What Is Life?
What are the characteristics of all living things?
If you were asked to name some living things, or organisms, you might name yourself, a pet, and some insects or plants. You would probably not mention a moss growing in a shady spot, the mildew on bathroom tiles, or the slime molds that ooze across lawns. But all of these things are organisms that share several important characteristics with all other living things.
The 7 Characteristics of Life
All living things are made of cells, use energy,
respond to a stimulus, reproduce, grow and develop,
change to fit their environment (adapt), and contain DNA.
Use the following information to fill out your note sheet on the 7 characteristics of life. You will need to:
1) Write the characteristic
2) Write a description (3-4 interesting facts)
3) An example or picture
1. ALL LIVING THINGS ARE MADE OF CELLS
All organisms are made of small building blocks called cells. A cell is the basic unit of structure and function in an organism. Organisms may be made up of one or more cells. Single-celled organisms, like bacteria, make up most of the living things on Earth. Single-celled organisms have everything they need within themselves to be self-sufficient. In other words, they contain all seven characteristics of life. In multi-cellular (made of more than one cell) organisms, the different cells have certain jobs. For example, humans are made up of trillions of cells such as bone cells, nerve cells and muscle cells. Plants have leaf cells and root cells.
2. ALL LIVING THINGS USE ENERGY
The sun is the source of energy for all living things on Earth. Organisms get energy from taking in and breaking down materials for their cells to use. Plants trap the energy from the sun to make their own food in a process known as photosynthesis. Other organisms eat plants to gain energy and then are eaten themselves and provide energy for other organisms. You are using energy just to read these words. Your eye and brain cells are hard at work!
3. ALL LIVING THINGS RESPOND TO STIMULI
What happens when you touch a hot stove? You feel the heat and then jerk your hand away. Have you ever seen a plant in a sunny window and observed that the plant’s stems have bent so that the leaves face the sun. Like a plant bending toward the light, all organisms react to changes in their environment. A change in an organism’s surroundings that causes the organism to react is called a stimulus (plural stimuli). An organism reacts to a stimulus with a response- an action or change in behavior. Another example is if you are cold, you shiver. The cold is the stimulus while the shivering is the response. Or when you are hot, you sweat. The sweat is a response to the stimulus- you being hot.
4. ALL LIVING THINGS REPRODUCE
Another characteristic of organisms is the ability to reproduce, or produce offspring that are similar to the parents. Reproduction ensures the survival of a species. Organisms reproduce in different ways. Sexual reproduction involves two parents that combine their genetic material to produce a new organism that differs from both parents. Mammals, birds, and most plants sexually reproduce. Asexual reproduction involves only one parent and produces offspring that are identical to the parent. They basically clone themselves. Bacteria reproduce this way.
5. ALL LIVING THINGS GROW AND DEVELOP
Growth is the process of becoming larger. You are not the same size you were 10 years ago! Development is the process of change that occurs during an organism’s life to produce a more complex organism. You started off as an egg cell and sperm cell joined together as one. But soon more and more cells started forming to create your entire body such as heart cells, skin cells, nerve cells, etc. Over time, you will develop into a mature adult just like a caterpillar will develop into a butterfly.
6. ALL LIVING THINGS CHANGE TO FIT THEIR ENVIRONMENT (ADAPT)
Polar bears are only found around the North Pole where it is cold and white because of the snow and ice. When people think of the color of bears, they usually think of them being brown or black. But polar bears are white! Over time, polar bears grew thick fur and became white to survive in this environment. The fur protects them from the cold and the white color helps them blend in with the snow and ice to help them sneak up on their food! Organisms become specially adapted to fit in their particular environments. Penguin wings have adapted to become more like fins to swim through the water to catch fish or to escape from a hungry whale. Most flowers are very bright and smell good to attract insects such as bees. The bees land on the flowers and get pollen stuck to their bodies. When they land on another plant, the pollen will come off and fertilize that plant (reproduction). Adaptation occurs over a very, very long period time up to millions of years. Organisms must be able to adapt to changes in their environment or run the risk of becoming extinct.
7. ALL LIVING THINGS CONTAIN DNA
DNA is the genetic material that carries information about an organism and is passed from parent to offspring. DNA stands for deoxyribonucleic (dee AHK see RY bo new KLEY ik) acid. DNA is what provides the instructions to make you who you are. It controls everything from how tall you are to your hair, eye and skin color. Copies of DNA are passed from parent to offspring. This is called heredity.