The Science of Biology

Chapter 1

Potatoes and Observations

1-1 What is the goal of Science?

• Investigate and understand the world around us

• Explain events in nature• Make predictions

The Scientific Method ObservationsState the Problem Conclusion

Hypothesis Data Collection and analysis

Experiment

Experimentation

• Controlled steps used to test the hypothesis

• Controlled Experiment-only 1 variable is changed and all others are kept the same.

• 2 Groups– Control Group: no IV tested; standard

for comparing with…– Experimental Group: IV tested

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/textureblue neck, large

teeth, soft cushion

Hypothesis

• A possible answer to a scientific question

Ex. Use hypothesis to discover how infected disease was contracted:

-spread by human contact?-spread through insect bites?**All of these are then tested to find the correct

explanation.

Procedures

• Procedural Drawings

Variables

• IV = Independent: the one that is tested (only 1); on X axis. AKA Manipulated Variable

• DV = Dependent: the one that is measured; on Y axis. AKA Responding Variable

• Controls: those that remain constant/unchanged

I.V. is changed by me- D.V. is the result I see!!!!

Data Collection and Analysis

• Displayed in table/graph• What does the data tell us??

– What does it mean?– How can I APPLY this information?

Conclusion

• Analyzing data brings you to a final decision/conclusion

• Evidence found supports or refutes hypothesis will test correct or wrong

• Validity• Future investigations New Qs• Improvements

Scientific method practice

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 challenge it.

May be revised or replaced by a more useful explanation.

1-3 Studying Life

• What do all living things have in common?

List 5 things that all living things do:

martian

Prosecutor-

Defense-

Is a hurricane alive?

Are flowers alive?

Is a fire alive?

Is a dragon fly alive?

Is a river alive?

Is a crowd alive?

What is Life?

6 Major Characteristics of Living Things:

• Grow• Genetic Information• Reproduce• Adapt and respond to their

environment• Made of Cells• Use and make Energy

• Remember: GGRACE !

Growth and Development

Universal Genetic Code**Everything living is based on this

the molecule of inheritance

Asexual ReproductionNew organism has a single

parent(ex. Budding hydra)

Sexual Reproduction2 cells from different parents unite

to produce new organism(ex. Sperm and egg)

Adapting 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

Living Things are Made of Cells

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.

Nothing Lives Without Energy

Energy = Capacity to do work

Evolution - as a group all living things change over

time

Evolution

• Genetically based change in a line of descent over time

• Population changes, not individuals

Homeostasis

• Maintenance of stable internal environment within range suitable for cell activities

• Ex. pancreas maintains level of sugar in blood by secreting hormones

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)

Work together

Redi’s experiment

What differences do you notice about the two groups?

Spallanzani’s Experiment

Pasteur’s ExperimentWhat do all 3 experiments have in common?

What does this tell us about where life comes from?

Spontaneous Generation

Real-life Connection!

Pasteur’s experiment

Is this process used today? (Hint- look at the scientist’s name)

What are the different levels of organization in Biology?

Smallest to Largest

Atom

• Smallest unit that takes up space

Molecules - groups of atoms

Organelle

• Membrane-bound internal compartment for specialized reactions

• Not found in most prokaryotic cells

Cells - smallest functional unit of life

Tissues

Organs

Organ Systems

Organism - an individual living thing

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

Community - Populations that live together in a defined area

Ecosystem - community and its nonliving surroundings

Biosphere - Part of the Earth that contains all ecosystems

You and the Levels of Organization

••••••

You

Atom Molecul

e

Cell Tissue

BiomePopulation

Organ systemsOrgan

CommunityEcosystemBiosphere

OrganisM

• Organization of Life Poster

1-4 Tools and Procedures

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

Metric Base Units

Mass- gram (g) Distance- meter (m)

Volume

Volume- liter (L)

Mnemonic

Kelly Had Dan’s Uncle

Drink Chocolate Milk

khdudcmKing Henry's Daughter Undercooks Delicious Chocolate Muffins

Units

Prefix SymbolFactor Number

Factor Word

Kilo k 1,000 Thousand

Hecto h 100 Hundred

Deca d 10 Ten

B A S E

Deci d 0.1 Tenth

Centi c 0.01 Hundredth

Milli m 0.001 Thousandth

Examples

• 1000 g = 1 kg

• 1000 m = 1 km

• 0.01 L = 1 cL

• 30 mL = ??? L

• 3.068 m = ??? mm

x1000 x1000

mg

mm

x10 x100 x1000

x1000

mL

x10 x100

x1000

Lab Materials per Group• Meter stick

• Metric ruler

• Test tube

• Rubber stopper

• Penny

• Triple beam balance

• 50 mL beaker

• 100 mL graduated cylinder

How can a graph help biologists to organize this

data?

Microscopes-produce magnified images of structures too small for

naked eye• Light Microscope-

produce magnified images by focusing visible light rays.

• Fig. 1-25 (compound light microscope)

• Up to 1000 times.• Live and dead

organisms

• Electron Microscopes- produce magnified images by focusing beams of electrons.

• Fig. 1-26 • Form images 1000

times smaller than those of light microscope.

• Only dead organisms.• Have no color. Why?