Topic – Scientific Classification

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Scientific Classification

Organisms are living things. They range from the tallest trees to the tiniest bacteria. They live everywhere in the world, from the hot deserts to the cold oceans. Scientists classify organisms according to their similarities and differences. By using the same classification system, they can share their knowledge about organisms.

This system groups organisms into large categories, then into smaller and smaller categories according to their characteristics. The biggest categories are called kingdoms. The kingdoms are animals, plants, fungi, protista, and monera. People know the animal and plant kingdoms because there are so many animals and plants around us that we can see. Some organisms in the fungi kingdom might be familiar because this is the kingdom that includes mushrooms. Most organisms in the protista and monera kingdom are so tiny that a microscope is needed to see them. An amoeba is from the protista kingdom. Bacteria belong to the monera kingdom.

Kingdoms are the first of seven categories in the system. There are six more categories. Each category classifies organisms into smaller groups. As you move down the system, the organisms in each category become more and more like each other. So the categories from biggest to smallest are: kingdom, phylum, class, order, family, genus, and species. Let us see how this works by looking at domestic cats that we have as pets.

Kingdom  The domestic cat belongs to the animal kingdom along with all the other animals in the world.

Phylum  The cat belongs to the chordate phylum. This category includes all the animals that have backbones or spines.

Class The cat belongs to the mammal class. This category includes animals that give birth to live babies that the females feed with their own milk. Mammals also breathe through their lungs.

Order The cat belongs to the carnivore order. This category includes animals that eat other animals.

Family The cat belongs to the felidae family. This category includes all felids. (Felids are all the cats in the world, from lions and tigers to the domestic cat.)

Genus The cat belongs to the felis genus. This category includes all the wild and tame small cats in the world. Small cats do not roar.

Species All breeds of domestic cats belong to the species catus.

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