An individual living thing

the basic unit of structure and function in living things

single-celled organisms

made of many cells

Any change or signal in the environment that can make an organism react in some way.

An action or change in behavior that occurs as a result of a stimulus

All of the changes that take place during the life of an organism to make it more complex

The process of becoming larger

The mistaken Idea that living things arise from non living sources

experiment in which only one variable is changed

An organism that makes its own food

organism that obtains energy from the foods it consumes; also called a consumer

The maintenance of stable internal conditions

The process of grouping things based on their similarities

The scientific study of how living things are classified

Classification system in which each species is assigned a two-part scientific name

A group of similar species

A group of similar organisms that can breed and produce fertile offspring

The gradual change in a species over time

Cells that do not contain nuclei

A part of the cell containing DNA and RNA and responsible for growth and reproduction; control center of the cell

Organisms with cells that contain nuclei

The preserved remains or traces of an organism that lived in the past