Unit 4 INVERTEBRATES

UNIT 4 INVERTEBRATES

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UNIT 4

INVERTEBRATES

VITAL FUNCTIONS OF LIVING THINGS All living things organisms have got three things in common: nutrition, interaction and reproduction.

NUTRITION. Nutrition is when living things use food, water and air to live and grow. For example, rabbits eat grass, drink water and breath air.

According to the food they eat, animals can be classified as herbivores, carnivores, omnivores and detritivores.

Carnivores are animals that only feed on meat.

Carnivores hunt other

Some carnivores are scavenger, which means to find and eat the bodies of dead animals. For example, vultures or hyenas

animals and eat them.

For example, eagles or wolves

Herbivores are animals that only feed on plants. For example, horses or deers Detritivores are animals that feed on other animal remains.

For example, worms.

Omnivores are animals that eat meat and plants.

For example, pigs or wild boar.

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INTERACTION. The process of interaction is the ability to detect and respond to changes in the environment.

First, animals receive information from their sorroundings. This information comes from their senses. Then, their bodies process the information and decide on a response. Finally, they carry out this response.

REPRODUCTION. The process of reproduction allowos animals to have offspring similar to theirselves. The mojority of animals have sexual reproduction. This means a male and female have to come together to reproduce.

According to how they reproduce, they can be oviparous or viviparous.

• Oviparous animals develop inside an egg that their mother lays.

• Viviparous animals develop inside their mother’s belly. The mother gives birth to live young.

The babies or young produced by a living organism

2. Write, at least, two animals of each category: o o o o o

Carnivore: ___________________________________________________________ Herbivore: ___________________________________________________________ Omnivore: ___________________________________________________________ Scavenger: ___________________________________________________________ Detritivore: __________________________________________________________

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INVERTEBRATES

Invertebrates are all around us! They live on land and in water. They walk, swim, crawl and fly. They can be big or small, but they all have one thing in common: they don’t have a backbone. Many inveretebrates have an exoskeleton or a shell to protect their body,

but some invertebrates jus have a soft body.

The most important groups are: sponges, cnidarian, worms, molluscs, echinoderms and arthropods.

SPONGES. They are very basic animal. Most sponges are founf in seawater. Sponges are in the shape of a big “U”. Water is sucked in through pores in the side of the sponge. When the water moves through the sponge, tiny food particles are filtered out of the water.

CNIDARIANS. Jellyfish swim and float through the oceans, but corals and anemones live fixed in one place. Jellyfish have got poisonous tentacles, which they use to hunt other aquatic organisms.

WORMS. Worms have got very long bodies.

Some are divided into segments or rings.

They can be aquatic or live on dry land like an earthworm.

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ACTIVITIES 1. Complete the sentences about the invertebrates. a) Invertebrates walk, _________________________________________________. b) Invertebrates all have one thing in common; they ________________________. c) Many invertebrates have ________________________ to protect their body. d) Some invertebrates have a __________ body.

2. Look at the photos. Identify and describe these invertebrates.

3. Work with your classmate. Describe one characteristic of sponges, cnidarians or worms in turns and try to find out which kind of invertebrate is.

They are a very basic animal

I think that is a sponge.

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MOLLUSCS. Molluscs have soft bodies, and some have flexible tentacles for sensing thier environment or grabbing things. Most molluscs grow a hard shell for protection, but their shell grows in only one or two pieces. There are three main groups of molluscs: Snails: nearly all snails grow a spiral shell that is all one piece.

Bivalves: they have two shells, and these shells are connected. For example: clams, oysters and mussels.

Squids and octopuses: they don’t have shell, but are larger, smarter and faster than the other groups. They use tentacles to hunt because they are predators.

ECHINODERMS. Echinoderms are usually shaped like a star or a ball.

They are covered in a shell.

The shell has got ling spines sticking out of it. Starfish and sea urchins belong to this group of invertebrates.

1.

Unscramble the letters to spell the next words and classify them. sfhisrta

mlac

pcotuos

esa huncir

sidqu

tysroe

lisna

lesmsu

Molluscs: _________________________________________________________ Echinoderms: ______________________________________________________ 2.

Look at the photo and answer the questions.

o Which is the group of this invertebrate? _________________ o How is its body? _____________________________________ ___________________________________________________ o Which do they use to hunt? ___________________________ o What is special about this animal? ______________________ __________________________________________________

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ARTHROPODS. These invertebrates have got a body covered in armour plates, called exoskeleton. They have got varios numbers of legs. Some have got wings and can fly.

There are aquatic arthropods like crabs and shrimps. Land arthropods include spider and centipides, or insects like flies and wasps.

The most numerous group are: insects, spiders, crustaceans and centipides.

Insects have an exoskeleton and their Spider have a body divided in two parts: body is divided into three parts: the head, the head and the abdomen. All spiders the thorax and the abdomen. They have have eight legs, none antenae and most two antennae, six legs and most insects spiders have eight eyes. have wings. For example, wasp or ant.

Crustaceans have ten legs and two eyes. Centipides have lots of legs and many They have antennae and a thick body parts. They have two antennae and exoskeleton. For example, crab or shrimp. they can move very quickly.

1. Classify the groups of arthropods depending on they are aquatic or land arthropods. ďƒź Aquatic: ____________________________________________________ ďƒź Land: ______________________________________________________ 2. Label this arthropod and describe it.

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UNIT 4 INVERTEBRATES C__________ (SCAVENGER)

HERBIVORE O_________

N__________ DETRITIVORE INTERACTION

VITAL FUNCTIONS

O________ R_________ VIVIPAROUS

INVERTEBRATES They don't have a backbone Mnay invertebrates have exoskeleton or shell and soft body

S__________

C___________ (JELLYFISH AND CORAL)

______________ - INSECTS

W______

- SPIDER

____________ (STARFISH AND SEA URCHIN)

M____________ - SNAILS - BIVALVES - SQUIDS AND OCTOPUSES

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- CRUSTACEANS - CENTIPIDES

UNIT 4: ACTIVITIES 1. True or false. Copy the sentences and correct the ones the are false. o o o o o o

Sponges are very complex animal. ________________________________________________

Corals swim and foalt through the oceans. ________________________________________________ Worms have got very long bodies. ___________________________________________________ Molluscs have soft bodies and all have flexible tentacles. ____________________________________ Echinoderms are not usually shaped like a star or a ball. _____________________________________ Arthropods have got a body covered in armour plates. ______________________________________

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2. Look at the pictures and complete the table with the information required.

Name

Group of invertebrate

Subgroup of invertebrate

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Characteristics