Download 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