1	Phylum Arthropoda
2	Defining Characteristics: Epidermis produces a segmented, jointed, and hardened (sclerotized) chitinous exoskeleton, with intrinsic musculature between individual joints of appendages Complete loss of motile cilia in adult and larval stages.
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4	General Characteristics Largest phylum in animal kingdom -- 75% of species. Arthropods are metameric, but serial repetition of similar segments is masked by fusion and modification for highly specialized functions. Specialization is called tagmatization Insects & Crustacea have 3 tagmata: head, thorax & abdomen
5	Organ systems
6	Arthropod exoskeleton Secreted by epidermal cells Has 2 major layers epicuticle is generally waxy, composed of a firm lipoprotein layer underlain by layers of lipid. Procuticle is composed of polysaccharide chitin and proteins. Chitin functions in protection, support, movement.
7	Processes of ecdysis and formation of new exoskeleton are under both neural & hormonal control.
8	The result is a shedding of the old cuticle, and its replacement with a new cuticle which hardens.
9	Insect heart contains perforations, called ostia, into which blood flows from the hemocoel.
10	Subphylum Trilobitomorpha Defining characteristic - 2 anterior-posterior furrows divide the body into 3 regions (2 lateral, 1 central) Class Trilobita Possessed compound eyes, chitinous lip (labrum), a pair of 2-branched (biramous) appendages.
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12	Subphylum Chelicerata Defining Characteristics Absence of antennae body divided into 2 distinct portions (the prosoma and the opisthosoma), with no distinct head first pair of appendages (the chelicerae) on the prosoma are adapted for feeding. Includes Classes Merostomata, Arachnida, Pycnogonida (=Pantopoda)
13	Class Merostomata Defining characteristics Appendages on the opisthosoma are flattened and modified for gas exchange as “book gills” terminal portion of body (telson) drawn out into an elongated spike. Head & thorax are fused into one single functional unit, the prosoma, or cephalothorax, covered with a carapace.
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15	Class Arachnida 70,000 spp., mostly terrestrial. Spiders, mites, ticks, scorpions. Head & thorax are fused to form a prosoma, which is covered by a carapace. Recent studies of hox gene expression during development suggest that the head of millipedes, centipedes, insects & crustaceans have a common evolutionary origin with chelicerate prosoma.
16	Characteristics of the prosoma 0 to 4 pairs of eyes, 4 pairs most common. Anteriormost pair of appendages are chelicerae, generally used to tear apart food for ingestion. The next pair, pedipalps, are modified for grabbing, killing, or reproducing. Basal segment of each pedipalp forms a maxilla, aids in preparation of food. Pedipalps are followed by 4 pairs of walking legs.
17	The arachnid abdomen, or opisthoma, is generally distinct from the prosoma.
18	Respiration by arachnids Primitive arachnids have pairs of modified, internalized book gills, now known as book lungs. These flattened respiratory surfaces are connected to the outside by means of openings called spiracles.
19	Spiders produce silk (Text from www.xs4all.nl/~ednieuw/ Spiders/Info/spindraad.htm ) Functions include safety lines during climbing egg sacs that protect embryos fine threads for the aerial dispersal of young (as in Charlotte’s Web) Air-tapping diving bells webs for trapping prey, building homes. “Spider silk is an extremely strong material and is on weight basis stronger than steel. It has been suggested that a pencil thick strand of silk could stop a Boeing 747 in flight.”
20	Subphylum Mandibulata Defining Characteristics 1) Appendages on the third head segment are modified as mandibles, for chewing or grinding food; Retinula of compound eyes contains 8 cells Animals have both uniramous and biramous appendages
21	Class Myriapoda Includes Orders Chilopoda and Diplopoda All appendages are uniramous Chilopods are generally fast-moving carnivores, living in soil, in humus, under logs. They are restricted to humid environments because they cannot close their spiracles è water loss.
22	Chilopod morphology Head bears a single pair of antennae, a pair of mandibles, a pair of 1st & 2nd maxillae and a pair of maxillipeds. They often lack eyes. They may have simple light receptors, ocelli. Chilopod head is followed by 15 or more leg-bearing segments.
23	Millipedes are slow-moving 10,000 spp. Generally deposit feeders. Pairs of segments have become fused, so that each diplosegment bears 2 pairs of legs.
24	Class Insecta (=Hexapoda) Defining Characteristics 1) Fusion of 1 pair of head appendages (the second maxillae) to form a lower lip (the labium); 2) loss of all abdominal appendages Are the most successful animal group Most numerous in terms of spp. & numbers Occupy all habitats except deep sea
25	Possible reasons for species diversity Feeding specializations Some species are adapted for biting and chewing, while others have straw-like beaks for sucking up juices Some are predators, others herbivores & parasites. Dispersal capabilities & predator-avoidance possibilities associated with flight.
26	Insect visual systems Ocelli are simple light detecting organs, usually occurring singly or in small clusters. Compound eyes are capable of forming images. Composed of many individual units, called ommatidia each ommatidium samples a narrow field of view.
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28	The orientation of each ommatidium is slightly different
29	Insect flight is possible because 1) Abundance of striated muscle specialized for rapid, strong contractions; 2) muscle antagonism by means of a lightweight, jointed skeleton; 3) small body size 4) Water-impermeable outer body covering, preventing dehydration; Efficient systems for gas exchange, nutrient storage, circulation Highly developed nervous & sensory systems for steering, navigating.
30	Insect social systems Eusocial species are those which form colonies composed of more or less sterile workers and 1 or more reproductive queens, multiple generations within a colony, and workers cooperate in the care of developing embryos and larvae. All ant species, many wasp spp., some arachnids are eusocial.
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33	Class Crustacea Head bears 5 pairs of appendages, including 2 pairs of antennae Development includes a triangular larval form (the nauplius) bearing 3 pairs of appendages and a single medial eye (From Pechenik’s Biology of the Invertebrates, edition 6).
34	Subclass Malacostraca Defining characteristics 1) Thorax with 8 segments, abdomen with 6 to 7 segments plus a telson; Appendages on the sixth abdominal segment are flattened to form uropods Includes nearly 75% of all crustacean spp. Decapods, Eupausiids, Stomatopods, Isopods, Amphipods.
35	Malacostracan Body Plan Tripartite, consisting of head, thorax, abdomen. Head may be covered by carapace, functioning as a single unit, the cephalothorax.
36	Crayfish internal anatomy
37	Miscellaneous subclasses of crustacea Subclass Branchiopoda Subclass Ostracoda Head & body are enclosed in a bivalved carapace, which lacks concentric growth rings; Trunk of body possesses no more than 2 pairs of limbs. Subclass Copepoda Thorax with 6 segments, abdomen with 5; first segment of thorax fused to head Loss of all abdominal appendages most species bear a single, “naupliar” eye. Cirripedia - barnacles.