Transcript evolution - biorocks

Evolution
The process of change (growth
and/or development)
THE EARTH
IS OVER 4.5 BILLION YEARS OLD
EVOLUTION
Geological change = change in the earth
EVOLUTION
Organic change = change of living
things
THE STRONGEST EVIDENCE OF
EVOLUTION IS…
THE FOSSIL RECORD
1. Amber – insects trapped in sticky resin from
trees called amber
2. Ice
3. Minerals, bones or teeth may be preserved
4. Tar pits
THE FOSSIL RECORD
5. Petrifaction – organisms in water
decay and the form is replaced by
minerals from the water that turns
to stone
6. Molds –hollow shape of an
organisms forms from minerals at
the bottom of a lake
7. Casts – minerals may harden in the
mold that forms a replica of the
organism
8. Impressions – prints left in the mud
that harden into stone
Evidence of Evolution
Complete page 3 in your packet
EVIDENCE OF EVOLUTION FROM
LIVING ORGANISMS
COMPARATIVE ANATOMY
I.
1.
HOMOLOGOUS STRUCTURES
2.
ANALOGOUS STRUCTURES
3.
VESTIGIAL STRUCTURES
EVIDENCE OF EVOLUTION FROM
LIVING ORGANISMS
Comparative anatomy – homologous structures
I.


Internally similar (anatomically and embryologically)
Different externally – adapted for different functions
EVIDENCE OF EVOLUTION FROM
LIVING ORGANISMS
Comparative anatomy – analogous structures
I.
•
•
Similar externally for similar functions (different types of
wings)
Different internally (structures have evolved differently)
EVIDENCE OF EVOLUTION FROM
LIVING ORGANISMS
Vestigial structures – structural remains were
functional in an earlier ancestral form (they have
evolved differently)
I.
•
•
•
•
Wisdom teeth
Appendix
Coccyx (tail bone)
Muscles of the ears and nose
EVIDENCE OF EVOLUTION FROM
LIVING ORGANISMS
Comparative embryology
II.

Embryos of closely related species show similar patterns
of development
EVIDENCE OF EVOLUTION FROM
LIVING ORGANISMS
III. Comparative biochemistry
Structural formula for cellulose
(polysaccharide found in plants’
cell walls)
Structural formula for chitin
(polysaccharide found in the
shells of insects)
Evidence of Evolution
Complete pages 6 and 7 in your packet
Theories of Change
Complete pages 8 and 9 in your packet
MODERN EVOLUTION
THEORY
Jean Baptist de Lemark (1809)
Lemark believed that
species evolved from
pre-existing species
because they needed
to adapt to changes in
the environment
Lemark’s Theories
LAW OF USE AND DISUSE:
 Characteristics used become stronger
and better developed
 Characteristics not used become
weaker and less developed
AND THE PROBLEM WITH
THIS IS?
 DNA does not pass on adaptations
from the environment that were
not in the original gametes
How was Lemark proven wrong?
 Weismann (1870) cut off tails of
mice for 22 generations – the 23rd
generation had normal length tails
Weismann said:
 According to this theory, variations occur
from time to time in the individuals of a
population, as a result of genetic mutations
 which occur to some extent naturally, by
copying errors,
 but can also be caused by chemicals known
as mutagens or by ionizing radiation,
especially X-rays or cosmic rays.
 Some variations are reproductively more
successful than others so that through this
indirect process,
 aided by the further processes of crossing
over, and assortative mating the genetic
structure of a breeding group gradually
changes.
Friedrich Leopold August
Weismann (1834-1914)
CHARLES DARWIN
(1831)
Darwinism
 On the Galápagos Islands, Darwin, collected birds, and
noted that finches differed depending on which island
they came from.
 Separated species had developed special adaptations to
their environment
Darwin’s Theory
of
Natural Selection
 Organisms with favorable variations
would be better able to survive and
reproduce than organisms with
unfavorable variations
 Nature selects the survivor
“On the Origin of the Species
by Means of Natural
Selection”
by
Charles Darwin
Darwin’s Key Ideas
1. OVERPRODUCTION: species produce more
offspring than needed because only a few will live to
reproduce
2. COMPETITION: space and food are limited and
species compete to survive
3. VARIATION: variations occur and the important
ones increase the chances of survival
Darwin’s Key Ideas
4. ADAPTATIONS: favorable adaptations will increase
survival and the chances for reproductions
5. NATURAL SELECTION: organisms with favorable
variations will produce in large numbers and the
offspring will inherit these variations
6. SPECIATION: over many generations, favorable
variations increase and unfavorable variations will
disappear
INTELLIGENT DESIGN
 Intelligent design is the assertion that "certain
features of the universe and of living things are
best explained by an intelligent cause, not an
undirected process such as natural selection"
Evidence of Evolution
Complete pages 11 - 13 in your packet
RATE OF EVOLUTION
GRADUALISM
•Organisms evolve
slowly
•Missing link fossils are
not found because they
are rare
RATE OF EVOLUTION
PUNCTUATED
EQUILIBRIUM
•Organisms remain the
same for long periods of
time (equilibrium)
•For a brief time there is
an interruption with a
new species
Rate of Evolution
Complete page 15 in your packet