Cells and Heredity: Chapter 1 Section1

Learning Targets: 1. I can explain how living things are

different from nonliving things. 2. I can describe how the microscope

led to the discovery of cells. 3. I 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

Materials could be oxygen, shelter, carbon dioxide, water, etc.

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 Organisms

Paramecium

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 van Leeuwenhoek

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

(tree bark) Anton Van 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

supportlife.

* 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

Pasteur’s Test

Redi’s Test

Francesco Redi also helped to disprove spontaneous

generation with this experiment.

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