Transcript Origin of Life Power Point - Panhandle Area Educational Consortium

Biology Partnership
(A Teacher Quality Grant)
Classification & Origin
October 26, 2013
Nancy Dow
Jill Hansen
Tammy Stundon
Gulf Coast State College
Panhandle Area Educational Consortium
5230 West Highway 98
753 West Boulevard
Panama City, Florida 32401
Chipley, Florida 32428
850-769-1551
877-873-7232
www.gulfcoast.edu
Our Approach
Q & A board
What is origin of life?
How did we get here?
How do we know?
Florida Next Generation Sunshine
State Standards
• SC.912.L.15.8 Describe the scientific
explanations of the origin of life on Earth.
(MODERATE)
– (Also assesses SC.912.N.1.3, SC.912.N.1.4,
and SC.912.N.2.1.)
Benchmark Clarifications
– Students will describe scientific explanations of the
origin of life on Earth.
– Students will identify situations or conditions
contributing to the origin of life on Earth.
– Students will identify ways in which a scientific claim is
evaluated (e.g., through scientific argumentation, critical
and logical thinking, and consideration of alternative
explanations).
– Students will assess the reliability of sources of
information according to scientific standards.
– Students will identify the criteria that differentiate
science from nonscience and pseudoscience.
Content Limits
– Items may address the conditions required for the origin of life on Earth but
may not require specific knowledge of the age of Earth or its eras, periods,
or epochs.
– Items may assess how contributions of scientists such as Pasteur, Oparin,
Miller and Urey, Margulis, or Fox aided in the development of the
scientific explanation of the origin of life but will not assess what each
scientist contributed.
– Items assessing the origin of organic molecules, chemical evolution, and/or
eukaryotic cells should be conceptual.
– Items may refer to the endosymbiotic theory but may not assess the term in
isolation.
– Items assessing a scientific claim are limited to the scientific explanations of the
origins of life on Earth.
Stimulus Attributes
None specified
Response Attributes
Responses in items referring to scientific claims, sources of
information, scientific inferences, and identifying what is
science should be specific to the context of the item instead of
generic statements.
Bell Ringer
• Big Bang  today
Millions of years ago versus Billions of years ago….
How to demonstrate to your students the difference.
Age example & Becker Bottles Demo
How Much is a Billion?
• 1,000 seconds = 16.7 minutes
• 1 million-s = 16,677 min = 11.6 days
• 1 billion-s
= 11,574 days = 31.7 years
• 1,000 pennies = ~ 88 ounces = 5.5 pounds
• 1 million pennies = 5,500 pounds (~1-Suburban)
• 1 billion pennies = 2,750 tons (~2 Space Shuttles)
Billion Grains of Rice
•
•
•
•
•
•
•
200 grains of rice in a teaspoon
9,600 grains of rice in a cup (48 tsp)
How many Cups are in a Gallon?
16 cups
How many grains of rice are in 16 cups?
9,600 x 16 = 153,600 grains of rice
How many gallons would it take to take to
equal 1 million grains of rice?
• 1,000,000 divided by 153,600 =
• 6.5 Gallons = 1 million grains of rice
• If 6.5 gallons equal 1 million how many
gallons would it take to equal 1 billion?
• 6.5 gallons x 1000 =
• 6,500 gallons = 1 billion
Chemical Evolution
(1 billion years)
Formation
of the
earth’s
early
crust and
atmosphere
Small
organic
molecules
form in
the seas
Large
organic
molecules
(biopolymers)
form in
the seas
Biological Evolution
(3.7 billion years)
Single-cell
prokaryotes
form in
the seas
Single-cell
eukaryotes
form in
the seas
Variety of
multicellular
organisms
form, first
in the seas
and later
on land
First
protocells
form in
the seas
Men in Black
Earth was very different
billions of years ago.
• There have been many hypotheses of the origins.
• The most widely accepted hypothesis of Earth’s
origins is the nebula hypothesis.
