4- Help me to learn about invertebrates

Activity 4: Help me to learn about...

INVERTEBRATES ANIMALS

Natural Science - 4th GradeUNIT 3

INDEX

Characteristics

Let's review

Types

Self-evaluation

Learn & play

Fast finishers

CHARACTERISTICS

• An invertebrate is an animal without a backbone.
• Invertebrates live in every part of the world. In fact, most of the animals on Earth are invertebrates. (97%)

• Invertebrates come in all different shapes and sizes. Some can be seen only through a microscope. But the giant squid is an invertebrate, and it can grow about 20 m.

• The simplest animals are invertebrates. These include protozoans with just one cell as well as sponges and other simple animals that live in the water.

TYPES OF INVERTEBRATES

ARTHROPODS

CRUSTACEANS

MYRIAPODS

ARACHNIDS

INSECTS

Other invertebrates

ANNELIDS & WORMS

MOLLUSC

SPONGES

CORALS

JELLYFISH

ARTHROPODS

• Arthropods are invertebrates with jointed legs. They make up about 75% of all animals on Earth and have a major role in maintaining ecosystems as pollinators, recyclers of nutrients, scavengers and food for other animals.
• They include many animals we come across in our gardens, such as spiders, ants, centipedes and slaters. Arthropods are divided into four major groups:

Insects, arachnids, myriapods and crustaceans.

INSECTS

• They have a hard exoskeleton, or shell, on the outside of their bodies that protects them.
• All insects have three parts: the head, the thorax and the abdomen.
• Insects have two antennae.
• They also have six legs.
• Most of them can fly with 2 or 4 wings.

• All insects hatch from eggs. The babies are called larva.

ARACHNIDS

• Spiders are probably the most well-known arachnid, but also the scorpion is an arachnid.
• Arachnids have eight legs.
• Their bodies are divided into two parts – the head and the abdomen.
• Most spiders have eight eyes, but some have only two, four or six.
• All spiders have venom, but only a few kinds of spiders are dangerous to people.

MYRIAPODS

The key characteristics of myriapods include:

• Many pairs of legs.
• Two body sections (head and trunk).
• One pair of antennae on the head
• Simple eyes.
• Mandibles (lower jaw) and maxillae (upper jaw).
• Some species have fewer than a dozen legs, while others have many hundreds of legs.

CRUSTACEANS

• Most crustaceans are aquatic, mostly marine.
• Crustaceans have three major body parts. They are: head, thorax, and abdomen.
• Generally, they have two pairs of antennae, two eyes, and three pairs of jaws on their head.
• Most breathe with gills.
• Lobsters and crabs have hard outer skeletons

ANNELIDS AND WORMS

• Annelids are sometimes simply referred to as ringed worms or segmented worms; some examples are earthworms and leeches.
• Annelids have soft, segmented bodies.
• They have no skeleton, internal or external.
• Annelids lay eggs.
• Some live in ocean habitats, others live in freshwater, and some live in moist land.

MOLLUSC

• They have a soft body that holds the heart, liver, digestive system, and other important organs.
• Most mollusks have a mouth structure called a radula. The radula is sort of like a rough tongue with lots of tiny teeth.
• A mollusk’s soft body has a covering called the mantle.m, the mantle makes a shell.
• Some mollusks, such as snails, have a single, solid shell.
• Other mollusks, called bivalves, have a shell with two halves. Oysters and clams are bivalves. Some mollusks, such as octopuses and squid, do not have a shell.

SPONGES, CORALS AND JELLYFISH

• The sponges and the cnidarians represent the simplest of animals.
• All sponges are aquatic and the majority of species are marine.
• Corals are sea animals that stay in one place throughout their adult lives. They have brilliant color underwater, most types fade when they die or are removed from the water.
• Jellyfish have no brain, heart, bones or eyes. They are made up of a smooth, bag-like body and tentacles armed with tiny, stinging cells.

LET''S REVIEW

Click the button to watch the vídeo about the invertebrates animals. Pay special attention to the pictures.

LEARN & PLAY

Read carefully the information and classify the characteristics in each group of animals. ENJOY!

SELF EVALUATION

Take your favorite colors and rate your effort, participation, solidarity and your interest and attention in this unit.

FAST FINISHERS

Have you finished all the activities? You can repeat your favourite activity or wait for another classmate to finish and play with this wheel. Remember to answer and add your ideas

¡I hope you liked the lesson!

WELL DONE

Author: Beatriz Fernández Garrido