Scientific Method

1. Scientific Method How Scientists Work

2. How Scientists Work:Solving the Problems • Much of biology deals with solving problems • These problems can be environmental, ecological, health related, etc. • No matter what types of problemsare being studied, scientists use the same problem-solving steps called… • The Scientific Method

3. Scientific Method Definition • The scientific method is- • A logical and systematic approach or process to problem solving.  • An organized way of using evidence to learn about the natural world.

4. Scientific MethodListing the Steps • Make an Observation • Define the Problem • Research the Problem • State the Hypothesis • Experiment to test Hypothesis • Collect and Record Data • Analyze Data • Draw Conclusions • Determine Limitations • Report Results

5. Question What does the scientist want to learn more about? First Then Research Gathering of information Next Hypothesis An “Educated” guess of an answer to the question Then Procedure/ Method Written and carefully followed step-by-step experiment designed to test the hypothesis Scientific Method An Overview Next Data Information collected during the experiment And And Observations Written description of what was noticed during the experiment Finally Conclusion Was the hypothesis correct or incorrect?

6. Scientific Method Ask Question • Let’s break each of these steps down into their individual components: Do Background Research Think! Try Again Construct Hypothesis Test with an Experiment Analyze Results Draw Conclusion Hypothesis is True Hypothesis is False or Partially True Report Results

7. Experimenting • Let’s look at the text book example of the Scientific Method using Redi’s Experiment on Spontaneous Generation • He was trying to disprove the idea of SpontaneousGeneration (or actually that flies came frommaggots, which camefrom flies) Francesco Redi (1668)

8. Stating the Problem • Example: How do new living things come into being? • Spontaneous generation once commonly accepted • Redi wanted to show what caused the appearance of maggots (and then flies) on meat

9. Belief based on prior observations • If leaf lands on water it becomes a fish • If bale of hay left in barn it produces mice • Muddy soil gives rise to frogs • Meat hung out in the market is the source of flies

10. Belief based on prior observations Redi observed that maggots appeared on meat a few days after flies were on meat No microscope = no way to see eggs But Redi believed that maggots came from eggs that were laid by flies

11. Forming a Hypothesis Redi’s Hypothesis: Flies produce maggots. • How could he test this? • Through a controlled experiment

12. Jars with meat Uncovered jars Covered jars Redi’s Controlled Experiment • Redi used two groups of jars • Jars that contained meat and no cover • Jars that contained meat and gauze cover

13. Uncovered jars Two groups of jars Covered jars Control and Experimental Groups Control group: • used as a standard of comparison • the group containing the factor (variable) that has been changed Experimental group: (manipulated or independent variable)

14. Variables in an Experiment • Variables - Factors that can be changed • Controlled Variables - all the variables that remain constant • Independent Variable - (also called the Manipulated Variable) - factor in an experiment that a scientist purposely changes • Dependent Variable- (also called the Responding Variable) - the outcome or results, factor in an experiment that may change because of the manipulated variable….what a scientist wants to measure or observe

15. Variables in Redi’s Experiment • Controlled Variables: jars, type of meat, location, temperature, time • Manipulated Variables: gauze covering that keeps flies away from meat

16. Two groups of Jars with meat Uncovered jars Covered jars Let’s think about this.… Uncovered jars • Which is the control group? • Which is the experimental group? Covered jars

17. Redi’s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Covered jars Uncoveredjars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

18. 6. Collect and Record Data observations and measurementsmade in an experiment Data: Types of Recorded Data • Quantitative - observations that involve measurements/numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters • Qualitative - observations thatdo not involve numbers, are of a descriptive naturei.e. white maggots covered the meat, leaves were all wilting

19. Recording the data Setting up a data table Graphing data

20. 7. Analyze the Data • Examine data tables, charts, and graphs • Examine experimental notes • Look for trends, patterns, and averages • What does the data show • Put your data into words

21. 8. Draw Conclusions • Restate the hypothesis: Example: Flies produce maggots. • Accept or reject the hypothesis. • Support your conclusion with specific, numerical data. • What was Redi’s conclusion? • Flies lay eggs too small to be seen. • Maggots found on rotting meat are produced from the eggs laid by flies. • Maggots are not appearing due to spontaneous generation!

