Why aren´t spiders and scorpions considered insects???

Question

Just curiosity

Answer 1

Spiders and scorpions belong to the phylum arachnida.
What is the difference between Arachnids and Insects? ... Arachnids differ from Insects in their anatomy and development from immature to mature stages
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Arthropod Phylum

Arthropod means "jointed legged creatures." All animals in the Artrhopod Phylum have jointed legs and exoskeletons. This means their skeleton is on the outside of their bodies. The Arthropod Phylum is split into Classes. Several Classes are listed below:

Insecta Class: Called "insects." These animals have six legs, two antennae, and three main body sections: head, thorax, abdomen. Most insects have two sets of wings. Insects have either a four-stage life cycle (egg, larva, pupa, adult) or a three-stage life cycle (egg, nymph, adult). Includes: Bees, Wasps, Flies, Dragonflies, Butterflies, Moths, Beetles, Grasshoppers, Crickets, Mantids, Ants, Termites, and Cicadas.

Arachnida Class: Called "arachnids." These animals have eight legs, no antennae, and two main body sections: cephalothorax and abdomen. Includes: Spiders, Ticks, Mites, and Scorpions.

Crustacea Class: Called "crustaceans." These animals have ten legs, four antennae, and two main body sections: cephalothorax and abdomen. Most live underwater. Includes: Crayfish, Water Fleas, Shrimp, and Crabs.

Chilopoda Class: Called "chilopods." These animals have long, flattend bodies with many segments. Each segment has one pair of legs. Includes: Centipedes.

Diplopoda Class: Called "diplopods." This animals have long, rounded bodies with many segments. Each segment has two pairs of legs. Includes: Milllipedes.

Answer 2

To put it more simply:

Spiders (and scorpions) belong to the same BIG group of animals as insects do - that is, Arthropods. All arthropods share certain characteristics, like having an exoskeleton (or shell) and laying lots of eggs with lots of babies, etc.

However, within that big grouping, there are lots of variations (or classes) to separate out the animals. Insects have certain things in common; They have 3 segments to their bodies, 6 legs, and change shape in some way during their life cycle. So even though some insects undergo complete metamorphasis (like the butterfly) and some just undergo partial metamorphasis, they still all have the basic stuff in common.

spiders and scorpions have some basic differences from insects; 8 legs instead of 6 being the easiest one to remember. Also, a baby spider looks like a little spider and a big spider looks like a big spider; they don't completely change from a larval stage to an adult stage (like caterpiller=butterfly.) so they get their own group, the arachnids.

Answer 3

there are three different subphyla in the phylum artropoda they are trilobita chelicerata and mandibulata this classification is done on the basis of mouth parts
the trilobita are the extinct animals which belonged to the paloezoic era
the second phyla consists of classes merostomata and arachnida the spiders and the scorpions belong to this class
the third phyla consists of crustacea
chilopoda diplopoda and insecta the insects belong to this group
the difference between spiders and scorpions and insects are
1 the body divisions 2 the respiratory structures 3 the excretory structures and many

Answer 4

No, they are not insects. They are arachnids. This is because insects have 6 legs and 3+ body segments, arachnids have 8+ legs and 1 or 2 body segments. Hope this helps.

Answer 5

Insects have three pairs of legs. Spiders and scorpions do not.

Answer 6

Arachnids have only 2 body parts vs 3 for insects (extra thorax)
Arachnids have 4 pairs of legs not 3
No antennae.

Answer 7

Insect=6 legs
Arachnid=8 legs.

That's why...

Answer 8

Insects need six legs and antannae.

Answer 9

I think it has to do w/ the number of legs or something like that...really I don't know so I'm just gonna shut up!

Answer 10

because they are creepy creatures specially scorpions... with their venom... eeeeeeeks...[ this is not the answer to your question though because im not a zoologist...]