1. Is it alive? An organism is an individual form of ___________.
Biologists often use five basic rules to classify something as ____________ or _________________.
Yeast is a living organism.
Each tiny sphere is an individual living thing.

2. Characteristics of Living Things
All living things _________________ to a stimulus. The sunlight is a stimulus and the frog’s choice to sun himself is called a response.
All living things take materials from their surroundings such as food, water, & gases and use these materials to get _____________.
Growth refers to an increase in _____________ and to an increase in number of cells.
The process of making more of the same kind of organism is called _____________________________.
A ________________________ is the smallest unit of a living thing.

3. Is it alive? This is a barnacle.
Read about the five characteristics of life on page 42.
Then decide whether it is alive.

4. Is it alive?
Barnacles respond to their _______________ by closing their shells at low tide, and opening them at high tide.
Barnacles ____________ & ____________. They begin life as free-swimming creatures. Once they find a good spot, they “glue” themselves to a rock and form a shell.
Barnacles _________________. After fertilization from a male barnacle, females hold the eggs in their shells until they hatch.
By waving their legs, barnacles capture food. They ________________ ________________ from the food to move their legs, open and close their shells, & carry out all life processes.
If you examined the legs of a barnacle with a microscope you would see that they are made of individual _______.

5. Types of energy
Energy is sometimes defined as the ability to cause change or do ___________.
There are many _________ of energy.
Any form can be _______________________ into any other form.