1.4 - Necessary Life Functions and Survival Needs
must be able to carry out several functions
in order to maintain life. If any of these necessary life functions
are disrupted, the organism
may not survive, or its species may not continue to exist. In addition to carrying out necessary life functions
have basic survival needs
that must be present within an acceptable range in order to sustain life.
Each species of organism
is uniquely capable of performing its necessary life functions
and fulfilling its survival needs.
Part 1: Necessary Life Functions
1. Maintain boundaries
- Separate the internal and external environments.
- Separate the internal environment into compartments that serve different functions.
3. Respond and react
- Change body and body part positions.
4. Ingest and digest nutrients
- Behavioral reactions and responses.
- Physiological responses to stimuli.
5. Carry out metabolism
6. Eliminate wastes
- Food is taken in (ingested) and broken down (digested) into molecules that can be used by the body for energy and the maintenance of the balance of body chemicals.
- The by-products of digestion and metabolism must be eliminated from the body.
- Body wastes are toxic and must be eliminated before they reach damaging levels.
- Cells must reproduce to maintain growth and health and to repair tissues in case of injury.
- Organisms must reproduce to continue the existence of their species.
- Organisms must grow to reach maturity and for maintenance.
- Some body parts get worn with use and must continually grow to be maintained.
Part 2: Survival Needs
- Nutrients are taken in by the organism and broken down into smaller molecules that can be used by the body for energy and building cells.
- Food is ingested and processed by the digestive system.
- Required for the breakdown of nutrients to harvest energy.
- Oxygen is removed from the air and transported to body cells by the respiratory and cardiovascular systems.
- Must be kept within a certain range; 37 degrees Celsius is ideal for humans.
- In vertebrates, heat is generated by skeletal muscles.
- Must be kept within a certain range for proper breathing and cellular metabolism.
- Gases dissolve only within certain pressure ranges.
- Lung function depends on balancing atmospheric air pressure with internal lung air pressure.