Perhaps when you heard somebody say the animals or animal kingdom, you might think right away about big animals, such as lions, whales, and even birds. But would you believe that an animal kingdom is mainly made up of smaller animals than a lion and that have jointed legs and have a hard outer shell? Arthropoda-this is the largest phylum in the animal kingdom.

Introduction to Phylum.

Now, before knowing about Arthropoda, let us explain what a “phylum” is. Science divides living things into groups and therefore helps us to figure out what makes them different from the rest as well as alike. There are many groups of animals, one of which is called a phylum. picture the largest group, called a phylum, that encompasses animals who share common characteristics. Within this massive phylum are smaller subgroups: classes, orders, families and more. One of the largest of all is Arthropods.

What Makes the Arthropods Special?

The word “Arthropoda” comes from Greek words. There, “arthron” translates to “joined”, and “pous” translates to “foot”. Animals classified within this phylum display three main characteristics:

Jointed Legs

All arthropods possess legs in sections which makes them bend at joints for easy movement.

Exoskeleton

On the contrary, arthropods possess an outer hard shell known as an exoskeleton. It covers their body and gives them support. It is made of a material known as chitin which is very tough yet quite elastic.

Segmented Bodies

Arthropods have segmented bodies. Most arthropods do, but the number of body segments is fewer than you might think. Most arthropods have three major body segments: head, thorax, and abdomen.

These are the reasons why arthropods are the most successful animals on Earth. They can survive in almost every environment.

How many arthropods are there?

According to scientists, there are more than a million known species of arthropods. That is approximately 75% of all the known species of animals. Arthropods can be found at virtually every corner of this earth-from the deep ocean bottoms to the summits of mountains, even to your own backyard.

Major Groups of Arthropods 

The phylum Arthropoda contains four taxonomic groups. 

1. Insects

Insects are the largest class of arthropods. They have three distinct parts of the body: head, thorax, and abdomen. Insects have three pairs of legs, two antennae, and normally two pairs of wings. Insects can be found almost everywhere, in forests, deserts, ponds, and in fields. 

Examples of insects are: Butterflies Bees Ants Beetles. Other crucial functions performed by insects include, Pollination of plants is carried out by insects, such as bees, and some rotting parts of both animals and plants and other pests like mosquitoes that cause diseases.

2. Arachnids

Any arthropod of class Arachnida is an arachnid. They have eight legs. Most arachnids are divided into two parts of their body: the cephalothorax, which basically consists of a head and thorax combined, and the abdomen. No arachnid has antennae or wings. The majority habitat of most arachnids is dry; however, there are some types of arachnids, like water mites that live in water.

Examples- Spiders make webs just to snare their prey. Scorpions They have pincers and the long, curved tail with shaft ending in a stinger. Ticks These are small parasitic blood feeders that suck blood from every living organism.

3. Crustaceans

Usually, the crustaceans have adaptations to stay in water; some of them live in salt water while others dwell in freshwater. They have at least two pairs of legs. They usually have two pairs of antennae. Most of them have an overlapping carapace that covers their bodies. They can also be small like plankton and big as lobsters

Examples of crustaceans include, Crabs, Lobsters, Shrimps, Barnacles. Crustaceans form an integral part of marine food chains. Many fish and birds are crustacean prey; even krill, a crustacean, feeds on whales.

4. Myriapods

Myriapods comprise: centipedes and millipedes. Some arthropods have hundreds of legs! A myriapod is characterized by its elongated, flat body, with each body segment of the myriapod bearing a pair (centipedes) or two pairs (millipedes) of legs.

Examples of myriapods comprise

Centipedes : They are active predators. For each body segment that they have, they do have one pair of legs.

Millipedes : They are feeble movers; they usually feed on decaying plant material. Each body segment will normally have two pairs of legs.

Myriapods will spend most of their lives in a moist environment such as the forests under rocks or soil.

How Do Arthropods Grow?

Since arthropods have a hard exoskeleton, they never grow up as the human does. Instead, they shed their skin. That is to say, the arthropod excretes the old exoskeleton and the new one develops, hence making it larger. At this time however sometimes they are at a disadvantage because the new exoskeleton takes some amount of time to set.

For arthropods, one part of their life cycle is that they can be larvae, for example, caterpillars and indeed transform to adults, such as butterflies. That in a way allows them to assume other roles within the environment at another level in their life.

Worms: Unsung Engineers of Our Ecosystem

Why Are Arthropods Important?

Actually, arthropods are pretty important for a lot of reasons

Pollination: Other than bees and butterflies, other insects pollinate plants, and it has so allowed them to produce fruits and seeds.

Food Chain: Many more consumers other than birds, fish, and mammals eat arthropods though without it would disrupt the food chain

Decomposers: the dead plants and animals are broken into tiny pieces by arthropods like beetles and millipedes. This has enabled the reuse of nutrients in the soil.

Human Use: Some crustaceans like crabs, lobsters, and shrimps have become amongst the most prized food resources.

However, arthropods include some animals which are pests, or may transmit diseases. For example, the mosquitoes transmit malaria while the ticks suffer from Lyme disease.

Cool Facts: Arthropoda of animal kingdom

The largest arthropod that exists on Earth can never be any other than the Japanese spider crab as it has a leg span up to 12 feet!

The fairyfly is the smallest insect. This is a species of wasp that is even smaller than half a millimeter in length.

Some spiders may produce silk that is as tough as the same thickness of steel!

Conclusion

In one sense, this would mean that Arthropoda is the largest phylum of the animal kingdom. Therefore we can find them almost everywhere. Animals of Arthropoda phylum of animal kingdom help to pollinate flowers, participate in small food chains. So animals hold a rather important position in this world. From the buzzing of a bee to the scuttle of a crab and the crawl of a centipede, arthropods are pretty cool animals keeping the world in balance.

The next time you are going to see a spider spinning its web or a beetle trundling along the dirt track, you will know you are seeing it in an astounding world of Arthropoda phylum of animal kingdom!