1. Organization: Living organisms are highly organized, with different levels of complexity. From atoms to molecules, cells, tissues, organs, organ systems, and organisms themselves, each level builds upon the previous one.
2. Metabolism: All living things carry out chemical reactions to sustain life. This includes breaking down nutrients for energy (catabolism) and building complex molecules (anabolism).
3. Growth and Development: Organisms grow and develop over time. Growth involves increasing in size and mass, while development refers to changes in complexity and function.
4. Responsiveness: Living things respond to stimuli from their environment. This can be a simple response like a plant turning towards light or a more complex response like an animal fleeing from danger.
5. Reproduction: Organisms produce offspring to ensure the continuation of their species. This can be through sexual or asexual reproduction.
6. Adaptation: Living organisms evolve over time to better suit their environment. This involves changes in their genetic makeup, leading to traits that improve survival and reproduction.
7. Homeostasis: Living organisms maintain a stable internal environment despite external changes. This includes regulating temperature, pH, and other factors crucial for life.
8. Cellular Structure: All living organisms are composed of at least one cell, the basic unit of life. This cell contains genetic material and carries out all the essential functions of life.
It's important to note that these characteristics are not always absolute. For example, viruses exhibit some characteristics of life, such as organization and reproduction, but they lack others, such as metabolism and cellular structure. Therefore, the line between living and non-living can be blurry in some cases.