G5 Science Reproduction in Plants

We've learnt....

Plants reproduce by going through a life cycle:

•A seed develops into a young plant.

•The young plant grows into an adult plant that bears flowers.

•The flowers develop into fruits with seeds.

We will learn to...

• State why living things reproduce.

• Identify the male and female parts of a flower.

• Recognise that pollination is the transfer of pollen grains from the anther to the stigma of a flower.

• Identify the agents that help in pollination.

• Describe the processes involved in fertilisation.

• Describe what happens after fertilisation has taken place.

How do flowering plants reproduce?

Parts of a flower - female

Parts of a flower - male

Parts of a flower - male

Knowing flowers

Knowing flowers

Knowing flowers

Pollination

Pollination

​•Besides insects, birds and wind also help to pollinate flowers.

Pollination

​•The pollen grains can be transferred within the same flower. This is known as self-pollination.

Pollination

​•The pollen grains can also be transferred from the anther of one flower to the stigma of another flower of the same species. This is known as cross-pollination.

Pollination

This stigma has been pollinated.

Poll

What do wind-pollinated flowers look like?

• Flowers with big, bright petals.

• Small and without any scent.

• Anthers may produce a large number of pollen grains,

• Sweet-smelling,

• The stamens are generally long and protrude out of the flower.

Wind Pollinated Flowers

• Wind pollinated flowers have light-colored petals and do not have a pleasant smell.

• Small, producing a large number of dry pollen grains.

• Examples, rice, barely, corn.

Open Ended

Why is this stigma moist and sticky?

Open Ended

Why are these stigmas so long?

Insect-pollinated and wind-pollinated flowers

Fertilisation

• When a pollen grain lands on the surface of a stigma, it produces a pollen tube.

• The inside of the tip of the tube contains the male reproductive cells of the flower.

• This tube grows downwards through the style to reach the ovules in the ovary.

Fertilisation

• Inside each ovule is an egg cell.

• Fertilisation takes place when the male reproductive cell fuses with the egg cell.

From flower to fruit

After fertilisation, the flower petals wither and fall off.

From flower to fruit

The ovary starts to swell to form a fruit.

Inside the ovary, the ovules begin to develop into seeds.

From flower to fruit

The seeds continue to develop inside the fruit and the fruit grows bigger.

Open Ended

Which part of the flower, if removed, would prevent the flowers from forming a fruit? Explain your answer.

Dispersal of fruits and seeds

After the fruit and seeds are developed, they will need to be scattered in order to grow well.

Open Ended

What happens when fruits and seeds are not scattered?

Overcrowding

If fruits and seeds are not scattered away from the parent plants, the seeds will grow too close to one another, leading to overcrowding.

Overcrowding

When overcrowding occurs, young plants compete with one another for space, sunlight, water and minerals, leading to poor growth.

Methods of dispersal

To reduce overcrowding, there are several methods of fruit and seed dispersal.

• Wind

• Water

• Explosive action / Splitting

• Animals

Wind dispersal

Fruits and seeds dispersed by wind are often dry, hairy, light or feathery.
Some of them have wing-like structures.

​Angsana Shorea Dandelion

Water dispersal

Fruits dispersed by water usually float and are carried along rivers, streams or seas.
They often have fibrous husks that trap air or waterproof coverings to help them float.

​ Coconut Pong pong Dungun

Dispersal by explosive action/ splitting

Some fruits split open when they are ripe. This shoots their seeds away.
These fruit walls have lines of tension that pull and curl up the walls when ripe and dry.

​ Rubber Cotton Saga

Animal dispersal

Some fruits or seeds dispersed by animals attach themselves to the animal’s body or human clothes or shoes using hooks or stiff hairs.

Lovegrass Mimosa Bur

Animal dispersal

Some fruits can be eaten by animals.

These fruits are normally fleshy, juicy or brightly coloured.

Big seeds are thrown away.
Smaller seeds are usually swallowed and passed out in the animal’s droppings.

Kiwi Watermelon Papaya

Open Ended

The pictures in the diagram show fruits A, B and C from three different plants.

Why do plants disperse their seeds?

Germination

The conditions for germination are:

• Air (oxygen)

• Water

• Warmth (a suitable temperature)

Open Ended

During germination, why is the root the first to grow out of the seed?

Germination

1. A root grows out of the seed.
   During this stage, the seedling cannot make its own food, but gets its energy for growth   from the food stored in its seed leaves.

2. The shoot appears.

Germination

The first leaves unfold, so the young plant can make its own food.
The plant grows and bears flowers and its seeds are dispersed.

The cycle repeats.

How do non-flowering plants reproduce?

• Non-flowering plants such as ferns reproduce from spores, which are mainly dispersed by wind.

• Spore bags containing spores can be found on the underside of a fern leaf.

Multiple Choice

Study the diagram.

What processes do P and Q represent?

• P: fertilisation

  Q: seed dispersal

• P: germination

  Q: fertilisation

• P: pollination

  Q: seed dispersal

• P: pollination

  Q: fertilisation

Multiple Choice

Study the diagram.

Which plant parts do R and S represent?

• R: flower

  S: spores

• R: fruit

  S: seeds

• R: fruit

  S: spores

• R: flower

  S: seeds

Summary

​Flowering plants undergo these processes in order to reproduce and continue the existence of their kind.

