UNIT 4: PLANTS

   
 4.- PLANTS

INDEX: 

4.1. Characteristics of plants.

4.2.- Parts of plants.

4.3.- Groups of plants.

4.4.- Plant nutrition.

4.5.- Plant reproduction.

4.1.- Characteristics of plants 

•      They are multicellular organisms.

•      They cannot move around.
•      They make their own food.
•       Almost all plants live on land. Some are aquatic.

4.2.- Parts of plants.       Click on: Parts of a plant

They have three parts:

- Roots: hold the plants in the ground and give them water and mineral salts.

- Stem: Give the plants shape.

- Leaves: make their food.

4.3.- Groups of plants

There are two groups of plants:

• Plants without flowers.  These plants do not have flowers or seeds.  They 

            reproduce with spores. 

•   Plants with flowers.  These plants reproduce with seeds.  

According to their size, We can classify plants with flowers into three groups: trees, shrubs and grasses.

	SIZE	STEM	BRANCHES	AGE
TREES	They are Large	They have Woody, hard  stems called trunks	They come from the trunk.	They live many years.
SHRUBS	They are Medium-sized	They have woody, soft and thin trunks	The branches come from the ground.	They live many years.
GRASSES	They are Small.	They have non-woody stems that are soft and flexible  stem.	They have no branches or leaves.	They live a few months.

4.4.- Plant nutrition.

Plants have three stages in their nutrition:

1.Getting nutrients:

• Plants get Carbon dioxide from the air through their leaves.
• Plants get water and mineral salts from the soil through their roots. This mixture is called Xylem sap.

2. Making food:

• Photosynthesis is the process of plants making their own food and producing  oxygen.  During this process, the green substance (called chlorophyll) in leaves catches the sunlight.
• The xylem sap (water + mineral salts) goes up the stem to the leaves through tubes called xylem vessels.

3. Transporting food:

• The leaves transport the phloem sap throughout the plants: roots, stem, flowers and other leaves.

4.5.- Plants  reproduction.

-         Plants with flowers have reproductive organs:

·         Stamens are the male reproductive orgnas. They have round sacs that produce pollen.

·         Pistill  is the female reproductive organ. It has a bottle shape  with ovules inside.

·         Corolla. It is made up of a group of coloured sepals and petals.

·         Calyx: It is a group of small leaves called sepals.

Plants carry out reproduction to make new plants that are similar. Stages in the reproduction:

1.Pollination: Grains of pollen are transported from the stamens to the pistil.

2. Fertilisation: In the pistil, the grain of pollen joins an ovule.

3. Fruit is a fertilized ovule and it has seeds inside.

4. Germination: The seeds grow into a new plant.

-         Plants without flowers reproduce by spores. Spores are special cells that germinate and grow into a new plant.

ACTIVITIES ________________________________________________

1.- Write a sentence with these words.

·         Can´t move around – make their own food – roots, stem and leaves

·         With flowers – without flowers

·         Trees – shrubs - grasses

2.- What are the three stages of plant nutirition?

3.- Match the substances to the parts of the plants that transport them.

            Xylem sap                                          roots

            Phloem sap                            phloem vessels

            Mineral salts and water       xylem vessels

4.- Complete the sentences.

·         Plants can be plants with ___________ or plants without _____________ .

·         The parts of a flower are: _______, ___________, ____________, and _____________ .

·         Pollination causes ________________ .

·         Seeds  ____________ and grow into a new plant.

·         Plants with flowers reproduce with ________________ .

·         Plants without flowers reproduce by _______________ .

5.- Write the stages of reproduction in order: fruit formation, pollination, germination, fertilization.