How plants grow. Activity

Transcription

1 How plants grow Objectives When you have completed this lesson you will be able to: describe how living things grow gradually record the germination and growth of different seeds arrange pictures of seedlings in order Plants are living things. Living things grow. leaves stem bean (seed) roots Many plants grow from seeds. FASCINATING Trees grow slowly all their lives. The rings in a tree trunk show how many years it grew. Each ring is one year. This tree was about 70 years old. A bean is a seed. When the conditions are right, it sprouts. We say that it germinates. First roots grow down into the soil. Then the stem grows up to the light. Leaves grow from the stem. Count the rings in this tree. How old is it? 10

2 Investigating the growth of seeds You will need: different seeds such as corn (maize), beans, cress and grass, plastic trays, sheets of paper towel. Lay paper in the trays and wet it. Put a different type of seed in each tray. Put the trays in a dark cupboard or box. Check the trays every day. Keep the paper moist. Draw the seeds as they germinate and the seedlings grow. Compare your seedlings. How are they similar? How are they different? Make a display of your observations. You could measure the seedlings with a ruler, and plot graphs. A digital camera is a good way of recording what happens. K E Y W O R D S germinates grow roots seeds stem Check your progress 1. Copy and complete these sentences using some of the key words. Plants grow from. When conditions are right a seed. First the roots down. Then the grows up. 2. Put the seedlings below in order. 11

3 Roots and stems Objectives When you have completed this lesson you will be able to: state the functions of a plant s roots state the functions of a plant s stem The parts of a plant do different jobs. The roots hold the plant in the soil. They anchor the plant. The roots take water from the soil for the plant. Investigating roots You will need: an onion or a hyacinth bulb, a glass jar with a funnel-shaped neck. 1. Fill the jar to the narrow part with water. 2. Add a few drops of liquid plant food. 3. Place the bulb/onion in the jar so that its base touches the water. 4. Put the jar on a warm windowsill. 5. Observe it every day. Record what you see. Roots usually keep trees standing when the wind blows, but they can t withstand a hurricane! Water water travels travels up the up the stem stem The roots act like drinking straws and take up water. The plant needs more water as it grows, so more roots are produced. The stem grows up from the ground. It supports the leaves so they can catch sunlight. The stem carries water from the roots to the leaves and flowers. The plant s roots take water from the soil water 12

4 Investigating stems You will need: some white flowers, food colouring, jars, water. 1. Make a clean cut through the flower stems at the base. 2. Add a teaspoon of food colouring to the water in the jars. 3. Stand the flowers in the jars. 4. Leave them in a warm place overnight. 5. Look closely at the flowers. What do you observe? Water travels through the stems inside hollow tubes called veins. You can see the coloured water inside the veins in the flowers petals. K E Y W O R D S anchor supports veins water Check your progress 1. Copy and complete these sentences using the key words. A plant s roots it in the soil. A plant s stem the branches and leaves. The roots take from the soil. Water travels up the stem through. 2. Fill in the missing labels on this plant. B Which arrow shows the way water? A moves through a plant, A or B?? 13

5 Branches and leaves Objectives When you have completed this lesson you will be able to: describe how branches support leaves explain that leaves make food for a plant and help it to breathe identify different leaf shapes As a tree grows, branches grow out from its stem (trunk). Leaves grow from the branches. Green leaves are a plant s food factories. They make food with the energy of sunlight. To do this they must face towards the Sun. Leaves are sun worshippers! You will need: a potted plant, a sunny window. leaves stem branch Stand the plant in the window for several days. Observe which way the leaves face. Now turn the plant around so that its leaves face away from the Sun. Leave it for a few more days. Have the leaves moved? Leaves help the plant breathe as it grows. You breathe in and out through your nose and mouth. A plant breathes through its leaves. As a plant gets bigger it needs more food and more air, so it must grow more leaves. It grows more branches so that the leaves are spread out, and do not shade each other. 14

