1. Biology Semester Review Fall 2009 The Nature of Science

3. Scientific Method PROBLEM / QUESTION OBSERVATIONHYPOTHESISEXPERIMENT COLLECT DATA ANALYSISCONCLUSION REFINE, RETEST

4. Observation vs. Inference Observation vs. Inference Observation –Used to collect data –States a fact Inference –Used to interpret data –States a conclusion

5. Variables in an experiment Independent variable:Independent variable: - variable being changed by you Dependent variable:Dependent variable: - variable that is measured/observed - responds to the independent variable Constant:Constant: anything in the experiment that remains unchanged.

6. Include a Control Something to compare your experimental results to.Something to compare your experimental results to. Helps us determine that the results were caused by the variables in our experiment.Helps us determine that the results were caused by the variables in our experiment. May be considered the “normal” conditions.May be considered the “normal” conditions.

7. Testing a Hypothesis What are you “testing” in the experiment?What are you “testing” in the experiment? –This is the INDEPENDENT variable –(Same as MANIPULATED variable) What effect will you be measuring in your experiment?What effect will you be measuring in your experiment? –This is the DEPENDENT variable –(Same as RESPONDING variable)

8. Hypothesis vs. Theory A THEORY is:A THEORY is: –a well-tested explanation that unifies a broad range of observations –supported by much data collected from many experiments and observations. A HYPOTHESIS is:A HYPOTHESIS is: –an prediction about the outcome of a single experiment. –supported or not supported based on one experiment. –must be testable –not an opinion

9. Accuracy How close the measured value is to the true or accepted value.How close the measured value is to the true or accepted value. ExampleExample : If an object has a real mass of 2 grams and the balance used gives a reading of 2 grams, the measurement is accurate. If the balance reads 1.8 grams it is inaccurate.

10. Precision How close together a group of measurements actually are to each other. Example: If an object has a mass of 2 grams and a person masses it as 5 g three time in a row. The person shows precision (but not accuracy)

11. Which ruler is more precise?

12. Data Collections Quantitative –A measurement that uses numbers –Ex. The plant grew 12 cm. Qualitative –Descriptive observation –Ex. The leaves on the plant turned brown.

13. Graphing in Science Title the graphTitle the graph Label and number your axesLabel and number your axes Scale the graph so it fills up the spaceScale the graph so it fills up the space Include unitsInclude units Make a keyMake a key Always……

14. DRY MIX Dependent Responding y-axisDependent Responding y-axis Manipulated Independent x-axisManipulated Independent x-axisEXAMPLE: Problem: You have a massive headache Question: Which pill works best? -Use 4 different types of pills -Record the speed of time when your headache is over -Concentration of the pills remains the same

15. Types of Graphs : see one variable over timeLINE GRAPH: see one variable over time : compares objectsBAR GRAPH: compares objects : parts of a whole/ percentagePIE GRAPH: parts of a whole/ percentage

17. What are the Characteristics of Living Things? Pg. 16 Composed of one or more cells Reproduction Universal Genetic Code Growth & development Energy use and metabolism Response to stimuli Maintenance of homeostasis Capacity for change (adaptation)

18. Cells Smallest unit capable of all life functions Unicellular Organisms - Entire organism is made up of one single cell Unicellular Organisms - Entire organism is made up of one single cell EX. Bacteria and protists Multicellular Organisms - The organism is made up of many cells Multicellular Organisms - The organism is made up of many cells Cells have specialized functions within the organism Cells have specialized functions within the organism EX. Trees, Humans, Mushrooms

19. Organization Atom Molecule Organelle Cell Tissue Organ Organ System Multicellular Organism

20. Reproduction All organisms reproduce in order for their species to continue life Asexual reproduction- involves only a single parent; the offspring would then be genetically identical to its parent Sexual reproduction- involves 2 parents; this produces genetically diverse offspring

21. Universal Gentic Code Genes carry hereditary information Genes are composed of DNA Determines the inherited traits of every organism on earth Heredity is the reason children resemble their parents

22. Growth & Development Single Celled Organisms – Grow to larger size Multicellular Organisms – Differentiation for specialized functions

