G.R.E.N.
Biology: Cambridge International GCSE Supplement, topic 1.1.3
Growth, Reproduction, Excretion and Nutrition
These are four characteristics of all living organisms:
Growth
- Growth is a permanent increase in size and dry mass (without including the water in the organism) by an increase in cell number or cell size or both.
- For example, a puppy will grow very rapidly in its first few months and will never return to its original tiny size.
Reproduction
- Reproduction is the processes that make more of the same kind of organism.
- For example, bacterial cells can split in two to make two bacterial cells.
Excretion
- Excretion is the removal from organisms of waste products from metabolism, toxic materials, and substances which are in excess of requirements.
- For example, oxygen is a waste product made by plants, and it leaves the plant through its leaves.
Nutrition
- Nutrition is the taking in of materials for energy, growth and development.
- For example, plants take in light, water and carbon dioxide, and animals need organic compounds and water.
Test yourself on G.R.E.N.
Which of these is not removed from an organism in excretion?
Which of these are found in the acronym MRS GREN?