1. The Science of Biology
Chapter 1

2. 1-1 What is the goal of Science?
Investigate and understand nature
Explain events in nature
Use those explanations to make useful predictions

3. What is Science?
An organized way of using evidence to learn about the natural world
Body of knowledge that scientists have built up after years of using this process

4. The Scientific Method Stating Problem/Observations Hypothesis
Experimentation
Data collection and analysis
Conclusion
Answer to problem
Validity (restate data)
Prove/Disprove hypothesis
Errors
Improvements

5. Observations *using the senses to gather/collect data
Quantitative
-observations based on numbers or quantities
Ex.Counting/measuring
7 birds, 14 miles, 200 people
Qualitative
-observations based on description
Ex. Color/texture
blue neck, large teeth, soft cushion

6. Objective vs. Subjective Observations
Objective-without a predetermined point of view, unbiased
Subjective-with a predetermined point of view, biased (dangerous-Jews inferior to Germans)

7. Hypothesis
A possible answer to a scientific question or an explanation for a series of observations.
Ex. Use hypothesis to discover how infected disease was contracted:
-spread by human contact?
-spread through insect bites?
-spread through contaminated air/water/food?
**All of these are then tested to find the correct explanation.

8. Experimentation Controlled steps used to test the hypothesis
Controlled Experiment-only 1 variable is changed and all others are kept unchanged, or controlled.

9. Variables
Independent/Manipulated: the one that is deliberately changed/tested (only 1); on X axis.
Dependent/Responding: the one that is measured and changes in RESPONSE to the independent variable; on Y axis.
Controls: those that remain constant/unchanged

10. Data Collection and Analysis
Clear, precise, and objective
Displayed in table/graph
Understanding and making sense of observations
What does your data tell you about the experiment?

11. Conclusion Analyzing data brings you to a final decision/conclusion
Evidence found supports or refutes hypothesiswill test correct or wrong

12. Role of Experiments
Procedures used to study a phenomenon under known conditions
Allows you to predict what will happen if a hypothesis is not wrong
Can never prove a hypothesis 100% correct

13. Experimental Design Control group Experimental group
A standard for comparison
Identical to experimental group except no independent variable present
Experimental group
Independent variable present and being tested

14. CONTROL GROUP EXPERIMENTAL GROUP
Draw samples from some aspect of nature
CONTROL GROUP
The variable being
tested is absent
EXPERIMENTAL GROUP
The variable being
tested is present
Compile results
Compile results
Compare and analyze the test results
Report on experimental design, test results, and conclusions drawn from results

15. 1-2 Spontaneous Generation
Belief that living things arose from non-living things
Examples:
Maggots come from meat
Mice from wheat
Beetles from cow dung

16. Their Explanation…
**Gods, witchcraft, mythology, devil

17. Francesco Redi and Spontaneous Generation
Section 1-2
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.
PROCEDURE
Uncovered jars
Covered jars
Controlled Variables:
jars, type of meat,
location, temperature,
time
Several
days pass
Independent Variables:
gauze covering that
keeps flies away from
meat
Dependent 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. What is Redi’s Conclusion?
Spontaneous generation does not occur.

19. The Return of Spontaneous Generation
Anton van Leeuwenhoek – uses a microscope to find tiny organisms swimming in pond water. “animalcules”
John Needham (mid 1700’s) performs an experiment that refutes Redi
Lazzaro Spallanzani – improves Needham’s experiment

20. What are the controlled variables? What are the independent variables?
Figure 1-10 Spallanzani’s Experiment
Section 1-2
What are the controlled variables?
What are the independent variables?
Gravy is boiled.
Flask is
open.
Gravy is teeming
with microorganisms.
Flask is
sealed.
Gravy is free of
microorganisms.
Gravy is boiled.
What are the dependent variables?

21. Controlled variables: Gravy, flask, heat
Independent variables: sealed flask
Dependent variables: presence/absence of microorganisms

22. The debate continues
In the 1800’s some believe the air contained a “life force” perpetuating the belief of spontaneous generation.
Louis Pasteur –1864, his experiment finally disproved spontaneous generation

23. Figure 1-11 Pasteur’s Experiment
Section 1-2
Broth is boiled.
Broth is free of
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with microorganisms.

24. Figure 1-11 Pasteur’s Experiment
Broth is boiled.
Broth is free of
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with microorganisms.

