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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