Phylum Arthropoda

General Characteristics

• Arthropod = _______________• Largest group of animals

–80% of described species–30-50 million species

• Most varied

General Characteristics Con’t

• Metamerism (body divided into segments)–_____________________________

• Paired, jointed appendages• Ecdysis-molting (growth)• Open Circulatory System• Complete digestion tract

Metamerism (Body Segments)

3 Segments2 Segments

General Characteristics Con’t

• Ventral Nervous System• __________________• Metamorphosis• 5 Subphylum

–Trilobitomorpha, Myriapoda, Chelicerata, Crustacea, Hexapoda

Exoskeleton

• Functions of exoskeleton–_______________–_______________–Minimize H2O loss

–Muscle attachment

Exoskeleton Structure

• Composed of _________________• Epicuticle: outer layer

–Water proof• Procuticle: inner layer

–Made of chitin

Ecdysis (molting)

• _____________________________–1. Enzymes digest old

exoskeleton–2. New exoskeleton secreted

New exoskeleton is soft–3. Scleratization (hardening)

Ecdysis (molting)• Molting is important for arthropod

growth–Can’t grow in a suit of armor

• Is also a dangerous time for arthropods–Typically animals about to molt, will

go into hiding just before the process begins

_________________________

• Changes in body form from larval to adult–Ex. Butterfly, Dragonfly

• Reduces competition for food and living space

Subphylum Trilobitomorpha

• ___________________!• All extinct and marine• Body with 3 sections

Subphylum Myriapoda

• Myriapoda- “many legs”• Millipedes, centipedes• Paired legs• _______________________

Millipedes vs. Centipedes

• Millipedes:–Herbivorous–Appear to have 2 legs per

segment–_____________–Non-venomous

Centipedes

–____________–Have only 1 pair of legs per

segment–Faster–Venomous

Subphylum Chelicerata

• Spiders, mites, ticks, scorpions, horseshoe crabs,

• Have chelicera- fangs• ________________

–Cephalothorax–Abdommen

_______________

• Appendages:–1st pair- chelicera: feeding

(often fang-like)–2nd pair- Pedipalps: feeding,

locomotion, reproduction

Subphylum HexapodaINSECTS

General Characteristics

• Hexapoda = “____________”• Includes the class Insecta

–30 million species–27 Major orders

•We will only learn 8

General Characteristics Con’t

• 3 pairs of legs–6 total

• 1 pair of antennae• Most have 2 pairs of wings• ______________________• 3 part body plan

–Head, Thorax, Abdomen

Insect Flight

• Is a unique trait to the insects• Different insects have wing

modifications for specific functions

Economic Importance Parasites

Ticks, fleas Are considered agricultural

pests.1949-European corn borer

caused $349 million in damage to the US corn crop

Economic Importance Con’t

• Provide goods–Honey–Beeswax–Yummy (to certain cultures)–Silk–Dyes

Economic Importance Con’t

• Also are vectors for many diseases–Bubonic plague (flea)–Malaria (mosquito)–_________________(mosquito)–African Sleeping Sickness

(Tsetse fly)

Subphylum Crustacea

General Characteristics Includes crabs, lobsters, crayfish,

shrimp, and barnacles

_____________________________

Biramous Appendage: branched Y-shaped appendages

General Characteristics Con’t

___________________Marine and Freshwater

2 or 3 body segmentsHead, Thorax, and Abdomen

ORCephalothorax and Abdomen

Reproduction• ______________• Few monoecious

(hermaphroditc)

Females retain eggs until hatching

Economic Importance

• Tasty—people like to consume them

• _____________

Ecological Importance

• Scavengers-eat dead material

• _______________(shrimps, barnacles)