25. Figure 1-11 Pasteur’s Experiment
Broth is boiled.
Broth is free of
microorganisms
for a year.
Curved neck
is removed.
Broth is
teeming with microorganisms.

26. Pasteur’s Conclusions
All living things must come from other living things.
Opening the jar (Redi) exposes the contents to come in contact with organisms in the air, just as breaking neck of flask
(pg.13)What improvement did Pasteur make to Redi’s experiment?

27. What is a Theory?
A well tested explanation that unites many observations (evidence builds up to make hypothesis very well supported)
Can be proven wrong when new data arises to refute it.
May be revised or replaced by a more useful explanation.

28. List 5 things that all living things do:
1-3 Studying Life
What do all living things have in common?
List 5 things that all living things do:

29. Is a hurricane alive?

30. Are flowers alive?

31. Is a fire alive?

32. Is a dragon fly alive?

33. Is a river alive?

34. Is a crowd alive?

35. Characteristics of Living Things:
Made of units called cells
Reproduce
Based on universal genetic code
Grow and develop
Obtain/use materials and energy
Respond to environment
Maintain stable internal environment
Change over time

36. Living Things are Made of Cells

37. A Cell
Collection of living matter enclosed by barrier separating the cell from its surroundings.
Smallest units of an organism that can be considered alive.
Small size, but highly organized and complex.

38. Asexual Reproduction New organism has a single parent (ex
Asexual Reproduction New organism has a single parent (ex. Budding hydra)

39. Sexual Reproduction 2 cells from different parents unite to produce new organism (ex. Sperm and egg)

40. Universal Genetic Code
Universal Genetic Code **Everything living is based on this the molecule of inheritance

41. Growth and Development

42. Required for Life… Metabolism
-chemical reactions an organism uses to build up and break down materials
-how cells acquire and use energy to grow and survive
(ex. Digestion, making proteins)
Homeostasis
-keeping the internal conditions of an organism stable
(ex. Body temperature, breathing, heart rate)

43. Nothing Lives Without Energy
Energy = Capacity to do work

44. Homeostasis
Maintenance of internal environment within range suitable for cell activities
Ex. pancreas maintains level of sugar in blood by secreting hormones

45. Sensing and Responding
Organisms sense changes in their environment and make responses to them
Receptors detect specific forms of energy
The form of energy detected by a receptor is a stimulus

46. Evolution - as a group all living things change over time

47. Evolution Genetically based change in a line of descent over time
Population changes, not individuals

48. Figure 1-21 Levels of Organization
Biosphere
The part of Earth
that contains all
ecosystems
Biosphere
Community and
its nonliving
surroundings
Ecosystem
Hawk, snake, bison, prairie dog, grass, stream, rocks, air
Community
Populations that
live together in a
defined area
Hawk, snake, bison, prairie dog, grass
Group of
organisms of one
type that live in
the same area
Population
Bison herd

49. Figure 1-21 Levels of Organization continued
Individual living
thing
Bison
Organism
Groups of
Cells
Tissues, organs,
and organ systems
Nervous system
Nervous tissue
Brain
Cells
Smallest functional
unit of life
Nerve cell
Groups of atoms;
smallest unit of
most chemical
compounds
DNA
Water
Molecules

50. What are the different levels of organization in Biology
What are the different levels of organization in Biology? Smallest to Largest

51. Atom
Smallest unit of an a element that retains the properties of that element

52. Molecules - groups of atoms

53. Organelle
Membrane-bound internal compartment for specialized reactions
Not found in most prokaryotic cells

54. Cells - smallest functional unit of life

55. Tissues

56. Organs

57. Organ Systems

58. Organism - an individual living thing

59. Population - group of organisms of one type (species) living in the same area

60. Community - Populations that live together in a defined area

61. Ecosystem - community and its nonliving surroundings

62. Biosphere - Part of the Earth that contains all ecosystems

63. 1-4 Tools and Procedures

64. Metric System-SI-International System of Units
To collect data and perform experiments
Decimal system of units scaled on multiples of 10
Measures: length, mass, volume, and temperature

65. How can a graph help biologists to organize this data?

66. Microscopes-produce magnified images of structures too small for naked eye
Light Microscope-produce magnified images by focusing visible light rays.
Up to 1000 times.
Live and dead organisms
Fig (compound light microscope)
Electron Microscopes- produce magnified images by focusing beams of electrons.
Form images 1000 times more detailed than light microscope.
Fig. 1-26
Only dead organisms.
Have no color. Why?