Why do animals reproduce? Here is the life story of Mimi. Let us see what stages she has experienced. 1 2 3 4 5 6 7 Mimi was born. One year old One-month old Three-month old Mimi gave birth. Mimi became older. Mimi finally died.

Why do animals reproduce? Let us see what stages Gigi, the bird, has experienced. 1 2 3 4 5 6 Growth Laying eggs Birth Death Become adult Old stage

Why do animals reproduce? How do animals change at different stages of life？ Birth Newborn animals are small in size. Growth Animals mature. They become bigger and stronger.

Why do animals reproduce? How do animals change at different stages of life？ Old age Death Animals become weaker and are easier to get sick. As the animals’ health gets worse, their body functions begin to fail and finally they die.

Why do animals reproduce? How do animals make their species continue 延續 ? By reproduction. 繁衍 All animals experience the stages of ________, ________, _________ and ________. Animals ___________ to ensure their species do not extinct (絕種). birth growth old age death reproduce

What similar characteristics特徵do the kitten and its mother have? The kitten looks almost the same as its mother. E.g. Both of them have whiskers鬚and paws.爪

Do other animals have their parents’ characteristics? Yes Red-crowned crane丹頂鶴 and its young

Do other animals have their parents’ characteristics? Yes A woman and her child

If animals cannot pass on their characteristics to their offsprings,後代 what will happen? The characteristics enable 確保animals to survive in their living environment. If their offsprings do not have such characteristics, it is hard for them to survive and their species will become extinct eventually. Animals can / cannot pass on their characteristics to their offsprings.

How do animals reproduce? Viviparous animals (胎生動物) Sperm ovum ovary 卵巢 testis 睪丸 After mating交配, the sperm combines with the ovum to form a fertilised egg.受精卵 The fertilised egg develops into an embryo胎兒in the mother’s womb. 子宮 Mature sex organs produce sperms精子and ova卵子.

How do animals reproduce? The foetus 胎兒gets nutrients 營養from its mother. When the foetus is fully developed, the mother gives birth to the baby.

How do animals reproduce? What is child of viviparous animal 胎生動物feed on? Its mother’s milk. 母乳 List three examples of viviparous animals. Cats, dogs, sheep etc. The embryo胚胎 of viviparous animal develops inside / outside the mother’s body. The mother gives birth to the young.

How do animals reproduce? Oviparous animals (卵生動物) Testicle Ovary A cock 公雞mates with a hen. The sperm of the cock combines with the hen’s ovum. The hen lays fertilised eggs. 產下受精卵

How do animals reproduce? The chicken hatches out. 出生 The embryo grows into a chicken 小雞 The embryo胚胎gets nutrients營養from the egg.

Can you list more oviparous animals 卵生動物 ? Butterfly 蝴蝶 Fish 魚

Can you list more oviparous animals 卵生動物 ? Snake 蛇 The fertilised egg of oviparous animal develops inside / outside the mother’s body.

Changing in form 形態 Growth of moths 蛾的生長過程 Fertilised eggs Larva 幼蟲 Mating After mating, the male’s sperm combines with the female’s ovum to form a fertilised egg. Adult 成蟲 Pupa 蛹 There are 4 stages in the life cycle of a moth. The form has completely changed. This is called “complete metamorphosis”.完全變態

Changing in form Growth of Frogs 蛙的生長過程 Tadpole 蝌蚪 Mating Tadpoles do not have legs but they have tails. During mating, the male frog sits on the female’s back. The female frog releases ova into the water, and the male frog releases sperms. The sperms and the eggs combine in the water. Fertilised eggs 受精卵

Front legs are formed 長出前腳 Hind legs are formed 長出後腳 Adult 蛙 Some animals go through big changes when growing up.

The life cycle of a mosquito

The life cycle of a grasshopper

The life cycle of a cockroach

Complete metamorphosis Incomplete metamorphosis 完全變態 Incomplete metamorphosis 不完全變態