What is science?

• The root sci- means “to know”.– Science is 1 way of investigating the world in which we

live!

• Science strives to:– Explore & understand the natural world– Explain events in the natural world– Use those explanations to make useful predictions

Things that are not science:

• Art• Religion• Literature• Opinion

Is science better than these things?

NO! It’s simply another way of exploring the world we live in.

Science can only concern itself with testable things and/or observable things!

The Nature of Science

Is scientific knowledge a set truth?

NO

• In our scientific explanations, we explain natural phenomena & how things work using the knowledge we have.– When our knowledge base changes, our explanations

may change.

Scientific knowledge changes all the time!

Flat Earth Theory

• During the Middle Ages, it was widely accepted that Earth was flat.

• Pythagoras, a great mathematician (Pythagorean Theorem), proved that the Earth was spherical mathematically in the 6th century BC.

Flat Earth Theory Video

Flat Earth Theory

• Even though Pythagoras disproved it, general society still believed the Flat Earth Theory.

• 1519 – Ferdinand Magellan, an explorer, was recruited by Spain to sail the distance around Earth.– If Earth was flat, Magellan’s ships

would fall off the edge of Earth!

Flat Earth Theory

• Magellan’s ships set sail in 1519.– His ships returned to Spain in 1522.

• The ships had successfully circumnavigated Earth, proving the Earth was spherical.

What is biology?

• The study of life

So… what is life?

• In order to be considered living, an organism has to have the following 8 characteristics:a. It is made up of units called cells.

A single drop of blood contains millions of

red blood cells.

Characteristics of Living Organisms

b. Reproduce

Some living organisms reproduce sexually, while some reproduce asexually.

Characteristics of Living Organisms

c. Has a universal genetic code

Characteristics of Living Organisms

d. Grows & develops

Characteristics of Living Organisms

e. Responds to the environment

Characteristics of Living Organisms

f. Obtains & uses materials & energy

Characteristics of Living Organisms

g. Maintains a stable internal environment (homeostasis)

Characteristics of Living Organisms

h. As a group, change over time (evolution)

Biologists study life at many different levels.

Molecular biologists study the molecules that build life.

Ecologists study how organisms interact with each other & their

environment.

Life can be explored on many different levels.

A. Molecules: built by atoms, the building block of all matter

Life can be explored on many different levels.

B. Organelles: perform specialized functions within cells

Life can be explored on many different levels.

C. Cells: the smallest functional unit of life

Life can be explored on many different levels.

D. Groups of cells: tissues, organs, organ systems

Life can be explored on many different levels.

E. Organism: individual living system

Life can be explored on many different levels.

F. Population: group of organisms of 1 type that live in the same area

Life can be explored on many different levels.

G. Community: populations that live together in an area

Life can be explored on many different levels.

H. Ecosystem: community & its non-living surroundings

Desert Rainforest

Life can be explored on many different levels.

I. Biosphere: the part of Earth that contains all ecosystems