BIOL 3454 1st Edition Lecture 25 lecture 11 12 I II III IV V subclass Cirripedia a barnacles plus 3 smaller orders of burrowing or parasitic forms b sessile as adults c carapace surrounds body and secretes shell of calcareous plates d head reduced no abdomen thoracic legs long many jointed cirri with harilike setae e cirri extended between plates for filter feeding f most hermaohroditic have internal fertilization g free living cyprid larvae that attach by their first antennae then metamorphose into adult form h longest penis in relation to body size of any animal class Malacostraca a 20 000 species largest class great diversity b Order isopoda the roly polys and ect c Order amphipoda like isopods but compressed laterally d Oder euphausiacea the krill e Order decapoda tasty guys lobsters crabs shrimp f Very important economically for food scavenging and forming the base of many food webs Order isopoda a Have invaded terrestrial habitats all the way to very deep water b Dorsoventrally flattened c No carapace d Have sessile compound eyes e Maxillipeds are the first pair of thoracic limbs and others are exopods f Development usually direct a few parasitic forms have complex life cycles Order Amphipoda a Resemble isopods but compressed laterally b Gills in typical malacostracan thoracic position c Thoracic and abdominal limbs differ in function 1 pair for swimming and the other for jumping d Direct development e No metamorphosis Order Euphausiacea a 90 species known as the krill b 3 6cm long c Carapace fused with all thoracic segments does not entirely enclose their gills d No maxillipeds but have thoracic limbs with expopods e Many bioluminescent bc of an organ called a photophore These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute VI VII f Very important to marine food weds Order Decapoda a 18 000 species b 3 pairs of maxillipeds c 5 pairs of walking legs d Some walking legs modified to form chalae claws e Largest arthropod is Japanese spider crab 4m f Homer Simpson s crab is Pinchy Hexapods a Most dominant group i Insects are the most important group to humans ii Extremely important in food webs iii Vectors of disease iv Are human health risks themselves v Agricultural pests vi Locust outbreaks can cover 20 of the land area of the earth and contain billions of individuals vii Multitude of invasive insects changed N American forests viii Exist in all terrestrial habitats ix More species than all other groups of all lifeforms combined b Subphylum Hexapoda i Named for the presence of 6 legs all uniramous ii 3 tagmata head thorax and abdomen iii 2 classes 1 Entognatha orders protura dipluran and collembolan 2 Insect everyone else iv Class Insecta 1 Roots Latin insectus cut into 2 1 1 million described species and many more not described 3 Ectognathus mouthparts 4 Usually 2 pairs of wings 5 Exoskeleton formed from a complex system of plates called sclerites connected by flexible hinge joints 6 Much more homogenous in tagmatization than crustaceans 7 External form and function a Usually have a pair of large compound eyes b Pair of antennae function as tactile olfactory and auditory c 3 ocelli d Mouthparts usually a labrum pair of mandibles a pair of maxillae a labium and a hypopharynx e Thorax with 3 segments prothorax mesothorax and metathorax each have a pair of legs and wings on the last 2 segments f Wings are cuticular extensions of the epidermis g Legs highly modifiable h Abdomen has 9 11 segments Sometimes with posterior cerci from 11th segment genitalia emerge from 8th and or 9th segment j All mouthparts antennae legs cerci and ovipositors are all modified appendages Walking in insects a Each individual static state usually involves a triangle of the first and last leg of one side and middle leg of the opposite side b Very stable 3 of the 6 on the ground at any time c Water striders extreme example that use expanded legs to sit on surface tension Flying in insects a Only invertebrates that can fly fully functional wings 400mya b Immense variation in wing design flies only have 1 pair beetles make 1st pair into hard outer covering butterflies cover in scales and hairs in caddisflies c Direct flight muscles attached to wing itself d Indirect flight muscles not attached to wing cause movement by altering shape of thorax Neural control of flight muscles a Synchronous single nerve impulse stimulates a muscle contraction and 1 wing stroke much slower wing beat dragon flies and butterflies b Asynchronous complex action that requires energy storage in part of the thoracic cuticle muscle contractions not in phase with nerve stimulation much fast wing beat flies beetles and ect Insect nutrition a Forgut mouth with salivary glands esophagus crop fro storage and gizzard for grinding b Midgut stomach and gastric ceca c Hindgut intestine rectum and anus d No absorption in foregut e Most absorption in midgut f Hindgut for resorption of water and ions Feeding modes a Most insects phytophagous feed on plant tissues and their juices b Many beetles and many larvae are saprophagous feed on dead animals c Some are predaceous feed on live animals d Many are parasitic exhibit hyperparasitism are parasites and parasitiezed parasitoids always kill their host eventually Form follow function for feeding a Insects have tremendously diverse feeding strategies so their mouthparts are almost infinitely modifiable i 8 9 10 11 12 13 b Sucking mouthparts usually form a tube in a mosquito all mouthparts are elongated together in a needlelike stylet called a fascicle but in butterflies it s a proboscis c Sponging of lapping mouthparts flies have little spinges that absorb soft food some pierce and then lap fluid up d Chewing mothparts many herbivorous insects toothed plates grind or tear food