Transcript Origins of Life Review

Origins of Life Quiz Review
Honors Biology
What Should I Study?
• Miller & Urey – their experiment, what they concluded
• Sequencing of origins of life to present day
• Prokaryotic vs. eukaryotic, anaerobic vs. aerobic,
heterotrophic vs autotrophic, unicellular vs
multicellular
• Oxygen was NOT present on early earth, formed later
from producers… then formed Ozone layer which
serves as a protection from the UV light now.
• Know how this production of oxygen (due to
photosynthetic organisms) changed our world!
Compare & Contrast…
Abiogenesis
Biogenesis
• a/k/a Spontaneous
Generation
• the idea that life can
arise from nonliving
material
• Examples
• the idea of life arising
from other living
organisms
• Examples
• mice come from
haystacks;
• Flies from rotting meat
– Cats make cats;
– humans make humans;
SEVERAL SCIENTISTS TRIED TO DISPROVE
ONE THEORY…
WHO WERE THEY?
WHAT WERE THEY TRYING TO DISPROVE
AND HOW DID THEY DO IT?
Which two
scientists created
the apparatus seen
here?
• Miller & Urey
Sequence these terms
•
•
•
•
POLYMERS
PRIMITIVE CELLS
SIMPLE ORGANIC COMPOUNDS (MONOMERS)
PROTOCELLS (PRE-CELLS)
Sequence these terms
• POLYMERS 2
• PRIMITIVE CELLS 4
• SIMPLE ORGANIC COMPOUNDS (MONOMERS) 1
• PROTOCELLS (PRE-CELLS) 3
What theory
were Miller and
Urey Testing?
• Theory of chemical
evolution
(Oparin/Haldane)
• the organic compounds
that made the first living
cells arose from chemical
reactions occurring on
primitive earth…
Miller and Urey tried to recreate the
atmosphere of…
• Primitive Earth
What does letter A
represent? Be Specific
in your description.
• Represents oceans –
boiling due to the
high heat conditions
of primitive earth
• Also created water
vapor which leads
into the next step
What gases were in the chamber “B”?
• Ammonia, hydrogen
and methane
Which gas was
notably absent?
• Oxygen!
What were the results of the Miller
Urey Experiment? (Letter E)
• Amino Acids (simple
organic compounds)
List 3 examples of energy sources on
Primitive Earth
1. Lightning
2. UV Radiation
3. Geothermal/Heat
Compare & Contrast…
Primitive Earth
• Lacked Free O2
• Extermely Hot
• Brown Oceans
• Pink Skies
• No life (originally)
• Abiogenesis…then
biogenesis
Modern Earth
• O2 & Ozone Layer
• Moderate
temperatures
• Blue Oceans
• Blue Skies
• Lots o’ life!
• Biogenesis only
THE EARLIEST CELLS…
Unicellular
Prokaryotic
Heterotrophic
Anaerobic
The earliest cells likely had RNA as the genetic
material.
Conditions for processes
that REQUIRE or USE O2
Conditions for processes
that DO NOT USE O2
Describe the differences between
Prokaryotes and Eukaryotes…
Prokaryotes
• LACK a nucleus
• Unicellular
• Do not have any
membranebound organelles
• Smaller, simpler
Eukaryotes
• Contain a nucleus
• Can be unicellular or
multicellular
• Contain membranebound organelles
• Larger, more
complex
Timing is everything
Be able to sequence these
events (each about a billion
years apart from each other)…
•
•
•
•
•
Important Dates!
• 10-20 billion years ago – Big
Bang
origin of the Earth (~4.5bya)
prokaryotic heterotrophs
• 4.5 billion years ago – Origin
(~3.5bya)
of Earth
prokaryotic autotrophs (first • 3.8 billion years ago – first
evidence of photosynthesis)
cells
(~2.5bya)
• 100,000-200,000 years ago
unicellular (single celled)
– modern humans (Homo
eukaryotes (~1.5bya)
sapiens)
multicellular eukaryotes
(~0.5bya)
Endosymbiosis
(hypothesis on the origin of
mitochondria and chloroplasts)
• https://highered.mheducati
on.com/sites/9834092339/s
tudent_view0/chapter4/ani
mation__endosymbiosis.html
•
Review the BBB •
• How did life on
Earth begin, and
how has it changed
over time?
• What are the 3
domains and 6
kingdoms into
which all living
organisms are
classified?
• How did prokaryotic
cells evolve into
eukaryotic cells?
•
•
•
•
•
•
•
Describe the conditions of the early Earth and the early
atmosphere.
Differentiate between biogenesis and abiogenesis and justify
why biogenesis prevails over abiogenesis on modern earth.
Explain how the conditions on early Earth may have led to
the formation of organic compounds, pre-cells (protocells)
and to the first cells.
Analyze Miller and Urey’s experiment in terms of its
purpose, design and results.
Rationalize the heterotroph hypothesis and the
endosymbiotic theory.
Infer whether the earliest life on Earth was likely aerobic or
anaerobic.
Weigh the significance of the evolution of autotrophs in
changing the conditions on early earth.
Provide evidence for the origin of mitochondria and
chloroplasts.
Construct an approximate sequence/timing of major points
in the evolution of life on earth from the origin of Earth
through the emergence of the human species.