Transcript EVOLUTION
EVOLUTION
EVOLUTION
The process of change through time.
Evidences of Evolution
Fossils-the remains of a once living organism
Types
of fossilization:
Petrification
Imprint
Tar/Ice/Amber
FOSSILS
Fossils always form in sedimentary rock
with the older organisms in the deeper
layers.
FOSSIL LAYERS
PETRIFIED FOSSIL
PETRIFIED WOOD
TAR
AMBER
IMPRINT
COMPARATIVE STUDIES
Evidence for evolution is also found by
comparing:
Embryology
Biochemistry
Cytology
Anatomy
COMPARATIVE EMBRYOLOGY
COMPARATIVE EMBRYOLOGY
Animals go through similar stages of
embryological development.
This
may show that they are related and may
share common ancestry
COMPARATIVE BIOCHEMISTRY
Organisms have similar chemicals, which
may show common ancestry.
Ex.
Hormones
are similar in many species.
Everything contains DNA.
Similar protein structure and construction.
Use ATP
….
COMPARATIVE CYTOLOGY
The study of cells is CYTOLOGY.
All
living things are made of cells, therefore,
they may share a common ancestor.
COMPARATIVE ANATOMY
Comparing the structures of different
animals to find similarities.
Homologous
Structures
Analogous Structures
Vestigial Structures
HOMOLOGOUS STRUCTURES
Structures having a similar origin, but are
adapted for different purposes.
Ex.
Human arm and whale flipper
Same structure-Different function
HOMOLOGOUS STRUCTURES
ANALOGOUS STRUCTURES
Structures are different but have the same
basic function.
Ex.
Bee wing and Bird wing
Different structure-Same function
VESTIGIAL STRUCTURES
Structures that presently have no known
function, but may once have been
needed.
Ex.
Tonsils, appendix, whale, snake
THEORIES OF EVOLUTION
Jean-Baptiste Lamarck (early 1800’s)
Theory
of use and disuse
He said that characteristics which are
acquired are inherited.
Ex.
Giraffes & Human Muscles
THEORIES OF EVOLUTION
August Weismann (late 1800’s)
Disproved
Lamarck’s theory
He said that acquired characteristics are NOT
inherited.
Studied mice
THEORIES OF EVOLUTION
Hugo de Vries (late 1800’s)
One
of the first geneticists
Developed mutation theory
Said
mutations are a result of genes segregating,
then recombining
THEORIES OF EVOLUTION
Charles Darwin
of Evolution”
Observed variation in species on the
Galapagos Islands
“Father
Famous
for his study of finches, among others.
DARWIN’S THEORIES
Natural Selection
Organisms with favorable adaptations tend to survive
and reproduce.
The 4 principles of Natural Selection:
1. Overproduction-populations overproduce
2. Competition-struggle for existence
3. Variation-leads to new generations that are better adapted
to environment
4. Survival of the Fittest - the ones best adapted, survive.
VARIATION
A bell curve shows variation within a
population.
VARIATION OF HEIGHT
GEOGRAPHIC ISOLATION
Species that are separated from one
another by natural barriers (mountains,
ocean, desert) can cause new species to
develop.
Ex.
Emu, Ostrich, Rhea
GEOGRAPHIC ISOLATION
SPECIATION
Speciation
Over
time, new species will develop due to
their isolation.
Ex.
Emu and Ostrich cannot interbreed
ADAPTATIONS
An adaptation is a characteristic of an
organism that helps it to function in it’s
environment.
ADAPTIVE RADIATION
The process by which a single species
evolves into several different forms that
live in different ways.
Causes diversity amongst the group of
organisms.
ADAPTIVE RADIATION
GRADUALISM
Slow steady change over time (gradually)
PUNCTUATED EQUILIBRIUM
Stable population makes a sudden and
rapid change into something new.
Punctuated equilibrium vs.
gradualism
ORIGIN OF LIFE
In the beginning…
______________,
which happened about
_____________ years ago.
Then…
Molten
earth cooled, forming a ___________.
Then…
Volcanoes
erupted, spewing gases, forming
the ____________.
ORIGIN OF LIFE
The first gases in the primitive
environment were:
NH
- Methane
CO -Carbon Dioxide
2
NH -Ammonia
3
H S-Hydrogen Sulfide
2
4
These
gases combined to form primordial soup
ORIGIN OF LIFE
Early Earth was being bombarded by
lightning and comets.
Lightning caused molecules in the
primordial soup to reassemble into CHON.
Therefore,
an organic molecule is born!
ORIGIN OF LIFE
Simple organic molecules began to
combine to form more complex molecules.
Ex.
Simple proteins, carbohydrates, lipids and
nucleic acids.
This occurred around 3 billion years ago.
ORIGIN OF LIFE
Simple archaebacteria are formed about
2.5 billion years ago.
Archaebacteria evolved and adapted to
the environment, forming simple monera,
which then evolved into____________,
which then evolved into____________.
Miller and Urey Experiment
In the 1950’s, the scientists conducted an
experiment to re create the formation of
life.
Experiment