Phylum Arthropoda

Jointed Legs

Number of species Mollusca Chordata Platyhelminthes Nematoda Arthropoda Porifera Annelida Echinodermata Sarcomastigophora Apicomplex Ciliophora

Characteristics of Arthropods Jointed appendages Extensive variation and adaptations(antennae, legs, wings. Mouthparts) Segmented (metameric) tagmatation- fusion of segments to form body regions(head, thorax, abdomen; cephalothorax in some) Open circulatory system Ventral nerve cord Compound eyes Bilateral symmetry Exoskeleton Ecdysis- “an escape” - growth by molting

Arthropods Most Successful Animals Number of species Diversity Distribution Longevity

Reasons for Success Versatile exoskeleton Segmentation Oxygen piped directly to cells (terrestrial) Highly developed sensory organs Complex behavior Metamorphosis

Modifications of Exoskeleton Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Modifications of Exoskeleton From A Life of Invertebrates, Copyright © 1979, W. D. Russell-Hunter.

Compound Eye

Metamorphosis: complete- Metamorphosis: complete- egglarvapupa adult incomplete- eggnymphadult

Monarch Butterfly Egglarva (caterpillar)pupa (in chrysalis) adult

Arthropod Groups Subphylum Trilobitomorpha Class Trilobita- extinct trilobites Subphylum Chelicerata Class Merostomata – horseshoe crabs Class Arachnida- spiders, mites, etc. Subphylum Mandibulata Class Myriapoda- centipedes, millipedes Class Insecta- insects Class Crustacea- lobsters, crabs, etc.

Subphylum Trilobitomorpha Trilobites Successful for 300 million years Extinct 200 MYA One pair of antennae appendages

Subphylum Chelicerata Chelicerae( fangs) No antenna No mandibles 4 pair of walking legs 1 pair of pedipalps

Class Merostomata Limulus Carapace Telson Dates back to Triassic 245 MYA Carapace Telson Blood used by pharmaceutical companies to test for endotoxins and pathogens

Fig. 18.2a

pedipalps Walking legs Fig. 18.2b Spines

Class Arachnida Spiders Scorpions Ticks Mites All Have book lungs

Class Arachnida Chelicerae (fangs) 1st pair of appendages around mouth- often with poison No antennae 4 pair of walking legs 2 body segments (cephalothorax + abdomen) Except mites & ticks Most are predators Inject enzymes into prey Suck fluid into pharynx

Arachnid Body Regions Prosoma or Cephalothorax Ophisthosoma or Abdomen

Order Scorpionida Large pedipalps Abdominal stinger Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Order Scorpionida Large pedipalps Abdominal stinger Photo (a) © SS#11/PhotoDisc

Order Araneae Spiders Fangs with poison glands Silk glands

Fig. 18.4

Fig. 18.5

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Arachnid Book Lung

Dugesiella Tarantula

Latrodectus mactans Black widow spider Neurotoxin

Loxosceles reclusa Fiddle back spider Necrotoxin Brown recluse Brown Violin Necrotoxin

Loxosceles reclusa Necrosis of tissue

Day 3

Day 4

Day 5

Day 6

Day 9

Day 10

Order Acari Ticks Mites Body segments fused

Rocky Mountain Spotted Fever Ticks are vector High fever Headache Muscle pain Rash BEGINS ON EXTREMETIES 25% fatal without antibiotics

Dermacentor variabilis Dog tick Dermacentor andersoni Wood tick

Fig. 18.16

Dermatophagoides Dust mite Allergies to fecal products 1 gram of dust holds 250,000 droppings

Trombicula Chigger mite Larva feed on skin Dermatitis

Subphylum Mandibulata Class Myriapoda centipedes and millipedes Class Insecta most diverse animal class flies, bees, beetles, ants, etc. Class Crustacea crabs, lobster, barnacles, copepod

Subphylum Mandibulata Two pair of antennae (anterior to feeding appendages) Third segment bear mandibles (jaws for chewing or grinding) Compound eye

Class Myriapoda “many appendages” Fewer than 10 to hundreds of appendages Millipedes (mostly herbivorous + plain in color) Centipedes ( colorful, carnivorous)

Class Insecta(FKA-Hexapoda) Most biodiverse class of animals Only invert.s that can fly Distinctive head, thorax, abdomen Typically –three pair of legs (6) Have metamophosis

Class Crustacea Biramous appendages- separate into two rays 3 pairs modified as mouth parts Two pair antennae Naupliar larval stage Crabs, copepods, crayfish, barnacles, lobster, shrimp, pill bugs

Class Crustacea: Pill Bug Only crustacean that is entirely terrestrial “rollie pollies”

Fig. 19.15c

Fig. 19.16c

Copepod

Barnacle Cirri Testis Penis Anus Mouth Stomach Ovary Cement gland

Fig. 19.24a Fig. 19.24a

Fig. 19.1

Crayfish

Fig. 19.2a

Fig. 19.2b

Gonopods 2. Opening of vas deferens(duct for sperm release) Opening of oviduct 4. Seminal receptacle (opening used to accept sperm for fertilization)

Fig. 19.5 Fig. 19.5

Fig. 19.6

Fig. 19.7 Fig. 19.7

The End