Cells and Heredity: Chapter 1 Section1• Learning Targets:• 1. Students can explain how living things are

different from nonliving things.• 2. Students can describe how the microscope led

to the discovery of cells.• 3. Students can describe the cell theory

Living Things are Different From Non-living Things

• Any individual form of life that uses energy to carry out its functions is an organism

Living things share these basic four characteristics:• 1. Organization• 2. Grow and Develop• 3. Respond to its surroundings (environment)• 4. Reproduce

Living Things are Different From Non-Living Things

• An organisms body must be organized in a way that enables it to meet its needs.

• Ex. – A kingfisher has wings for flying, a heart for pumping blood, and eyes for seeing.

• Another characteristic for most organisms is that they grow and develop

• Organisms also respond to the world outside of them.

Needs of Life• All organisms need energy, materials, and living

space to carry out daily life activities.• The energy used by almost all forms of life on Earth

comes from the Sun

All Living Things Are Made of Cells• The cell is the smallest unit of a living thing.• Organisms made up of a single cell are called

unicellular organisms.• Unicellular organisms are usually to small to be

seen directly.• Organisms made up of many cells are called multi-

cellular organisms.• Ex. – Water Lily, Frog • Multi-cellular organisms have different types of cells

that make up their body parts.

Unicellular OrganismsParamecium Euglena

The Microscope Led to the Discovery of Cells

• Most cells are microscopic• A microscope is an instrument which makes an

object appear bigger.• Robert Hooke and Anton von Leeuwenhoek were

among the first people to see cells. • Robert Hooke looked at dead cells of a cork (tree

bark)• Anton Von Leeuwenhoek was one of the first

people to describe living cells.• Leeuwenhoek looked at a drop of pond water under

a microscope.

Robert Hooke & Anton van Leeuwenhoek

Robert HookeAnton van Leeuwenhoek

Robert Hooke - Cells

Cells Come From Other Cells

• The three concepts of the cell theory are:• 1. Every living thing is made of one or more cells.• 2. Cells carry out the functions needed to support

life.* 3. Cells come from other living cells

The Cell Theory is Important to the Study of Biology

• A scientific theory is a widely accepted explanation of things observed in nature.

• A theory must be supported by evidence, including experimental evidence and observations

• A theory can prove its value when it explains new discoveries and observations

Louis Pasteur• Pasteur observed that milk that turned sour

contained large numbers of single celled organisms called bacteria.

• He developed a process, now known as pasteurization, in which heat is used to kill bacteria

Bacteria and Spontaneous Generation• In a process known as spontaneous generation,

scientists once believed that bacteria grew from non-living materials.

• Pasteur conducted an experiment that disproved spontaneous generation.

• Pasteur began his experiment with sealed flasks containing broth.

• In the first experiment, the flask remained sealed while in the second experiment, the top of the flask was broken to expose the contents to air.

• Bacteria grew in only the second flask

Bacteria Cells