• 13,600 years ago
• Galaxies are moving away from us
• Black hole areas of intense gravitational pressure
particles collide rise in
WHAT DO YOU THINK EARLY EARTH WAS
• HOW OLD?
• 4.5 BILLION YEARS
• BIG BANG - GRAVITY CAUSES DUST PARTICLES TO
• METEORS FOR MILLIONS OF YEARS - HOW HOT
WOULD THE EARTH BE?
• EARTH HAS TO COOL DOWN - STEAM ESCAPES
AND RAIN ALLOWS COLLECTION OF WATER -
EARTH NOW HAS……
• ATMOSPHERE OF AMMONIA, METHANE,
WATER VAPOR, CO2, AND NITROGEN
• WHAT IS MISSING? No O2 Too reactive
1st organic molecules didn’t
• The energy for forming the organic
molecules was provided by:
– frequent thunder storms and lightning strikes
– volcanic activity
– meteorite bombardment
– high temperatures due to
– UV radiation
(no ozone so was extreme)
The organic molecules may have been generated on
Earth or introduced from space????
HOW WERE THE FIRST CELLS MADE?
• DOES ANYONE KNOW FOR SURE?
• SPONATEOUS GENERATION VS BIOGENESIS
Tales of Miletus/Aristotle 4 elements
• FRANCESCO REDI
• LOUIS PASTEUR’S EXPERIMENT
Pasteur filled a flask with medium, heated
it to kill all life,and then drew out the neck
of the flask into a long S.
This prevented microorganisms in the air
from entering the flask, yet allowed air to
flow freely. If the swan neck was broken,
microbes could enter the flask and grow.
Earth’s atmosphere was ‘reducing’ in the
early days. It did not contain oxygen gas
until after plants started photosynthesising
The gases came from
abundant volcanic activity
• ALEXANDER OPARIN - CREATION OF
• STANLEY MILLER AND HAROLD
RAIN OCEANS LIPIDS
• FIRST BACTERIA AROUND 3.5 BILLION YEARS AGO
• SOME ARE CYANOBACTERIA - THESE ARE
• WHAT ARE THESE BACTERIA GOING TO PRODUCE?
• ALMOST 10% ABOUT 2.5 BILLION YEARS AGO
• WHAT TYPE OF CELLS ARE BACTERIA?
• WHAT TYPE OF CELLS ARE ALL OTHER ORGANISMS?
• WHERE DID EUKARYOTIC CELLS COME FROM?
ONE CELL ORGANISMS NOW!
BEGINNING OF THE EUKARYOTIC CELLS
• EVIDENCE FOR ENDOSYMBIOSIS
Life introducedfrom outer space!!!
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
• Panspermia- “seeds everywhere”
– Life came from space on comets
• Hydrocarbons, amino acids, water(s) and bacteria
Fixism is is the theory that says that life on earth has
always been composed by the species we have today.
Creationism is a religious form of fixism. A supernatural
being created the world the way we see it.
Binomial nomenclature/ father of
the rules of
• First Evolutionist
• Acquired traits can be inherited NO!!!
• Use and Disuse
– Organisms change as their
• Published “Origin of Species”
• Traveled around the world in the Beagle
• He proposed that:
– Organisms produce more offsprings than the available
resources can support
– Organisms fight for limited resources like food, territory, and
other necessities of life. Only those who survive can produce
their own offspring
– Variation exists within species.
– Natural Selection - The environment
selects organisms with beneficial traits
Gradual change from one form to
another through a period of time
The environment selects organisms with beneficial
A form modified to fit a changed
- The environment induces the organisms to change.
- These changes are always positive (perfection drive)
- Use and disuse.
- Inheritance of acquired characters (ALSO SHARED BY
- Pre-existing variation
- Not all the variations are equally adaptative in a given
-S truggle to survive: The best adapted survive and leave more
offspring:the next generation will be better adapted (survival of
Evidence of Evolution
• Any preserved part or tissue of an organism that
The mold is filled
leaves that form
replace the hard
• Indicate that some
organisms have similar
DNA sequences, which
suggest common ancestry