1 Why Do Animals Reproduce?

Transcription

1 1 Why Do Animals Reproduce? Tick (ü) the boxes next to the statements that are TRUE. 1 Living things reproduce to ensure the continuity of their own kind. 2 A life cycle is made up of all the stages of an animal s life. 3 All mammals give birth to their young alive. 4 Not all fishes lay eggs. 5 The life cycles of animals and the life cycles of plants are the same. 66 Additional Teacher s Resources

2 2 What Are the Life Cycles of Some Animals? Complete the flowchart below by filling in the missing words in the boxes. Use the words below to help you. Each word or words can be used only once. Mealworm Four stages Laying eggs Cockroach Chicken Rabbit Ways of Reproduction Giving birth to young alive Have life cycles with Three stages Frog Butterfly Mosquito Science SMART Teacher s Guide Grade 4 67

3 3 Why Do Young Grow Up to Look Like Their Parents? Which of the following characteristics can be inherited? Which of them cannot be inherited? Complete the flowchart below. Eye colour Nail length Hair length Single or double eyelids Scars Characteristics Dimples Can be inherited Cannot be inherited 68 Additional Teacher s Resources

4 Fun and Games Can You Spot Them? The young of some animals look like their parents, while the young of other animals do not. Spot the animals and their young. Circle each pair or group of adult animals and their young with a different colour. Science SMART Teacher s Guide Grade 4 69

5 Exam Practice Process skills: Observing, Inferring Tom visited a farm. He saw a hen sitting on its eggs. a. Why did the hen sit on its eggs? [1 mark] b. Tom knows that chicken eggs must be kept at a temperature of about 41 C for 21 days for the chicks to develop. He built a simple machine as shown below to keep eggs warm. He bought three fertilised chicken eggs from the farm and placed them inside the machine. He observed the eggs for 21 days. However, after 21 days, the eggs did not hatch into chicks. Air holes Wire mesh Bowl of water Egg Lightbulb Styrofoam box What could be the reason why the eggs did not hatch? [1 mark] Hint: How does the temperature affect how the chicks in the eggs develop? 70 Additional Teacher s Resources

6 Science SMART Teacher s Guide Grade Class: A life cycle is made up of all the stages of an animal s life. All mammals give birth to their young alive. Not all fishes lay eggs. The life cycles of animals and the life cycles of plants are the same Answers to Additional Teacher s Resources Living things reproduce to ensure the continuity of their own kind. Date: 1 Tick (ü) the boxes next to the statements that are TRUE. Why Do Animals Reproduce? Name: 2 Class: Date: Rabbit Mosquito Mealworm Chicken Cockroach The Life Cycles of Animals Answers to Additional Teacher s Resources Butterfly Frog Four stages Three stages Have life cycles with Chicken Rabbit Laying eggs Ways of Reproduction Laying eggs Cockroach Giving birth to young alive Mealworm Four stages Complete the flowchart below by filling in the missing words in the boxes. Use the words below to help you. Each word or words can be used only once. What Are the Life Cycles of Some Animals? Name:

7 Chapter 1 Answers to Additional Teacher s Resources Answers to Additional Teacher s Resources Can You Spot Them? Fun and Games 3 Why Do Young Grow Up to Look Like Their Parents? Which of the following characteristics can be inherited? Which of them cannot be inherited? Complete the flowchart below. The young of some animals look like their parents, while the young of other animals do not. Spot the animals and their young. Circle each pair or group of adult animals and their young with a different colour. Eye colour Nail length Hair length Single or double eyelids Scars Dimples Characteristics Can be inherited Cannot be inherited Eye colour Nail length Single or double eyelids Hair length Dimples Scars Pupils should circle each pair or group of adult animals and their young with a different colour: farmer and girl; frog and tadpoles; chicken and chicks; cow and calf; butterfly and caterpillar. 72 Additional Teacher s Resources

8 Hint: Exam Practice Process skills: Observing, Inferring Tom visited a farm. He saw a hen sitting on its eggs. a. Why did the hen sit on its eggs? [1 mark] To provide warmth for the chicks inside the eggs to develop. b. Tom knows that chicken eggs must be kept at a temperature of about 41 C for 21 days for the chicks to develop. He built a simple machine as shown below to keep eggs warm. He bought three fertilised chicken eggs from the farm and placed them inside the machine. He observed the eggs for 21 days. However, after 21 days, the eggs did not hatch into chicks. Air holes Egg Wire mesh Lightbulb Bowl of water Styrofoam box What could be the reason why the eggs did not hatch? [1 mark] The machine did not provide enough warmth How does the temperature affect how the chicks in the eggs develop? for the chicks inside the eggs to develop. Answers to Additional Teacher s Resources The Life Cycles of Animals Science SMART Teacher s Guide Grade 4 73

9 Chapter 1 Glossary Chapter 1: Cocoon The protective casing which some insects make for themselves while they grow in their pupal stage Gene Heredity Larva Life cycle Metamorphosis Moult Nymph Pupa Trait The part of the cell that controls or influences the physical characteristics of a living thing, and can be passed down from parents to their young The passing down of traits from parent to child (plural: larvae) The newly hatched young of an insect that is wingless and worm-like The stages through which a living thing goes through in its life, from the beginning of its life, to undergoing changes, reaching maturity as well as reproduction A great change in appearance in some animals when they become an adult Shed the old skin or covering and replace it with new growth so that the body can grow bigger The young insect that looks almost like the adult except that it is smaller and has no wings The stage of development between larva and adult, during which the larva does not eat and undergoes complete transformation within a cocoon A characteristic or condition 74 Glossary