Download Evolution Lecture #1

Evidence of Evolution
15.1
Blindfold Demo
I. Evolution Definitions
A. Evolution- Change in inherited
traits of a POPULATION (not
individuals) over time.
B. Variation- Changes between
members of the same species
caused by DNA mutations.
II. Charles Darwin
A. It all began on the English
ship, the HMS Beagle
1. Darwin worked as the
naturalists
2. He took samples of living
specimens and fossils
II. Charles Darwin
B. Darwin’s observations in the
Galapagos Islands
1. Species are unique, yet
similar to species elsewhere
2. Species produce many
offspring, but don’t overrun the
earth
II. Charles Darwin
3. Individuals in a species
struggle to survive
a. Compete for food
b. Compete for shelter
c. Compete for water
d. Etc
II. Charles Darwin
C. Pigeon experiments
1. Darwin realizes that he can
select and breed specific
pigeons to get a desired trait.
II. Charles Darwin
2. Artificial Selection- Breeding
organisms with specific traits in
order to produce offspring with
identical traits.
a. Similar to a force in nature
that causes changes
II. Charles Darwin
D. Natural Selection- Organisms
with favorable traits for their
environment survive and
reproduce. Organisms without
favorable traits die!
1. Survival of the fittest!!!
2. Causes changes in populations
a. Car demo
II. Charles Darwin
E. Principles of Natural Selection
1. Organisms produce more
offspring than can survive
2. Differences, AKA variations
occur among individual species
3. Some variations are passed
to the offspring
II. Charles Darwin
4. Some variations are helpful
and help organisms to survive
and reproduce better.
5. Over time, individuals with
the helpful variations make up
more of the population and
often becomes a separate
species.
RUEBEN VS. CARS DEMO
III. Evidence for Evolution
A. Adaptations that
increase survival
1. Structural
a. Body parts
b. Camouflage
c. Mimicry
III. Evidence for Evolution
2. PhysiologicalChanges in
metabolism
a. Penicillin
resistant bacteria
b. Pesticide
resistant insects
III. EVIDENCE FOR EVOLUTION
B. Fossils & Transition Fossils
1. Archeopteryx: intermediate
between reptiles & birds
2. Eustheopteron: fish to
amphibians
3. Seymouria: amphibian to
reptiles
4. Therapsids: reptiles to
mammals
III. EVIDENCE FOR EVOLUTION
C. Anatomical Evidence
1. Homologous StructuresStructure with similar origins
(shape, function, etc)
a. Provides evidence of
common ancestor
b. Ex: Forelimbs of whales,
crocodiles and birds
Anatomical Evidence
Homologous Structures
III. EVIDENCE FOR EVOLUTION
2. Analogous StructuresStructures that DO NOT have
similar origin, but DO have
similar functions
a. Not closely related
b. Wing of a butterfly and
wing of a bird
Anatomical Evidence
analogous structures
III. EVIDENCE FOR EVOLUTION
3. Vestigial StructuresStructures that no longer serve
their original purpose
1. Ex: Human ear muscles,
whale feet, blind mole-rat
eyes
Anatomical Evidence
vestigial structures
III. EVIDENCE FOR EVOLUTION
4. Embryology Evidence
a. Embryo- Earliest stage of
growth & development
b. All embryos look similar
Evidence from Embryology
•http://www.exploratorium.edu/exhibits/embryo/embryo.html
III. EVIDENCE FOR EVOLUTION
5. Biochemistry
Evidence
a. DNA is similar
in all species
b. Evidence of
common
ancestor
III. EVIDENCE FOR EVOLUTION
c. The more DNA alleles in
common, the more closely
related two organisms are!
1) Humans & chimps have
97% of the same DNA