# Chapter 2: Marine Biology - What Makes Something Alive?
## Key Characteristics of Life
1. **Cellular Organization**: All living things are composed of one or more cells,
the basic unit of life.
2. **Metabolism**: Living organisms undergo chemical processes to convert food
into energy. This energy is used for growth, development, and maintaining life.
3. **Homeostasis**: The ability of an organism to maintain stable internal
conditions despite changes in the external environment.
4. **Growth and Development**: Living things grow and develop according to
instructions in their DNA.
5. **Reproduction**: Organisms reproduce, either sexually or asexually, to pass
on genetic information to offspring.
6. **Response to Stimuli**: Living organisms can react to changes in their
environment.
7. **Adaptation and Evolution**: Over generations, organisms adapt to their
environments, and these changes help them survive over time.
---
## Metabolism
- **Metabolism**: The process through which organisms take energy from their
surroundings to sustain life, develop, and grow.
- Carbohydrates, Proteins, and Chitin: Key macromolecules involved in
metabolism.
- Amino Acids: Building blocks of proteins.
- Nucleic Acids (DNA & RNA): Carry genetic information.
- Glycogen: A form of stored energy (sugar) used by the body for excess energy
storage.
## Key Characteristics of Life
1. **Cellular Organization**: All living things are composed of one or more cells,
the basic unit of life.
2. **Metabolism**: Living organisms undergo chemical processes to convert food
into energy. This energy is used for growth, development, and maintaining life.
3. **Homeostasis**: The ability of an organism to maintain stable internal
conditions despite changes in the external environment.
4. **Growth and Development**: Living things grow and develop according to
instructions in their DNA.
5. **Reproduction**: Organisms reproduce, either sexually or asexually, to pass
on genetic information to offspring.
6. **Response to Stimuli**: Living organisms can react to changes in their
environment.
7. **Adaptation and Evolution**: Over generations, organisms adapt to their
environments, and these changes help them survive over time.
---
## Metabolism
- **Metabolism**: The process through which organisms take energy from their
surroundings to sustain life, develop, and grow.
- Carbohydrates, Proteins, and Chitin: Key macromolecules involved in
metabolism.
- Amino Acids: Building blocks of proteins.
- Nucleic Acids (DNA & RNA): Carry genetic information.
- Glycogen: A form of stored energy (sugar) used by the body for excess energy
storage.
