GCSE Biology - Characteristics of Living Things (Organisms)
Characteristics of Living Things
Overview of Organisms
- The video discusses the characteristics that define living organisms, including animals, plants, bacteria, fungi, and protists.
- There are seven key features common to all living things summarized by the acronym MRS GREN: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, and Nutrition.
Key Features of Living Things
Movement
- Refers to the ability of organisms to move; this can be whole-body movement (e.g., a cow walking) or part movement (e.g., a plant turning its leaves towards sunlight).
Respiration
- Involves chemical reactions in cells that break down nutrients like sugars to release energy for metabolism. Metabolism encompasses all chemical processes necessary for life.
Sensitivity
- The ability to detect and respond to changes in the environment. This includes temperature changes prompting responses such as sweating or shivering. Plants also exhibit sensitivity by responding to water and light conditions.
Growth
- Describes a permanent increase in size or dry mass. For example, a kitten growing into an adult cat or bacteria enlarging from smaller cells.
Reproduction
- The process through which organisms produce more of their kind. Examples include cats having kittens or bacteria dividing into two.
Excretion
- Refers to removing waste products from metabolism and excess substances. This includes eliminating urea and carbon dioxide as well as excess water and minerals.
Nutrition
- Involves taking in materials necessary for energy growth and development. Animals typically consume food while fungi and bacteria absorb nutrients from their surroundings through diffusion or active transport.
Commonality Among Living Organisms
- All living organisms consist of one or more cells; viruses do not qualify as living because they lack the seven characteristics discussed.
Conclusion