6 You can recognise trees by the shapes of their leaves. Looking at leaves You will need: a paint brush, coloured poster paints, a pen, sheets of thick paper, water, newspaper. 1. Make a collection of leaves from different trees and bushes. 2. Cover a table with newspaper. 3. Place your leaves on the newspaper, shiny side down. Then paint the underside of each leaf with a thin coat of paint. 4. Press the painted side of the leaf firmly onto the thick paper, then peel it off to leave a print. Look carefully at the leaf print. Can you see the veins? These are the thin tubes that carry water and food to and from the leaf. Take leaf prints from different trees. Can you name them? Use guidebooks to help. Compare the shapes, sizes and edges of the different leaves. K E Y W O R D S branches breathe food leaves Check your progress 1. Copy and complete these sentences using some of the key words. A plant grows to spread its leaves. A plant s leaves make. Leaves help a plant to. 2. Explain why a big plant needs more leaves than a small plant. 15

7 Looking at flowers Objectives When you have completed this lesson you will be able to: identify and name some different flowers explain that the flowers of some plants become fruits that contain seeds collect, preserve and label specimens Many plants grow beautiful flowers. Can you name these flowers? What other flowers do you know? Brightly coloured flowers with sweet smells attract insects and birds. Bees and hummingbirds feed on the sweet nectar a flower makes. A powder called pollen sticks to insects and birds as they visit a flower. Inside another flower, pollen brushes off. Pollen makes some flowers change into fruits. The fruits hold the seeds. flower fruit FASCINATING Sunflowers look like the Sun. They follow the Sun too. Their heads turn as the Sun moves across the sky from sunrise to sunset. 16

8 Collecting flowers You will need: sheets of paper towel, heavy books, glue, card. 1. Collect some garden flowers (do not take whole plants leave the roots and leaves so that more flowers will grow). 2. Open a large book and lay two sheets of paper towel on it. 3. Arrange the flowers flat on one sheet. 4. Close the book and stack some more books on it or use a flower press if you have one. 5. After about four weeks, take out the pressed flowers. 6. Glue your flowers onto card. 7. Label each flower with its name. The pressed flowers last because they dry out on the paper towel between the pages of the book. They do not wilt like fresh flowers. You can use pressed flowers to decorate greetings cards. K E Y W O R D S flowers fruits nectar pollen Check your progress 1. Copy and complete these sentences using some of the key words. Birds and insects visit a plant s. They carry from one flower to another. This makes some flowers change into. 2. Explain why some flowers are brightly coloured and have a sweet smell. 3. What do some flowers change into? Why do you think this is important for the plant? 17

9 Animals that lay eggs Objectives When you have completed this lesson you will be able to: classify animals according to whether they do or do not lay eggs discuss the numbers of eggs laid by different animals Animals are living things. Living things reproduce. They have young that grow up to be like themselves. Mammals give birth to live young. A baby mammal grows inside its mother. Birds, fish, reptiles, amphibians and insects lay eggs. A baby hen grows inside an egg outside its mother s body. The mother sits on her eggs to keep them warm. When the chick is ready, it breaks out of the eggshell. We say that it hatches. Can you match these eggs to their parents? How many eggs does each animal lay a few or many? turtle pelican frog butterfly 18

10 Hatching eggs You will need: a jar of warm water, sea salt, fish food, brine (salt water) shrimp eggs (from a pet shop that sells aquarium supplies), magnifying glass. 1. Stir about 50 grams of salt into 500 millilitres of warm water until all the salt has dissolved. Let the water cool. 2. Add a little fish food. 3. Sprinkle some brine shrimp eggs onto the water. Leave the eggs to hatch. This will take about 2 days. sea salt fish food warm water (Brine Shrimps) brine shrimp eggs (Brine Shrimps) large jar Look at the water through a magnifying glass. What can you see? K E Y W O R D S birth egg hatches lay reproduce Check your progress 1. Copy and complete these sentences using some of the key words. Humans and other mammals give to live young. Birds, fish, reptiles and many other animals eggs. The baby grows inside the. When it is ready, it. 2. Say which of these animals lay eggs and which do not. crocodile goat bee dolphin manatee parrot 19

11 Animals with bones Objectives When you have completed this lesson you will be able to: classify animals with backbones as vertebrates classify vertebrate animals as mammals, birds, reptiles, fish and amphibians list the characteristics of different vertebrate groups People and many other animals have bones inside their bodies. Bones give the body shape. Animals with bones and backbones are called vertebrates. There are five different groups of vertebrates. These are called mammals, birds, reptiles, fish and amphibians. Mammals Mammals feed their young with milk. They are warm-blooded. Most mammals have fur or hair on their skin. Their young are born alive. Birds Birds have feathers. They are warm-blooded. They lay eggs. 20

