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The History of
Evolution
I. Basic Terminology
A.Evolution- The process of
change in life forms over time.
B. Species- a group of individuals
with similar anatomical
characteristics and capable of
interbreeding to produce fertile
offspring.
Basic Terminology
C. Variation-Differences in
characteristics among
individuals of a species
D. Adaptation-Any alteration of
structure, behavior, or function
that makes an organism more
reproductively successful.
Basic Terminology
E. Speciation- The evidence of new
species evolving
F. Phylogeny- The evolutionary history
of a species
G. Camouflage- blend into their
surroundings
H. Diversity- the number and relative
abundance of species in a biological
community
Basic Terminology
• I. Extinction-coming to an
end or dying out of a species
or other taxon
• J. Mimicry
• K. Natural Selection
• L. Vestigal Structure
II. Lamarck 1744-1829
A.1809 First to
complete
theory on
evolution
B. Lamarck’s Theory:Theory of
Inheritance of Acquired
Characteristics
1. Organisms are capable of changing their
form, proportions, color, agility etc. In
response to a specific environmental
change.
2. The more they use a particular body
part the stronger and better developed
that part becomes
3. The physical characteristics that an
organism develops through use or disuse
can be passed on to their offspring
C. Example
1. Giraffe stretches
its neck to reach
food, it then
passed this trait
to it’s children
…so giraffes have
long necks
III. Charles Darwin
( 1809-1882)
A. Father of the modern
theory of evolution
B. In 1836 accompanied
the Beagle on a
scientific expedition
(S. America and S.
Pacific) as an
naturalist
C. He observed
variations in
animals and
plants from
different
continents;
fossil record
and geological
formation.
D. Galapagos Islands( sm. Islands
1000km off the West Coast of S.
America)
1. Observed tortoises, mockingbirds,
finches and other species
2. Noted that each island supported its
own form of animal and plant life
3. These were closely related yet
different from island to island.
D. Darwin’s Survival of
the
Fittest!
• Explanation for
Evolution:
Natural Selection:
Individuals that have
physical or behavioral
traits that better suit their
environment are more
likely to survive and will
reproduce more
successfully than those
that do not have such
traits.
E. Darwin’s Natural
Selection Theory
. Natural Selection:
Mechanism for change in
a population that occurs
when organisms with
favorable variations for
a particular environment
survive, reproduce, and
pass these variations on
to the next generation
1
C. Malthus vs. Darwin
Malthus believed the
availability of a food supply
influenced human
population
1. Darwin believed in struggles
for existence: Competitiona. Food
b. Space
c. Escape from
predators
F. On the Origin of Species
by Natural Selection
1. Published in
1859
2. Believed that
the earth is not
static, but
always evolving.
Darwin vs. Lamarck
• Darwin believed that the desires of animals have nothing to
do with how they evolve, and that changes in an organism
during its life do not affect the evolution of the species. He
said that organisms, even of the same species, are all different
and that those which happen to have variations that help them
to survive in their environments survive and have more
offspring. The offspring are born with their parents' helpful
traits, and as they reproduce, individuals with that trait make
up more of the population. Other individuals, that are not so
well adapted, die off. Most elephants used to have short
trunks, but some had longer trunks. When there was no food
or water that they could reach with their short trunks, the ones
with short trunks died off, and the ones with long trunks
survived and reproduced. Eventually, all of the elephants had
long trunks. Darwin also believed that evolution does not
happen according to any sort of plan.
IV. R.A. Fisher 1930
A. 1st attempt to
combine
Darwin’s theory
of natural
selection with
Mendel’s Laws
B. The Genetical
Theory of
Natural Selection
V. Thomas Hunt Morgan
1932
A. Discovered mutation
changes in DNA that
can cause variation
B. Mutation can bring
about evolutionary
change
C. Fruit Fly experiments
Adaptations:
Evidence of
Evolution
According to Darwin
I. Structural Adaptations-can
develop over millions of years
A. Ex. Teeth and claws
of a mole-rat
B. Mimicry: enables
one species to look
like another species
C. Camouflage: blend
into their
surroundings
II. Physiological Adaptations-can
develop more rapidly
A. Bacteria
resistance to
antibiotics
Ex. Penicillin
B. Insects
resistance to
pesticides
III. Fossils-Indirect Evidence of
Evolution
A.Record of
earlier life
B.Incomplete
fossil record
C.Horse
IV. Anatomical Studies
A. Evolutionary
Relationships
B. Structural similarities
as evidence that
organisms evolved from
a common ancestor
C. Homologous
Structures-similar in
arrangement and/or
function-evolutionary
origin
Anatomical Structures
D. Analogous
Structures-don’t
have a common
evolutionary
origin, but are
similar in function
but not structure
… Independently
adapted to similar
ways of life
V. Vestigial Structures
A. Body structure that is
reduced in function in a
living organism-but
may have been used in
an ancestor.
B. Ex. Eyes on cave fish
C. Ex. Flightless Birds
with wings
D. Ex.Whales with pelvic
bones
E. Ex. Appendix
VI. DNA Comparisons
• DNA and
Protein
sequences
• Related animals
share more
DNA and have
more amino
acids in common