1. Biology, Chapter 1.1
What is Science?

2. Ch 1-1 Vocabulary
science
observation
data
inference
hypothesis

3. Science
organized way of using evidence to learn about the natural world; also, the body of knowledge that scientists have built up after years of using this process

4. Observation
use of one or more of the senses and / or our technology to gather information

5. Data
evidence; information gathered from observations
Data can be qualitative (descriptive), or quantitative (expressed as a number)

6. Inference
logical interpretation based on prior knowledge and experience

7. Hypothesis
possible explanation for a set of observations or possible answer to a scientific question.
A hypothesis is an “educated guess”, as it is based on knowledge, evidence, and logical inference from that data.

8. What Science Is and Is Not
Science seeks the best explanation for natural events, and uses those explanations to make useful predictions.

9. By the way - Science is NOT:
A faith
The “opinions” of smart people
A system of values*
A bunch of people who think they know everything!

10. Thinking Like a Scientist
(Decide what you want to know)
Observation
Data collection (qualitative & quantitative)
Form a hypothesis
Test the hypothesis (controlled experiment if possible)
Confirm or reject hypothesis
Publish results
Other scientists try to replicate results

11. Science as a Way of Knowing
Scientific knowledge is an ongoing process, it is always subject to change with new data.
Good scientists are “skeptics”, they question new and existing ideas

12. Science and Human Values
Scientific knowledge affects every aspect of our lives.*
What we CAN do is determined by science
What we SHOULD do is determined by educated people of our democracy

13. Section 1-1 Assessment Checkpoint
1. What does science study? 2. What does it mean to describe a scientist as skeptical? Why is skepticism considered a valuable quality in a scientist?

14. Section 1-1 Assessment Checkpoint
3. What is the main difference between qualitative and quantitative observations?
4. What is a scientific hypothesis? In what two ways can a hypothesis be tested?

15. Section 1-1 Assessment Checkpoint
5. Is a scientific hypothesis accepted if there is no way to demonstrate that the hypothesis is wrong? Explain your answer.

16. 6. Suppose a community proposes a law to require the wearing of seatbelts in all moving vehicles. How could scientific research have an impact on the decision?

17. 1–2 How Scientists Work

18. Vocabulary
spontaneous generation
controlled experiment
manipulated variable (independent variable)
responding variable (dependent variable)
theory

19. Spontaneous Generation
hypothesis (disproven) stating that life could arise from nonliving matter

20. Controlled Experiment
a test of the effect of a single variable by changing it while keeping all other variables the same

21. Independent Variable
(manipulated variable) factor in an experiment that a scientist purposely changes

22. Dependent Variable
(responding variable) factor in an experiment that a scientist wants to observe, which may change in response to the Independent (manipulated) Variable

23. Theory
well-tested explanation that unifies a broad range of observations

24. The Scientific Method*
State the Problem
Analyze Results
Form a Hypothesis
Draw a Conclusion
Set Up a Controlled Experiment
Publish Results*
Record Results

25. Redi’s Experiment on Spontaneous Generation
Since ancient times, people
believed that some animals
(like flies) spontaneously arise from non-living matter
1668 Francesco Redi, Italian physician and scientist proposed that maggots come from flies (laying eggs)

26. Redi’s Experiment 1668 Observation – insects lay eggs
State Problem: where do maggots come from?
State Hypothesis: Maggots come from flies laying eggs.

27. Set up a controlled experiment:
Control Group: meat in open jars
Experimental Group: meat in covered jars

28. Independent variable: covering on jars
Dependent variable: maggots appearing
Constants:
Type of meat - Type of jar
Temperature -Time
Etc.

29. Record Results
No maggots produced!!
Maggots produced

30. Analyze results: when flies can’t touch the meat, no maggots were produced
Draw conclusions: maggots are not spontaneously generated from rotting meat!

31. Publish results & repeat investigations
Mid 1700’s,
John Needham
investigates spontaneous
generation of microorganisms. He (mistakenly) concluded that microorganisms appear by spontaneous generation.

32. Repeat Investigations - Spallanzani
1768, Lazzaro Spallanzani tests Needham’s results
His findings refute Needham’s work

33. Spallanzani’s Experiment Control Group
Gravy is boiled
Left uncovered
Micro-organisms develop

34. Spallanzani’s Experiment Experimental Group
Gravy is boiled
Flask is sealed
No micro-organisms develop!!

35. Repeat Investigations - Pasteur
1864 – Louis Pasteur
improves upon
Spallanzani’s experiment
Pasteur’s experiment definitively disproves the hypothesis of spontaneous generation

36. Pasteur’s Experiment Broth is free of Broth is Curved neck Broth is
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with micro-organisms.
Broth is
boiled.

37. When Experiments are Not Possible* How a Theory Develops*

38. Section 1-2 Assessment Checkpoint
Why is Redi's experiment on spontaneous generation considered a controlled experiment?
How does a scientific theory compare with a scientific hypothesis?

39. Section 1-2 Assessment Checkpoint
3. How do scientists today usually communicate their results and conclusions?
4. How did the design of Pasteur's flask help him successfully refute the hypothesis of spontaneous generation?

40. Section 1-2 Assessment Checkpoint
5. Evaluate the impact of Pasteur's research on both scientific thought and society. What was the effect of Pasteur's investigations on scientists' ideas and people's lives?

41. 1–3 Studying Life

42. Section 1-3 Vocabulary biology cell
sexual reproduction asexual reproduction
metabolism stimulus
Homeostasis evolution

43. Section 1-3 Vocabulary
Biology - science that seeks to understand the living world
Cell - basic unit of all forms of life

44. sexual reproduction - process by which two cells from different parents unite to produce the first cell of a new organism

45. asexual reproduction - process by which a single parent reproduces by itself

46. Metabolism - set of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes

47. Stimulus - a signal to which an organism responds; any kind of detectable signal that carries information

48. Homeostasis - process by which organisms maintain a relatively stable internal environment

49. Evolution - change in a kind of organism over time; process by which modern organisms have descended from ancient organisms

50. Characteristics of Living Things
are made up of units called cells.
reproduce.
are based on a universal genetic code.
grow and develop.
obtain and use materials and energy.
respond to their environment.
maintain a stable internal environment.
Taken as a group, living things change over time.

51. Living Things are Organized at Many Levels
The Biosphere
Ecosystems
Communities
Populations

52. Levels of Organization - continued
Organisms
Tissues, organs, organ systems
Cells
Atoms & molecules

53. 1–4 Tools and Procedures metric system microscope
compound light microscope
cell culture
cell fractionation
electron microscope

54. A. Common Measurement System
B. Analyzing Biological Data
C. Microscopes
1. Light Microscopes
2. Electron Microscopes
D. Laboratory Techniques
1. Cell Cultures
2. Cell Fractionation
E. Working Safely in Biology