12 Reptiles Reptiles bodies are covered with scales. They are cold-blooded. Most reptiles lay eggs, though some snakes keep the eggs inside their bodies until they hatch. The young hatch on land. Fish Amphibians Fish live in water, breathe through gills and swim with fins. Many fish are covered with scales. They are coldblooded. Amphibians are cold-blooded. Their eggs and young hatch and grow in water, but the adults can live on land. FASCINATING The blue whale is the biggest animal ever. It lives in water but it is a mammal, not a fish. It is warm-blooded and feeds its young with milk. 21

13 Classifying animals Copy this table. List at least three animals in each group. Add more if you can. Mammals Birds Reptiles Fish Amphibians K E Y W O R D S amphibians birds fish mammals reptiles vertebrates Check your progress 1. Copy and complete these sentences using some of the key words. There are five different groups of vertebrates. and have warm blood. and have cold blood and lay their eggs in water. have cold blood and lay their eggs on land. 2. Which is the odd one out: shark, tuna, dolphin, tilapia? Say why. 3. A turtle lives in the sea, is cold-blooded and lays its eggs on land. Which animal group does it belong to? Explain your answer. 22

14 Insects Objectives When you have completed this lesson you will be able to: distinguish between insects and non-insects state the characteristics of insects Worms, snails, crabs, squid and many other animals do not have bones in their bodies. The biggest group of animals without bones are the insects. Insects have a hard skin to give their body shape. The picture shows the main parts of an adult insect. Adult insects have six legs. Their bodies are divided into three main parts. Many insects have wings and can fly. This picture shows some of the different kinds of insects. ladybird beetle bee antenna eye moth legs cricket wings 3 body parts dragonfly ant fly stick insect butterfly Look for insects around your home and school. Count the number of kinds you see. Some insects are useful to human beings, but others harm plants, people and animals they are called pests. flea FASCINATING mantis Beetles are insects. There are at least half a million different species of beetle more than any other animal group. 23

15 Have you seen these insects? fly locust termite bee weevil aphid mantis louse mosquito cockroach Say whether each of the insects above is harmful or helpful. Match each insect to the harm or the good it does (it may do more than one thing). spreads disease damages wooden houses pollinates flowers eats insect pests damages crops lives on our body makes honey K E Y W O R D S insects legs pests wings Check your progress 1. Copy and complete these sentences using some of the key words. Adult have six legs and three main body parts. Many insects have and can fly. Insect harm plants and animals. 2. Which of these animals are insects? Say how you know. spider scorpion wasp cricket 24

16 Life cycles Objectives When you have completed this lesson you will be able to: explain that different animals have different life cycles observe the life cycle of a butterfly describe the life cycles of an insect and a frog A new life begins when an animal is born. The animal changes as it grows, and has babies of its own. These changes are called the animal s life cycle. A human baby looks like a small grown-up. It gets bigger, but its shape does not change very much. baby 13 years child (6 years) adult Some animals change completely as they grow. The human life cycle. egg The fly larva (or maggot) hatches from the egg. It changes into a pupa. Inside the pupa its body changes completely to an adult fly. This is called metamorphosis. adult pupa The life cycle of a fly. larva (maggot) 25

17 In the frog life cycle the change from a tadpole to an adult frog is also called metamorphosis. adult egg Observing a life cycle tadpole The life cycle of a frog. You will need: a large box, a net, a pot, soil. 1. Collect a plant with butterfly eggs on its leaves. 2. Grow the plant in a pot. Keep the pot in a large box with an open side. Cover the side with a net. 3. Observe the eggs hatch. 4. Over the following weeks observe what happens. Keep daily records of what you see. 5. Release the adults back to the wild. 26

18 The stages in a butterfly s life cycle are egg, caterpillar, chrysalis and adult. Draw these stages in order and add arrows to show the life cycle. eggs chrysalis adult caterpillar K E Y W O R D S chrysalis larva life cycle metamorphosis pupa Check your progress 1. Copy and complete these sentences using some of the key words. The changes that an animal goes through as it grows up are called its. A caterpillar changes to an adult butterfly by. This takes place inside a. 2. Write these life-cycle stages in the correct order: (a) adult fly pupa egg maggot (b) tadpole adult frog egg 27

