules)
existing organisms would consume organic molecules
before they could assemble into something more complicated
what are the 4 potential steps in the chemical origin of life?
abiotic synthesis of organic monomers
monomers being converted it polymers
origin of self-replicating molecules
(allowing for inheritance)
packaging into membrane-enclosed bags
what did Miller and Urey try to do?
tried to
recreate the conditions of the early earth
to test how monomers might have formed on the young earth
what did Miller and Urey find after their experiment?
found several amino acids had formed
Monomers forming into polymers is called?
dehydration synthesis
how can dehydration synthesis occur in the early earth?
can occur if
dilute monomer solutions drip onto hot rocks or sand
what natural elements can increase reaction rates? (2)
clay
: have polar and charged areas
some metals
: like iron in pyrite act as catalysts
what unnatural elements speed up reactions? (3)
heat
catalyst
concentration
what are 5 reasons of why RNA may have come before DNA?
single strand
short pieces can be made abiotically
is autocatalytic
binds to amino acids,
helping them to join
DNA is more stable
and must have come after
what are protobionts?
"pre-cells" (membrane bags)
how can protobionts be made abiotically?
phospholipids in water
what evidence could suggest that organic molecules got here from space?
amino acids
and
strings of sugars
have been found
in meteorites
what evidence could suggest that organic molecules began in the ice?
bits of
nucleic acids can be form
ed in ice in the lab
As water freezes, other molecules are concentrated into tiny __________________ within it.
liquid water bubbles
what element can be formed in the ice when in a lab?
bits of nucleic acids
Author
CanuckGirl
ID
256200
Card Set
Bio 1215-Chapter 1
Description
earth, living things
Updated
1/16/2014, 6:45:24 PM
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