Transcript Speciation

If a fossil is found in a rock with
20% of the isotope carbon 14 left
in it. How old is the fossil?
Speciation – creation of a new
species from an old one.
Where do species come from?
Microevolution vs. Macroevolution
Fast
 Can see it happen
 in one human life.
Slow
Can’t see it happen
in one human life.
antibiotic
resistance
dinosaurs and
humans
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Antibiotic Resistance
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There are millions of bacteria in a host.
There are many freaks and variations among the
population. Each with unique traits.
If antibiotics are given to a person for a long time
then all or most of the bacteria is killed.
If you stop after a short while the variety that can
handle the antibiotic for a short time will be the
only ones left.
Soon you have a person infected with antibiotic
resistant bacteria.
Can you see how this might be dangerous?
Antibiotic Resistance
Antibiotic Resistance
Antibiotic Resistance
Pesticide Resistance: Bed Bugs
http://www.youtube.com/watch?v=SQbLY
Oh5hA0
 Over use of home treatments cause
resistance.
 Some survive due to variations. They
reproduce and the population evolves.
 Major epidemic in New York.
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HIV Drug Resistance
The same process occurs within the HIV
virus.
 The drugs eventually don’t work because
the resistant variants are the only ones to
survive.
 They repopulate the host and levels are
back up.
 They are now all resistant.
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Darwin’s Dangerous Idea
Survival of the fittest & HIV part 1
 http://www.youtube.com/watch?v=VYnmJ
_IIIIw
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Survival of the fittest & HIV Part 2
http://www.youtube.com/watch?v=g7j8QL3Z
6qg first 2:00
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MRSA Article
Natural Selection
vs.
Artificial Selection
Natural Selection – nature selects the
traits best suited for an environment.
 Artificial Selection – humans select the
traits we like the best.
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 Crops
that produce the most yield.
 Cows that have the best beef.
 Fruit trees with the biggest fruit.
Dogs
All dogs are the same species:
 Canis Lupus
 Humans have
selected the
breeds they
like the best
and kept
breeding
those traits.
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Wild Mustard
What is a species?
A population that can mate to produce a
viable offspring.
 Frogs and Horses – can’t mate
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Oliver the Humanzee
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http://www.youtub
e.com/watch?v=9
kJF7hRmKE0
What is going on here?
What
causes
the
split?
The Galapagos Islands & The MS Beagle
Darwin traveled to the Galapagos Islands
and studied different finches.
 Each island had a different finch type.
 Islands with mountains dividing them in half
had 2 types of finches.
 He asked the question why?
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Speciation
So why don’t all organisms look the same
if they all evolve? Why doesn’t the arctic
wolf and the African dog look the same?
They’re both dogs.
 Different environments!
 Where do different species come from?
 Different environments!
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Geographic Isolation
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Whenever a physical barrier
divides a population evolution
can take different paths.
OCEANS
MOUNTAINS
PACIFIC SIDE
DESERTS
BOUNDARIES –
Changes in land forms
ATLANTIC SIDE
Creating a New Species
Two islands.
 Both have the same birds. (the same beak
variations)
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Creating a New Species
Only one island has a drought and only
the large beaked finches survive.
 On the other island tree worms become
abundant and only slender beaks survive.
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Creating a New Species
After some time they can no longer mate
together.
 You now have two different species, each
on a different island.
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Evolution of a Species
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If there is no geographical isolation then the
whole species can evolve into a new one.
1
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to
2
If there is geographical isolation then the
species can split into two different species.
Both can be new or only one.
1
to
1
2
Phylogenetic Tree of Horses
Shows the
evolution of the
species.
 Speciation new species
formed.
 Extinction species go
extinct.
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Speciation and all evolution
Rabbit Evolution Fast Forward
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http://archive.peabody.yale.edu/exhibits/tr
eeoflife/film_discovering.html
Chimps evolution
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http://www.pbs.org/wgbh/evolution/library/
07/3/l_073_03.html
Fossil #1
Fossil #2
A B C D
A B C d
Fossil #1
A B C D
Fossil #3
C
A B
D
Fossil #4
Fossil #5
a B C d
a B C d
Fossil #2
Fossil #3
Fossil #4
A B C D
a B C d
A B c d
Age:
Fossil #2
Fossil #1
20 million
years ago
A B C D
A B C d
Age:
Fossil #1
80 million
years ago
A B C D