1. Module 1: How to Define Life
The Nature of Biology
Module 1: How to Define Life

2. How do you design an experiment?
A. Problem/Purpose
The question the lab will answer
Identifies the independent and dependent variables
Independent variable – the factor the scientist changes from group to group
Dependent variable – the factor the scientist measures to see the effect of the independent variable
Variables and Controls Videoclip

3. How do you design an experiment?
B. Research/Background Information
Lets the reader learn about the topic
Helps the scientist develop an educated hypothesis
C. Hypothesis
An educated prediction
Can be tested, proven false, and agrees with previous research

4. How do you design an experiment?
D. Procedure/Experiment
Steps must be precise and detailed
Has one control group
Normal conditions or absence of independent variable
Used for comparison
Experimental group(s) have only one changing variable (which is the independent variable)

5. How do you design an experiment?
E. Observations/Data
Must be objective.
Good Example: The bacterial colony is yellow.
Bad Example: The bacterial colony is nasty.
Use measurements whenever possible.
Good Example: There are 50 bacterial colonies.
Bad Example: There are a whole bunch of colonies.

6. How do you design an experiment?
E. Observations/Data
Do not draw conclusions in the data section of the report.
Good Example: There are bacteria and fungal colonies in the shoe section.
Bad Example: The shoe was really dirty and so it was the most contaminated and grew a lot of stuff.
Should be organized.
May use a graph, table, or drawing(s).
Always include units of measurement and a title.

7. How do you design an experiment?
F. Analysis/Conclusions
Answers the purpose question.
Accepts or rejects the hypothesis.
Explains what can be inferred from the data.

8. How do we know it is “good science”?
A. Scientific knowledge must be shared, which allows other scientists to repeat and verify the work of others (peer review).
A. Scientific knowledge is tentative.
Theories are the most logical explanation based on current evidence, become stronger as more evidence is gathered, and give us a basis for prediction.
Laws are universal generalizations that are virtually unchanging.

9. How do you know something is alive?
A. Biology means the study of (-ology) all life (bio-) and includes many branches.
B. Biologists organize living things into kingdoms. There are currently six kingdoms
Kingdom
Example
Archaebacteria
Extremophile bacteria
Eubacteria
Typical bacteria
Protista
Seaweed, Amoeba, Slime Mold
Fungi
Yeast, Mushrooms
Plantae
Moss, Fern, Holly, Oak tree
Animalia
, Fish, Birds, Frogs, Humans

10. How do you know something is alive?
Characteristics of Life - Alive! Videoclip
1. Organization (The level of complexity) a.
Organism
Organ System
Organs
Tissues
Cells
Molecules
Atoms / Elements
Meet the Elements - They Might Be Giants

11. How do you know something is alive?
All living things need six essential elements (atoms): Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur (CHNOPS)
All living things are made of cells.
One-celled organism – unicellular
Many-celled organism - multicellular

12. How do you know something is alive?
2. Energy Use
a. Organisms need energy constantly to build molecules (synthesis) and cells and to break down (digest) substances (such as breaking down food for nutrition)
b. Organisms must transport nutrients to be used in cellular respiration to produce energy.
c. An organisms’ chemical reactions are called its metabolism

13. How do you know something is alive?
3. Reproduction
a. Organisms must replace themselves so the entire species will survive.
b. May be asexual (only one individual contributes genetic material) or sexual (two individuals contribute genes).

14. How do you know something is alive?
4. Growth and Development
a. Growth – to increase in size. Increases the number of cells of a multicellular organism.
b. Development – change that takes place in structure and function of an organism during its life cycle.
Example: Embryo becomes a fetus

15. How do you know something is alive?
5. Respond to Stimuli
a. A quick, non-permanent change
b. Stimulus – any condition that causes an organism to react.
Example – A loud noise (stimulus) causes your dog to run under the bed (response).

16. How do you know something is alive?
Adjust to Environment
a.Homeostasis - the regulation of an organism’s internal environment to maintain conditions suitable for life
Ex: Getting rid of wastes by excretion

17. How do you know something is alive?
b. An adaptation is an inherited structure, behavior, or internal process that enables organisms to better survive an environment.
Ex: Gills on a fish

18. Life Processes: STERNGRR
Synthesis – making materials
Transport – moving materials
Excretion – getting rid of wastes
Respiration – gas exchange AND production of energy (ATP)
Nutrition – gaining and using energy from food
Growth and Development – getting bigger and/or changing
Regulation – controlling internal processes
Reproduction – producing new cells or new organisms

19. What technology allows biologists to study microscopic life?
A. Compound Light Microscope
Has two lenses – ocular (eyepiece) and objective
In order to be viewed, specimen must be thin (so the light may shine through the specimen) and placed on a slide.
Specimen may be stained to better see structures

20. What technology allows biologists to study microscopic life?
B. Electron Microscope
Uses electrons to produce an image
Types:
Scanning Electron Microscope (SEM)
Sends a beam of electrons across the object’s surface
Produces a 3-D image
Transmission Electron Microscope (TEM)
Designed to look at structures inside a cell
Capable of greatest magnification
Eye of an ant

21. What technology allows biologists to study microscopic life?
C. Limitations of microscopes
Magnification is limited by the strength of the lens.
Calculating magnification:
Ocular lens x objective lens = total magnification
Example:
Ocular (10x) x objective (40x) = 400x
As magnification increases resolution/(sharpness) decreases.