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

• A

• B

• C

• D

Multiple Choice

The drawing below shows a process that is important to plants. What is most likely happening?

• The bee is bringing water to the plant.

• The plant is being pollinated by the bee

• The plant is getting nectar from the bee.

• The bee is removing insects from the plant.

Multiple Choice

What is the main function, or job of the flower?

• to make seeds for new plants (reproduction)

• to help in the process of photosynthesis

• to make chlorophyll

Multiple Choice

Seedless plants reproduce by

• spores
• seeds
• binary fission
• mitosis

Multiple Choice

Jamie wanted to grow tomato plants. He placed five seeds in the soil and watered them. A few days later he noticed that the seeds were beginning to break open, and a plant was emerging. What process did Jamie most likely observe?

• pollination

• fertilization

• germination

• condensation

Multiple Choice

The transfer of seeds away from the parent plant is known as what?

• Dispersal

• Pollination

• Germination

• Evolution

Multiple Choice

Which of the following IS NOT required for germination to occur?

• Suitable temperature

• Light

• Water

• Oxygen

Multiple Choice

Which part of the flower becomes the fruit

• Ovule

• Root

• Anther

• Ovary

Multiple Choice

What part of the flower becomes the seed?

• Ovary

• Ovule

• Embryo

• Cotyledon

Multiple Choice

How is the following plant pollinated ?

• Wind

• Insect

• Water

• Fox

Multiple Choice

Pollination is the transfer of pollen from where to where?

• Anther to stigma

• Filament to style

• Stigma to ovary

• Anther to ovary

Multiple Choice

Where is the female gamete made in the flower?

• Stigma

• Ovule

• Anther

• Style

Multiple Choice

Which of the following about pollination is true?

• Cross-pollination occurs between flowers of same plant.

• Cross-pollination occurs between flowers of different plants that is of the same species.

• Self-pollination occurs between flowers of different plants.

• Cross-pollination occurs between flowers of different plants that is of different species.

Multiple Choice

Which of the following shows the female reproductive parts of a flower?

• anther, filament, ovary, ovule

• stigma, filament, ovary, ovule

• stigma, style, ovary, ovule

• anther, filament, ovary, ovule

Multiple Choice

A seed can move by wind, water, and ________.

• clouds
• singing
• cars
• animals

Multiple Choice

Jamie wanted to grow tomato plants. He placed five seeds in the soil and watered them. A few days later he noticed that the seeds were beginning to break open, and a plant was emerging. What process did Jamie most likely observe?

• pollination

• fertilization

• germination

• condensation

Multiple Choice

Which statement describes a structural adaptation of a wind-pollinated flowers?

• They have long filaments so that the anthers hang outside of the flower

• They have round,sticky sepals to trap pollen grains

• Their large petals protect the stigma

• Their stamens are feathery so there is a large surface area

Multiple Choice

When fertilization has occurred the fertilized ovule changes and so does the ovary.

What do they turn into?

• The fertilised ovule turns into honey and the ovary turns into nectar.

• The fertilised ovule turns into the fruit and the ovary turns into the seed.

• The fertilised ovule turns into a seed and the ovary turns into the fruit or pod.

• The ovule grows bigger and the ovary withers.

Multiple Choice

Plants disperse their seeds in many ways to prevent overcrowding. Otherwise, the young plants would compete with each other for mainly the following, except...

• Carbon dioxide

• Sunlight

• space

• water

Multiple Choice

What is meant by "seed dispersal"?

• the development of seed into a new plant

• the spread of seed away from the parent plant

• the development of ovule into a seed after fertilization

• the spread of seed to the stigma of another flower

Multiple Choice

An experiment is set-up to investigate the factors required for seed germination.

Predict which seeds will germinate after one week.

• A

• B

• C

• D

Multiple Choice

What is the correct description of pollination?

• Pollen grains are transferred from anther to the ovary

• Pollen grains are transferred from the anther to the stigma

• Pollen grains are transferred from the ovary to the stigma

• Pollen grains are transferred from the stamen to the anther

Multiple Choice

Insect-pollinated flowers typically have

• Small, inconspicuous flowers

• No scent

• Light, powdery pollen grains

• Relatively large, and often sticky grains of pollen

Multiple Choice

The diagram shows a section of a flower that has been cross pollinated.

Which statements about this flower are correct?

1. The pollen produced by this flower will be genetically different from the pollen on the stigma

2. The pollen was carried to the stigma by wind

3. This flower is insect- pollinated because the stigma is enclosed by the petals.

4. The pollen was produced by another flower on the same plant

• 1,2, and 4

• 1 and 3

• 3 only

• 2 and 4 only

Multiple Choice

The process of the nucleus of the pollen fusing with the nucleus of the ovule is called ________________.

• pollination

• fertilisation

• germination

• reproduction

Multiple Choice

Which part of the flower is usually feathery or sticky?

• Petals

• Stigma

• Anther

• Nectar

Multiple Choice

Why are shorea seeds able to be dispersed by the wind?

• It is light and has wing-like structure

• It has hooks to hook onto the fur of animals

• It has a fibrous husk that makes it float

• It has dry pods that split open

Multiple Choice

All the following are the seed dispersal methods, except.......

• By wind

• By warmth

• By animals

• By explosive mechanism