Chapter 1: The Science of Biology

Pages 2-33

Chapter 1-1: What is Science?

Pages 2-7

Vocabulary 1-1

observationdatainferencehypothesistheory

Question: Why do we study science?

Three Main Goals of Science: 1.  To investigate and understand

nature2.  To explain events in nature3. To use explanations to make

useful predictions

Science starts with observation – using our senses to gather

information!• Info gathered is called data • Two types of observations:

1)Quantitative: involves #’s (ex. counting, measuring)

2)Qualitative: involves things that cannot be counted (ex. color, texture)

What are some quantitative observations from this photo?

What about qualitative?

Processing the Data• Observations are interpreted – called

inferences (a logical interpretation based on prior knowledge or experience)

• Inferences lead to a hypothesis (a possible explanation for a set of observations or an answer to a problem)

Hypotheses must be testable! They are only supported or refuted, NEVER PROVEN!

Processing the Data

• When numerous tests and evidence support a hypothesis, it becomes a theory (a well-tested explanation that unifies many observations)

What makes a good scientist?

• Curiosity• Honesty• Openness• Skepticism• Recognition that science has limits

Remember…achieving the goals of science does not depend on science alone – very often our society, laws, morals all play a part in making final

decisions regarding science.

Chapter 1-2: How Scientists Work

Pages 8-15

Chapter 1-4: Tools and ProceduresPages 24-28

Vocabulary 1-2 and 1-4

scientific methodcontrolvariableelectron microscopemetric systemmicroscopelight microscope

Question: What steps do scientists take to solve

problems?

Answer: They use the Scientific Method.Definition: an organized way to solve a

scientific problem

Scientific Method

1) Stating the problem•Use observations to define a problem

2) Forming an hypothesis

•Use prior knowledge and experience to make a prediction

3)  Setting up a controlled experiment• Test your hypothesis with a

controlled experiment

• In a controlled experiment, only one variable in the experiment is tested at a time – all other variables must be kept the same (or controlled)

• control: factor that is not changed

• variable: factor in an experiment that can change

A little more on variables…

• independent variable – the variable that is deliberately changed (point of comparison)

• dependent variable – changes in response to the independent variable (support or refute hypothesis)

***All other variables must be controlled, or kept constant.***

4) Recording and analyzing results•Keep accurate records of all data•Data is only useful after it is analyzed

5) Drawing a conclusion

•Review hypothesis and draw a conclusion – either the hypothesis was supported or refuted

•An hypothesis is never proven…only supported or refuted!!

Example: Controlled Experiment –

Growth of Bread Mold

Let’s go through the scientific method to create a controlled

experiment…

Famous series of experiments using the

Scientific Method: • Redi (1600’s) – Spontaneous

Generation

Question: How do scientists collect data?

• Scientific measurements must always have a NUMBER and a UNIT

• Metric system: a decimal system based on certain standards and scaled on multiples of 10

• Also known as the International System of Units, or SI

• Base unit tells the type of measurement

• Prefix indicates the size of each unit in relation to base unit

Common Prefixes

•kilo - (k) - 1000x

•hecto - (h) - 100x

•deka (da) or (dk) - 10x

•deci - (d) - .1x

•centi - (c) - .01x

•milli - (m) - .001x

Common Metric UnitsLength = Meter (m) Mass = Gram (g)

1 meter (m) = 100 centimeters (cm)

1 gram (g) = 1000 milligrams (mg)

1 meter (m) = 1000 millimeters (mm)

1 kilogram (kg) = 1000 grams (g)

1000 meters (m) = 1 kilometer (km)

1000 kilograms (kg) = 1 metric ton (t)

Volume = Liter (L) Temperature = Celsius (°C)

1 liter (L) = 1000 milliliters (mL)

0°C = freezing point of water

1 liter (L) = 1000 cubic centimeters (cm3)

100°C = boiling point of water

Common Measurements

•Length = distance from one point to another (meter)

Measurement Tools: Length

Tools: Meter stick or ruler

Common Measurements

•Volume = the measure of the amount of space an object takes up (liter)

Measurement Tools: Volume

Tools: Graduated Cylinder or Beaker

Using the Graduated Cylinder

• A graduated cylinder is a glass tube that is marked with divisions to show the amount of liquid in it.

• The surface of the liquid will have a “belly-down” curve called a meniscus.

• Place the cylinder on a flat surface.

• Read the mark that lines up with the bottom of the curve.

