Evolution

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Evolution

• Kansas Science Assessment Review

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Can you think of something that doesnt change?

• 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

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Tiktaalik-Fish or Amphibian?

• Is this organism a fish or an amphibian?

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Tiktaalik

• 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

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Archaeopteryx- Bird or Dino?

• Is this a bird or a dinosaur?

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Archaeopteryx

• 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

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Four Winged Dinosaur

• Another transitional Fossil- Microraptor

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Warm Blooded Dinosaurs

• In both breathing systems, air passes through the
  lungs twice, increasing metabolism and making the
  dinosaurs warm-blooded rather than cold-blooded

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Evidence for Evolution

• There are transitional fossils
• Found in rock layers with oldest at the bottom
  and newer fossils at the top

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Evidence of Evolution

• The Fossil Record
• Huge amount of diversity among fossils
• Observable similarities and differences among
  fossils and living organisms
• Homologous structures

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Genetics and Evolution

• Genetics provided a vast amount of evidence for
  evolution
• DNA comparisons are also used

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Life is Very Old

• Bacteria-like life existed billions of years ago
• 3.5 billion years ago forms like this existed
• Stromatolites in Australia formed by Cyanobacteria

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Can you observe evolution?

• Bacteria have been used because of their short
  life cycle
• Resistance to multiple antibiotics

Methicillin Resistant Staphylococcus Aureus
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What is Evolution?

• Changes in life forms over time
• Fuel of evolution
• Variation
• Selection
• Time
• Two main points
• Natural Selection
• Descent with Modification

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Phylogenetic Tree or Cladograms

• Used to demonstrate relationships between species

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Lamarck

• One of the first hypotheses of evolution
• Acquired Characteristics
• 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.

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Natural Selection

• Survival of the Fittest
• 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

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Natural Selection

• Each species has adapted to its environment and
  fills a niche
• Environmental niche- the position or function of
  a species in a community
• Some insects are only capable of pollinating one
  type of flower

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Natural Selection Speciation

• Can happen due to geographic isolation
• Darwins finches- isolated on islands

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Natural Selection- Reproductive

• Temporal reproductive isolation
• Some cicadas have a 13 or 17 year life cycle
• This life cycle has not been figured out by the
  predators

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Populations Evolve

• Populations evolve, not individuals
• Natural Selection is usually a slow process
• Lamarck didnt know the whole story
• Nature will select the favorable traits and the
  population will adapt to their environment.

evolve
evolve
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Artificial Selection

• Humans select the favorable traits
• Breed organisms that have those traits
• Dogs are a great example
• All dogs are the same species
• Humans have bred certain qualities into dogs for
  different purposes
• Bloodhounds for hunting
• Greyhounds for running

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Where does variation come from?

• Gene Mutations
• Crossing Over
• Independent Assortment
• Fertilization (Mom Dad Kid)
• Variations can be passed on to offspring

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Mutations

• Most mutations are neutral
• Most of DNA is made of introns (non-coding)
• However, standards say that most are harmful.
  (They are wrong)
• If the mutation happens in a coding region, then
  it is usually harmful
• Some are beneficial for that environment and lead
  to selection

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Mutations

• Think of your watch
• If I randomly took a part out of my watch would
  it most likely be bad or good for my watch?
• Most likely bad

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Genetic Drift

• Random change in allele frequencies
• Founder effect and Bottleneck
• 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
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Cheetahs-Bottleneck

• 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

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Extinction

• Happens when species cant adapt fast enough or
  at all
• Beneficial traits change when environments change
• When a species heritable traits dont change
  then the species will become extinct

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Extinction

• Caused by mostly natural events
• Not always related to human activities but it can
  be

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Extinction

• 99.9 of species that ever lived are extinct!

Examples of extinct species
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Questions

• 1. Tiktaalik and Archaeopteryx are
• A. Examples of transitional fossils
• B. Extinct dinosaur fossils
• C. Extinct tetrapod fossils
• D. Warm Blooded fossils

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Questions

• 2. Evidences for evolution include (mark all that
  apply)
• A. Fossils in rock layers
• B. DNA and genetics
• C. Huge diversity in living things
• D. Homologous Structures
• E. Species currently going extinct

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Questions

• 3. Lamarck proposed which of the following to
  explain how animals changed?
• A. Acquired characteristics
• B. Stretching of giraffes necks caused them to
  become longer.
• C. Natural Selection
• D. Artificial Selection
• E. Survival of the fittest

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Questions

• 4. Natural Selection includes (mark all that
  apply)
• A. Variation among a species
• B. A species desire to change
• C. Characteristics that can be inherited
• D. Competition for resources

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Answers

• 1. A
• 2. All of the above
• 3. A, B
• 4. A, C, D

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Questions

• 5. Which of these groups is the smallest unit to
  evolve?
• A. Individuals
• B. Phyla
• C. Populations
• D. Kingdoms

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Questions

• 6. Mutations within a DNA sequence are
• 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

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Questions

• 7. Which of these best illustrates natural
  selection?
• 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.

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Questions

• 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
• 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

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Answers

• 5. C
• 6. A
• 7. A
• 8. B

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Questions

• 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?
• 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.

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Questions

• 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?
• 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.

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Questions

• 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
• 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.

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Questions

• 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?
• A. episodic isolation
• B. temporal isolation
• C. geographic isolation
• D. behavioral isolation

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Questions

• 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
• A. climatic variation
• B. episodic speciation
• C. biological diversity
• D. geographic isolation

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Answers

• 9. D
• 10. D
• 11. C
• 12. C
• 13. C