The Living World
生物界
Living things are all around us — from a tiny ant to a huge tree. In this lesson you will learn what makes something alive, the seven signs of life, and how we group living things.
生物在我們身邊無處不在——由微小的螞蟻到高大的樹。在這一課，你會學習甚麼令東西有生命、生命的七個特徵，以及我們怎樣把生物分類。
1 · What is a living thing?
甚麼是生物？
A living thing is called an organism. Something is alive if it can move, grow, eat food, and make new living things. Animals, plants, mushrooms and tiny germs are all organisms.
生物又稱為有機體。能移動、生長、進食，並且能生育新生命的就是生物。動物、植物、蘑菇和微小的細菌都是有機體。
2 · The seven signs of life
生命的七個特徵
Scientists remember the seven signs of life with the letters MRS GREN:
科學家用 MRS GREN 這組字母來記住生命的七個特徵：
- Movement — living things can move by themselves.移動——生物能自己移動。
- Respiration — living things breathe to get energy.呼吸——生物呼吸以獲取能量。
- Sensitivity — living things feel and react to the world around them.感應——生物能感受並對周遭世界作出反應。
- Growth — living things grow bigger over time.生長——生物會隨時間長大。
- Reproduction — living things make new living things (babies).繁殖——生物會生育新生命（後代）。
- Excretion — living things remove waste.排泄——生物會排出廢物。
- Nutrition — living things need food for energy.營養——生物需要食物來獲取能量。
3 · Living and non-living
生物與非生物
A rock, a chair and a car are non-living things. They do not grow and they do not breathe. A cat, a tree and a flower are living things because they grow and breathe.
石頭、椅子和汽車都是非生物。它們不會生長，也不會呼吸。貓、樹和花都是生物，因為它們會生長和呼吸。
Living things grow, breathe and reproduce. Non-living things do none of these.
生物會生長、呼吸和繁殖。非生物這些都不會做。
4 · Groups of living things
生物的分類
We sort living things into groups:
我們把生物分類：
- Animals — mammals, birds, fish and insects.動物——哺乳類、鳥類、魚類和昆蟲。
- Plants — flowers, trees and grass.植物——花、樹和草。
- Fungi — mushrooms and mould.真菌——蘑菇和黴菌。
- Microorganisms — tiny living things such as bacteria.微生物——像細菌一樣的微小生物。
5 · Quick check
小測驗