Pill bugs taste like shrimp


An "arthropod" is an invertebrate animal with an exocelet, an segmented body, and articular appendages. The following families of organisms are examples of arthropods: In ects


An "arthropod" is an invertebrate animal with an exoskeleton, segmented body, and articular appendages. The following families of organisms are examples of arthropods:

  • Insects like ants, dragonflies and bees
  • Arachnids like spiders and scorpions
  • Myriapods (a term that means "many feet") such as millipedes and milipedes
  • Crustaceans such as crabs, lobsters, and prawns

It can be helpful to remember that the term "arthropod" comes from the Greek words for "articular foot". If the organism has an exoskeleton with joints between its feet and body, it is likely an arthropod!

Arthropods are a lineage of life that evolved skeletons on the outside - their hard shells made from a material called "chitin" - rather than on the inside for structural support.

The bodies of arthropods also have other important differences from those of vertebrates like us - their organ systems are simpler and less efficient, which limits the size that arthropods can reach.

For example, an ant the size of a human would not be able to pump oxygen through its blood to feed all tissues because the arthropod's circulatory system is simpler and less efficient than that of a human. "

All arthropods are believed to have evolved from a single common ancestor, although scientists aren't sure what that common ancestor looked like or when exactly it lived.

Arthropod characteristics

The characteristics of all arthropods include:

  • Chitin exoskeletons
  • Highly developed sense organs
  • Articulated limbs (the limbs must be joined together like the joints in armor because the exoskeleton is rigid and cannot bend to allow movement).
  • Segmented body
  • Ventral nervous system. "Ventral" means "in front," which means that the arthropod's nervous system runs along the front of their body near their stomach, rather than along their back like animals' spinal cords.
  • Bilateral symmetry. This means that an arthropod's left and right sides are the same - it has the same number and arrangement of legs, eyes, etc. on the right side of its body as it does on the left.

Types of arthropods


Trilobites were an ancient family of marine arthropods that became extinct during the Permian Triassic extinction. Today they are known to us mainly through fossils such as the following.

They lived on the ocean floor and occupied ecological niches similar to those occupied by crustaceans today.

Asaphus platyurus


Chelicerata are a branch of the arthropod family tree that at first glance may not seem related.

This family includes arachnids (like spiders and scorpions), spider crabs (which look similar to arachnids but have some important differences), and horseshoe crabs (which, despite their name, have important differences from other crustaceans).


The term "Myriapod" means "many legs" - so it is not surprising that millipedes, milipedes, and other multi-legged creatures are part of this family.

Myriapods can have fewer than ten legs - up to over 750! That just seems excessive.

Myriapods are usually found in forests and other ecosystems where there is plenty of rotting plant and animal material to feed on.


Crustaceans are a family of primarily aquatic arthropods that include lobsters, crabs, shrimp, crayfish, barnacles, and the odd wood lice, also known as pill bugs or "chubby".

Unlike their aquatic cousins, wood lice live primarily on dry land and are found in settings such as gardens and forests, where they survive by ingesting rotting plant and animal material.

You may also be surprised to see barnacles on this list: adult barnacles develop hard shells that stick to their surroundings, such as: B. the bottom of boats or other underwater surfaces.

But earlier in their life, before they freeze, barnacles have bodies with legs, much like the other crustaceans!


The term "hexapod" literally means "six feet". You may not be surprised to learn that insects - all of which have six legs - are hexapods.

Insects include most of the six-legged "beetles" such as flies, ants, termites, beetles, dragonflies, mosquitoes, cockroaches, butterflies and moths.

There are also three much smaller groups of animals in the "Hexapod" category. Collembola, Protura, and Diplura were once considered insects, but small differences were later noted that set them apart from other insects.

Examples of arthropods


When you think of a stereotypical arthropod body, you probably think of an ant. Ants have tough exoskeletons and articulated legs. They also have bodies that are clearly divided into a head, rib cage, and abdomen.

Ants display a type of social organization developed by arthropods. Ants, bees and termites are all so-called "eusocial" organisms - organisms that live in extreme cooperation with "colonies" that function almost like a single organism themselves.

Most arthropod species are non-eusocial, but living in eusocial colonies is one of the fascinating paths arthropod evolution has taken.

be crazy

Spiders are also arthropods, which have tough exoskeletons, segmented bodies, and articulated limbs.

Spiders usually eat smaller arthropods like mosquitoes and flies - although they will eat any living thing they can catch, and some particularly large spiders have been known to eat birds or rodents!

Spiders have developed a variety of strategies for capturing their prey - some sticky, almost invisible webs that prey animals wander into and get stuck in. Others are active hunters, including jumping spiders that use special mechanisms in their legs to jump at extreme speeds.

Some spiders combine these two strategies, such as "trap door" spiders that set traps by creating hiding places - and then jump out to grab unsuspecting prey that is passing by!


With lobster now considered a luxury food, it's easy to forget that lobsters belong to the same family as spiders and ants.

Crustaceans can grow larger underwater than on land - and lobsters can weigh nearly 50 pounds!

The body design of lobsters has changed little in the last 100 million years, and their anatomy is spectacularly strange. The lobster's kidneys are in its head, its brain in its throat, and its teeth in its stomach. Its “ears” for picking up sounds are in its legs, and its taste buds are in its feet like those of insects.


Butterflies are the best known example of arthropod metamorphosis.

At some point in their life cycle, all arthropods undergo a drastic change from their larval stage to their adult form. But butterflies are the only ones whose adult forms are so beautiful that we pay attention to this change.

The common features of the exoskeleton, limbs, and segmented body can be seen in adult butterflies.

Facts about arthropods

  • Arthropods populated the land about 100 million years ago vertebrates. It is believed that colonizing land was easier for them for a number of reasons - including the fact that they had already developed legs with which to walk on the ocean floor.
  • About 80% of all animal species are arthropods! We don't see them very often in our daily life, but all kinds of bugs and crustaceans on earth add up!
  • All arthropods go through metamorphosis - a process by which their bodies radically change as they move from the larval stage to the adult stage. Butterflies are best known for entering cocoons as caterpillars and coming out very differently, but all arthropods do something similar!
  • When arthropods grow out of their old exoskeleton, they must molt - leaving their previous skin behind and growing a new one. All arthropods need to do this at least once in their life.
  • Crustaceans and arachnids - two types of arthropods - have blue blood instead of red blood! This is because their blood uses a blue copper compound to carry oxygen instead of the red iron compound used by animals.
  • The hard exoskeletons of the arthropods consist of chitin - a derivative of sugar glucose! But chitin wouldn't taste sweet and you wouldn't be able to eat it. To make it hard and strong, the glucose is modified in such a way that our body no longer recognizes it as sugar.

Related biology terms

  • Common ancestor - A common ancestor is an individual or a species from which several individuals or species have evolved.
  • evolution - The process by which populations change over time due to random mutations and the pressures of natural selection.
  • die out - The process by which a species ceases to exist after the death of its last member. Most of the species that have previously lived on earth are now extinct.