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Evolution

Understand the scientific theories of Lamarck and Darwin, including natural selection and evidence of evolution through DNA, fossils, and adaptation. Discover how species change over time and adapt to their environment through genetic variations.

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Evolution

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  1. Evolution A Scientific Theory

  2. Scientific Theory: Subject to verification Explains observed phenomena based observable scientific facts. Continually being tested as new evidence is found

  3. Evolution is change through time: • The traditional view is that evolutionary changes were SLOW and gradual. • Sharing a common ancestor!

  4. EVOLUTION • A theory: is supported by evidence and generally accepted as true but is not yet considered a fact • 2 main Theories of Evolution Lamarck’s & Darwin’s

  5. Lamarck's Explanation • Hypothesized that acquired traits were passed on from one generation to the next • Acquired traits are traits that are NOT determined by genes • The acquired trait occurs during the organisms lifetime from behavior or experience

  6. Lamarck Cont… • Examples of Lamarck's theory: • Giraffes necks increasing in length reaching for food  produce offspring with the longer necks • An athlete who increases muscle mass producing offspring who have increased muscle mass • The hypothesis was not accepted and dismissed

  7. Charles Darwin: • Studied the Galapagos Island • Organisms were isolated • Determined that a small # of plants and animals started out on the island • Through reproduction and time the offspring became different from their mainland relatives • organisms “adapted” to their new environment • Darwin clip

  8. Darwin's’ studies: Finches

  9. Charles Darwin: Natural Selection • Process where organisms that are able to adapt to their surroundings are more likely to survive and reproduce • The favored traits get passed on from one generation to another • Unfavorable traits gradually disappear because the organisms die out • N.S. leading force in Evolution

  10. Factors that effect natural selection: • Overproduction- producing more offspring than can possible survive Ex. Sea turtles, fish, amphibians 2. Competition – food and resources are limited. (only the strongest survive) • Variations – slight differences among offspring some can be beneficial to the organisms Adaptations occur only when there are genetic varieties in the offspring.

  11. Theory of Natural Selection Cont… Natural Selection- some variations are more helpful than others therefore a natural selection against those that cannot adapt • Inheritance of Variations –beneficial, provides an advantage for the organism • Survival of the Fittest – variations that allows an organisms to live and reproduce • Ex. Brown fur color in woodlands vs. white fur

  12. Adaptations: occur only when there are genetic varieties in the offspring.

  13. Mutations: • Are large variations in the offspring that randomly occur in the genes • Some are harmful…. albino mouse…? • Some are beneficial… brighter flower petals…? • In general, organisms change over time through mutations and sexual reproduction

  14. Proof (Evidence) of Evolution: • Body structure – Homogulous Structures Similarities in body and skeletal structure Vestigial structures: Tailbone, appendix, molars

  15. Ex. Homogulous Structures

  16. Homologous Structures vs. Analogous Structures Homologous structure = similar body parts found in different species Analogous Structures = Structures used for similar purpose BUT not similar in structural makeup: • Ex. Butterfly wing and Bird wing both used for flight but one has bone other does not

  17. Proof (Evidence) of evolution: 2. Early Development Comparing the embryonic development many vertebrates look very similar during early development

  18. 1 2 3 4 5 Which one in the: Turtle, chicken, eel, human, cat?

  19. Evidence of evolution: • Similarities in DNA • the more amino acids 2 organisms share, the more closely related they are believed to be • ex. The protein (coded for by amino acids) in blood: • 67 different amino acids b/w human and frog. • only 1 amino acid difference between humans and gorilla’s

  20. Evidence of evolution: 4. Fossils • Formation of fossils remains of organisms become buried • sediments: soils, rocks build up and cover the remains • these layers harden and become SEDIMENTARY ROCK • types include: • casts • imprints • Petrifaction • can be found in: ice, tar pits, rock, amber