19 Animal habitats Objectives When you have completed this lesson you will be able to: identify some different habitats and animals that live in them describe how animals are adapted to survive in different habitats The place where an animal lives is its habitat. A dolphin s habitat is the ocean. A crocodile s habitat is the river. A chimpanzee s habitat is the forest. There are many different habitats in our world. Deep oceans, hot, dry deserts, steaming rainforests, snowy mountains animals live in them all. Animals bodies suit the place where they live. We say that they are adapted to their habitat. A crocodile has its eyes high on its head so that it can see above the water. A polar bear has thick fur to keep it warm in the ice and snow. An elephant s big ears help to keep it cool in the hot sun. 28

20 Look at these animals and habitats found in the Caribbean. 1. Match each animal to the habitat in which it lives. 2. Describe ways in which each animal is adapted to its habitat. clown fish humpback whale howler monkey ruddy turnstone rainforest coral reef seashore deep sea FASCINATING Coral reefs and rainforests are two of the richest wildlife habitats in the world. There are more species of plants and animals in these habitats than in any other. Both habitats are found in the Caribbean. K E Y W O R D S adapted habitat Check your progress 1. Copy and complete these sentences using the key words. The kind of place where an animal normally lives is called its. Animals bodies are to help them survive in their habitat. 2. Describe how an animal could be adapted to survive in a cold habitat. 3. Describe how an animal could be adapted to move underwater. 4. Name two different habitats in the Caribbean. List some animals that live in them. 29

21 Predators, prey and camouflage Objectives When you have completed this lesson you will be able to: define the terms predator and prey describe how predators and prey use camouflage An animal that hunts other animals for food is called a predator. The animals it hunts are its prey. The shark is a fierce predator. It catches and eats other animals in the sea. Predators and prey Match the predators to their prey in these lists: Predators: shark snake spider jaguar FASCINATING A skunk squirts a very smelly liquid to repel a predator. It is one of the smelliest animals in the world! Prey: fly tapir mouse fish Predators have adaptations that help them hunt. Look at these predators. Name one adaptation each has for hunting. Prey animals have adaptations to protect them from predators. scorpion eagle octopus Look at these prey animals. Name one adaptation each has to protect it from predators. tortoise porcupine 30

22 Camouflage patterns and colours make an animal difficult to spot in its normal habitat. Both predators and prey may be camouflaged. Can you see the predator in this picture? How does camouflage help it catch its prey? Can you see the prey in this picture? How does camouflage help it survive? Camouflage test Spots, stripes and patches of colour help to disguise an animal s shape. But which are best? Draw animal shapes like these. Colour them to camouflage them against different backgrounds in a tree, on a stone, in the grass. Which camouflage works best? Hold a competition. The last animal to be found wins. K E Y W O R D S camouflage predator prey Check your progress 1. Copy and complete these sentences using the key words. A hunts and eats other animals. The animals it hunts are its. Patterns and colours that hide an animal s body are called. 2. Name two predators. What are their prey? 3. Why are prey animals often camouflaged? 31

23 End-of-Unit Test 1. Name the parts of this plant. Say what each part does.?? 2. True or false? A plant s leaves make its food. T/F? Fruits change into flowers. T/F? When a seed germinates, the root is the first part to grow. T/F? A plant s stem anchors it in the soil. T/F?? 3. Name the odd-one-out in each of these lists. Explain your choice. Hint think about how the animals reproduce. (a) horse, human, hen, hamster (b) frog, fox, fly, fish (c) bird, butterfly, bee, bear (d) mosquito, manatee, mouse, monkey 4. Copy these boxes. Write the names of two animal species in each box. Add more species if you can. mammals birds reptiles amphibians fish 5. (a) Name an insect that is helpful to human beings. Explain how it helps us. (b) Name two insects that harm human beings. Explain how they harm us. 32

24 6. Find the four stages in the life cycle of a butterfly in this word grid. c a t e r p i l l a r h q e g f r a a g x y e s f g a d u l t l e r y i g s Write the stages in order. In which stage does metamorphosis take place? What happens? 7. Name some of the different animals that live in each of these habitats. rainforest coral reef seashore deep sea 8. Select a word from the list below to match each of these definitions. An animal that hunts other animals. An animal that is hunted. Patterns or colours that disguise an animal. When an animal s body is suited to the way it lives. adapted camouflage predator prey 33