1. Comparisons:Mollusca
SQUID vs. Octopus
Squid: schools, fins, good simmers, two extra tentacles
Octopus: solitary, bottom dwellers, 8 legs, jumpers

2. ARTHROPODA
Phylum

3. Bilateral Symmetry

4. Major Classes Arachnida: spiders, scorpions, ticks, mites
Diplopoda: millipedes
Chilopoda: centipedes
Insecta: insects
Crustacea: crabs, lobsters, crayfish, shrimp, barnacles

5. Orders of Insects Hymenoptera Lepidoptera Diptera Coleoptera Odonata
(a chosen few; there are many more)
Hymenoptera
Lepidoptera
Diptera
Coleoptera
Odonata
Orthoptera
Siphonopter

6. Common Features of Arthropods
Exoskeleton(external skeleton) is made of layers of protein and chitin, provides attachments for muscles, and is impermeable to water.
Molting: shedding of cuticle in order to secrete a larger one. Makes the arthropod vulnerable.
Open circulatory system: hemolymph fluid flows through open spaces (sinuses) which surround organs and tissues. Important for nutrient transport.
molting spider

7. Common Features of Arthropods (cont.)
Malpighian tubules: excretory organs that remove waste from hemolymph in the circulatory system
Tracheal system: branched tubes with chitin lining that carry O2 directly to cells (insects only)
Spiracles: openings in exoskeleton that allow air to enter tracheal system (insects only)

8. Two body plans
Head, thorax, abdomen
Cephalothorax, abdomen

9. Mandibles: and lots of mouth parts

10. Unique Arthropod Features
Book lung: respiratory organ of most spiders that contains stacked plates in an internal chamber that exchanges gases (mostly O2 and CO2) with a spider’s body and the air
Chelicerae: claw-like feeding appendages contained by chelicerates (arachnids)
Mandibles: jaw-like feeding apparatuses contained by unimarians (centipedes, millipedes, insects) and crustaceans
camel spider eating a frog

11. Camel Spider (class Arachnida; order Solifugae)
It does not spin webs or have book lungs. Many rumors about the camel spiders’ speed, size and venom. In the middle east, it was said that these big, fast spiders would come into your tent at night and inject an anaesthetizing venom that would put its victims to sleep and feed on victim leaving a gaping wound. This is false, except that they do leave a large bite prone to infection.

12. Spider Feeding
Spiders use a fang like chelicerae equipped with poison glands to kill prey caught in web. Instead of fully chewing their prey, the spider will spill digestive juices onto prey. This softens the food and the spider will suck up the liquid.

13. Unique Arthropod Features (cont.)
Antennae: sensory organs that come in pairs on the organism’s head
Compound eyes: eyes with many parts and multiple separate focusing elements

14. Metamorphosis: a relatively abrupt change in form or structure
Life Cycle
Metamorphosis: a relatively abrupt change in form or structure

15. Incomplete Metamorphosis
Young are similar to adults, but have different body proportions and are smaller. There are a series of molts that eventually lead to the organism reaching full size.

16. Complete Metamorphosis
There are several distinct stages:
Larval stage - specialized for eating and growing
Pupal Stage - actual change occurs
Adult stage - specialized for reproduction

17. Centipede vs. milliped e
Centipede; fangs, venom,carnivore, fast moving 1 pair of legs per segment
Millipede: slow, herbivore, rounder body, 2 pairs of legs per segment
giant millipede
giant cenitpede eating a tarantula

18. More Arthopod
monarch emerges
nymph dragonfly
bee hive
lobster walk
pistol shrimp
mantis shrimp