Examples of Invertebrates: Definition, General Characteristics, Classification, and Their Names

Examples of Invertebrates – The number of animals is basically a lot. With a very large number, animals are divided into two groups based on their backbone, that is, animals that have a backbone are included in the vertebrate group. Meanwhile, animals that do not have a backbone will be included in the invertebrate group.

Invertebrates themselves can be understood as a group of animals that do not have a backbone. Basically, the spine is a row consisting of several vertebrae and stretches from the neck to the tail. This group of invertebrate animals is also known to be found in almost every habitat on earth.

Apart from not having a backbone, there are several characteristics that can be used to distinguish between invertebrates and vertebrates, starting from the nervous system, how to reproduce, to the structure of the organs.

For those of you who want to learn more about invertebrates. The following is an explanation of the characteristics and examples of invertebrate animals. Not only that, this article will also discuss the classification or division of the invertebrates themselves. Let’s see in full until the end!

A. General Characteristics of Invertebrates

As previously stated, the main characteristic of invertebrate animals is that they do not have a backbone. However, the main characteristics of invertebrate animals are not only that. So, here are some of the main characteristics that distinguish invertebrate animals from other animals or organisms, including:

1. The body skeleton of invertebrate animals is usually found outside the body or exoskeleton.

2. Excretory organs in lower invertebrates have never been found. Meanwhile, for higher invertebrates, it is known that they have not focused on an organ.

3. The nervous system of invertebrate animals is still simple and there is no central nervous system. However, this does not apply to several types of animals that have a nerve center in the form of a collection of nerve nodes or ganglions.

4. Invertebrates reproduce generatively and/or vegetatively.

5. Invertebrate animal blood circulation is open. Blood that comes from the blood vessels will enter the heart and some will continue to circulate through the veins to enter other parts of the heart.

B. Classification and Examples of Invertebrates

After knowing the two groups in the animal world and the differences between the two, in this section we will discuss the classification for the invertebrates themselves. Invertebrates can be grouped into six phyla, namely porifera or porous animals, vermes or worms, coelenterata or hollow animals, arthropods or book animals, molluscs or soft animals, and echinoderms or animals with thorns. The following is an explanation of the six groups of invertebrate animals, including:

1. Porifera

As the name implies, sponges are a group of animals whose entire body surface has pores. This animal has a body that is almost the same as the shape of a sponge, with a skeleton made of horn substance. Porifera are usually known to have irregular or asymmetrical bodies.

The shapes of the sponges vary, ranging from those that are shaped like tubes, flower vases, bowls, and some even have a branched shape like a plant with very diverse body colors. These animals basically live in water and can still reproduce, either by mating or not mating. Unmarried reproduction can occur by forming a bud.

In everyday life, you can use several types of sponges such as Spongia and Hippospongia as bath tools, bath sponges, and scrubbing tools.

Examples of sponge animals include the following:

a. Scypha

b. Euspongia

c. potion

2. Coelenterata

Coelenterata is a type of animal that lives in water with cavities in its body. The body of the coelenterata has two types of shapes, namely the polyp shape and the medusa shape.

Coelenterata with polyps are known to have a tube-like shape. In addition, these animals live by sticking to their place of life. Meanwhile, medusa has a shape like a bell or an umbrella. Medusa itself has arms or tentacles that surround it floating in the water.

The tentacles of the medusa can be used to catch prey. If there is prey that sticks to or approaches the tentacles of the medusa. Poisonous cells contained in the medusa tentacles will secrete poison so that it can paralyze the prey.

Examples of coelenterata include, namely:

a. Obelia

b. Hydras

c. Jellyfish

d. Anemone


Vermes or commonly called the term worm is a type of animal that has a small size with an elongated and soft body shape. Like the skeletons of other invertebrates, vermes lack a skeleton and have no legs. However, the body of the vermes is bilaterally symmetrical or can be understood as a worm’s body which can be divided into left and right halves.

