The Characteristics of Living Things Biologists use six characteristics to classify something as a living thing. Made of cells Composed of certain chemicals Use energy React to changes Grow and develop Reproduce

The Characteristics of Living Things All living things have these six characteristics. Anything without one of these six characteristics is nonliving. Living things are called organisms.

1. Cellular Organization Organisms are made up of one or more cells. A cell is the basic unit of structure and function in living things. Cells = the “Building Blocks" of life.

2. The Chemicals of Life Cells are composed of certain important chemicals like: Carbohydrates – main energy source Proteins and lipids – building materials Nucleic acids – genetic material

3. Energy Use All organisms need and use energy to live. Energy is the ability to do work. Sunlight is the source of energy for most living things. Plants use the energy in sunlight to make food, and animals get energy by eating plants or other animals that have eaten plants.

4. Response to Surroundings Organisms react to change in their surroundings. Any reaction to change is called a response. For example: A bright light may cause you to blink.

5. Growth and Development All organisms grow and develop. Living things change, or develop, during their lifetimes. One way organisms change is by growing. Living things may also change in appearance. For example: tadpoles and frogs

6. Reproduction Organisms produce more organisms of their own kind. Reproduction allows organisms to continue living on the earth.

Needs of Living Things All living things need four things to survive: Water Food Living space Stable internal conditions

1. Water Helps organisms to: * Break down food * Grow * Move substances within their bodies * Reproduce

2. Food Used to get energy for life functions Autotrophs/Producers= plants Heterotrophs/Consumers= most animals * Carnivores- eat meat * Herbivores- eat plants * Omnivores- eat plants and animals

3. Living Space Place where they can get food, water, find shelter Organisms may compete for this space

4. Stable internal conditions Homeostasis- organisms need to maintain stable conditions inside their body * Temperature * Amount of water Allows cells to function properly