Transcript Origin of Life

Beginning of Life
Early Earth= not a friendly place
Atmosphere was mostly methane,
nitrogren, water vapor, and ammonia…
nearly no oxygen
 The earth was very hot with many
volcanoes exploding at once
 Many thunder and lightning storms

Alexander Oparin

Believed that life began in the oceans.

He believed that sun and lightening made
organic molecules form.
 Rain
then washed these molecules into the oceans
and made a primordial soup.
Oparin’s hypothesis
Rain + earth’s heat + lightning + CO2=
life’s first lipid membrane in a shape of a
sphere
 The small sphere of lipid membrane is
called a protocell.
 These were located in the ocean and were
the very first beginnings of life.

Was he right?

Miller & Urey 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…

They found:
Carbohydrates, amino Acids, and other small
ORGANIC (living) molecules
 Small protocells

 This
evidence supported Oparin’s hypothesis.
Prokaryotes evolved to become
eukaryotes by endosymbiosis: Big
cells swallow little cells that
perform specific functions
Prokaryote
ingests aerobic
bacteria
Prokaryote
Aerobic bacteria
ingests
produces energy
cyanobacteria
inside
prokaryote 
Mitochondria
Cyanobacteria
contains
photosynthetic
pigments 
chloroplasts
The very first cells were autotrophs
They made their energy from the sun.
Because they were doing photosynthesis,
they were releasing oxygen into the
atmosphere.
This allowed more complicated life to
evolve.
Two other possible theories of where life began
Space!
Hydrothermal vents
Spontaneous Generation

Believed that simple living organisms
could come into being by spontaneous
generation.

non-living objects can give rise to living
organisms.
 It
was common “knowledge” that simple organisms
like worms, beetles, frogs, and salamanders could
come from dust, mud, etc., and food left out,
quickly “swarmed” with life.
Terms to Know
Prefix for life?
Bio-
Word for beginning?
Genesis
Biogenesis=beginning with life
Prefix for
without?
A-
Abiogenesis
Life beginning from
a non living thing
Spontaneous generation = abiogenesis
Some believed that
bees could form if you
left meat under your
house for 23 days
Virgil-Roman Poet
Others believed that if you left dirty clothes out for 7 days
rats would form
Jan Baptista van Helmont- physician in 1600s
Early Thoughts?
Spontaneous Generation- the idea
nonliving material can produce life
 1668- Francesco Redi

Disproved the idea that decaying meat
produced maggots (immature flies)
 Disproved the spontaneous
generation of large
organisms.

The first true experiment?
Open Jars
Francesco Redi -1600s Italian scientist
Disproves spontaneous
generation
Closed Jars
Even with different types of meat
closed jars=no maggots
Did this show that life did not
come from non-life?
Vital Source

Scientists thought that there must be a
vital source in the air that makes
microscopic organisms grow.
In the mid 1800’s Louis Pasteur designed an
experiment that disproved the spontaneous
generation of microorganisms.
 In his experiment air, but not microorganisms
could touch the broth.

Louis Pasteur

French Scientist, who in 1859 finally
disproved spontaneous generation
Pasteur’s Experiment
Biogenesis

This experiment led to the idea that:

Living organisms come only from other
organisms.

But how did life START on Earth?
 How
ago?
does life come from non-life 4.6 billion years
Molecules of the Atmosphere
Carbon Dioxide
Hydrogen Cyanide
(HCN)
Create your own Primordial Soup
Cans
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 Theory
 Individuals
can
evolve to adapt
to changing
conditions
(acquired
traits)
Darwin’s Theory
Traits that help in
survival are passed
on to offspring
 Traits that do not
help in survival are
lost from the gene
pool

Darwin’s Theory of Natural Selection
1. There is variation in
individuals.
2. Living things overreproduce.
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?
https://www.youtube.com/watch?v=ewtw_
nZUIDQ

Why does evolution matter now?
 https://www.youtube.com/watch?v=WWumllRPLI
