Download Evidence for Evolution

Evolution
The change in a population’s
genetics or inherited traits over
time
The Myth
• Life originates by spontaneous
generation
– Nonliving material gives rise to living
material
– i.e. maggots and flies spontaneously appear
from rotted meat
Enter the Mythbusters
• Redi- disproved spontaneous generation
of flies
• Pasteur- disproved spontaneous
generation of bacteria
• How?
Mythbusters
• Redi
History continues- mid 1800s
S shaped neck:
Prevents entry
Of microorganisms
Nutrient Broth:
Heated to kill life
Nutrient Broth:
Grew bacteria if exposed
SPONTANEOUS GENERATION
Biogenesis
Living organisms only come from
other living organisms
Next Myth
SO WHERE DID LIFE BEGIN?
So… Where did life begin?
• Oparin- life began in
oceans
• Organic molecules
formed
Enter the Mythbusters…
Again
Miller and Urey
Miller and Urey
Lightning
Atmosphere
Rai
n
Volcanoes
Ocean
Miller and Urey
Organic molecules can be made
Why couldn’t
we blow
more stuff
up?
This myth is
true!
Now back to Evolution
How did we get so much
biodiversity?
How are species formed?
• Lamarck –use and
disuse
– if you don’t use it, you
lose it
– Variation created!
– organisms pass on
acquired traits
– Ex. cut of mouse’s tail,
offspring will have no
tail
Darwin’s Idea
• Natural Selection
• Variation already
exists
• Good variations =
survival
• Pass on good
variations
• Bad variations
selected against
Let’s Investigate
DON’T BELIEVE ME
Choose a partner
• Each table is a group
• Partners measure each other
– Height
– Forearm length
– Shoe Size
All in cm!!!
• Create Google account at Google Docs
– Enter data into table
Oscar
Brittany
Ques
Ian G.
Jana
Jorge
Dora
Elizabeth
Ty
Dominique D
Josh
India
Dominique
Please get your lab notebook and move to your group
Jose
Brett
Mike
Jolisa
Kiniesha
Mike
Jeremy
Hope
Jade
Maria
Jason
Ian R.
In Lab Notebooks
• Title: The Clipbirds
• Copy onto a clean sheet
• Groups of four to five people
VARIETY… THE SPICE OF
LIFE
Variety in your own class
# of People in Height Range
10
9
8
7
6
5
4
3
2
1
0
140 - 143 148 - 151 156 - 159 164 - 167 172 - 175 180 - 183 188 - 191 196 - 199
# of People in Height Range
O.K. So We Agree!
But how does variation help?
CLIPBIRD ACTIVITY
Choose Your Weapon…
Carefully
• Select one beak type
• Islands have one
type of food
• Eat as much as
you can!!!
• Record amount
Eaten
• Move to next island
Afterwards
• Enter data into
Google Docs
• Answer in notebook
• Do you see any
trends?
• Was any beak
better?
• Was it always the
same beak?
• Did it matter which
food it was?
WHY IS VARIATION GOOD?
Why is variation good?
Why is variation good?
Why is variation good?
Natural
Selection
• Process by which advantageous or
favorable traits become more common
How does natural
selection work?
Inheritance of traits
• Thanks Mom and
Dad!
• Where else would
you get the good
looks?
Variation
• Creates more options
for survival
Competition
• Best variations
survive
• Fight for survival!
Overproduction of offspring
• Produce more offspring than can survive
• Creates Competition
Natural Selection
Inherit Traits
Increase in
Favorable Traits
Reproduce
Receive
Variations
Out Compete
• Given enough
time
• Variations build
• May form a new
species
• Will not
reproduce
Natural selection
• Populations evolve through natural
selection
• 3 main types of natural selection
1. Stabilizing selection
2. Directional selection
3. Disruptive selection
Stabilizing selection
• Average individual favored
Directional selection
• Extreme variations favored
– i.e. giraffe with longest neck
Disruptive Selection
• Both extremes is favorable
– Ex. light and dark shells blend in, medium
are seen and eaten
How do new species form?
• Speciation- the evolution of new species
– Species can only reproduce with same
species
• 3 ways for speciation to occur
1. Geographic isolation
2. Reproductive isolation
3. Adaptive radiation
Geographic Isolation
• populations separated by geography
(river, mountain, etc.)
• Stop reproducing
 become 2 different
species
Reproductive Isolation
Adaptive radiation
• All from one species
• Different islands =
different food
• Lead to variations
How fast does speciation occur?
• 2 timeframes for speciation
1. Graudalism
2. Puntuated equilibrium
• Both result in new species
Gradualism
• A steady, slow
divergence
Punctuated Equilibrium
No one has ever seen a species evolve!
HOW DO WE KNOW
EVOLUTION HAPPENS?
Evidence for Evolution
Similar
Structure
Evidence for evolution
Evidence for Evolution
Similar development
= common ancestor
Genes from one
species can be used
in another
Forms healthy
organism!!
Same genes turned
on in same order!
Evidence for Evolution
More similarities =
more related
Evidence for Evolution
Clearing up the issue…
• There is no goal
• No top species
• No final product
Clearing cont.
• Streamlined bodies = • Not random
speed = survival
• Advantageous
variations = survival
= reproduction
• Non-random
selection!
Clearing cont…
• Doesn’t satisfy a
need
• Organisms don’t try
to evolve!!
For the Test
• Know the
contributions of
–
–
–
–
–
Redi
Pateur
Darwin
Miller-Urey
Oparin
• Selection graphs:
which traits favored?
– Stabilizing
– Directional
– Disruptive
• Definition of natural
selection
• Evidence: How do
they support
evolution?
– Homologous and
analogous structures
– Vestigial structures
– Fossils
– Embryology
– Biochemistry