  21. STOP!!! CK POINT!! Topic: Evolution-Darwin 1. DNA in humans, gorillas and chimpanzees is more than 98% the same. Which answer best explains this • They evolved from the same ancestor • They evolved from each other • Their evolution is complete • They evolved at the same time

  22. STOP!!! CK POINT!! Topic: Evolution-Darwin 2. Many scientists believe the earliest cells on Earth were relatively simple, lacking nuclear membranes and other cellular structures. Over time, more complex cells developed from these simple cells. These statements describe the concept of 1 inheritance of acquired characteristics 2 evolution 3 dominance 4 use and disuse

  23. STOP!!! CK POINT!! Topic: Evolution-Darwin 3. What causes insect populations to evolve and become resistant to chemical insecticides? a. Biological control 2. low survival value 3. natural selection 4. vegetative propagation

  24. STOP!!! CK POINT!! Topic: Evolution-Darwin 4. Biochemical analysis uses similarities in which of the following as evolutionary evidence? • Amino acid sequence • Bone structure • Cellular architecture • movement

  25. STOP!!! CK POINT!! Topic: Evolution-Darwin 5. In the early stages of development, the embryos of dogs, pigs, and humans resemble one another. This observation suggests that these animals may have 1 a similar number of chromosomes 2 similar habitat requirements 3 the same blood components 4 a common ancestry

  26. Fossils- Examples

  27. Layers (strata) of fossils mold youngest oldest

  28. Types of Fossils Petrified • Turned to stone. • The soft parts of the organism are replaced with minerals.

  29. Types of Fossils Imprint on a rock (mold) • Imprint on a rock (mold) • Turned to stone. The imprints are replaced with minerals.

  30. Types of Fossils AMBER • Organisms trapped liquid tree sap. Soft body parts stay preserved.

  31. Types of Fossils • Bones preserved in tar pits • Organisms trapped in tar pits. Soft body parts stay preserved. • images

  32. 10,000 year old fossil

  33. ADD TO YOUR NOTES!!Proof (Evidence) of Evolution: 5. Structural Adaptations: • Structural differences that are inherited • Ex. • Mimicry: one specie looks like another

  34. Cont. Ex • Camouflage: cannot be easily seen, blend in with their environment

  35. STOP!!! CK POINT!! Topic: theory of evolution From pg. 37: #6. #9 From pg.38: #11 #15 #18

  36. Patterns of Evolution: • Patterns in evolution were recognized • Include: • Use of pesticides and antibiotics • Co-evolution • Convergent evolution • Divergent evolution • Adaptive radiation

  37. Use of Pesticides &antibiotics Modern Times: Use of Pesticides • ex. NY black flies sprayed with pesticide DDT • most of the flies disappeared, some were resistant • those resistant reproduced, increasing in # • Thus producing pesticide resistant flies

  38. Use of Antibiotics: • new antibiotics continuously developed because bacteria become resistant to old meds • Viruses/bacteria changing strains, vaccines are not effective

  39. Ebola Virus

  40. Co-Evolution: • A change in a species in response to one another • The pressure on one influences which specie will thrive for the other • Ex. A flower and the animal that pollinates it

  41. Convergent evolution • Organisms that are not related but very similar in appearance • Similar Environmental demands work on 2 different organism • Results in similar appearances • Ex. Shark (fish) and dolphins (mammals)

  42. Convergent Evolution Ex DOLPHINS

  43. Divergent Evolution • Species become more different over time • A response to different habitats • Ex. Adaptive Radiation • Many new species evolve from a single ancestor • Finches on the Galapagos Island • Various primates

  44. Divergent Evolution Cont. • DE can occur on its own or be accelerated by outside forces (man) • Ex. Peppered Moths

  45. Peppered Moth: • 2 basic colors: light and dark • before Industrial Revolution light moths able to blend and avoid predators, the dark moths stood out to predators therefore decreased in population • after the I.R., the trees covered in soot, making the dark moth less visible than the white moth • white moth population decreased

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