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Evolution Notes
Zoology
Mrs. McCarthy
May 24, 2017
I.
A.
B.
What is evolution?
Evolution is any change in the genes of a population
over time
Examples:
1.Antibiotic resistance in bacteria
2.Loss of legs by snakes and whales
II. Different kinds of theories of how
the world became as it is today
A.
B.
C.
Big Bang – explosion of a mass of matter to create
the universe (solar system ~ 4.6 billion years old)
Creationism – Everything created by a divine being
Spontaneous generation – life “just appears”
II. Different kinds of theories of how
the world became as it is today
D.
Abiogenic molecular evolution
1.Organic molecules gradually assembled from
inorganic elements
2.Haldane’s belief
a.
“Hot dilute soup” – Earth’s primitive
atmosphere had H2O, CO2, ammonia
b.
Organic molecules formed with energy
from UV radiation
II. Different kinds of theories of how
the world became as it is today
3.Oparin’s belief
a.
Energy from the sun, lightning, and
volcanic heat formed organic molecules
II. Different kinds of theories of how
the world became as it is today
E.
Evolution – gradualism – SLOW change over time
1.First life was probably a “protocell”
a.
membrane bound cell that reproduced
b.
Heterotrophic (photosynthesis came later)
c.
Prokaryotic – early bacteria
2.Probably happened 4 billion years BP (before the
present)
3.Life may have originated more than once!
III. History of Evolutionary Theory
A.
Jean Baptiste de Lamarck – French biologist
1.First to notice that fossils were remains of past
life
2.Lamarckism, or The Theory of Use and Disuse
a.
organisms acquire adaptations during their
lifetime and pass them on to their
offspring
III. History of Evolutionary Theory
b.
examples:
1.
Snakes lost legs to move well in
dense vegetation
2.
Giraffes developed long necks from
stretching
3.
Any change would be passed on to
their offspring
3.This theory was later disproved by genetics
If Lamarckism was true, women
wouldn’t need to do this:
Or this:
III. History of Evolutionary Theory
B.
Charles Darwin – English naturalist
1.Life history
a.
expelled from medical school, not good
student
b.
22 years old, became naturalist for H.M.S.
Beagle
c.
(almost wasn’t accepted, captain didn’t like
the shape of Darwin’s nose)
III. History of Evolutionary Theory
d.
e.
f.
made extensive collections of flora/fauna
on his 5 year journey
spent time in Galapagos Islands – noticed
different organisms
published The Origin of Species
III. History of Evolutionary Theory
2. Developed the theory of Natural Selection – survival of
the fittest
a.
ALL organisms show variation
b.
more offspring are produced than can survive
c.
struggle for survival (to meet basic needs)
d.
some have a better chance for survival than
others
e.
survival of the fittest
f.
new species originate
III. History of Evolutionary Theory
3.Darwin believed that genes of parents blend in
the offspring
a.
Gregor Mendel’s studies in genetics
proved this incorrect
IV. Support for the theory of evolution
A.
Sequence of fossil types
1.Fossils – evidence of past life (bones, teeth,
shells, imprints, coprolites)
2.Rocks are formed in layers – older rocks are
deeper
3.Fossils in old layers are older and more simple
IV. Support for the theory of evolution
B.
Vestigial organs – have no CURRENT function
1.Appendix
2.Wisdom teeth
3.Wings on flightless birds
4.Little toe
IV. Support for the theory of evolution
C.
Homologous Structures
1. Same structures, but different functions
2. Shows origin in a common ancestor
3. Vertebrate pentadactyl limb
a.
human arm
b.
horse leg
c.
bird wing
d.
whale flipper
e.
bat wing
IV. Support for the theory of evolution
D.
Embryological Development
1.Organisms go through similar development
2.Humans had gill slits, tail, fine covering of hair
IV. Support for the theory of evolution
E.
Agricultural/Animal Domestication
1.Selective breeding (pets, farm animals, crops)
2.Each generation is not the same
IV. Support for the theory of evolution
F.
Competition for Existence
1.More animals produced than could ever survive
2.Compete for food, water, shelter, mates
IV. Support for the theory of evolution
G.
Genetics
1.Genetic variation
2.Change in gene frequencies over time
IV. Support for the theory of evolution
H.
Wiesmann’s Continuity of Germplasm
1.Sex cells must change for evolution to occur
IV. Support for the theory of evolution
I.
DeVrie’s Theory of Mutations
1.
Change is caused by mutations
V. Example of Natural Selection
A.
B.
Microevolution – change of genes in one population
Peppered moth in England
1.
Industrial melanism (change in color)
2.
Moths were originally white or peppered gray
3.
Industrial revolution caused pollution
4.
Soot covered trees, causing them to be darker
5.
Birds saw and ate light moths on dark trees
6.
Dark “mutations” of the moth could blend in and
survive
7.
Population shifted to the dark version of the moth
Peppered Moth
Mimicry as an adaptation
Ladybug Adaptations
Poisonous Frog Adaptations
Crocodile Adaptations
Crane Adaptations
VI. Speciation – development of new species
A.
Reproductive isolation
1.
Groups of same species can not contact
each other
2.
Adapt to separate environments
3.
Develop into different species
VI. Speciation
B.
Allopatric speciation – complete geographic
isolation of populations
VI. Speciation
C.
Adaptive radiation
1.
One common ancestor develops into
different species based on competition,
location, food supply
2.
Example: Darwin’s finches
VI. Speciation
D.
Punctuated Equilibrium – Eldredge and Gould
1.
Macroevolution – large evolutionary
changes
2.
New species suddenly emerge
3.
Species change little, become extinct
4.
Explains the gaps in the fossil record
VI. Speciation video clip
VI. Speciation
E.
Hardy – Weinberg Equilibrium
1.
Mathematical formula to prove genes
remain constant under certain conditions
a.
large populations
b.
random mating
c.
no mutations
d.
no selection (survival of the fittest)
e.
no migration