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Evolution

Evolution. Change in a population over time. Evolution is a Theory. You do not have to believe in the theories of evolution presented in these chapters. Many different theories will be presented. You are responsible to know about all the theories.

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Evolution

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  1. Evolution Change in a population over time

  2. Evolution is a Theory • You do not have to believe in the theories of evolution presented in these chapters. • Many different theories will be presented. • You are responsible to know about all the theories. • We will spend the most amount of time on the Theory of Natural Selection which is the one currently popular.

  3. FACTS of Evolution • Life on earth has changed overtime. • It is the change in the relative frequency of alleles in a population • This is well documented. • It can be replicated in the laboratory • THE PROCESS BY WHICH EVOLUTION HAS OCCURRED CAN BE EXPLAINED BY MANY THEORIES

  4. Theories of Evolution • 1. Theory of Creationism- • God created the world in 6 days • rested on the 7th. • “Let there be light” • Book of genesis- mirrors modern day theory just turn days into millions of years - man has a soul Man knows right and wrong- has a conscience

  5. Theories of evolution • 2. Theory of intelligent design • Organisms too complex just for random chance to explain how we came to be. • Must be a higher being guiding this process of natural selection • Photosynthesis?? • Respiration??

  6. Theories of evolution • 3. Extraterrestrial effect- • Life came from other planets- • Zeus, Apollo,- Greek gods really were visitors from another planet • Lines on plateau in Nazca Plateau, • Peru

  7. Theories of Evolution • 4. Natural Selection- • Mistake in DNA occurs. (change in the order of bases) • It changes the phenotype of an organism • Changes the amino acid or protein chain • Environment decides if mutation is beneficial or not. • If Trait is good – offspring will live • If trait is bad offspring will die • Nature selects for the best trait

  8. Proof of Evolution • 1. Fossil record supports evolution- although lots of gaps in record

  9. 2. homologous structures- same embryonic tissues but different adult function- • Batwing, human hand, whale fin

  10. 3. DNA similarities

  11. Proof of evolution • Vestigial organs • Organs reduced in size or non functioning • Skinks – useless legs

  12. Vestigial organs • Human- tailbone- appendix • Hipbone in whales

  13. Proof of evolution geographic distribution of species

  14. Turtles of the Galapagos Islands

  15. Charles Darwin

  16. Charles Darwin- • HMS Beagle voyage 1831( same time as Abe Lincoln) • Flunked out of medical school • Flunked out of the ministry • Traveled world- made observations and took careful records • Wrote book-” Origin of Species” 1836 • Would not publish it until 1859 only published it because Wallace papers destroyed in a fire.

  17. Wallace • Wallace came to same theory • Darwin was already famous for his other work. • Darwin wanted Wallace to present the theory.( and be excommunicated) • Wallace’s evidence – his notes that supported his paper -were destroyed in a fire. • So both presented the theory using Darwin’s notes as evidence • so Darwin got the credit for the theory. he was excommunicated)

  18. Darwin observations • A. no rabbits in Australia • B. no kangaroos in England • C. saw a rocky shoreline rise 9ft as the result of an earthquake • D. Went to the Galapagos Islands • Different islands • Different climates • Different animals

  19. Darwin influenced by many popular theories of his day( theories don’t just pop out of nowhere) • Hutton – geologist- earth results from processes going on for millions of years • Earth at least a million years old- very new idea • Now we know earth is 4.5 billion years old radioisotopes data

  20. Lyell theory of geology • The processes that shaped Earth’s past must still be working • Glaciations • Erosion • Volcanic eruption • Meteor strikes • Darwin witnesses an earthquake- saw a 9 ft rise in a range of earth

  21. Malthus- theories of population growth • If babies are born faster than people are dying • Then the population will increase • Eventually run out on room on earth • This does not happen as lots of babies die • Darwin realized that not all offspring must survive

  22. Lamark Theory - Use it or lose it • Lamark was wrong--- very popular Idea but wrong • Organisms acquire or lose certain traits during their lifetime and those traits are passed on to their young……… • If you become body builder- children will have big muscles

