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EVOLUTION
Who is Charles Darwin?
Where were the founding ideas of Evolution?
What is evolution?
Where are the Galapagos Islands?
“change
EVOLUTION
over time”
Well
tested and supported idea
You
do not have to agree with a theory
Evidence
THEORY
to support
 Born
Feb 12th, 1809
 England
 After
college visited many
continents as a part of the crew
on the HMS Beagle
 Naturalist
 Observed
diversity in organisms
CHARLES DARWIN
https://www.youtube.com/watch?v=xOl0tHVV6Ck
“characteristics of
many animals and
plants varied from
one island to the
next.” – Charles
Darwin
GALAPAGOS ISLANDS
https://www.youtube.com/watch?v=NKG2qH8778U
https://www.youtube.com/watch?v=-FT3FU2XOgo
PEOPLE DIDN’T BELIEVE THAT THINGS
CHANGED…
WHAT DOES THIS HAVE TO DO WITH
CHARLES DARWIN AND EVOLUTION?
 Two
geologists who recognized that the Earth
changes
 Rocks
form/change slowly (rock cycle)
 Many
forces at work
 Proposed
that the Earth had to be older than
previously thought
CHARLES LYELL
JAMES HUTTON
1795
Present
events
events help to explain past
Processes
Change
are ongoing
does occur
CHARLES LYELL
JAMES HUTTON
1795
Can
living
organisms change
as well?
If
so…they would
change
slowly…over time
DARWIN CONSIDERS THIS…
 Early
theory of
evolution
 Species
descend
from others
 Living
things
change over time
LAMARCK
“selective use or disuse of
organs, organisms
acquired or lost traits in a
lifetime. Traits can be
passed to offspring…over
time this leads to a change
in a species.”
1)
Tendency
towards perfection
(birds want to fly)
2)
Use/Disuse (front
legs to wings)
3)
Inheritance of
acquired traits
LAMARCK’S PRINCIPLES
There
were issues
with Lamarck’s
principles…but it
was a start.
Adaptation
Inheritance
LAMARCK’S PRINCIPLES
Individual
differences among species…
NATURAL VARIATION
 Nature’s
own variations.
 Darwin
considered this
and decided that
species naturally have
genetic differences.
ARTIFICIAL SELECTION
Fitness-
ability of an
individual to survive and
reproduce
Adaptation-
inherited
(behavior or physical) trait
that increases an organisms
chance of survival.
FITNESS
ADAPTATION
 “Survival
of the fittest”- individuals that are
better suited for the environment are more
likely to survive and therefore reproduce
passing off genetic variances to their offspring.
NATURAL SELECTION
https://www.youtube.com/watch?v=AMtT5_AQmLg
 Vestigial
 Fossil
organs
record
https://www.youtube.com/watch?v=OAfw3akpRe8
https://www.youtube.com/watch?v=GOKW_7KajCU
 Homologous
body
 Geographic
distribution
structures
of species
EVIDENCE FOR EVOLUTION
 Galapagos
finches
 Individual
traits
suggest specific
niches for birds and
give indicators of
feeding habits and
habitats.
https://www.youtube.com/watch?v=l25MBq8T77w
BIRD ADAPTATIONS
https://www.youtube.com/watch?v=XzHQ5-lYvrk
 Gene
Pool- Combined
genetic combination of an
entire population.
 -combinations
of alleles
(A,B,O,AB blood types), (eye
colors etc.)
 How
often do you see those
traits?- Relative frequency
GENES AND VARIATION
Blood Type
and Rh
United
States
Frequency
% of U.S.
Population
O+
1 in 3
37.4%
O-
1 in 15
6.6%
A+
1 in 3
35.7%
A-
1 in 6
6.3%
B+
1 in 12
8.5%
B-
1 in 67
1.5%
AB+
1 in 29
3.4%
AB-
1 in 167
0.6%
 1)
Genetic shufflingrandom draw of genetic
traits during meiosis.
Crossing over. 8.4 million
combos of genes in 23
chromosomes.
 2)
Mutations
https://www.youtube.com/watch?v=qVmusHZtQms
HOW DOES A POPULATION GAIN
GENETIC VARIATION?
 Review Single
gene (controlled by a
gene with two alleles) Widows
Peak
 Poly
gene (controlled by two
or more genes with multiple
geno/phenotype possibilities)
Height, eye color, skin color.
SINGLE GENE VS. POLY GENE TRAITS
selection acts on phenotypes
not so much genotypes
 Nat
 Evolution acts on populations not
individuals
 What
factors can change the
frequency of alleles in a population?
16-2 NATURAL SELECTION AND
POPULATIONS
 Adding
cards to the deck
 Removing
cards from the deck
 (AKA-
deaths without
reproducing, individuals
producing an abundance
of offspring)
FACTORS THAT AFFECT ALLELE
FREQUENCY
 Simpler
to calculate
and understand
 Coloration
in an
organism…
 Allele
could altogether
disappear
 Adaptations
that
enhance traits will
survive
SINGLE GENE FREQUENCY
 More
complicated
to predict
 Ex.
height
POLY GENE FREQUENCY
Selection
at
one end of the
curve
increases due
to higher
fitness.
DIRECTIONAL SELECTION
 Individuals
at the
center (norm) of
curve have a
higher fitness than
the ends of the
curve.
 Ex.
Baby weight
STABILIZING SELECTION
 Individuals
at
high/low
extreme of
curve have a
higher fitness
that in the
middle
(norm)
DISRUPTIVE SELECTION
 Random
change
in allele frequency
 Can
cause an
allele to become
more or less
common over
time
GENETIC DRIFT
Allele
frequency
is constant
Population
is not
evolving
GENETIC EQUILIBRIUM
 In
order to have
genetic equilibrium…
 1-
No mutations
 2-
No natural selection
 3-Random
 4-Large
mating
population
 5-No
movement into or out
of population
HARDY-WEINBERG PRINCIPLE
 Formation
of a new
species
 Organisms
that breed
with one another and
produce fertile
offspring.
 Common
gene pool
SPECIATION
As
new species
evolve populations
become
reproductively
isolated from
one another
REPRODUCTIVE ISOLATION
 Species
have
different behavioral
practices such as
mating song, and
technique so they
don’t reproduce
together.
BEHAVIORAL ISOLATION
Reproduction
is
isolated due to a
physical barrier
such as water, a
landform
(mountains) etc.
GEOGRAPHIC ISOLATION
Reproduction
is isolated due
to different
reproduction
dates/times.
(spring/fall)
TEMPORAL ISOLATION