Download - 3ero 1 historyof life mine
What are the theories that explain
life?
Life Sciences-HHMI Outreach. Copyright 2006 President and Fellows of Harvard College.
Big Bang• 13,600 years ago
• Galaxies are moving away from us
• Black hole areas of intense gravitational pressure
particles collide rise in
temperature
quarksProtons
neutronselectronsatoms
H He
(hellium)
Temperature fell
Matter concentrated
temperature
cooled down
WHAT DO YOU THINK EARLY EARTH WAS
LIKE?
• HOW OLD?
• 4.5 BILLION YEARS
• BIG BANG - GRAVITY CAUSES DUST PARTICLES TO CONDENSE
• 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
oxidize
• The energy for forming the organic
molecules was provided by:
– frequent thunder storms and lightning strikes
– volcanic activity
– meteorite bombardment
– high temperatures due to
greenhouse gases
– 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
LOUIS PASTEUR
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.
BiogenesisEarth’s atmosphere was ‘reducing’ in the
early days. It did not contain oxygen gas
until after plants started photosynthesising
The atmosphere
contained: Hydrogen
Nitrogen
Water vapor
Methane
Ammonia
Hydrogen sulfide
The gases came from
abundant volcanic activity
• ALEXANDER OPARIN - CREATION OF MACROMOLECULES WITHOUT OXYGEN (BIOGENESIS)
• STANLEY MILLER AND HAROLD UREY EXPERIMENT
COACERVATES
With RIBONUCLEIC
ACIDS (multiplication)
ORGANIC
MOLECULES
RAIN OCEANSLIPIDS
+PROTEINS
=
MEMBRANE
• FIRST BACTERIA AROUND 3.5 BILLION YEARS AGO
• SOME ARE CYANOBACTERIA - THESE ARE
PHOTOSYNTHETIC BACTERIA
• 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?
• ENDOSYMBIOSIS
ONE CELL ORGANISMS NOW!
Their own
food+ O2
PROKARIOTS
UNICELLULAR
Mammals
Flatworms
Annelids
Insects
Coelenterates
Fish
Birds
Reptiles
Crustacea
Amphibia
Single celled
organisms
Monocots Herbs Shrubs Trees
Dicots
Flowering plantsConifers
Mosses
Liverworts
Algae
Ferns
Fungi
Multicellular
plantsMulticellular
animals
Mollusc
Life introduced from 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.
Fixism vs Evolutionism
Binomial nomenclature/ father of
modern taxonomy
the rules of
heredity/ genes
Lamarck’s Theory
Fixism vs Evolutionism
• First Evolutionist
• Acquired traits can be inherited NO!!!
• Use and Disuse
• Adaptation
– Organisms change as their
environment changes
Darwin’s Theory
• 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
traits
A form modified to fit a changed
environment
Lamarck's theory
- The environment induces the organisms to change.
- These changes are always positive (perfection drive)
- Use and disuse.
- Inheritance of acquired characters (ALSO SHARED BY
DARWIN!!!)
Darwin's theory
- Pre-existing variation
- Not all the variations are equally adaptative in a given
environment.
-S truggle to survive: The best adapted survive and leave more
offspring:the next generation will be better adapted (survival of
the fittest)
Types of Fossils
Casts
The mold is filled with another
material
Molds
Hard body structures
Imprints
Feathers and leaves that form impressions on
rocks
Petrified Fossils
When minerals replace the hard
parts of organisms
Biochemical Evidences
• Indicate that some
organisms have similar
DNA sequences, which
suggest common ancestry
DNA
OTHER EVIDENCE OF EVOLUTION
– EMBRYOS
– VESTIGIAL STRUCTURE
APPENDIX- COCCYX-PLICA
SEMILUNARIS(eye)- MUSCLES OF THE
EAR- GOOSE BUMPS-PALMAR GRASP
REFLEX
• GEOGRAPHIC ISOLATION
• REPRODUCTIVE ISOLATIONWHAT IS
SPECIATION?
A SPECIES is A group of individuals with similar features that
can interbreed (exchange
genes) and produce a fertile offspring