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These vermes or worms can be further grouped into three groups based on their body shape, namely, from flat, elliptical without segmented to round and elongated and segmented love-shaped.

a. Platyhelminthes, namely worms that have a flat shape. Examples of this type of worm are tapeworms and heartworms.

b. Nemathelminthes, which are worms that have a non-segmented elliptical shape or can also be called roundworms. Examples of this type of non-segmented round worm are stomach worms, pinworms, roundworms, and hookworms.

c. Annelids, namely worms that have a long round body shape and are segmented or can be included in the roundworm group. Examples of this roundworm group are earthworms, pacet, and leeches.

4. Arthropods

Arthropods have a segmented body shape consisting of a head (caput), chest (thorax), and abdomen (abdomen). Arthropods are also equipped with a bilateral symmetrical body shape and have a protective substance in the form of chitin on their outer skeleton.

Meanwhile, arthropods have a complete body organ system, starting from the circulatory, digestive, nervous, respiratory, excretory, reproductive systems, to sensory organs that are able to respond to touch, heat as well as smells.

Arthropods also have compound eyes or can be understood as an eye consisting of thousands of small eyes with a hexagonal shape. These eyes are known as facet eyes.

Arthropods are known to be one of the largest phyla compared to several other animal phyla. The phylum of arthropods itself can be grouped into 4 classes, including the following:

a. Insecta (insects), with examples: nerds, butterflies, grasshoppers, ladybugs, and beetles;

b. Crustaceans (crustaceans), with examples: prawns, crabs and crabs;

c. Arachnoidea (spiders), with examples: spiders, scorpions, fleas, ticks;

d. Myriapoda (centipedes), with examples: centipedes, millipedes.

5. Mollusca

Molluscs are basically a type of invertebrate animal that has a soft body, contains a lot of mucus, and is wrapped in a mantle. Molluscs themselves generally have a shell made of limestone and can be used to protect their bodies.

Molluscs live in various regions of the earth so that they can be found both on land, sea, fresh water, to hot and cold areas. Molluscs are also animals that already have digestive, respiratory, excretory, circulatory, nervous, muscular and reproductive systems.

Just like other invertebrate animals, molluscs can also be divided into 3 groups, namely:

a. Pelecypoda or clams

b. Gastropods or squid

c. Cephalopods or slugs

6. Echinodermata

Echinodermata is a type of invertebrate animal that has a skin of thorns. The skin of this animal consists of several limestone plates with many small spines on the surface. The body of Echinodermata also has a shape like a star, round, flat, elongated round, some even have a shape resembling a plant.

Echinoderms are able to move using ambulacral legs. Ambulacral itself can be understood as a tube equipped with a suction device. The digestive system of Echinodermata itself also consists of a mouth, esophagus, stomach, intestines and anus. Meanwhile, its nervous system consists of a ring of nerves with a circular shape around the esophagus and its various branches that lead to each arm.

Echinoderms reproduce by sexual means or mating. Not only that, this type of animal also has the ability to regenerate, such as the ability to regrow severed body parts.

Examples of animals that belong to the echinoderm group include:

a. Starfish

b. Sea urchin

c. Sea cucumbers

C. Examples of Invertebrates

After knowing the characteristics and classification of invertebrate animals, this section will explain examples of invertebrate animals that are around us. So, here are some examples of invertebrate animals that you need to know, including:

1. Butterfly

Butterflies are an example of an invertebrate animal equipped with six legs, two antennae and three body parts. There are also types of butterflies that have wings, but some are wingless. Butterflies can be said to be a type of insect that undergoes a complete metamorphosis.

The Smithsonian Institution states that there are about 17,500 species of butterflies in the world. Butterflies can live in all regions of the earth, except for the Antarctic region. Butterflies reproduce in a variety of habitats, from salt marshes, mangroves, sand dunes, lowland forests, wetlands, grasslands, to mountains.

2. Ants

Ants are an example of an invertebrate animal with a body consisting of three main parts, namely the head, chest (where three pairs of legs are attached), and stomach (where vital organs are located).

Quoted from the National Geographic report, there are currently more than 10,000 species of ants in the world. Ants themselves are very easy to find in tropical rain areas with structured nests located underground, mounds on the ground, even trees.

