Origin of Life

Remember:Remember:

•Spontaneous Generation: Spontaneous Generation: Francisco RediFrancisco Redi

Origin: Early Ideas

Redi’s Experiment:Redi’s Experiment:

Not REJECTED until mid-1800’s

•Only Only living living organisms organisms can produce other can produce other livingliving organisms. organisms.

*Experiment done by *Experiment done by Louis PasteurLouis Pasteur

Theory of Biogenesis:

Pasteur’s Experiment:

Broth is boiled Broth is freeof microorganismsfor a year.

Curved neck isremoved.

Broth is teeming with microorganisms.

Conclusively Conclusively disproveddisproved the the hypothesis of spontaneous hypothesis of spontaneous

generationgeneration

Big Bang Theory•Theory about origin of the universe (Earth)

•Universe formed approx. 13.7 billion years ago

Earth’s Early History

•Densest elements pulled to core – gravity

•Many meteorites

When did “life” begin?

•Approx. 3.5 – 3.9 billion years ago

•1st organisms were prokaryotic & lived in extreme conditions

•Theory: explanation of a natural phenomenon based on many observations & experiments

How did “life” begin?

1.Extraterrestrial Origin

•Asteroid…not alien•Carried amino acids

3.5 byo fossilized cyanobacteria

2. Primordial SoupEnergy + Atoms = Life

2. Primordial Soup (cont)

•97% of organisms contains the elements

•These elements combine to form “life” ingredients

C H N O P S

Miller-Urey Experiment

•Water

•Methane

•Ammonia

•Hydrogen

RESULT = Amino Acids

Hydrothermal Vents

•Modern prokaryotes called Modern prokaryotes called “archaea”“archaea” are the closest are the closest living relatives of Earth’s living relatives of Earth’s first cells. first cells.

•Found:hot springs or Found:hot springs or volcanic vents in the deep volcanic vents in the deep sea.sea.

Hydrothermal Vents

Creation•Religious, not scientific theory

•Eukaryotes formed Eukaryotes formed from afrom a symbioticsymbiotic relationship with relationship with several differentseveral different prokaryotic prokaryotic organismsorganisms. .

Endosymbiotic Theory:Endosymbiotic Theory:

Endosymbiotic Theory:Endosymbiotic Theory:

•Lynn Margulis – 1960’s Lynn Margulis – 1960’s

•Evidence: Evidence: mitochondriamitochondria and and chloroplastchloroplast similar similar DNA to bacteria.DNA to bacteria.

Endosymbiotic Theory:Endosymbiotic Theory: