The components of organisms can be divided into smaller units to examine life on different levels of organization. Learn how scientists categorize components of living things, such as cells, tissues, or organ systems, by comparing their structure and function.
Living things are broken down in to 8 levels from smallest to largest.
1. Atoms: All things are made up of atoms.
2. Molecule: Two or more atoms together. Ex: A water molecule is made up of 2 hydrogen atoms and 1 oxygen atom.
3. Organelle: Organelles are parts of a cell that have certain roles to help the cell to properly function. Examples: nucleus, cytoplasm, endoplasmic reticulum
4. Cells: All living things are made up of cells. Cells are the smallest unit of living things.
5. Tissue: A bunch of the same cells together will form a type of tissue and different tissues perform different functions. Example: brain tissue
6. Organ: When a group of tissues combines they can form an organ. Each organ performs a different function. Example: Your heart is made up of several types of tissues.
7. Organ system: When a group of organs combine they form an organ system. Example: your digestive system is made up of your esophagus, stomach, small intestine and large intestine
8. Organism: An individual living thing such as you! Other examples: cat, dog, fish