Download A is for Arthropods……

A is for Arthropods……
And other fascinating creatures…..
By Kayla Fries
A is for Arthropod…..
Arthropods are fascinating creatures. They make up most of the animal kingdom, and they have an
exoskeleton. An exoskeleton is a hard, outer covering, that all arthropods have. It is one of the adaptations
that helps to protect them, and defend them from predators. Scientists also classify arthropods, or divide
them into groups, by their segmented or jointed parts. All arthropods have parts on their body, that can
easily be seen.
If you look down at your body, imagine a thin, black line that cuts you right in half. Each side would look
exactly the same, which is called symmetry. When there is only one line of symmetry, like people have, it
is called bilateral symmetry. Arthropods share this same characteristic. They, unlike us though, have no
backbone. They are called invertebrates. Another different characteristic of arthropods is that they have an
open circulatory system. This is when a vessel, something that replaces a heart, pumps blood throughout
the body.
So, I am sure you are wondering, “Exactly, what are some examples of arthropods?” Insects, crustaceans,
millipedes, centipedes, and arachnids are all examples of arthropods.
B is for Body parts…..
Arthropods have many similar body parts. The exoskeleton, as we already said, protects the arthropod.
Many arthropods also consist of three main body sections: the head, the thorax, and the abdomen. The
head often has an antenna on it, and the thorax, if the arthropod has one, is the middle section of the body.
You can find the wings and the legs attached to this part. The abdomen is the hind section of some
arthropods’ bodies, and has the reproductive organs, that allow the animal to produce babies.
C is for Crustaceans and Crayfish….
Crustaceans are a type of arthropod. They have an exoskeleton, and a segmented body, which puts them
in the category with arthropods. There are thousands and thousands of species of crustaceans- about
30,500 in total- and none of them have an internal skeleton, only an external. If you look very closely at a
crustacean’s head, you can see that it has many parts that humans do not! Crustaceans have two
compound, or complex, eyes and two pairs of antennae. The exoskeleton helps them as a defense
mechanism in dangerous times.
Because there are so many different types of crustaceans, it is sometimes hard to remember a good
example. One organism, called the crayfish, is pretty easy to remember. They can also be called crawfish
or crawdads, but they all mean the same thing. Just in North America, there are 150 species of crayfish!
Amazing! You can also find 540 different species of crayfish in the whole world. Their homes are found
in streams, swamps, or other bodies of freshwater. They have a total of eight walking legs- way more then
we have! They have two pair of antennae, and, like all crustaceans, have compound eyes.
Its breakfast may be a little bit different than yours: crayfish eat fish, shrimp, water plants, worms, insects,
snails or plankton!
D is for Diet….
Many people in the world are vegetarians, or herbivores. This means that they only eat plants, not meat.
Few are carnivores, because that limits their diet to nothing but meat. Arthropods are like this too; some
are herbivores, some are carnivores, and some eat both plants and meat. They are heterotrophic, and have
to move to eat their food.
E is for Eighty Segments….
Another species of arthropods are millipedes. They have more than eighty segments on their body! They
have more legs than any other arthropod, because they have two pair of legs on each segment. Most of
them are herbivores, and eat decaying or decayed leaves. They have adapted to a life of danger, because
when disturbed, they can curl up into a sheltered ball. If the danger continues, they squirt a terriblesmelling liquid.
One type of millipede is the Ommatoiulus moreleti, which are two very long words for a black species,
only about as long as your middle finger! They are commonly found in houses, and are called pests!
F is for Firefly…..
Fire flies, a type of arthropod, are often fun to chase around in the dark. They have bioluminescence, and
therefore can light up from an internal change of chemicals.
G is for Gradual Metamorphosis…. and other
types of metamorphosis…..
Metamorphosis is when a baby grows up through stages to become an adult. Gradual metamorphosis, one
of the two types of metamorphosis, is when the egg hatches to a nymph, or young animal. As the nymph
grows, it eventually becomes an adult. The other kind of metamorphosis is called complete
metamorphosis. This is when the egg hatches as a larva, and the larva eventually grows into a pupa. The
pupa then grows into an adult. It may be confusing to understand, but don’t worry! These stages of
metamorphosis are just the phases an arthropod goes through in order to become an adult.