• It suggests that 4.6 billion years ago,
the sun formed from a nebula (a cloud
of gas and dust in space)
• Over time, most of the material in the
nebula pulled together due to gravity.
• Over millions of years, repeated
collisions of this space debris built up
into planets of our solar system.
THE EARLIEST LIFE ON EARTH?
Fossils of 3.4-billion-year-old
cells that may have been
among the first living
organisms on earth
THE OLDEST ROCKS ON EARTH-- THAT WERE FOUND IN
GREENLAND--ARE ABOUT 3.8 BILLION YEARS OLD. Recent
scientific discoveries possibly link back rocks to 4.4-4.6 b.y.a (in
Australia)
Early Earth Conditions
The early atmosphere differed from
that of today – very little water vapor
and no free-floating oxygen.
Early Earth:
Rough conditions.
• no ozone layer to
block harmful UV
radiation
• no troposphere
to control the
Earth’s thermostat
Early seas called the
“PRIMORDIAL
SOUP “— They
were filled with
chemicals that would
later build organic
compounds; molecules
of life as
Suggested by Oparin.
4.4 b.y.a early atm had just a little water vapor, but lots of
CO, CO2, H2, N2, NH3 (ammonia), CH4 (methane), H2S .
For life to form….
• Group of organized atoms (N, O, C, H, etc.) 
molecules (proteins, carbohydrates, water)  cells
(which is the smallest unit of life)
Cells 1) reproduce
2) grow and develop
3) respond to stimuli
4) obtain and use energy
5) made up of cell (s)
The Earth will need to increase the concentrations of
water and oxygen to support the life.
Theories of the origin of life
• Spontaneous Generation (abiogenesis) – life arises
for non-life; old theory that has been disproved.
– General experiment with meat
1668 Redi – disproved this common belief but only
for large organisms– his experiment:
• Still considered what are microorganisms as the
‘vital force of air’
1864 Pasteur – disproved the entire theory
On both macro and micro level…..
But still, where did life come from?
Life needs water and oxygen!
• There are different hypotheses of early cell
structure.
– iron-sulfide bubbles hypothesis- biological molecules
combined in compartments of hydrothermal vent
chimneys on the ocean floor. (these compartments acted
like the first cell membranes)
– lipid membrane hypothesis
lipid spheres could form
around a variety of organic
molecules giving rise to
the first true cells.
– meteorite
hypothesis- amino
acids may have
arrived on Earth
through meteorites
or asteroid impacts
The Oparin-Haldane Theory of the
Origin of Life
• According to their theory, life evolved in the oceans during a period when
the atmosphere was reducing - containing H2, H2O, NH3, CH4, and CO2, but
no free O2.
• Organic compounds were synthesized nonbiologically by ultraviolet light
energy, which in the absence of an ozone shield would penetrate the upper
layers of the ocean.
• Without free O2 to oxidize them, these organic molecules would be stable,
and would accumulate in a warm, dilute broth that has been nicknamed
"Haldane soup.“
• This Oparin-Haldane theory was a remarkably complete blueprint for the
ideas still held today. It was especially remarkable because in 1929 virtually
none of the biochemical details of the previous chapters were known.
THE UREY-MILLER EXPERIMENT
In 1953, Stanley Miller and Harold Urey developed a simple four-step
experiment that demonstrated how complex organic molecules could have
arisen in earth’s early environment.—IN THE ‘PRIMORDIAL SOUP’
OR AS DARWIN CALLED IT---THE ‘WARM LITTLE POND’—
conditions had to be just right for these organic molecules to form.
THE UREY-MILLER EXPERIMENT
1
2
They created a model of the chemicals present in the "warm little
pond" with the gases H2, CH4 (methane), and NH3 (ammonia)
Why does this sound familiar?
The atmosphere was subjected to sparks, to simulate lightning.
3
The atmosphere was cooled so that any compounds in it would
rain back down into the water.
