The seven characteristics of life
Introduced| English | Meaning |
|---|---|
| organism/ˈɔːɡənɪzəm/ | Individual living things. |
| movement/ˈmuːvmənt/ | A change of position of an organism or its parts; one of the seven life processes. |
| respiration/ˌrespɪˈreɪʃn/ | The chemical reactions in cells that release usable energy from nutrient molecules. |
| sensitivity/ˌsensɪˈtɪvɪti/ | The ability to detect and respond to changes in the environment. |
| excretion/ekˈskreʃn/ | The removal from an organism of metabolic waste and substances present in excess of its requirements. |
| nutrition/njuːˈtrɪʃn/ | Taking in materials for energy, growth and repair; one of the seven life processes. |
| egestion/ɪˈdʒestʃn/ | The removal of undigested food from the digestive tract, rather than the excretion of metabolic waste. |
What makes something alive?
- A rock, a river and a robot can move — but none of them is alive.
- Biologists agree on seven things every living organism 生物体 does. Miss one, and it isn't life.
Characteristics of life lab
Classify real observations by the life process they show.
The mnemonic MRS GREN helps you remember:
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MRS GREN lists the seven life processes.
How many characteristics of living things does MRS GREN list?
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There are seven: movement, respiration, sensitivity, growth, reproduction, excretion, nutrition.
MRS GREN
- A famous way to remember the seven characteristics: MRS GREN.
- Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.
The seven life processes spell MRS GREN
In MRS GREN, the "R" for respiration means:
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Respiration releases energy from food in every living cell.
Detecting and responding to changes in the surroundings is:
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Sensitivity is detecting and responding to stimuli.
The first four
- Movement 运动: all living things move some part of themselves.
- Respiration 呼吸作用: releasing energy from food.
- Sensitivity 应激性: detecting and responding to surroundings.
- Growth: a permanent increase in size.
A prokaryote (bacterium): E. coli seen under an electron microscope
Excretion removes waste made by the body's own reactions.
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Egestion removes undigested food; excretion removes metabolic waste.
Taking in materials for energy, growth and repair is called ______.
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Nutrition is the N in MRS GREN.
The last three
- Reproduction: making more of the same kind.
- Excretion 排泄: removing the waste made by reactions in the body.
- Nutrition 营养: taking in materials for energy, growth and repair.
Excretion is not the same as egestion 排遗. Excretion removes waste made by the body (like carbon dioxide). Egestion removes undigested food that never entered the cells. Only excretion is one of the seven characteristics.
A scientific name: a capital-letter genus and a small-letter species
You've got it
- all living things show seven characteristics — remember MRS GREN
- Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition
- excretion (waste from reactions) ≠ egestion (undigested food)