1.A Characteristics of living organisms

1.1 Biology Edexel IGCSE MRS GREN C

What are the 8 life processes?

Movement

Respiration

Sensitivity

Homeostasis/Control

Growth

Reproduction

Excretion

Nutrition

Movement

• An action by an organism or part of an organism causing a change of position or place

• E.g climbing plants move their tendrils (growth from their stems) around fixed objects so that they can climb walls

Respiration

• The chemical reaction in cells that break down nutrient molecules and release energy for metabolism (chemical reaction in cells). Organisms can respire (produce energy) aerobically or anaerobically

• E.g when a human eats an apple, the sugars in the apple are broken down to release energy

Sensitivity

• The ability to detect or sense stimuli in the internal or external environment and to make appropriate responses

• E.g a deer detects movement in the nearby grass and runs away from a potential predator

Growth

• A permanent increase in size and dry mass (without including the water in an organism) by an increase in cell number, cell size or both

• E.g a puppy will grow very rapidly for the first few months and will never return to its original small size

Reproduction

• The process that makes more of the same kind of organism (offspring). This can occur sexually and asexually

• E.g bacterial cells can split in two to make two bacteria cells

Excretion

• The removal from organisms of waste products from metabolism, toxic materials and substances which are in excess of requirements (like water)

• E.g oxygen is a waste product made by plants and it leaves the plant through its leaves

Nutrition

• The taking in of materials for energy, growth and development

• E.g plants take in light, water and carbon dioxide and animals need organic compounds (food) and water

Control

• Organisms are in control of their internal environments

• Keeping internal conditions (such as temperature) the same is known as homeostasis