Beginning of LifeBeginning of Life

Early Earth= not a friendly placeEarly Earth= not a friendly place

Atmosphere was mostly Atmosphere was mostly methane, methane, nitrogren, water vapor, and ammonianitrogren, water vapor, and ammonia… … nearly no oxygennearly no oxygen

The earth was very The earth was very hothot with many with many volcanoes exploding at oncevolcanoes exploding at once

Many Many thunder and lightning stormsthunder and lightning storms

Alexander OparinAlexander Oparin

Believed that life began in the oceans.Believed that life began in the oceans.He believed that sun and lightening made He believed that sun and lightening made

organic molecules form.organic molecules form.Rain then washed these molecules into the oceans Rain then washed these molecules into the oceans

and made a and made a primordial soup.primordial soup.

Oparin’s hypothesisOparin’s hypothesis

RainRain + + earth’s heatearth’s heat + + lightninlightning + g + COCO22= =

life’s first lipid membrane in a shape of a life’s first lipid membrane in a shape of a spheresphere

The small sphere of lipid membrane is The small sphere of lipid membrane is called a called a protocellprotocell. .

These were located in the These were located in the oceanocean and were and were the very first beginnings of life.the very first beginnings of life.

Was he right?Was he right?

Miller & UreyMiller & Urey tested Oparin’s hypothesis tested Oparin’s hypothesis

Water vapor, ammonia, methane, Hydrogen

Add electricity

Cool mixture to produce liquid

Collect & analyze

The Miller-Urey Experiment

Organic molecules appear here

After one week…After one week…

They found:They found:Carbohydrates, amino Acids, and other small Carbohydrates, amino Acids, and other small

ORGANIC (living) molecules ORGANIC (living) molecules Small protocellsSmall protocells

This evidence supported Oparin’s hypothesis. This evidence supported Oparin’s hypothesis.

Prokaryotes evolved to become Prokaryotes evolved to become eukaryotes by endosymbiosis: eukaryotes by endosymbiosis: Big Big

cells swallow little cells that cells swallow little cells that perform specific functionsperform specific functions

Prokaryote ingests aerobic bacteria

Aerobic bacteria produces energy inside prokaryote

Prokaryote ingests cyanobacteria

Cyanobacteria contains photosynthetic pigments

Mitochondria

chloroplasts

The very first cells were The very first cells were autotrophsautotrophs

They made their energy from the They made their energy from the sunsun..

Because they were doing photosynthesis, Because they were doing photosynthesis, they were releasing they were releasing oxygenoxygen into the into the atmosphere.atmosphere.

This allowed more complicated life to This allowed more complicated life to evolve.evolve.

Two other possible theories of where life began

Hydrothermal vents

Space!

Spontaneous GenerationSpontaneous Generation

Believed that simple living organisms Believed that simple living organisms could come into being by spontaneous could come into being by spontaneous generation. generation. non-living non-living objectsobjects can give rise to living can give rise to living

organismsorganisms. . It was common “knowledge” that simple organisms It was common “knowledge” that simple organisms

like worms, beetles, frogs, and salamanders could like worms, beetles, frogs, and salamanders could come from dust, mud, etc., and food left out, come from dust, mud, etc., and food left out, quickly “swarmed” with life. quickly “swarmed” with life.

Terms to Know

Prefix for without? A-

Word for beginning? Genesis

Prefix for life? Bio-

Biogenesis=beginning with life

Life beginning from a non living thing

Abiogenesis

Spontaneous generation = abiogenesis

Virgil-Roman Poet

Some believed that bees could form if you left meat under your house for 23 days

Jan Baptista van Helmont- physician in 1600s

Others believed that if you left dirty clothes out for 7 days rats would form

Early Thoughts?Early Thoughts?

Spontaneous Generation- the idea Spontaneous Generation- the idea nonliving material can produce lifenonliving material can produce life

1668- Francesco Redi1668- Francesco RediDisproved the idea that decaying meat Disproved the idea that decaying meat

produced maggots (immature flies)produced maggots (immature flies)Disproved the spontaneousDisproved the spontaneous

generation of large generation of large

organisms.organisms.

The first true experiment?Open Jars

Closed Jars

Francesco Redi -1600s Italian scientist

Did this show that life did not come from non-life?

Even with different types of meat closed jars=no maggots

Disproves spontaneous generation

Vital SourceVital Source

Scientists thought that there must be a Scientists thought that there must be a vital source in the air that makes vital source in the air that makes microscopic organisms grow. microscopic organisms grow. In the mid 1800’s Louis Pasteur designed an In the mid 1800’s Louis Pasteur designed an

experiment that disproved the spontaneous experiment that disproved the spontaneous generation of microorganisms.generation of microorganisms.

In his experiment air, but not microorganisms In his experiment air, but not microorganisms could touch the broth. could touch the broth.

Louis PasteurLouis Pasteur

French Scientist, who in 1859 finally French Scientist, who in 1859 finally disproved spontaneous generationdisproved spontaneous generation

Pasteur’s Experiment Pasteur’s Experiment

BiogenesisBiogenesis

This experiment led to the idea that:This experiment led to the idea that:Living organisms come only from other Living organisms come only from other

organisms. organisms.

But how did life START on Earth?But how did life START on Earth?How does life come from non-life 4.6 billion years How does life come from non-life 4.6 billion years

ago?ago?

Molecules of the Atmosphere

Carbon Dioxide

Hydrogen Cyanide (HCN)

Create your own Primordial Soup Create your own Primordial Soup CansCans

Include:

1. Ingredients

2. How to make it

An early theory of evolution was proposed

by Jean Lamarck

Lamarck proposed organisms acquired traits during their lifetime and passed them on to their offspring. This is known as Lamarckism.

What is wrong with this theory?

Lamarck’s TheoryLamarck’s Theory

Individuals can Individuals can evolve to adapt evolve to adapt to changing to changing conditions conditions (acquired (acquired traits)traits)

Darwin’s TheoryDarwin’s Theory

Traits that help in Traits that help in survival are passed survival are passed on to offspringon to offspring

Traits that do not Traits that do not help in survival are help in survival are lost from the gene lost from the gene poolpool

Darwin’s Theory of Natural Selection

1. There is variation in individuals.

2. Living things over-reproduce.

3.There is a struggle to survive.

4.Those that survive are the most fit.

Who was Charles Darwin?How Does Evolution Really Work?How do we know Evolution Happens? How do we know Evolution Happens?

https://www.youtube.com/watch?v=ewtw_nZUIDQ

Why does evolution matter now?Why does evolution matter now?https://www.youtube.com/watch?v=W-https://www.youtube.com/watch?v=W-

WumllRPLIWumllRPLI