Arthropods

The most varied and largest phylum of the animal Kingdom.

​Main Arthropods Classes

​There are over 20 classes of Arthropods!

​Insects

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Crustaceans (including slaters, prawn, crabs, and lobsters)

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​Myriapods (including centipedes and millipedes)

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​Arachnids (including spiders, mites, and scorpions)

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​Amazing Arthropods

Invertebrates With

-They have Bilateral symmetry

-Jointed Body Parts

​-They have segmented bodies

-Pairs of Legs

-Their bodies are protected by an exoskeleton

​-They have articulated parts: Appendages

​Their Bodies

​Arthropods have segmented bodies that can be one of three types:

​1.- Head, thorax and abdomen

2.- Cephalotorax and abdomen

3.- Head and trunk (trunk is both body and tail)

​Vital functions: Interaction

​Their nervous system and sense organs are more developed than in other invertebrate groups

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They have two types of eyes: Simple and compound eyes

​Ocelli

​Ocelli (singular Ocellus) are simple photo-receptors (light detecting organs).

They consist of a single lens and several sensory cells. Unlike compound eyes, ocelli do not form a complex image of the environment but are used to detect movement

​Compound Eyes

​Compound eyes are made up of clusters of ommatidia, but simple eyes are made up of only one single unit of eye.

​Respiratory system

​Aquatic arthropods breathe throug gills

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Terrestrial arthropods breathe throug tracheae

​Reproduction

​Reproduction is sexual

They are oviparus (eggs laid) and carry out a process called metamorphosis:

1. Incomplete metamorphosis: a nymph hatches from an egg and grows.

2. Complete metamorphosis: Larva, pupa and adult

​Insects

​3 Pairs of Legs (6 Legs)

3 Body Segments

Most Have Wings

Antennae

​Arachnids

​4 Pairs of Legs (8 Legs)

​2 Body Segments

​Feelers for Touching

​Do NOT Have Wings (THANK GOODNESS!!!)

​Crustaceans

​8 or More Legs​

Live Near or On Ocean Floor

Can Live on Land

Antennae

Crust (Exoskeleton), acean (Ocean)

​Centipedes/Millipedes

​Many Legs (Usually Fewer Than 100)

Many Body Segments (Rolls Up for Protection)

Antennae

Lives Under Rocks or In Dark Places