3. Bees

Bees are an example of an invertebrate animal that has a thin exoskeleton. The body of the bee can be divided into three parts, namely the head with two antennae, the chest with six legs and the abdomen. The body of the bee itself is equipped with two pairs of wings and only the female bee has the ability to sting.

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Based on The National Wildlife Federation, there are more than 20,000 species of bees spread throughout the world. Just like ants, bees usually live on every continent on earth, except Antarctica. In a region like North America, about 4,000 species of bees occupy different ecosystems, whether in forests, deserts, and of course grasslands.

4. Star of the Sea

Sea stars are one example of invertebrate animals that live in water areas. Starfish themselves are generally known to have a central disc which is divided into five arms. Although some other species have more arms. However, the starfish’s arms would be covered with pincers and suction cups that could be used along the ocean floor.

According to a report published by National Geographic, it is known that there are about 2,000 species of starfish that live throughout the world’s oceans, both in tropical habitats and in low-temperature ocean floor habitats. The most common species of sea star is the five-armed one. In addition, there are species of starfish that have arms reaching 10, 20, and even 40 pieces.

5. Jellyfish

Just like starfish, jellyfish are examples of invertebrate animals that live in the sea and belong to the phylum Cnidaria. Phylum Cnidaria is a phylum that is not equipped with a brain, bones, heart, and even eyes. The body of the jellyfish generally consists of a soft and transparent to immobilize prey before eating it.

The structure of the jellyfish itself consists of three layers, namely first, the outer layer or epidermis, second, the middle layer which is made of a thick elastic substance similar to jelly or mesoglea. Third, the inner layer or commonly called the gastrodermis.

6. Spiders

Spiders are an example of an invertebrate animal with an exoskeleton consisting of a cuticle and made of chitin. This animal has a body divided into two main parts, namely the cephalothorax and abdomen. Most spiders have eight eyes and a mouth known as chelicerae. Inside the chelicerae are equipped with fangs that can be used to inject poison into their prey.

Quoted from the Encyclopedia Britannica, there are more than 43,000 species of spiders in the world. These spiders live in almost all parts of the earth, except for the polar regions, the highest mountains and the oceans.

7. Snail

Snails are invertebrate animals with soft bodies and heads that have tentacles to feel their surroundings. Snails themselves have a mouth made of a radula or a tool that can be used to scrape food from most surfaces.

Snails are known to have strong, muscular legs and thick slime. This will be very helpful for movement on rough surfaces. Mucus owned by snails can also prevent it from drying out. However, the mucus can also harden to form a blockage.

8. Squid

Squid is an example of an invertebrate that belongs to the Mollusca phylum. Today, there are hundreds of species of squid scattered throughout the world’s oceans, from the shallowest waters to the deepest.

Squids also have a tubular body, a small internal shell like a rod, and are equipped with two tentacles that are much longer than the arms. In addition, squid can change color and swim backwards. This is done by utilizing the thrust of water that comes out of his body.

9. Worms

Worms are examples of legless invertebrates with flat or round bodies with heads and tails. Worms themselves are known as animals that do not have a hard skeleton. Worms are usually found in water or wet soil, they can even be in other, larger animals.

Worms are animals that can live in a variety of habitats, such as parks, hydrothermal vents, deep ocean, toxic environments, to the cold waters of Antarctica. The size of the worms themselves varies greatly, ranging from small worms such as microscopic sizes to very long worms.

10. Leeches

Leeches are an example of an invertebrate animal that belongs to the phylum Annelida. The leech itself has a bilaterally symmetrical shape and thick muscles. The shape of the leech itself is almost the same as a worm, it’s just that there are many leeches that have a shape similar to a pear and are wide.

Most leeches spend their habitat in fresh water. However, there are some juha leeches that can live on land and sea. Land-dwelling leeches are especially easy to spot on the ground or low leaves in wet rainforests. Leeches are known to be unable to swim in water, but they can live by immersing themselves in water.

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