22. 9. Determine Limitations • Scientists look for possible flaws in their research • They look for faulty (inaccurate) data • They look for experimental error or bias's • They decide on the validity of their results • They make suggestions for improvement or raise new questions

23. 10. Publish Results • Communication is an essential part of science • Scientists report their results in journals, on the internet, or at conferences • This allows their experiments to be evaluated and repeated • Scientists can build on previous work of other scientists Redi’s experiment on insects generation

24. What is the difference • between • Hypothesis • Theory • Law

25. Introduction to Biology

26. THE SCOPE OF BIOLOGY • Biology is the scientific study of life • Interactions between different kinds of organisms affect the lives of all

27. Life’s levels of organization define the scope of biology • A structural hierarchy of life, from molecules to ecosystems, defines the scope of biology • An ecosystem consists of: • Biotic factors • all organisms living in a particular area • Abiotic factors • all nonliving physical components of the environment that affect the organisms (soil, water)

28. Ecosystems include: • all the organisms in an area, which make up a community • interbreeding organisms of the same species, a population • At the top of life’s hierarchy is the ecosystem

29. organ systems • organs • tissues • cells • molecules • Organisms are made up of:

30. THE PROCESS OF SCIENCE Scientists use two main approaches to learn about nature • In discovery science, scientists describe some aspect of the world and use inductive reasoning to draw general conclusions • Example: birds migrate South each year during colder months because it is warmer.

31. They propose a hypothesis • They make deductions leading to predictions • They then test the hypothesis by seeing if the predictions come true • In hypothesis-driven science, scientists use the “scientific method”

32. With the scientific method, we pose and test hypotheses • The main steps of the scientific method

33. Experiments designed to test hypotheses must be controlled experiments Experimental Design • Control groups must be tested along with experimental groups for the meaning of the results to be clear • Independent variable • Dependent variable

34. EVOLUTION, UNITY, AND DIVERSITY The diversity of life can be arranged into three domains • Grouping organisms by fundamental features helps make the vast diversity of life manageable for study • Scientists classify organisms into a hierarchy of broader and broader groups

35. Domain Bacteria - Domain Eukarya • Most classification schemes group organisms into three domains: • Domain Archaea

36. Unity in diversity: All forms of life have common features • All organisms share a set of common features, signs of unity in life’s vast diversity • All are made of cells • All have DNA as their genetic blueprint • These orchids show the variety possible within one species

37. Each species has its own nucleotide sequence • DNA is made of chemical units called nucleotides

38. Characteristics of Living Things: • The genetic information in DNA underlies all of the features that distinguish life from non-life • Order and regulation (homeostasis) • Growth and development • Use of energy from the environment • Response to environmental stimuli • Ability to reproduce • Evolutionary change

39. Evolution explains the unity and diversity of life • Charles Darwin is a central figure in biology • He synthesized the theory of evolution by natural selection • A theory in science is a comprehensive idea with broad explanatory power • Evolution is the core theme of biology

40. The theory of natural selection explains the main mechanism whereby all species of organisms change, or evolve

41. Evolution happens when populations of organisms with inherited variations are exposed to environmental factors that favor the success of some individuals over others • Natural selection is the editing mechanism • Evolution is based on adaptations

42. BIOLOGY AND EVERYDAY LIFE Connection: Biology is connected to our lives in many ways • Biology is connected to a great number of important issues • Environmental problems and solutions • Genetic engineering • Medicine

43. Evaluating everyday reports in the press about a large range of subjects requires critical thinking and some familiarity with many areas of biology • Many technological advances stem from the scientific study of life

44. Your turn…. • WAIT for Ms. Allard tell you to turn on your clicker and log in. • NO talking. You can use your notes but do not use each other! • You will NOT be able to change your answer so be sure you have read and understand the question(s) before you hit SEND! • Do NOT log off until Ms. Allard tells you to do so!

45. iRespond Question Multiple Choice F The ability to move and use oxygen are 2 characteristics of all living things. A.) true B.) false C.) D.) E.)

46. iRespond Question Multiple Choice F Biology can be related to our every day lives. A.) true B.) false C.) D.) E.)

47. iRespond Question Multiple Choice F The core theme of biology is A.) a hierarchy B.) the scientific method C.) DNA D.) evolution E.)

48. iRespond Question Multiple Choice F The prefix "a" means A.) with B.) without C.) single or solitary D.) one E.)

49. iRespond Question Multiple Choice F The prefix "bio" means A.) self B.) story C.) life D.) study of E.)