Primary Lower Block Cycles: Life Cycles Introduction to ... · A life cycle is a pattern that...

PSLB | Cycles | Notes 2

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Primary Lower Block Cycles: Life Cycles Introduction to Notes 2

The worker bees clean the brood cells during the first few days of their adult lives.

They must also dispose of dead bees and larva in places away from the beehive.

They then become nurse bees who feed and care for the young.

From the 7th day, they tend to the queen bee whose only job is to lay eggs.

Wax-producing worker bees will need to eat 8kg of honey to produce 1kg of beeswax.

The beeswax produced appears through tiny pores in the bee’s abdomen and will need to be chewed on by the bees before it becomes soft enough to be used to repair and build more honeycomb cells.

We know children like comics! Using that to our advantage, we introduce complicated concepts in a fun way.



Later, the young worker bees pack and store pollen and nectar brought home by the older foraging bees so that they can be used as food for the rest of the colony.

They also help to keep the hive cool by fanning it with their wings using water brought home by the water-carrying bees.

* The above pictorial representations of the honey bees are for the purpose of providing information about their activities only. Please find realistic illustrations of the bees on the next page.

The guard bees station themselves near the entrance to the hive and stand guard, letting only family members into the hive.

The worker bees finally ‘graduate’ from being house bees after 21 days. They are now foraging bees and will leave the hive to gather pollen and nectar.



In today’s lesson, you will learn to:

describe the four-stage life cycle of a/an:

ladybird beetle

mosquito

butterfly

ant

queen bee worker bee drone bee

Different Types of Honey Bees

There are three types of honey bees.

The queen bee’s only job is to lay eggs. There is only one queen bee in each honey bee colony.

The second type of honey bees are the male drones and their job is to mate with queen bees from other colonies. There may be several hundred drones in a colony.

The worker bees are the third type of honey bees. All the worker bees in a colony are female and they are responsible for all the tasks in a beehive except laying eggs. The worker bees perform several jobs one after another during their lifetime. The youngest worker bees take care of the young and the queen. They then become housekeepers and storekeepers. The older worker bees become the guards to the hive and finally, the oldest worker bees become gatherers which bring nectar and pollen back from outside the hive. There are about 20 000 to 80 000 worker bees in a colony.



RECAPITULATION A cycle is a pattern that repeats itself continuously.

A life cycle is a pattern that repeats the stages of development in the lives of the

living things.

Metamorphosis refers to the big changes in the form and habits of an animal from

birth to adult.

Animals which undergo complete metamorphosis have young that look very

different from the adult.

Example: Insects that undergo a four-stage life cycle: butterfly, ladybird beetle

Animals which undergo incomplete metamorphosis have young that look similar

to the adult.

Example: Insects that undergo a three-stage life cycle: grasshopper, cockroach

Primary Lower Block Cycles: Life Cycles Notes 2

adult

egg

larva 4 stages in the life cycle of an

insect

pupa

adult

3 stages in the life cycle of an

insect

egg

nymph



FOUR-STAGE LIFE CYCLES CASE STUDY A

Life cycle of a ladybird BEETLE

The female ladybird beetle lays its eggs on the underside of leaves.

The eggs resemble tiny yellow jellybeans.

The larva feeds on aphids, mites and even other ladybird beetle eggs.

It grows rapidly and when its body grows too big for its skin, a new skin grows

beneath the old one.

The process by which the old skin is shed is known as moulting.

The insect attaches itself to a leaf during the pupal stage.

During this stage, the pupa does not feed and there is very little movement. However,

the adult structures develop within it.

The adult beetle emerges after about a week.

The cycle repeats when the female ladybird beetle reproduces.

larva

3 weeks to a month

pupa

About 1 week

About 1 week

egg

adult beetle (2 – 3 months)

The tiny yellow eggs are laid on the underside of leaves.

1

The larva feeds and grows rapidly.

2

The pupa does not feed while its adult structures develop.

3

The adult ladybird beetle emerges after a week.

4

Visuals help our students to grasp the concepts quickly.



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The monarch butterfly

The Monarch Butterfly is also known as “Milkweed Butterfly”. The Monarch butterfly only lays its eggs on the milkweed plant because its caterpillar only eats

the leaves from the milkweed plant. The Monarch butterfly is poisonous and distasteful to birds and mammals. It is thought that the bright colours of the larva and adult function as warning colours.

CASE STUDY D

Life cycle of OTHER INSECTS

Number of stages Organisms

3-stage life cycle

Cricket – lays eggs in warm damp soil

Dragonfly – lays eggs in water

4-stage life cycle

Bee – lays eggs within the cells in the hive

Mealworm beetle – lays eggs on leaves

cricket nymph

mealworm beetle larva



The Silkworm A silkworm is the caterpillar of the silkworm moth of the mulberry tree. They were domesticated from the wild silkworms about 2000 years ago! They are bred for the

production of raw silk. In the pupa phase, the silkworms enclose themselves in cocoons made up of raw silk produced by their salivary glands. The silkworm pupae are then boiled and killed. If the moths were allowed to emerge from the cocoon, the silk will be destroyed as the moths produce enzymes that will damage the silk.

