Features of living things 10T2K© Ten Things to Know Features of living things

Thing 1: Living things are made of one or more cells. The cell is the smallest unit of life. Break a cell into smaller parts and it’s not alive anymore.

Thing 2: Living things grow and develop. Some non-living things (e.g., fire and crytsals) grow, but they don’t change inside as they do so. Even single-celled life undergoes internal changes as it grows and develops.

Thing 3: Living things reproduce. Living things make more of themselves by passing on genes, chemical instructions for the organism.

Thing 4: The genes of all living things are made out of DNA. Some viruses, which are not alive, have genes made out of a related substance called RNA.

Thing 5: All living things consume energy. Some organisms, such as humans, get energy by eating other organisms. Some organisms, such as plants, get energy from a non-living source such as sunlight.

Thing 6: Living things have a metabolism. Metabolism is all the chemical reactions that go on in a living organism. Some reactions build molecules, and some break molecules down. Viruses don’t have a metabolism. That’s why they’re not alive.

Thing 7: Living things sense and respond to the environment. When a plant grows toward a light, the light is an environmental stimulus, and the direction of growth is a response. Gravity is the stimulus that results in the response of roots growing down.

Thing 8: Living things perform homeostasis. Homeostasis is the fancy word for keeping a more or less constant internal environment. Sweating to cool off and shivering to warm up are examples of homeostasis.

Thing 9: Living things adapt and evolve. Think of the example of insects and insecticides. The population of insects changed over time because of the presence of the insecticide. Individual insects didn’t change; they lived or died. The population changed based on who lived long enough to reproduce.

Thing 10: Living things have hierarchical order. Each level of order has features that the previous order doesn’t have. The next slide shows part of the hierarchical order of living things.

Some hierarchical order. Living things have cells. Cells have features that their parts don’t have. Tissues are made of cells. Tissues have features that cells don’t have. Organs are made of tissues. Organs have features that tissues don’t have. Systems are made of organs. Systems have features that organs don’t have.