WHAT IS LIFE?Key concepts:

What characteristics do all living things share?Where do living things come from?

What do living things need to survive?

List in your notes what you know about living things. What is this?

It is a slime mold. It grows and is found usually on damp, decaying material in a forest floor.

What are the characteristics of all living things?

1. Have a cellular organization 2. Contain similar chemicals 3. Use energy 4. Respond to their surroundings 5. Grow and develop 6. Reproduce

Cellular organization

All living organisms are made of small building blocks called “cells”.

The cell is the basic unit of structure and function in an organism.

How do we see cells?

Most must be seen with the aide of a microscope. That is why you are learning how to use one.

How many cells are in organisms?

Some are composed of only one (1) cell! Organisms with only one cell are

called “unicellular”, or single-celled organisms.

These are the most numerous in the world and the group includes bacteria.

How are these unicellular cells made up?

As you can see, there are many parts. Each part has an important job to do to keep the bacteria cell alive. Many of the parts in a unicelluar bacteria, are also found in the multi-celled organisms.

Draw this:

Flagella & pili-movement. Capsule is to protect-jelly-like and sticky. Cell Wall -to keep the cell in shape and also protect. Cytoplasm-jelly-like fluid that fills the inner bacteria.

Multicellular organisms

These are composed of many cells and the cells are specialized to do a certain task.

Your body has literally trillions of cells. You have muscle and nerves cells, brain

cells, bone and skin cells—get the picture?

Muscle cells take messages from the nerve cells that take messages from the brain and you move!

The chemicals of life

Most abundant is water! Carbohydrates = energy source Proteins = building materials as well

as lipids—a fancy word for FAT. Nucleic acids are the genetic

materials = instructions to your cells. This is your DNA!

Energy Use

It takes energy to complete all the jobs a cell must do—like grow and repair any injured parts. Your body is busy right now and cells are regenerated all the time. Your stomach may be digesting food or your mind wandering into last night’s adventure instead of thinking about science!!

Your blood cells are taking oxygen to your organs:

White blood cells are fighting infection and bacteria in your body.

White blood cells are like soldiers in an army to protect your body.

Response to Surroundings

Anytime a change in an organism’s surroundings causes the organism to react, this is called a stimulus. The plural of this word is stimuli.

Examples of a stimulus would include any change in temperature, light, sound, and can include other factors also.

An organism reacts to a stimulus with a response—an action or change in behavior.

Stimulus and response

You either jump away to avoid getting milk on you or cry over “spilled milk”—ha, ha!

The sudden spilling of the milk caused your reaction or response.

Growth and Development

All living things grow and develop Growth = getting larger Development= process of change

that occurs during an organism’s life to produce a more complex organism.

These processes require energy.

Reproduction

To produce offspring that are similar to the parents.

Apples produce seeds that produce apple trees.

Robins produce baby robins. Mildew on your bathroom tile will produce

more mildew if you do not clean it off! YUK!

Turn to your textbook page 10A and read 10A-11A.

What you should have found out: Living things arise from living things

through reproduction Spontaneous generation is a mistaken

idea that living things can arise from nonliving sources.

Flies from decaying meat came from eggs laid on the meat in the jar w/o a lid.

The manipulated variable in this controlled experiment was a lid or not a fly.

Francesco Redi’s experiment

Pasteur’s experiment

The needs of living things

Flies, bacteria, and all organisms have the same basic needs as you.

Food, water, living space, and stable internal conditions (homeostasis=internal balance).

Food

This is the source of energy Plants capture the sun’s energy and use it to make food.

Organisms that can make their own food are called “Autotrophs”. They can make their own food from the sun.

Organisms that cannot make their own food are called “heterotrophs”. They must obtain their energy by feeding on others.

They use sun’s energy also but it comes from consuming other organisms that have eaten the sun’s energy. What does this remind you of? A food chain

Remember the Food Chain

Water

This goes without saying! You cannot live without water for very long at all.

Water carries important chemicals that the organisms need. H2O is Hydrogen and Oxygen.

Water can dissolve more chemicals than any other substance on earth. Blood carries many chemicals to the body that have been dissolved in the water in blood. (food, oxygen, to cells and carries waste CO2 out of the cells).

Living Space

A place for shelter whether in a tree or Anarctic or a desert.

More about living space

Space is limited on Earth. Every organisms must compete for space. Trees in a forest compete with other trees for sunlight and their roots compete for water and minerals from the soil.

Animals compete for caves and space in a tree for a home.

Every living thing must compete for their needs in order to live.

Stable Internal Conditions

Conditions inside the body must be stable. If the temperature goes up outside, your body still must remain at 98.6 degrees or your cells may suffer damage. In order to keep you cool, what does your body do for you?

Perspire or “sweat” to cool you off.

What does your body do if you are exposed to hours of sun and wind?

Your brain tells you that you are thirsty and to get a drink of water.

Study your notes!

Remember: The six characteristics of living things. Cellular organization, similar chemicals,

energy use, response to surroundings, growth and development and reproduction

The concept of spontaneous generation--the mistake that living things can arise from

nonliving things. What four things do all living things need to

survive? A source of energy (food), water, living

space, and a stable internal condition.

Grooooovy Baby!!!!

OK----any questions or do you have it now?