Using the Graduated Cylinder

Common Measurements

•Mass = a measure of the amount of matter in an object (gram)

Measurement Tools: Mass

Tool: Balance

Organizing Data

• After collecting data from an experiment, it is important to present it in an organized manner, either with graphs or tables

• Graphs provide a visual representation of the collection of data or results of the experiment

Graphs

Complete graphs contain:1) A title2) Labels for the X and Y axes

• X axis typically shows the constant (ex. time)

• Y axis typically shows the factor that is changing (ex. number of offspring)

• Both labels must contain units

3) Key

Microscopes• Devices that produce images of

structures that are too small to see withthe unaided eye

Two types important in biology:1) Light microscope2) Electron microscope

Light Microscope

•Most commonly used microscope•Magnify objects up to about

1000 times•Can be used to see tiny

organisms and cells while still alive

•Special dyes can be used to show different structures

Electron Microscope

• Uses electrons as its source of illumination or vision

• Can form images of objects 1000 times smaller than those visible using a light microscope

• Two types:1) Scanning (SEM) – electrons go across image and make 3-D

image of surface2) Transmission (TEM) – electrons go through object – must be

thin

• Cannot be used to study live specimens (processes used would kill them)

SEM (very large, very expensive)

Mosquito Head (SEM Image)

X 200X 200 X 1,000X 1,000

Cell Parts (TEM Image)

endoplasmic reticulum/mitochondria/ribosomesendoplasmic reticulum/mitochondria/ribosomes

Chapter 1-3: Studying Life

Pages 16-22

Vocabulary 1-3

biospheretissueecosystemcommunitypopulationhomeostasisspecies

evolutionorganismDNAcellbiologysexual

reproductionasexual

reproductionmetabolism

BIOLOGY IS THE STUDY OF LIFE.

Living things have 8 common characteristics:

1) Made up of cells2) Reproduce3) Based on a universal genetic code4) Grow and develop5) Obtain and use materials and energy6) Respond to their environment7) Maintain a stable internal environment8) Change over time

1) Made up of units called cells

Cell: a collection of living matter enclosed by a barrier that separates the cell from its surroundings

• cells are the smallest unit of an organism that is considered alive

• some living things are composed of 1 cell (unicellular); others are composed of several cells (multicellular)

2) Reproduce

Two kinds of reproduction:1) Sexual - 2 cells from different parents unite to produce the first cell of the new organism

2) Asexual - a single parent reproduces by itself (ex. budding)

3) Based on a universal genetic code

• Genetic code of DNA determines the inherited traits of every living thing on Earth

What does this mean?• DNA is a molecule that

contains the directions for inheritance

4) Grow and develop• Each type of organism has a

distinctive life cycle – they grow in size and number of cells

• The cells also differentiate for specialized tasks (ex. heart cells vs. brain cells)

5) Obtain and use materials and energy

• metabolism – combination of chemical changes in which an organism builds and breaks down materials as it carries out its life functions

6) Respond to their environment

7) Maintain an internal balance• homeostasis – the process by which

organisms keep their internal conditions relatively stable, despite changes to external environment; it is necessary for survival

8) Change over time as a group, or evolve• a single individual does not evolve

but a group of individuals can evolve or adapt over a long period of time

Living things can be studied on many levels…from very large to

very small.• Biosphere – sum total of all the

ecosystems on Earth• Ecosystem – communities and

their non-living environment• Community – populations living

together in the same area• Population – members of the

same species living together in the same area

Levels of Organization

• Species – organisms that: 1) can mate

2) produce fertile offspring3) in nature (the wild vs. the lab)

• Organism – individual living thing

Levels of Organization

•Tissue – group of cells working together to do a job

•Cell – smallest functional unit of life

Levels of OrganizationBiosphere

Ecosystem

Community

Population

The part of Earththat contains allecosystems

Community and its nonliving surroundings

Populations thatlive together in a defined area

Group of organisms of onetype that live in the same area

Biosphere

Hawk, snake, bison, prairie dog, grass, stream, rocks, air

Hawk, snake, bison, prairie dog, grass

Bison herd

Levels of OrganizationOrganism

Groups ofCells

Cells

Molecules

Individual livingthing

Tissues, organs,and organ systems

Smallest functionalunit of life

Groups of atoms;smallest unit of most chemicalcompounds

Bison

Nervous tissue Nervous systemBrain

Nerve cell

Water DNA

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Have you ever heard of“nesting dolls?”