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Life Science 2 nd Semester Exam Review

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  1. Life Science 2nd Semester Exam Review

  2. Basic Concepts

  3. Structure of Ecosystems/Levels of Organization • Organism – individual living (biotic) thing • Population – group of organisms, all of one species, which live in the same place and the same time • Community – all the populations of different species, same place, same time • Ecosystem – Populations of plant and animals that interact with each other in a given area and with the abiotic parts (non-living) • Biosphere – The portion of Earth that supports life

  4. Ribosomes and DNA Has Nucleus No Nuclear Membrane

  5. CELL STRUCTURE Cell Structure

  6. Cell Structures • 1. Cell wall: rigid layer of nonliving material that surrounds the cells of plants • Made of cellulose • Protects and supports the cells

  7. 2. Cell membrane: Boundary that protects the cell from the environment & controls what comes in and out • All cells have • Like a screen door

  8. 3. Nucleus: control center for the cell

  9. 4. Ribosomes: grain like bodies on the ER & in the cytoplasm

  10. 5.Endoplasmic Reticulum: (called ER) carry proteins and materials within the cell

  11. 6. Golgi Body: receives and packages proteins from ER and distributes around cell and body (mailroom)

  12. 7. Cytoplasm: clear gelatinous fluid inside a cell

  13. 8. Vacuoles: storage area of the cellPlant has one large vacuoleStores food, waste, & enzymes

  14. 9. Mitochondria = powerhouse of the cell; where cell energy comes from.

  15. 10. Chloroplasts: ONLY IN PLANTS captures sunlight and produces food for the cell

  16. 11. Flagella = used for movement

  17. 12. Cilia = used for movement; tiny hair-like structures; found on cells that need to move mucus

  18. D. Absence of a nuclear membrane

  19. B. Viruses require a host cell to reproduce.

  20. C. flagellum

  21. B. flagella


  23. Questions they (OGT) has asked the last 4 years.

  24. D. Place the rabbit in a cage with a heated floor.

  25. B. D.

  26. Evolution Charles Darwin (1809-1882) • Natural Selection • “Only the strongest survive” • Darwin hypothesized that when animals had traits that helped them live, they would pass them on to their offspring. • Animals who did not possess these traits died.

  27. Darwin’s Example • Darwin noted the different beak structures of finches depended on the island they came from. • Finches who lived on islands plentiful in nuts and berries had different beaks than finches who lived on islands plentiful in insects.

  28. Even though all these birds are finches they developed different beaks depending on the plentiful food source of specific islands.

  29. Examples of Natural Selection • Galapagos Iguanas • Some iguanas have evolved to eat algae. • Some iguanas have developed large claws to help them cling to rock. • These iguanas evolved from other iguanas because they need those two traits to survive. • The algae eating, long clawed iguanas passed these trait on to their young. • Iguanas not having that trait. Everyday green iguana Galapagos marine iguana

  30. Camaflouge a. Enables species to blend in with their surroundings. Other adaptations Can you find the snake’s head?

  31. 2. Mimicry – enables a species to look like other species What part of the plant is this? It’s not part of the plant at all, it’s an insect.

  32. Darwin Hypothetical • Let’s say there was a new “killer” virus that affected dogs. • This flu bug only affected dogs with long hair. So, if a dog had long hair (more than ¾ inch long) it would get the virus and die. • In 20 years, will all dogs have long or short hair? WHY? • All dogs would have short hair because all the long hair dogs have died from the virus. There would only be short haired dogs mating with short hair dogs. • You could say all dogs with short hair were “naturally selected” to live. The dog species has evolved from having both short and long hair to having only short hair.

  33. REMEMBER • Populations evolve not individuals.

  34. B.

  35. C. Had a higher survival rate than light moths in the same area

  36. One last thing the OGT might get you on…… • Jean Baptiste Lamarck (1744-1821) • Came before Darwin • Had some of the same ideas as Darwin • No one ever believed him. • Died in obscurity and poverty.

  37. Genetics 1. The dominant trait will always be visible 2. Dominant-always masks the recessive; represented by uppercase letter (T, H, D, R) • Recessive-will be masked by dominant; represented by lowercase letter (t, h, d, r) -For a recessive trait to be visible, there must be two (tt, hh, dd, rr)

  38. XY XY XX C C C c Pedigrees XY XX c C C Father Mother Son Daughter Son

  39. Down Syndrome Karyotype

  40. Darwin’s Background • Born in England, 1809  • Studied Medicine at Edinburgh University • Transferred to Cambridge University • Studied to be a Minister Library of Congress, Prints and Photographs Division [reproduction number, e.g., LC-USZ61-104].

  41. Charles Darwin • Wrote in 1859: “On the Origin of Species by Means of Natural Selection” • Two main points: 1. Species were not created in their present form, but evolved from ancestral species. 2. Proposed a mechanism for evolution:NATURAL SELECTION

  42. Section 1 History of Evolutionary Thought Chapter 15 Darwin’s Voyage

  43. Example of Natural Selection