Why isn't a spider considered an insect ?

Answer 1

It has 8 legs and 2 body segments.

Insects have 6 legs and 3 body segments.

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Answer 2

A spider is an arachnid and it has 8 legs whereas insects have 6 legs attached to the thorax and abdomen.

Answer 3

Spiders, unlike insects, have only two body segments (tagmata) instead of three: a fused head and thorax (called a cephalothorax or prosoma) and an abdomen (called the opisthosoma). The exception to this rule are the assassin spiders, whose cephalothorax seems to be almost divided into two independent units. Except for a few species of very primitive spiders (family Liphistiidae), the abdomen is not externally segmented.

Answer 4

All insects must have:

three body parts - a head, thorax, and abdomen
six jointed legs
two antennae to sense the world around them
an exoskeleton (outside skeleton)

Spiders are not insects because they have eight legs and don't have three body parts.

Answer 5

What are the differences between spiders and insects?

Spiders have two main body parts, eight walking legs, simple eyes and piercing jaws (fangs), abdominal silk spinning organs, anterior abdominal genital opening.
Insects have three main body parts, six walking legs, compound eyes, antennae, chewing jaws (mandibles - often secondarily modified), posterior abdominal genital opening.
Spiders can't fly.
Many insects can fly.

If you want more info on spiders or the difference between spiders and insects check out this site

http://www.austmus.gov.au/spiders/

Answer 6

Insects have 3 major body parts: the head, the thorax, and the abdomen. Spiders only have two parts, the head and the abdomen i believe. spiders fall into the arachnid category, because they have eight legs and two body sections. they couldn't fall into the insect category, because they have more than six legs. other types of arachnids are ticks, and scorpions.

Answer 7

Spiders share a closer kinship with scorpions, ticks, mites, daddy longlegs, and other arthropods that have, as their most obvious characteristic, eight legs arranged in four pairs. These eight-legged arthropods are called arachnids. Insects, in contrast, have six legs arranged in three pairs.

Answer 8

Because insects have six legs and three parts to their body, like an ant.

Spiders belong to the Arachnid family. Arachnids have eight appendages and two parts to their body, like a scorpion (they count the two claws scorpions have as appendages)

Answer 9

It has eight legs and only two segments in its body. An insect has six legs and three segments.

Answer 10

They are all insects/pests... but also, all insects/pests have different classifications depending on their biological and physical make-up so scientists can put them into groups easier. Spiders are arachnids... and so on.