Cells - the basic unit of life. All organisms are made up of cells, which are the smallest unit of life that can exist independently. Cells come in a variety of shapes and sizes, but they all share some common features. All cells have a cell membrane, cytoplasm, and DNA. The cell membrane is a thin layer that surrounds the cell and protects it from its surroundings. The cytoplasm is the jelly-like substance that fills the cell and contains all of the cell's organelles. Organelles are small structures that carry out specific functions within the cell. DNA is the genetic material that is passed on from parents to offspring.
Metabolism - the sum of all chemical reactions that occur within a living organism. Metabolism is essential for life because it provides the energy and molecules that organisms need to grow, reproduce, and maintain themselves. There are two main types of metabolism: catabolism and anabolism. Catabolism is the process of breaking down molecules to release energy. Anabolism is the process of building up molecules from smaller molecules.
Reproduction - the process by which organisms produce offspring. Reproduction is essential for life because it ensures that the species continues to exist. There are two main types of reproduction: sexual and asexual. Sexual reproduction is the process by which two organisms combine their genetic material to produce offspring. Asexual reproduction is the process by which a single organism produces offspring without the involvement of another organism.
Response to stimuli - the ability of an organism to detect and respond to changes in its environment. This ability is essential for life because it allows organisms to adapt to their surroundings and survive. There are a variety of ways that organisms respond to stimuli, including moving, changing their behavior, or changing their physiology.
Growth - the process by which organisms increase in size and complexity. Growth is essential for life because it allows organisms to reach maturity and reproduce. There are two main types of growth: determinate and indeterminate. Determinate growth is the process by which organisms reach a predetermined size and then stop growing. Indeterminate growth is the process by which organisms continue to grow throughout their lives.
Homeostasis - the ability of an organism to maintain a stable internal environment. Homeostasis is essential for life because it allows organisms to function properly. There are a variety of ways that organisms maintain homeostasis, including regulating their body temperature, blood pressure, and pH levels.
Adaptation - the process by which organisms change over time in order to better survive in their environment. Adaptations are essential for life because they allow organisms to cope with changing environmental conditions. There are a variety of ways that organisms adapt, including developing new traits, changing their behavior, or moving to a new environment.
