Arthropods - An Introduction

Arthropods The Most Successful Animals on Earth

VARIETY

Hermit Crab Fairy Shrimp Centipede Horseshoe Crab

Size What Is Different about Each of These Animals? Color Shape Method of Movement

What Do These Animals Have In Common? Jointed Legs Exoskeleton Segmented Body Distinct Head Compound Eyes (most cases)

Centipedes, Millipedes, Sow Bugs, Pill Bugs Myriapods

Crustaceans Crayfish, Lobsters, Crabs, Shrimp

Spiders Mouthparts modified into pincers or fangs Head, Cephalothorax, (Thorax & Abdomen fused together) 6 – 8 Pairs Simple Eyes 4 Pairs (8) Walking Legs Some have Stingers Carnivores Terrestrial

SPINNERETS

Scientists at NASA wondered what happens when you get a spider stoned. The experiments show that common house spiders spin their webs in different ways according to the psychotropic drug they have been given. They discovered the more toxic the chemical, the more deformed was the web.

Spiders on marijuana started spinning webs but appeared to lose concentration about half-way through.

Those on Benzedrine - "speed" - spin their webs "with gusto, but without much planning leaving large holes”.

Caffeine makes spiders incapable of spinning anything better than a few threads strung together at random.

On chloral hydrate, an ingredient of sleeping pills, spiders "drop off before they even get started".

Insects Most Numerous of All Animals Has A Three Part Body Plan Head, Thorax, Abdomen Life Cycle is Metamorphosis – Complete & Incomplete First Animals to Fly – Most Adults Do Fly Divided Into Many Orders