1. Chapter 1

2. What is Science?
Process that tries to explain how events in nature occur
Defined as systematic process of inquiry

3. Biology Science of life
Studies organisms – complete and entire living things

4. Characteristics of organisms
All organisms are made up of cells
Cells – basic unit of life
Organism can be one cell or millions of cells
Unicellular – organism made of one cell
Why is a virus not a cell?

5. Characteristics Continued
Organisms reproduce
Process by which organisms make more of their own
Necessary or there would be extinction
But it is not necessary that all organisms reproduce
Two kinds of reproduction
Asexual reproduction – no joining of cells, one parent, no variations in offspring
Sexual reproduction – joining of two cells, two parents, variations in offspring

6. Characteristics Continued
Organisms have metabolism – total sum of all chemical activities in an organism
Organisms must obtain and use energy to grow, move, and process information
Two kinds of metabolic activity:
Anabolic – activities that build materials, such as photosynthesis, protein synthesis
Catabolic – activities that tear down substances, such as digestion, cellular respiration

7. Characteristics Continued
Organisms maintain homeostasis – steady state of balance
Organisms respond to changing conditions internally & externally
Organisms respond so that they can maintain homeostasis
How do we maintain homeostasis of our body temperature?

8. Characteristics Continued
All living things exhibit heredity – passing of traits from parents to offspring
This is done through genes – basic unit of heredity – section of DNA
Mutation – changes in DNA, can be harmful or helpful
Example: sickle cell anemia
If mutation is in a sex cell – harm to offspring
If mutation is in a body cell – harm to individual

9. Characteristics Continued
Evolution – change in the inherited traits of a species over time
Species – group of similar organisms that can mate and produce fertile offspring
Fertile – able to reproduce
Some members of a species have differences called variations
These variations make them survive better and produce more offspring
So species changes gradually over time
Natural selection – organisms with favorable genes are more likely to survive and reproduce

10. Characteristics Continued
Interdependance
Organisms in a biological community live and interact with each other
Ecology – branch of biology that studies the interactions of organisms with one another and with the nonliving part of their environment.

11. Branches of Biology: Cytology – study of cells
Genetics – study of heredity
Evolution – study of changes in organisms over time
Ecology – study of how organisms effect each other and their environment
Microbiology – study of small organisms
Taxonomy – study of the classification of organisms

12. Branches of Biology: Anatomy – study of the structures of organisms
Physiology – study of how the structures of organisms work
Paleontology – study of extinct organisms
Botany – study of plants
Zoology – study of animals
Ethology – study of animal behavior

13. Occupations that require Biology
Doctor, nurse, vet, marine biologist, physical therapist, dietician, pharmaceutical representative, farmer, landscape designers, dentist, dental hygienist, eye doctor (these are just a few of the many careers in the field of Biology)

14. Scientific Method
To find out how things work, scientists use the scientific method
Scientific method is defined as a logical and orderly way to solve a problem

15. Steps: Observe and state the problem
Form a hypothesis. Hypothesis – educated guess
Test the hypothesis
2 setups for this: control & experimental
Only difference between them – variable
Independent variable – factor that is changed from the control to the experimental groups
Dependent variable – factor that is measured in the experiment
Record & analyze data. (Refer to page 9 table & graph)
Form a conclusion
Be able to replicate your work. Take clear notes as you work

16. Hypothesis:
Is tested and confirmed by others becomes a theory – time-tested concepts that make useful and dependable predictions about the natural world

17. The metric system
Science works best when scientists everywhere read each other’s papers, check each other’s experiments and agree about what those experiments mean. To do this a universal system of measurements is needed. The metric system is used and the universal system of measurements. It is called the International System of Units or the SI. It is based on multiples of 10 which makes it easier to use than the English system.
(Refer to table of page 11)

18. Metric Units:
Length – how long an object is. The basic unit of length in the metric system is the meter (39.4 inches). Centimeters or millimeters are used for small objects. Kilometers are used for longer distances.
Centi means 1/100 or one-hundredth
Milli means 1/1000 or one-thousandth
Kilo means 1000

19. Metric Units:
Volume – amount of space an object occupies. The basic unit of volume in the metric system is the liter. It is a little more than a quart. Milliliters are used to measure small amounts of liquid
Cubic centimeters (cm³) is used to measure the volume of solid objects. Displacement in water is used to measure solid, irregular objects
Length x width x height is used to measure the volume of regular, solid objects.
1 ml = 1 cm³ = 1 cc

20. Metric Units: Mass – measure of amount of matter in an object
Weight – measure of the pull of gravity on an object
On Earth, mass and weight are usually the same and used interchangeably.
Basic unit of mass in the metric system is the kilogram. Grams are used to measure the mass of small objects

21. Metric Units:
Temperature is measured in degrees Celsius. On the Celsius scale:
Boiling point of water = 100
Freezing point of water = 0
Room temperature = 21
Body temperature = 37

22. Tools of the Biologist:
Microscope – used to enlarge an image
Kinds:
Compound light microscope – has 2 lenses that work together along with light to produce a visible, enlarged image
Magnification – enlargement of an image
Resolution – production of a clear image
Light is the energy source
Two lenses are located in the eyepiece and the objective
To determine the magnification of the microscope:
magnification of the eyepiece x magnification of the objective
Limitation of the light microscope:
The greater the magnification, the less resolution. This means the larger the image is the less clear id is.

23. Tools Continued
Electron microscope – uses a beam of electrons as the energy source
Has tremendous magnification – up to 200,000x
However, living materials cannot be used due to the way that materials have to be prepared to be used in the electron microscope
Two kinds of electron microscope
Transmission electron microscope (TEM)
Used to view the internal structures. Done in a vacuum. The image is projected onto a screen
Scanning electron microscope (SEM
Use to view the 3-D surface of an object. Object is coated with a metal

24. Tools Continued Scanning tunneling microscope
needle-like probe to measure differences in voltage caused by electrons that leak from the surface of an object being viewed
Produces a 3-D image of surface