What Is Life?5.1

What Are the Characteristics of All Living Things?• 1. Cellular Organization: Organisms can

either be composed of only one cell or many cells.• Unicellular- single celled organisms

(bacteria)•Multicellular- many celled organisms –

the cells become specialized to carry out certain functions.

•2. The Chemicals of Life: •Water- most abundant•Carbohydrates- main energy source•Proteins and Lipids- building

materials•Nucleic Acid- are the genetic

material (carry the chemical instructions that cells need to carry out the functions of life

• 3. Energy Use• Organisms get energy from taking in and

breaking down materials. The combination of chemical reactions through which an organism builds up or breaks down materials is called METABOLISM.• Cells use energy to grow and repair.

• 4. Response to Surrounding:• All an organisms react to changes in their

environment. • Stimulus- change in an organism’s

surroundings that caused the organism to react• Response- an action or a change in behavior

• Ex: You knock over a glass of water causing you to jump.• Stimulus?• Response?

5. Growth and DevelopmentAll living things grow and develop.

*Development is the process of change that occurs during an organism’s life, producing a more complex organism.

• 6. Reproduction• Organisms reproduce in different ways.• - Asexual reproduction- involves only

one parent and produces offspring that are identical to the parent• -Sexual reproduction- involves two

parents and combines their genetic material to produce a new organism that is different from both parents.

Let’s Discuss…

• A bird sitting in a tree flies away as you walk by. Which of the life characteristics explains the bird’s behavior?• Response to surroundings• Trees do not move like birds do, but they

are living things. Why?• They have all of the characteristics of life.

Movement is NOT a characteristic of life.

What Do Living Things Need to Survive?1. Food

Autotrophs ????Heterotrophs ????

2. Water3. Living Space4. Stable Internal Conditions

Homeostasis- maintenance of stable internal conditions

Let’s Discuss…

• Which basic need is a fox meeting by feeding on berries?• Getting energy by eating food• The arctic fox has thick, dense fur in the winter

and much shorter fur in the summer. How does this help the fox maintain homeostasis?• It helps the fox keep its internal body

temperature stable even though the temperature of the fox’s surroundings change.