Biology Ch24 - (A Closer Look at Anthropods)

Arthropods features

Exoskeleton (made of chitin)

Jointed appendages

Segmented body parts

Appendage extinction used for walking or swimming

Crustaceans

Live in oceans, freshwater streams, and on land

Chelicerae’s

Specialized daggerlike mouthparts

Insects

Most live on land, have six legs

Myriapods

Long bodies and have many pairs of legs in each segments

Exoskeleton

Hard material that protects the body, must be shed in order to grow (molting), made out of many layers of chitin

Open circulatory system

Sensory organs such as antennas are made of modified cuticle, compound eyes that are made of thousands of visual units

Crustaceans features

Two distinct body sections, cephalophorax and abdomen

Pair of appendages per segment

Two pairs of antennae

Exoskeleton

Crustaceans appendages’ functions

Collecting and manipulating food

Attracting females

Protection

Crustaceans appendages

Claws, antennae, walking legs, mandibles, swimmerets

Decapods

Lobsters and crabs, have ten legs

Barnacles

Sessile filter feeders wrapped in a hard shell

Arachnids

Group of chelicerae’s that include spiders and their relatives

Chelicerae’s features

No antennae, four pairs of walking legs, one pair of chelicerae’s and pedipalps

Arachnid features

Eight legs, fanglike pincers that inject venom, silk glands (spinnerets)

Arachnid features to reduce water loss

Waterproof cuticle, book lungs covered in humid chamber

Arachnids include

Mites, ticks, chiggers, and scorpions

Insects’ body parts

Head, thorax, abdomen

Incomplete metamorphosis

Insects look like miniature adults when they hatch

Include metamorphosis stages

Egg (larva), nymph, adult

Complete metamorphosis

Insects changes form completely

Complete metamorphosis stages

Egg, larva, pupa, adult

Insects’ mouth parts

Sucking mouth parts, chewing mouthparts, both sucking and chewing mouth parts