9. Arthropods Largest and most successful phylum in the animal kingdom. 85% of all animals! Largest and most successful phylum in the animal kingdom.

9. 9. ArthropodsArthropods

Largest and most successful phylum in the Largest and most successful phylum in the animal kingdom. 85% of all animals!animal kingdom. 85% of all animals!

Exoskeleton made of Chitin (light/hard Exoskeleton made of Chitin (light/hard polysaccharide).polysaccharide).

Jointed Appendages.Jointed Appendages. Cephalization-compound eyes, ocelli Cephalization-compound eyes, ocelli

(eyespots), antennae.(eyespots), antennae.

SUBPHYLUM CHELICERATE SUBPHYLUM CHELICERATE

Fang-like mouthparts Fang-like mouthparts (Chelicerae)-Pedipalps (Chelicerae)-Pedipalps for sense. 2 Classes.for sense. 2 Classes.

Class Class MerostomataMerostomata--Horseshoe crabs.Horseshoe crabs.

Class Class ArachnidsArachnids-8 legs-8 legs 2 body parts-spiders, 2 body parts-spiders,

ticks, mites, scorpions.ticks, mites, scorpions. Book lungs/gillsBook lungs/gills

Horseshoe CrabHorseshoe Crab

1. Carapace1. Carapace 2. Telson2. Telson 3. Compound eye3. Compound eye 4. Anterior spine4. Anterior spine

ARACHNIDSARACHNIDS

SpidersSpiders

ScorpionsScorpions

TicksTicks

SUBPHYLUM SUBPHYLUM MANDIBULATESMANDIBULATES

Antennae, Mandibles & MaxillaeAntennae, Mandibles & Maxillae Includes 4 classes-Crustacea, Diplopoda, Includes 4 classes-Crustacea, Diplopoda,

Chilopoda & Insecta.Chilopoda & Insecta. CrustaceansCrustaceans-add some limestone to the -add some limestone to the

chitinous exoskeleton.chitinous exoskeleton. Lobsters & crabs are the giants of this group-Lobsters & crabs are the giants of this group-

most are a few centimeters long.most are a few centimeters long.

CrustaceansCrustaceans

In addition to lobsters & crabs, shrimp, In addition to lobsters & crabs, shrimp, copepods and barnacles all belong to this copepods and barnacles all belong to this class.class.

Due to the nature of their rigid exoskeleton, Due to the nature of their rigid exoskeleton, crustaceans must “molt” or shed their shell in crustaceans must “molt” or shed their shell in order to grow.order to grow.

They use an enzyme to split their shell & then They use an enzyme to split their shell & then crawl out.crawl out.

MILLIPEDES & CENTIPEDESMILLIPEDES & CENTIPEDES Class DiplopodaClass Diplopoda-The -The

millipedes only have millipedes only have about 100 legs with 2 about 100 legs with 2 pairs-legs/segmentpairs-legs/segment

Class ChilopodaClass Chilopoda-The -The centipedes have fewer centipedes have fewer legs (1 pair/segment).legs (1 pair/segment).

While millipedes While millipedes scavenge on decaying scavenge on decaying plant material, plant material, centipedes are centipedes are predators w/venom predators w/venom glands.glands.

CLASS INSECTACLASS INSECTA

Class Class InsectaInsecta-largest group of animals in the -largest group of animals in the world!world!

3 Body parts-Head, Thorax & Abdomen3 Body parts-Head, Thorax & Abdomen 6 legs, Antennae, Mandibles6 legs, Antennae, Mandibles Malpighian tubules (Kidneys) get rid of their Malpighian tubules (Kidneys) get rid of their

wastes.wastes.

INSECT ANATOMYINSECT ANATOMY

METAMORPHOSISMETAMORPHOSIS

One last reason for arthropod success is their One last reason for arthropod success is their ability to go through stages that exploit ability to go through stages that exploit different food at different times in their life.different food at different times in their life.

Incomplete Metamorphosis-Egg-Nymph-Adult. Incomplete Metamorphosis-Egg-Nymph-Adult. The nymph stage is like a miniature form of The nymph stage is like a miniature form of the adult.the adult.

Complete Metamorphosis-Egg-Larvae-Pupae-Complete Metamorphosis-Egg-Larvae-Pupae-Adult.Adult.