The Theory of Evolution - Explaining how organisms change over time

Origin of Life on Earth

  1. ______- non-living materials can produce life, life could be created out of nothing, from the air
  2. ______- living organisms only come from other living organisms
  3. Earth approximately ______billion years old
  4. Beginning- earth’s atmosphere Hot, gases like CO2 and nitrogen, little O2
  5. Gases helped to create the atmosphere
  6. 3.5 to 4 billion years ago
  7. Organic Molecules
  8. Protocells
  9. ______cells (heterotrophs)
  10. First simple ______/producer
  11. Eukaryotic cells
  12. ______organisms

Addressing the Misconceptions

WHAT EVOLUTION IS NOT

Biological Evolution...

  1. is NOT just a theory
  2. Is NOT concerned with the origin of life
  3. Is NOT just concerned with the origin of humans
  4. was NOT discovered or first explained by Charles Darwin
  5. is NOT the same thing as natural selection
  6. is NOT something that happened only in the past
  7. is NOT something that happens to individuals
  8. is NOT an accidental or random process
  9. does NOT have any evidence against it
  10. does NOT conflict with any religion
  • Organisms are always getting better
  • Natural selection gives organisms what they ‘need.’
  • Evolution will create a "perfect" creature

So what exactly is evolution?

  • Evolution- change in ______over time
  • Better Definition = Descent with ______
  • A trait has be passed from parents to offspring
  • Evolution can only happen to ______

The Big Picture

  1. DNA ______
  2. ______adapt
  3. ______evolve

Evolution - Creating the Idea...

Darwin vs. Lamark...one was right, one was wrong...

Charles Darwin

  1. Charles Darwin traveled the world on the HMS Beagle
  2. He was a ______, who noticed patterns of living things
  3. Published his book, "The Origins of Species" describing ______through ______.
  4. Coined it “______”
  5. Being biologically fit = being able to have successful sex or produce viable offspring

Lamark

  1. Lamarck- organisms change due to the pressures of their environment, ______
  2. He proposed that by using or not using its body parts, an individual tends to develop certain ______, which it passes on to its offspring.
  3. A giraffe ______its long neck because its ancestor stretched higher and higher into the trees to reach leaves, and that the animal’s increasingly lengthened neck was passed on to its offspring.

Natural Selection

  • Natural Selection- organisms with traits ______to the environment survive have more ______
  • Natural Selection happens because of ______variations
  • Overtime, natural selection results in changes in the inherited characteristics of a population.
  • These changes increase ______fitness (survival rate).
  • Fitness = determined by ______success
  • Not necessarily bigger, faster, stronger
  • Fitness is not determined by one trait but by the ______in the organism
  • Examples of Natural Selection
  • Vestigial Organs

Natural Selection – Summary

  1. Organisms are locked into historical constraints
  2. Adaptations are often compromises as with seals that need to swim and walk
  3. Not all evolution is adaptive
  4. Organisms can’t get a trait just because they “need” it.

Natural Selection Facts

  • Fact 1: Over-reproduction occurs in nature
  • Fact 2: Populations do not increase exponentially
  • Fact 3: There are limited natural resources (food, shelter)
  • Fact 4: Variation exists in populations
  • Fact 5: Much of the variation is heritable
  • Fact 4 was physically observed. Darwin’s weakness was the 5th fact

Inferences

  • Inference 1: struggle for survival ensues
  • Inference 2: Organisms with the best variations survive the struggle for life
  • Inference 3: Unequal survival of organisms with different variations leads to favorable variations accumulating over time

Adaptations

  1. Adaptation- change in a species that makes it better suited to its environment
  2. Structural
  3. Changes in structure or anatomy
  4. Example: bird’s beak or claws
  5. Mimicry- a harmless species resembles a harmful one, predators learn to avoid both species
  6. Camouflage- species features blend in with the environment
  7. Physiological
  8. Changes in chemical makeup
  9. Examples: digestion enzymes, snake venom, octopus ink
  10. Behavioral
  11. Responses to the environment
  12. Example: bird migration and bear hibernation

Evidence of Evolution

  1. Fossils
  2. Fossils = ______or ______of organism left in rock, fossilized bone and teeth life becomes more complex over time
  3. record is ______
  4. Relative dating- layers in rock bed used to date organisms
  5. Deeper is ______, shallow is ______
  6. What can fossils tell us?
  7. when organisms lived
  8. Radioisotope dating
  9. what organisms looked like
  10. similarities and differences in organisms
  11. Comparative anatomy
  12. the study of the ______of different ______
  13. ______parts modified structures among different groups of descendants
  14. ______- structures in organisms that have no common origin but serve the same function
  15. Vestigial Organs-organs having no functions in the living organism
  16. Example:
  17. Comparative embryology
  18. Comparative ______the study of developing plants and animals
  19. Biochemistry
  20. comparison of ______and ______in the body
  21. Example: comparison of hemoglobin (blood protein) in human, chimp, and dog. Human and chimp hemoglobin more alike than dog
  1. Genetic evidence
  2. ______- mistakes in the genetic code
  3. Largest cause of variation in a population
  4. Causes changes in populations over time
  5. Direct evidence
  6. Rapid Evolution
  7. Strains of bacteria becoming ______to antibiotics
  8. Weeds and pesticides
  9. Insects and pesticide
  10. Antibiotic ______occurs when bacteria change in some way that ______or ______the effectiveness of drugs, chemicals, or other agents designed to cure or prevent infections. The bacteria survive and continue to multiply causing more harm.

Mechanisms for Evolution

  1. Species- group of organisms that can ______AND ______viable offspring
  2. ______NOT individuals
  3. Gene pool- ______
  4. Over time gene pools shift to traits that are best suited to the environment
  5. Allelic frequency- the percent of any specific gene in a population
  6. Genetic Equilibrium- when the percentage of alleles in a population remains stable over time
  7. Selection Types (You will see these later)
  8. 1.stabilizing – ______
  9. acts against extreme phenotypes and favors intermediate
  10. 2.directional – ______
  11. shifts the overall makeup of the population by favoring variants at one extreme of the distribution
  12. 3. disruptive – ______
  13. favors variants at both ends of the distribution

Origin of a Species

  1. ______– formation of a new species, members of similar populations no longer interbreed
  2. ______Isolation
  3. Physical barrier divides population
  4. River, canyon, mtn. splits group
  5. ______Isolation
  6. Change in behavioral patterns that separate breeding patterns.
  7. Frog calls
  8. ______Isolation
  9. Change in when organisms emerge or become reproductively active
  10. ______Radiation
  11. one______l species evolves into a number of species to exploit a number of habitats.
  12. Divergent Evolution
  13. one species ______into two species with ______characteristics (get more and more different from each other)
  14. We show this by using ______
  1. Convergent Evolution
  2. Convergent evolution – distant or unrelated species evolve similar characteristics to take advantage of similar environments
  3. Example: fish and dolphin