A Simple Explanation of the Six Kingdoms of Life for Kids
There are many different kinds of living things or organisms on Earth. Scientists have grouped them together into kingdoms. These kingdoms are called:
The organisms in each kingdom are similar in certain ways.
You are most familiar with the plant and animal kingdoms. As you can see, they are very diverse groupings. A blade of grass and a giant tree may seem very different, but both are still plants. Elephants and grasshoppers are very different, but both belong in the animal kingdom.
Placing organisms into different groups is called taxonomy.
Animal Kingdom (Animalia)
There are lots of different kinds of animals, such as mammals, birds, insects, reptiles and amphibians. Humans are mammals. So, why are so many diverse organisms in one kingdom? Well, they have some things in common. All animals can move on their own. Animals are heterotrophic. This means they can't make their own food. They must eat to survive.
Animals can be divided into other groups: Vertebrates and invertebrates. Vertebrates have backbones. Invertebrates don't. Humans have a backbone, so we're vertebrates. Worms are invertebrates.
Each type of animal group can be divided into even more groups. Mammals can be divided into groups like primates (apes, monkeys), rodents (rats, squirrels), cetaceans (dolphins, whales), marsupials (kangaroos, koalas) and monotremes (eggs laying mammals like the platypus).
Plant Kingdom (Plantae)
Animals are heterotrophic, which means they must find and eat food. Plants are autotrophic. They can make their own food using a process called photosynthesis. Plants use air, water and sunlight to make the food they need to survive. Unlike animals, plants can't move around on their own.
Plants can be divided into two major groups: vascular and nonvascular. Vascular plants soak up water using their roots. Nonvascular plants use their whole bodies to soak up water. Most plants you see, like trees and flowers, are vascular. Moss is an example of a nonvascular plant.
Vascular plants can be divided up into even more groups: flowering and nonflowering. Most plants are flowering plants. Fruits and seeds grow in flowers. Ferns are an example of a nonflowering plant.
Bacteria are organisms made up of just one cell. Plants and animals are made of millions of cells. Many people think bacteria are bad. But there are both good and bad types. Bacteria are everywhere. They are all over your body. They even help you digest your food. Bacteria are used to make some foods like yogurt and cheese. Bacteria called decomposers break dead plants and animals down into the soil. Bacteria make more of themselves by splitting in half.
Archaebacteria are bacteria that can survive in places no other organism could live. Thermophiles are bacteria that can survive in extremely hot places like the geysers in Yellowstone National Park. Methanogens are bacteria that produce a gas called methane. They can live in areas that don't have any oxygen. Halophiles can live in very salty places like the Dead Sea. They would die in fresh water.
You are probably very familiar with one type of fungi. You've likely seen it on pizza. It's the mushroom. Fungi (pronounced fun-guy) are related to both plants and animals. Mushrooms may look like plants. But like animals they are heterotrophic. They can't make their own food. They use something called enzymes to break up decaying organisms that they can absorb as food. So, fungi are decomposers. Decomposers are very important. Without them dead plants and animals would litter the ground and would prevent the growth of new plants.
Protists are related to either plants, animals or fungi. There are different types. Like fungi, slime molds absorb nutrients from their environment. Protozoans mainly live in water. They are heterotrophic, which makes them more like animals. Algae are autotrophic, which means they make their own food. So, they are similar to plants. Seaweed is a type of algae. You may sometimes see green slimey stuff in water. That is usually algae as well.