23. Energy Use & Metabolism Metabolism- the sum of all chemical processes that occur within a living organism in order to maintain life Organisms use energy to carry out every day functions All organisms MUST acquire energy somehow Ex. Plants require Sunlight Humans require food

24. Organisms react to stimuli: Light Light Temperature Temperature Odor Odor Sound Sound Gravity Gravity Heat Heat Water Water Pressure Pressure An example is a plant’s leaves and stems growing toward light

25. A stable state of conditions in the body that are necessary for life Body temperature Body temperature Blood volume Blood volume pH balance pH balance Water balance Water balance

26. Adaptation A process that enables organisms to become better suited to their environment A process that enables organisms to become better suited to their environment Species obtain adaptations through evolution over great periods of time Species obtain adaptations through evolution over great periods of time Evolution- organisms change over time through natural processes that select individuals with the best adaptations

28. What is Geologic Time? “Eons” – Largest -“eras” -“periods” -“epochs” Usually the oldest sections are shown on the bottom and the most recent sections are shown on the top

29. How is Time Divided? Major changes in Earth’s history mark the boundaries between the sections Most sections have been divided because a major organism developed or went extinct.

31. Precambrian Time

32. Time from the formation of the Earth (~4.6 billion years ago) to 542 million years ago The Earth was very different then -there was no oxygen or living things The first organisms appeared in the oceans 3.6 billion years ago -They were called Prokaryotes

33. Paleozoic Era Began 542 million years ago and ended 251 million years ago Divided into 6 periods Many new life forms appeared during the 1 st period, the Cambrian Period = “Cambrian Explosion” For the first time on Earth, organisms had hard parts (shells, exoskeletons) Some organisms that were alive during this period still exist today (ferns and salamanders) but they were giants!

34. Mesozoic Era

35. Began 251 million years ago Surviving reptiles and amphibians evolved into many other species (like dinosaurs) = “Age of Reptiles”

36. Cenozoic Era

37. Began 65 million years ago and continues today Scientists know the most about this Era because the fossils are in the top rock layers and are easier to find Land & climate has changed a lot What big change will happen that will end this era & start the next?

38. Determining How Old Things Are

39. Fossil Record When comparing fossils found in rock layers, the deeper the layer, the older the fossil.

42. Water carries small rock particles to lakes and seas Dead organisms are buried by layers of sediment, which forms new rock. The preserved remains may later be discovered and studied.

43. Radiocarbon Dating

44. Method of Radiocarbon Dating

45. Radiometric Dating: History dinosaurs humans first life origin of Earth en.wikipedia.org/wiki/Image:Eopraptor_sketch5.png © World Health Org. © NASA first complex cells

46. Geologic Time and Earth History

48. Ecology

49. Levels of Organization

50. Energy Pyramid Shows the amount of energy available at each trophic level 100% 10% 1% 0.1% Primary Consumer Secondary Consumer Tertiary Consumer Producer L4 L3 L2 L1

51. Niche - the total role of a species in an ecosystem –All the physical and biological conditions a species needs to live & reproduce in an ecosystem Interactions in an Ecosystem

52. Predation – one organism captures and feeds on another Interactions in an Ecosystem  Relationships

53. Predator – Prey Cycle SOURCE: Isle Royale Wolf/Moose Study | GRAPHIC: By Patterson Clark, The Washington Post - July 21, 2008

54. Interactions in an Ecosystem  Relationships Competition – organisms of the same or different species attempt to use the same resources at the same time

55. Interactions in an Ecosystem  Relationships Symbiosis – any relationship in which 2 species live closely together –Mutualism –Commensalism –Parasitism

56. Mutualism: Win-Win Relationship Both of them benefit Pollination of flowers by insects Oxpeckers and black rhinoceros

57. Commensalism: Using without harming One is helped and has little or no effect on the other Burrs are carried by animals. This helps scatter the seeds for the parent plant.

58. Parasitism: Sponging Off of Others One benefits and the other is harmed Mosquitos Tapeworms

59. Limiting Factors Biotic or abiotic resource that limits the size of a population

60. What is the carrying capacity?

61. Populations can grow until competition for resources increases & the carrying capacity is reached

62. Biomagnification Concentration of toxin at higher trophic levels