Transcript Evolution

Evolution
Kansas Science Assessment
Review
Can you think of something
that doesn’t change?
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Did you think of the amount of energy in the
universe?
Very intuitive!
It is safe to say that most things do change.
Is it then safe to say that life forms change…
Tiktaalik-Fish or Amphibian?
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Is this organism a fish or an amphibian?
Tiktaalik
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Lived 375 million years ago
Found in Canada in 2004
Intermediate between fish and tetrapods
Scales and fins like fish
Flat head with eyes on top like amphibians
Archaeopteryx- Bird or Dino?
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Is this a bird or a dinosaur?
Archaeopteryx
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Lived 155-150 million years ago
Intermediate between reptiles and birds
Long bony tail, beak with teeth, and claws
like a reptile
Feathers and skeletal features like birds
Four Winged Dinosaur
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Another transitional Fossil- Microraptor
Warm Blooded Dinosaurs
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In both breathing systems, air passes through
the lungs twice, increasing metabolism and
making the dinosaurs warm-blooded rather
than cold-blooded
Evidence for Evolution
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There are transitional fossils
Found in rock layers with oldest at the bottom
and newer fossils at the top
Evidence of Evolution
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The Fossil Record
Huge amount of diversity among fossils
Observable similarities and differences
among fossils and living organisms
Homologous structures
Genetics and Evolution
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Genetics provided a vast amount of evidence
for evolution
DNA comparisons are also used
Life is Very Old
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Bacteria-like life existed billions of years ago
3.5 billion years ago forms like this existed
Stromatolites in Australia formed by
Cyanobacteria
Can you observe evolution?
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Bacteria have been used because of their
short life cycle
Resistance to multiple antibiotics
Methicillin Resistant
Staphylococcus
Aureus
What is Evolution?
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Changes in life forms over time
Fuel of evolution
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Variation
Selection
Time
Two main points:
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Natural Selection
Descent with Modification
Phylogenetic Tree or
Cladograms
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Used to demonstrate relationships between
species
Lamarck
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One of the first hypotheses of evolution
Acquired Characteristics
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Giraffes could stretch their necks to
get food and make their necks longer
This long neck could be passed on to offspring
Body Builders do not pass on their muscles
to their kids.
Natural Selection
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Survival of the Fittest
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Variation exists in every species
There are not enough resources
for every individual to survive
Some variations allow organisms
to take advantage of resources
These organisms survive and reproduce, passing
on their variations
Natural Selection
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Each species has adapted to its environment
and fills a niche
Environmental niche- the position or function
of a species in a community
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Some insects are only capable of pollinating one
type of flower
Natural Selection & Speciation
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Can happen due to geographic isolation
Darwin’s finches- isolated on islands
Natural Selection- Reproductive
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Temporal reproductive isolation
Some cicadas have a 13 or 17 year life cycle
This life cycle has not been “figured out” by
the predators
Populations Evolve
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Populations evolve, not individuals
Natural Selection is usually a slow process
Lamarck didn’t know the whole story
Nature will select the favorable traits and the
population will adapt to their environment.
evolve
evolve
Artificial Selection
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Humans select the favorable traits
Breed organisms that have those traits
Dogs are a great example
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All dogs are the same species
Humans have bred certain qualities into dogs for
different purposes
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Bloodhounds for hunting
Greyhounds for running
Where does variation come
from?
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Gene Mutations
Crossing Over
Independent Assortment
Fertilization (Mom + Dad= Kid)
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Variations can be passed on to offspring
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Mutations
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Most mutations are neutral
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Most of DNA is made of introns (non-coding)
However, standards say that most are
harmful. (They are wrong)
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If the mutation happens in a coding region, then it
is usually harmful
Some are beneficial for that environment and lead
to selection
Mutations
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Think of your watch
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If I randomly took a part out of my watch would it
most likely be bad or good for my watch?