H is for House Centipede…..
A centipede, another arthropod, is a fast, carnivorous creature. They have adapted to life on land by using
their venom, or poison, to kill prey with their quick jaws. They eat a variety of foods, including insects,
spiders, slugs, earthworms, and other small animals. One type of centipede is the house centipede, which
has compound eyes, and is roughly an inch and one half long. Don’t be frustrated though! House
centipedes are not all bad! They eat other pests, such as cockroaches or moths.
I is for Insects…..
Insects are arthropods, with three body sections, six legs, and one pair of antennae. Most of them also
have a couple pair of wings. You probably see them all over your yard: monarch butterflies, dragonflies,
and bees are just a few examples. They go through either complete or gradual metamorphosis, and eat
plants. A few insects even drink blood, or eat animal droppings. They have adapted to specific ways of
getting food with their certain mouthparts.
J is for Joints…..
If you bend your arm, you are bending it at the joint. Humans have jointed limbs, such as elbows, knees
and wrists. All arthropods have jointed legs and appendages too, just like us!
K is for Kids….
Many kids are afraid of arthropods, especially insects. As long as you have a firm understanding of them,
there is no need to worry!
L is for Legs…..
If an arthropod, such as a crayfish, accidently loses its leg, it has the ability to regenerate, or re-grow that
leg! This really comes in handy if the crayfish is hurt by a predator.
M is for Molting….
As little children grow, they buy new clothes and new shoes, because they have outgrown the old ones.
This is similar to what arthropods do as they grow older! Molting is when an arthropod sheds its
outgrown exoskeleton, and grows a new one!
N is for Nymph…..
A nymph is a young, immature form of an arthropod going through the stages of gradual metamorphosis.
O is for Omnivore….
You have already learned that some arthropods eat only plants, and some eat only meat. But what about
the ones that eat both? Organisms that eat both plants and meat are called omnivores.
P is for Picnics…..
Have you ever sat down to eat a wonderful picnic on a sunny day? If you have, then I’m sure you’ve met
ants before! Ants are a type of insect that live in colonies. In the colony, you will find the queen, the
workers, the soldiers, and the males.
Q is for Queen…..
In a colony of ants, as you learned before, there is always a queen. No, she doesn’t have a big castle, or a
royal crown, but she does have a very important function in the colony. She spends each day laying eggs,
and providing the colony with more workers and helpers.
R is for Reaction…..
Reaction to your surroundings is very important if you are the size of an arthropod! Arthropods use
camouflage to blend in with their surroundings.
S is for Spiders…..
Spiders are predators that mostly eat insects. Some can run down their prey, but others wait for their prey
to come to them. They have hollow fangs, an adaptation, filled with venom to inject into prey. Don’t be
alarmed though, spider bites rarely harm humans. An example of spiders is the Black Widow Spider, who
has venom so poisonous, it turns the tissue of its prey to liquid. They live in dark places, and are always
marked with a red hour-glass shape on their backs. They eat many things, from small reptiles, to flies.
T is for Touch…..
Many arthropods have antenna on their heads. The antenna holds the sense organs to help the arthropods
to find food, and feel, or touch, their way.
U is for Unite…..
Ants have adapted to life in a colony, by working together and uniting to get the job done. As a team, they
obtain, or get, food, and survive.
(Above Picture: An Ant Colony, Working Together To Survive)
V is for Venom…..
Many arthropods, including spiders and centipedes, have venom used for killing prey. The venom can
paralyze prey, or turn tissues to mush.
W is for Web….
Some arthropods, such as spiders, spin webs. Many use their webs to catch prey, the sticky “thread”
wrapping the prey up, and trapping it. This adaptation of spiders helps them to catch dinner!
X is for eXoskeleton…..
Arthropods have exoskeletons, which act as protection in times of danger. Have you ever seen a turtle
curl into its shell? That is a similar protection technique, or plan, as the exoskeleton. It is made of chitin,
which is a rigid material.
Y is for Yellow Jacket…..
Yellow jackets, a type of wasp, often tunnel their nests into the ground. This is another unusual location
for an arthropod’s habitat.
Z is for Zoo…..
You don’t need a zoo to find all these arthropods: look in your backyard! You have learned a lot about
them, and know what characteristics to look for! Good luck and have fun!