Objective: Class Arachnida

Arachnida

• Two body sections 1. cephalothorax: fused

head and thorax

2. abdomen

• 4 pairs of legs

2 pairs of mouthparts

• chelicerae: fanglike, paralyze prey• pedipalps: used to manipulate prey

Body Characteristics

• Malphighian tubules: . Reduce water loss; absorb water from waste

• book lungs: exchange gases with atmosphere

Spiders

• Hunters• Search for prey

• tarantulas

• Weavers• “sit-and-wait”• Weave a web from

silk glands• spinnerets: organs

that spin fibers

• All produce silk, but not all produce webs

Scorpions

• Nighttime hunters• Live in deserts• Pedipalps are pincers

• Used for defense and prey

• Poisonous stinger

Mites and Ticks

• Parasites• Plants or animals• Ticks! Lyme Disease• Sucking mouthparts

and claws to hold onto host

• Free-living

WARNING! Graphic Pictures on next slide

Arachnid Bites

Day 6

Day 10

Brown Recluse Bite

Lyme Disease (severe)

Crustacea

Decapods

• Means “ten legs”

Decapod Body

• Cephalothorax and abdomen

• Exoskeleton:• Made of calcium carbonate

carapace: shield that covers back of cephalothorax

• mandibles: mouthparts

Barnacles

Copepods

• Krill• Food for whales and

fish

Isopods

• Terrestrial• Pill bugs (wood lice)

• “rolley-polley”

Class Insecta

Characteristics

• Head, thorax, abdomen• Wings

• Extension of exoskeleton

• Malpighian tubules• Trachael system

• no book lungs

• Compound eyes

Insect Success

• Ability to Fly• Escape predators• Find food• Find mates• New habitats

Metamorphosis• Immature to mature• Incomplete(Simple) Metamorphosis

• Juvenile(nymph) to adult• Juvenile smaller, no wings

Complete Metamorphosis• Larva and adult different

Class Diplopoda

• Millipedes• 2 pair legs per

segment• Eat decaying matter

Class Chilopoda

• Centipedes• Pair of legs per

segment• Predators