Characteristics of Life Organisms are things that exhibit all of the characteristics of life

1. Organization Living things are organized into specialized structures that carry out specific functions that help the organism function as a whole Ex/ Muscles are organized into the muscular system which helps organisms move Ex/ Organelles like a cell wall protects plant cell, provides structure

Multicellular organism = two or more cells working together Unicellular organisms = one cell (organelles are the structures that carry out each life function) Multicellular organism = two or more cells working together Generally, multicellular organisms have different TYPES of cells that do different jobs They can be organized into more complex systems (tissues, organs, organ systems)

2. Growth and Development Both unicellular and multicellular organisms grow. Unicellular - increase in size, Multicellular – increase the number of cells Development occurs as each living thing goes through its life cycle and matures

3. Reproduction Living things must be able to create more living things (new organisms) This can happen in different ways: Sexual reproduction – requires a mate Asexual reproduction – one parent (divides, etc.)

4. Response to Stimuli Adjust and respond to changes in the environment Internal Stimuli – changes within the organisms internal environment Getting a fever when you are sick, feeling thirsty or hungry External Stimuli – changes in the environment around an organism Sweating when its hot, shivering when its cold, eyes dilating when its bright out Plants grow towards sunlight, animals fluffing their fur when its cold

5. Homeostasis Maintaining stable internal conditions Each organism has a certain set of requirements that have to remain relatively constant in order for them to be able to function Ex/ maintaining a certain body temperature, blood pressure, fluid levels, nutrient levels, oxygen levels, etc.

6. Obtaining and Using Energy Living things need to obtain (get) and use energy to carry out all of the other life needs Living things obtain energy in different ways: producers, consumers, decomposers, etc.

Homework Choose an organism. Explain how it shows each characteristic of life.