Phylum Arthropoda “jointed foot”

What is an Arthropod? An invertebrate with an exoskeleton, jointed appendages and a body that is divided into sections. Ex. Crustaceans(crabs, lobsters and shrimp) Insects Arachnids (spiders, ticks and scorpions) Centipedes and Millipedes

Body Sections of Arthropods Head or carapace May be fused as one piece: Cephalothorax Thorax Abdomen

Basic Characteristics of Arthropods Bilateral symmetry Coelom with organ systems Localized brain and nervous system Segmented body Exoskeleton made of protein called chitin -- Exoskeleton range from hard to waxy

Groups/Classes of Arthropods Arthropods are classified based on the number and structure of their body segments and appendages, particularly mouthparts

1. Crustaceans Primarily aquatic 2 pair of antenna 2 or 3 body segments Chewing mouthparts called Mandibles 2 main groups: Decapods (10 legs): Crabs, lobsters, shrimp Barnacles

2. Arachnids (Spiders and relatives) 2 body sections (cephalothorax and abdomen) 4 pair of walking legs Most lack antenna Fang-like mouthparts called chelicera 2 main groups: Horseshoe crabs Spiders, ticks and scorpions (arachnids)

Horseshoe Crabs

Spiders Largest group of arachnids Contain spinnerets (Web makers) Fang-like chelicera with associated venom glands External digestion of food Liquefied food sucked in with pumping stomach Females may have bright colors/patterns on abdomen (ventral surface)

Female Patterns

Chelicera

Brown Recluse

Spider Bite—Day Three

Spider Bite—Day Five

Spider Bite—Day Six

Spider Bite– Day 9

Spider Bite– Day 10

Mites and Ticks Small in size Parasitic Needle-like chelicera Liquid diet (blood) May transmit disease Ex. Lyme disease transferred by deer tick to humans and other animals

Deer Tick Ixodus dammini

Human Parasitic Mites Itch Mite Sarcoptes scabiei burrows into skin, between fingers, wrists, buttocks, groin etc… transferred by close contact with infected human causes an itchy rash

Follicle Mite Demodex folliculorum found in the follicles of facial hair transmitted through close human contact mouthparts pierce skin and feed on skin cells or oil from sweat glands usually no symptoms

Scorpions Found in warm climates Claw-like appendages Venomous stinger on abdomen= aculeus Chew food with mandibles

Arizona Bark Scorpion Only deadly scorpion in the United States

3. Insects

Basic Facts about Insects 3 body segments 3 pair of legs May have one pair of antenna Compound eyes (multiple lenses) 2 pair of wings (+ or -) Breathing tubes in abdomen (spiracles)

Sensory Adaptations Eyes Chemical receptors Sensory hairs Ears Detect color change and movement Chemical receptors On mouth, antenna and legs Sensory hairs Sense changes in environment, usually movement Ears Thin, vibrating membrane = tympanum Usually found on legs

Feeding Adaptations Chewing mouthparts Needle-like Sponge like

Common Insect Parasites Head Louse Pediculus capitis Found on human hair and scalp Transferred through hair to hair contact with infected human Feed on blood of scalp and hair follicle

Crab Louse Pthirus pubis Found in human pubic region & may infest facial or armpit hair Transmitted through sexual contact or close social contact Causes itching and spots on skin

Insect Metamorphosis Process of changing shape or form Two Main Types: Incomplete Complete

Incomplete Metamorphosis Larva looks like the adult, only smaller Ex. some types of beetles, grasshoppers and crickets

Complete Metamorphosis Larva looks completely different than adult Dormant, pupa stage Ex. Butterfly, housefly, ladybug, darkling beetle