Evolution

1. Evolution

2. EVOLUTION • Theory, which means: based on fact, but not proven

3. EVOLUTION • 3.5- 3.9 billion years ago, first organisms appeared • probably prokaryotes; one celled without a nucleus • eventually mutations occurred that formed eukaryotes • one celled organisms with a nucleus.

5. Fossil evidence • evidence of plants and animals that used to live • found in sedimentary rock • relative dating: the oldest is on the bottom layer, the newest fossil is on the top layer

6. radiometric dating • using radioactive isotopes to find age of fossils

7. mass extinction • when many organisms stop existing all at the same time

8. Extinction • Give a possible reason this species died out

9. Reasons may include • Loss of food • Loss of habitat (change in shelter or protection) • Increased predation • Sudden Climate change Scientific name: Smilodon

10. Evolutionary relationships • This diagram illustrates a proposed evolutionary path for certain organisms. • 2 organisms that will probably have the greatest similarity of DNA base sequences are • H and J

11. shows that change takes time and is not predictable • the most recent ancestor of organism F is organism C • if A is a multicellular heterotroph, organism B is probably a multicellular heterotroph

12. Beaks of Finches

13. The technique in use today that will speed up the evolution of a species • is genetic engineering because DNA is being changed in a lab, not waiting for a change to occur with normal reproduction (ex. firefly gene into mice)

14. Adult T cell lymphoma leukemia (ATLL cancer) • took a firefly glow gene inserted it into tumor cells. • That gene produces the enzyme luciferase in the insects which, when combined with another compound, luciferin, causes the firefly's distinctive glow. • The mice then received these genetically modified tumor cells and the researchers injected luciferin into the animals. Cancer cells containing the luciferase would combine with the luciferin and glow in the dark, giving the team a clear picture of the extent of disease inside the animal. • Then did drug studies to see what drugs worked better

15. Mice in dark chamber, low light detecting camera

16. NATURAL SELECTION(page 401) • Darwin, 1831, sailed on ship called the Beagle to the Galapagos Islands • Darwin knew that most species overproduce, but do not overrun their ecosystem. • Most species struggle to survive because of • Food, water • space • competition … predators

17. Finches • Found that the birds on the islands were finches, but had different characteristics than the finches back in England. • If a species can eat, it will reproduce, therefore passing its genetic code or traits to the next generation. This is the basis for Natural Selection • The finches therefore had different beaks because of different food supplies

18. CAUSES OF NATURAL SELECTION • change in food, change in predator, change in climate • change in reproductive patterns • Amish exhibited higher incidence of rare alleles, after religion was established • Bacteria that develop penicillin resistance- rare one survives, and can reproduce. Over time, increases in population

19. What we are seeing now, with increased drought • Forest turns to desert, (desertification); insects with tan color used to be 0.5% of population, • now tan survives, becomes 99%, • green color is now 0.5%

20. EVIDENCE FOR EVOLUTION • An adaptation is any variation that allows survival • Usually occurs over long periods of time • 2 variations that help organisms include • Mimicry : look like dangerous organism • Camouflage: blend in • Evidence for Evolution includes Fossils

21. Homologous structures • structures that look similar • 2 examples include: whale and crocodile • Both have a forelimb

22. Vestigial Structures • a body part with no apparent function • For example appendix in humans • eyes on blind mole-rats get it?

23. Embryology • Embryos of different organisms develop through similar stages • For example tail and gill slits in human embryo

24. fish salamander turtle chicken cow rabbit human pig

25. Biochemistry • comparing DNA and RNA and proteins from different species. • all life has DNA…. That is amazing • And all DNA is made of sugars and phosphates with • Adenine, thymine, cytosine and guanine as the nitrogen bases…..wow

26. OTHER NAMES IN EVOLUTION(Science Dudes) • Redi: late 1600’s- used a controlled experiment to disprove spontaneous generation, meaning organisms could just (poof!) appear from the air • formed theory of BIOGENESIS meaning life only comes from living creatures

27. Linneaus • late 1700’s (time of our Revolution) • father of modern classification: based classification system on characteristics of the organism (shape of leaf, number of legs)

28. LaMarck • early 1800’s • Scientist who thought that a trait was created by a force in nature, and could be passed to the next generation. • for example, • giraffe’s neck is long due to its need to stretch to reach the leaves. • if you lose an arm, your child will have a problem with its arm

29. Pasteur • mid 1800’s- • proved milk goes sour because of microorganisms (bacteria), NOT because of bad spirits in the air. • Disproved spontaneous generation (POOF!)- Developed Pasteurization which heats and cools milk quickly to stop growth of bacteria

30. Work on the questions • Alone • By yourself

31. Sub: stop here