4
They examined the water, looking for organic molecules.
Produce energy in the
absence of oxygen!
Electrical charge
2
1
3
Cool
4
Then they did the
experiment again:
Added N2 & CO2.
Results:
 ATP - Implication?
 Cytosine & Uracil Implication?
RNA came before
DNA!
Heat
No life was created.
1st experiment
results: 5 different
amino acids, urea,
and lactic acid
Implications?
Sidney Walter Fox
• The production of amino acids from inorganic
molecules
– 1964 Dr. Sidney Fox based his experiments off of the information found
in the Miller-Urey experiment.
• The creation of proteinoids
– He demonstrated that amino acids could spontaneously form
small peptides. These amino acids and small peptides could be
encouraged to form closed spherical membranes,
called proteinoid microspheres, which show many of the basic
characteristics of 'life
• The assembly of proteinoids into microspheres
What is the origin of life?
Even though scientifically the origin is uncertain, scientist do
know that the earliest life form had to have had:
1. Heterotrophic – cloudy atm, too much radiation for
photosynthesis or chemosynthesis
2. Anaerobes – live w/o oxygen in the atm (Earth was
acidic/plate disruptions)
3. Others? Single-celled, prokaryotic, asexual binary fission
And for life to rapidly evolve, oxygen was needed to first
develop the ozone layer (UV filter) and then to gather in
concentration in the troposphere for aerobic respiration
What developed to allow Oxygen to increase in concentration?
Ancient form of photosynthesis – used H2S instead of H2O
Stromatolites (cyanobacteria) changed that by utilizing the little H2O
vapor which released the oxygen; led to modern day photosynthesis.
O2  ozone layer  Oxygen in troposphere  more life, BOOM!
How Do Scientists Know the
Contents of the Ancient
Atmosphere and Age?
Most kids will say Carbon-14; but that is
really for fossils and we are discussing a time
billions of years before fossils!
• Ice Sheets can trap in gasses
• Radiometric dating – the breakdown
of an isotope
Radiometric Dating
Remember the proton is the defining characteristic of an element!
Overtime the element decays, thus converting into another element
 How much
Time to convert? 
1.25 billion years!
What is this called?
Decay of Candium
Species Timeline
Activity
Earth in 24 hours
Modern humans (Homo
sapiens) appear about
2 seconds before midnight
Age of
reptiles
Insects and
amphibians
invade the land
Age of
mammals
Recorded human history
begins 1/4 second before
midnight
midnight
Origin of life (3.6–3.8
billion years ago)
First fossil
record of
animals
Plants
begin
invading
land
noon
Evolution and
expansion of life
24 hour clock perspective
32
One Year Perspective
The Football Field Perspective
Endosymbiosis
Theory
• Dr. Lynn Margulis was
the first to claim the
endosymbiont nature of
mitochondria and
chloroplasts with a
handful of conclusive
evidence
Evidence of Endosymbiosis theory
• Chloroplast and Mitochondria
– Double membranes
• Outer membrane is of eukaryotic
origin
• Inner membrane is of prokaryotic
origin
– Single loop of DNA
– Reproduce by binary fission
– Have ribosomes of prokaryotic origin
– About the same size as prokaryotes
Video
Living Fossil
-
Establishes the understanding of who
determines extinction
Analysis of structures – possible missing
link
Reinforces reading and discussion
Nice transition into Natural Selection
Ask the students if this organism reminds
them of any cartoons characters…..
Scientist to Know!
Understanding Geological Time- Berkley
Video tutorials - history of earth, origin of life; Urey and Miller
EOC review from Pace HS – check these answers! Found wrong
answers with their scientist section – it is a pdf so I could not
make changes. Otherwise, still a very good source/format
Virtual lab Classifying organism into Kingdoms
Exploring Life’s Origins
Interactive Geologic Time Scale I
Interactive Geologic Time Scale II
The Evolution of Organelles
Follow up
•Q & A
•Post Test