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Classification & OriginOctober 26, 2013

Nancy DowJill 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

Biology Partnership

(A Teacher Quality Grant)

Our ApproachQ & 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

Formationof theearth’searly

crust andatmosphere

Small organic

moleculesform in

the seas

Large organic

molecules(biopolymers)

form inthe seas

First protocells

form inthe seas

Single-cellprokaryotes

form inthe seas

Single-celleukaryotes

form inthe seas

Variety ofmulticellularorganismsform, first

in the seasand lateron land

Chemical Evolution(1 billion years)

Biological Evolution(3.7 billion years)

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 INGREENLAND--ARE ABOUT 3.8 BILLION YEARS OLD. Recent scientific discoveries possibly link back rocks to 4.4-4.6 b.y.a (in Australia)

The early atmosphere differed from that of today – very little water vapor and no free-floating oxygen.

Early Earth Conditions

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 .

Early Earth: Rough conditions. • no ozone layer to block harmful UV radiation • no troposphere to control the Earth’s thermostat

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) reproduce2) grow and develop3) respond to stimuli4) obtain and use energy5) 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 theoryOn 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.

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

THE UREY-MILLER EXPERIMENT

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.

The atmosphere was cooled so that any compounds in it would rain back down into the water.

They examined the water, looking for organic molecules.

2

3

4

1

1

2

3

4

1st experiment results: 5 different amino acids, urea, and lactic acid

Heat

Electrical charge

Cool

Implications?

Then they did the experiment again: Added N2 & CO2.Results:

No life was created.

ATP - Implication? Produce energy in the absence of oxygen! Cytosine & Uracil -Implication? RNA came before DNA!

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 chemosynthesis2. 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 DatingRemember the proton is the defining characteristic of an element!Overtime the element decays, thus converting into another element

How muchTime to convert?

1.25 billion years!

What is this called?

Decay of Candium

SpecieS Timeline AcTiviTy

Earth in 24 hours

32

Plants begininvadingland

Evolution and expansion of life

First fossilrecord ofanimals

Age of reptiles

Age of mammals

Insects and amphibians invade the land

Modern humans (Homo sapiens) appear about2 seconds before midnight

Recorded human history begins 1/4 second before midnight

Origin of life (3.6–3.8 billion years ago)

noon

midnight

24 hour clock perspective

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 remindsthem 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