CELL IS BASIC UNIT OF LIVING THINGS

• Living Things are different from nonliving things: they have CHARACTERISTICS & NEEDS

• All living things are made of Cells• Microscope led to discovery of Cells• Cells come from other Cells• CELL THEORY is important to study of

BIOLOGY

CHARACTERISTICS OF LIVING THINGS

• Living things have these characteristics:– Organization

( body must be organized to help it meet its needs)

– Ability to develop & grow

– Ability to respond to the environment

– Ability to reproduce

NEEDS OF LIVING THINGS• Organisms need energy, material & living space. • All organisms need a steady supply of ENERGY to

stay alive.– Most all forms of life use energy originally from the Sun.

Some, like plants & bacteria, can capture the Sun’s energy to store it in food. The food animals eat comes from plants or other organisms (that eat plants)

• MATERIALS: Some comes from food for growth & reproduction. Some from Nitrogen, Oxygen, Carbon Dioxide & Water.

• LIVING SPACE: Need space to live & grow.• If any one of these requirements is missing, an

organism will die.

ALL LIVING THINGS ARE MADE OF CELLS

• Cell is smallest unit of living thing.

• One celled organisms are UNICELLULAR.

• If made of many cells: MULTICELLULAR

• Needs & characteristics of single celled organisms are the same as for multicellular.

• In multicellular, many different types of cells work together to carry out basic activities of life.

MICROSCOPE LED TO DISCOVERY OF CELLS

• Microscope = instrument which makes an object appear bigger than it is.

• In 1660’s, Robert Hooke used a microscope to look at many materials. While looking at dead cork cells (from oak bark) he saw tiny, empty chambers or “cells”. He came up with the term CELL.

• In 1670’s ANTON van LEEUWENHOEK looked at actual living cells in blood, teeth scrapings and rainwater.

Cells Come From Other Cells• By 1850’s, scientists saw

cells actually dividing.

• Observations and evidence gathered over many years by scientists became summarized in 3 concepts of CELL THEORY:

• Every living thing is made of 1 or more cells.

• Cells carry out the functions needed to support life.

• Cells come only form other living Cells

CELL THEORY IS IMPORTANT TO STUDY OF

BIOLGOY• French Scientist,

Louis Pasteur showed how microscopic organisms caused food spoilage & disease.

• Found way to heat milk to kill bacteria, that he knew spoiled milk.

• Using a microscope, Pasteur found microorganisms everywhere (air, water, & soil)

• Pasteur did an experiment (with boiling broth) showing bacteria are present in air & don’t grow spontaneously.