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Most likely bad
Genetic Drift
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Random change in allele frequencies
Founder effect and Bottleneck
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A very small amount of individuals become
isolated
The population will have the alleles that these
founders had
Increased chance of a damaging allele being
“fixed”
Group
becomes
isolated
Cheetahs-Bottleneck
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Habitat Destruction caused a high number of
cheetahs to die
Some of the ones that were left had a
damaging allele causing infertility
Inbreeding of these cheetahs decreased
variation
One outbreak of a disease
could kill them all
Extinction
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Happens when species can’t adapt fast
enough or at all
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Beneficial traits change when environments
change
When a species’ heritable traits don’t change then
the species will become extinct
Extinction
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Caused by mostly natural events
Not always related to human activities but it
can be
Extinction
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99.9% of species that ever lived are extinct!
Examples of extinct species
Questions
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1. Tiktaalik and Archaeopteryx are:
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A. Examples of transitional fossils
B. Extinct dinosaur fossils
C. Extinct tetrapod fossils
D. Warm Blooded fossils
Questions
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2. Evidences for evolution include (mark all
that apply)
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A. Fossils in rock layers
B. DNA and genetics
C. Huge diversity in living things
D. Homologous Structures
E. Species currently going extinct
Questions
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3. Lamarck proposed which of the following
to explain how animals changed?
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A. Acquired characteristics
B. Stretching of giraffes necks caused them to
become longer.
C. Natural Selection
D. Artificial Selection
E. Survival of the fittest
Questions
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4. Natural Selection includes (mark all that
apply)
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A. Variation among a species
B. A specie’s desire to change
C. Characteristics that can be inherited
D. Competition for resources
Answers
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1. A
2. All of the above
3. A, B
4. A, C, D
Questions
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5. Which of these groups is the smallest unit
to evolve?
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A. Individuals
B. Phyla
C. Populations
D. Kingdoms
Questions
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6. Mutations within a DNA sequence are
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A. Natural processes that produce genetic
diversity
B. Natural processes that always affect the
phenotype
C. Unnatural processes that always affect the
phenotype
D. Unnatural processes that are harmful to
genetic diversity
Questions
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7. Which of these best illustrates natural selection?
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A. An organism with favorable genetic variations will tend to
survive and breed successfully.
B. A population monopolizes all of the resources in its
habitat, forcing other species to migrate.
C. A community whose members work together utilizes all
existing resources and migratory routes.
D. The largest organisms in a species receive the only
breeding opportunities.
Questions
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8. A species of finch has been studied on one of the
geographically isolated Galapagos Islands for many
years. Since the island is small, the lineage of every
bird for several generations is known. This allows a
family tree of each bird to be developed. Some
family groups have survived and other have died
out. The groups that survive probably have
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A. interbred with other species
B. inherited some advantageous variations
C. found new places on the island to live
D. been attacked by more predators
Answers
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5. C
6. A
7. A
8. B
Questions
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9. Earth has undergone some catastrophic
changes from time to time. Which of these
most likely explains why life on Earth
continued following these catastrophes?
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A. Dominant species had a slow mutation rate.
B. Many species filled the same niche.
C. A strong species had many different
characteristics.
D. A wide diversity of species existed.
Questions
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10. A small population of chimpanzees lives
in a habitat that undergoes no changes for a
long period. How will genetic drift probably
affect this population?
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A. It will accelerate the appearance of new traits.
B. It will promote the survival of chimpanzees with
beneficial traits.
C. It will increase the number of alleles for specific
traits.
D. It will reduce genetic diversity.
Questions
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11. A single species of squirrel evolved over
time into two species, each on opposite sides
of the Grand Canyon. This change was most
likely due to
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A. higher mutation rates on one side.
B. low genetic diversity in the initial population.
C. the isolation of the two groups.
D. differences in reproductive rates.
Questions
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12. Fossil evidence suggests that a number
of members of one fish species from an
ancient lake in Death Valley, California,
became several isolated species. Which of
the following best explains the cause of this
speciation?
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A. episodic isolation
B. temporal isolation
C. geographic isolation
D. behavioral isolation
Questions
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13. If a paleontologist finds fossils of many
different species existing in the same area at
approximately the same time, the
paleontologist can conclude that the
ecosystem in this area had a high degree of
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A. climatic variation
B. episodic speciation
C. biological diversity
D. geographic isolation
Answers
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9. D
10. D
11. C
12. C
13. C