Biology is the science that studies living organisms.
What defines living?
Defining what is "living" can be tricky however. Typical characteristics of a living organism are:
They have the ability to be organised (internal structure).
They take and use energy from the environment.
They grow and develop.
They can reproduce.
They respond to stimuli.
They adapt to the environment.
A living organism may exhibit all or just some of these characteristics however. A neutered dog for example is clearly alive but unable to reproduce. A common definition of life is that the organism is self-aware. This also has its problems though as plants are clearly alive but not self aware, at least in the sense that we are self aware. Another definition is that the organism can die, i.e. stop working and be unable to be fixed.
Foundation of Biology
The foundation of biology is split into five seperate principles:
- Evolution: A population's traits are inherited through the generations.
- Genetic Theory: Traits of the organism are contained in segments of DNA known as genes.
- Energy: Required for metabolism, which is essential for an organism to maintain its state (Homeostasis).
- Cell Theory: All organisms are made of cells. Cells derive from other cells through cell division.
- Homeostasis: The ability for an organism to maintain its internal state, regardless of the environment (within limits).
There are many areas of specialisation in Biology, such as:
- Botany - Plants
- Zoology - Animals
- Microbiology - microorganisms
- Biochemistry - the chemistry of life
- Molecular biology - systems of biological molecules and how they interact
- Cellular biology - studies of the cell
- Physiology - physical and chemical systems of the tissues and organs of the organism
- Ecology - how organisms live and survive within their environment