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Summary 1. A butterfly’s egg will hatch into a l____________ which is also known as a

c_____________________.

2. A l____________ will develop into a p____________ before it turns into an adult.

3. A mosquito l____________ is also known as a w____________.

4. A mosquito w_______________ breathes through a b___________________

t____________.

5. The process whereby the old skin is replaced by the new skin is known as

m___________________.

6. During the p____________ stage of an insect, it does not feed at all while the adult

structures are developing within it.

Summarising the chapter helps our students to recap what has been taught during the lesson!

PSLB | Cycles | Practice 2


Primary Lower Block Cycles: Life Cycles Practice 2

Our notes are complemented by a comprehensive Practice paper.

A typical practice will have 15 multiple-choice questions and 5 open-ended questions for our students to attempt. This is then followed by an ‘ACE’ question to further enhance the understanding of our students. This proprietary technique is uniquely found at JustEdu and has helped numerous students to break down and analyse the question before attempting. Furthermore, this same technique can be used to answer multiple-choice questions as well. An example of an ‘ACE’ question is given next:



Use the ACE Question Answering Technique to answer the question below.

Karine placed an egg of an insect together with some food and water into a sealed container that had some holes in its lid. After some time, she observed that the young that had hatched from the egg did not feed or drink for a period of about a week. However, the insect could still develop into a healthy adult. (a) Give an example of an insect that Karine could have kept in her tank.

(b) Explain your answer in part (a).

Circle the important information in the question above. Study the question and write down in the space below the information that you can obtain from the question.

Topic: ________________________________________________________________ (a) and (b) Concepts:

The young of an insect does not _______________ or drink during the

_______________ stage.

The _____________-stage life cycle of an insect includes the egg, _______________,

_______________ and adult stages.

Insects such as the _______________, ______________ and _______________

undergo a four-stage life cycle.

(b) Key points: _________________________________________________________

_________________________________________________________

STEP 1: ANALYSE THE QUESTION

STEP 2: CONCEPT ANCHORING



Link the requirements in the question with the keywords listed above. You may use arrows or a simple concept map to help you.

Answers:

(a) Give an example of an insect that Karine could have kept in her tank.

___________________________________________________________________ (b) Explain your answer in part (a).

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

STEP 3: ESTABLISH RELATIONSHIPS AND LINKAGES



Use the ACE Question Answering Technique to answer the question below.

Karine placed an egg of an insect together with some food and water into a sealed container that had some holes in its lid. After some time, she observed that the young that had hatched from the egg did not feed or drink for a period of about a week. However, the insect could still develop into a healthy adult. (a) Give an example of an insect that Karine could have kept in her tank.

(b) Explain your answer in part (a).

The insect young was provided with air, food and water.

Topic: ________________________________________________________________ (a) and (b) Concepts:

The young of an insect does not _______________ or drink during the

_______________ stage.

The _____________-stage life cycle of an insect includes the egg, _______________,

_______________ and adult stages.

Insects such as the ________________________, ______________ and

_______________ undergo a four-stage life cycle.

(b) Key points: _________________________________________________________

_________________________________________________________

STEP 1: ANALYSE THE QUESTION

STEP 2: CONCEPT ANCHORING

Answers

Life Cycles

feed

pupa

four larva

pupa

ladybird beetle

housefly

butterfly

Four stage life cycle, young in the pupa stage

does not feed or drink.



Link the requirements in the question with the keywords listed above. You may use arrows or a simple concept map to help you.

Answers:

(a) Give an example of an insect that Karine could have kept in her tank.

___________________________________________________________________ (b) Explain your answer in part (a).

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

STEP 3: ESTABLISH RELATIONSHIPS AND LINKAGES

The pupa does not feed or drink in this stage

Four-stage life cycle of an insect

Includes

butterfly / housefly / ladybird beetle

example

Egg stage

Larva stage

Pupa stage

Adult stage

Butterfly / housefly / ladybird beetle (any one)

The butterfly / housefly / ladybird beetle undergoes a four-stage life cycle which includes a pupa stage. The insect does not feed or drink during the pupa stage.

Answers

PSLB | Cycles | Concept Map (for student’s reference only)

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Animals

4 stages

Butterfly

Housefly

Mosquito

Egg

Larva Adult

Pupa

3 stages

Chicken

Cockroach Grasshopper

A pattern that repeats itself to show the stages of development of a living thing

Egg

Young Adult

Flowering Plants

3 stages

Tomatoes

Seed

Young plant

Adult plant

Life Cycles

Primary Lower Block | Cycles: Life Cycles | Concept Map

At the end of each topic, students are equipped with a concept map and a list of keywords and phrases to reinforce the key concepts of the topic.

PSLB | Cycles | Concept Map (for student’s reference only)


List of Keywords and phrases

growth

incubation

larva

nymph

outer covering of an animal is replaced through the process of moulting

pupa

reproduction

seed leaves

vegetative propagation

warmth, oxygen and water are needed for germination

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