  23. Darwin’s book was called" On the origin of species” • Written in 1836 published in 1859 • 1. All species struggle for existence • A. All species compete for food, air, water, space • B. Not all survive • (battle at Kruger)

  24. Fittest? • Darwin used term Fittest • “Survival of Fittest” • Organism best suited to its environment is the most fit. Or has the best fit • Meaning it lives and reproduces • May not be the biggest or strongest – • it has the best fit

  25. adaptation An adaptation is any characteristic that increases fitness. POPULATIONS ADAPT… INDIVIDUALS DO NOT In a cave with no light color is NOT an adaptation. Smell might be. Giraffe adaptations / anything that might enable a giraffe to survive a 6ft drop during birth? NATURE | Tall Blondes | "Birth of a Giraffe" | PBS

  26. Peppered moth

  27. Darwin’s Theory of Natural Selection • Different traits exist in a population • Organisms with Traits best suited to the environment live and pass those traits on to their offspring • NATURE SELECTS THE BEST TRAITS OVER A LONG PERIOD OF TIME. • EVOLUTION- CHANGE IN A POPULATION OVER TIME

  28. In modern terms :Genes and Variation • 1. Gene pool: • All the alleles of a gene that are present in a population • 2. Relative frequency of an allele • The number of times that the allele occurs in a population • EVOLUTION is THE CHANGE IN THE RELATIVE FREQUENCY OF ALLELES IN A POPULATION • ( HOW OFTEN A GENE OCCURS -CHANGES)

  29. Sources of genetic variation • 1. mutations- change in DNA bases changes the order of amino acids – proteins • 2. gene shuffling- genes get mixed up – by chance – only some genes get passed on • a. sexual reproduction • b. death

  30. Evolution as genetic change • Single gene traits-easy to observe natural selection • Peppered moths and finches

  31. Polygenetic traits • Natural selection works 3 ways in polygenetic traits. • 1. directional selection- individuals at one end of curve selected for

  32. Directional selection-

  33. Stabilizing selection- • individuals in middle of curve selected for

  34. Disruptive selection • Individuals at upper and lower ends selected for- two species will result

  35. Genetic drift- sometimes nature does not select the best sometimes it just selects • Completely random change in allele frequency – may be quite sudden change • A. organisms • leave a • Population • B. organisms • killed off by • Random • chance –

  36. Evolution is occurring now • Formation of new species • A population becomes so different from another that interbreeding is no longer possible • Reproductive isolation • Behavioral- courtship rituals • Geographic isolation- physical barriers • Temporal isolation- reproduce at different times

  37. Peter and Rosemary Grant Studied finches in the Galapagos islands for 20 years. Noticed how birds with bigger beaks were selected for in times of drought. Evolution still occurring!

  38. Types of selection Natural Selection-nature selects the best “fit” organisms for that particular environment. Artificial selection-man selects the organisms that are best for him- not the organism. This can be a problem! Horse breeding Rats bacteria

  39. Rat evolution Rats killed by putting out rat poison in Oxford, England Over time only rats left are those that had a mutation that enabled them to eat rat poison and live Eventually rats evolved who could eat rat poison for lunch.

  40. Antibacterial resistance is rising Causes Overuse of antibiotics Antibiotics improperly used Antibiotics given to Chickens , cattle

  41. Current prescriptions

  42. Prevention of antibacterial resistance Vary antibiotics used Use correctly Use only when needed Vary cleaning products used

  43. How will humans evolve? • Give three ways the environment will change in the future • Give three ways humans might look if they have evolved to fit into this new environment. • Draw a picture

  44. Evolution vs. Genetic Equilibrium • Genetic Equilibrium-If allele frequencies do not change than evolution will not occur. • Hardy- Weinberg principle- to maintain genetic equilibrium a population must have these 5 : • A. Random mating • B. large population • C. no movement in or out • D. no mutation • E. no natural selection • (hw videos 3)

  45. evolution Variation exists in a population Man selects or Nature selects or Just random chance Evolution= change in a population over time

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