Six Kingdoms of Life
by Beth Rowen
Every living creature on Earth belongs to a kingdom. Scientists debate how many kingdoms there are, with many arguing that there are six. Here is how the six kingdoms are organized. Or, seehow some other scientists categorize life into five kingdoms.
Archaea bacteriaArchaebacteria are bacteria with internal membrances and are found in deep-ocean thermal vents, hot springs in Yellowstone, and brine marine environments.
Eubacteria are single-celled organisms that don?t have a nucleus. Bacteria make up the entire kingdom. There are more forms of bacteria than any other organism on Earth. Some bacteria are beneficial to us, such as the ones found in yogurt. Others can cause us to get sick.
Protists are mostly single-celled organisms that have a nucleus. They usually live in water. Some protists move around, while others stay in one place. Examples of protists include some algae, paramecium, and amoeba.
Fungi are usually motionless organisms that absorb nutrients for survival. They include mushrooms, molds, and yeasts.
Plants contain chlorophyll, a green pigment necessary for photosynthesis, a process in which plants convert energy from sunlight into food. Their cell walls are made sturdy by a material called cellulose, and they are fixed in one place. Plants are divided into two groups: flower- and fruit-producing plants and those that don?t produce flowers or fruits. They include garden flowers, agricultural crops, grasses, shrubs, ferns, mosses, and conifers.
Animals are the most complex organisms on Earth. Animals are multi-celled organisms, eat food for survival, and have nervous systems. They are divided into vertebrates and invertebrates and include mammals, amphibians, reptiles, birds and fish.