Lab 8: Animals II: Non-molting and Molting Protostomes

Non-molting unsegmented muscular foot (may be highly modified) mantle – membrane present in all; in most, secretes and maintains one or two calcerous valves (shells) most have a radula (rasping tongue with chitinous teeth) Phylum Mollusca - Mollusks

diverse group, over 100,000 living species (2 nd ranking in number among animal phyla) of 7 classes, 4 classes covered in lab: Polyplacophora (chitons) Gastropoda (gastropods) – snails, slugs, and nudibranchs (sea slugs) Bivalvia (bivalves) – scallops, oysters, clams, etc. Cephalopoda (cephalopods) – octopuses, squid, cuttlefish, etc. Phylum Mollusca - Mollusks

Video: The Shape of Life: Episode 6 – Survival Game (Molluscs) body plan radula octopus camouflage Phylum Mollusca - Mollusks

examine the preserved specimens in the mollusk box and on display, note the following: Polyplacophora – chiton (display only): gills mantle foot Task A-1:Phylum Mollusca

examine the preserved specimens in the mollusk box and on display, note the following: Gastropoda – snail and slug: coiled valve (snail) or no valve (slug) broad, flat foot Task A-1:Phylum Mollusca

examine the preserved specimens, note the following: Bivalvia – clam: Task A-1:Phylum Mollusca

examine the preserved specimens, note the following: Cephalopoda – squid: muscular foot with tentacles (with suction discs) thick mantle but no external shell (true for most cephalopods) excurrent siphon (for jet propulsion) large eyes Task A-1:Phylum Mollusca

molting (ecdysis) – periodic shedding of protective cuticle so that organism can grow or change pseudocoelomate complete digestive system dioecious longitudinal muscles for movement many are free-living, but many are parasites very common in soil Phylum Nematoda – roundworms

examine the preserved specimens in the Nematoda box prepare and examine a slide with live vinegar eels; note their movement, powered by longitudinal muscles examine Ascaris cross section slide; note structures from figure 8-3 Task B-1:Phylum Nematoda

“joint-foot” – jointed appendages segmented – often with some fusing and distinctive regions (details later); very distinct cephalization exoskeleton containing chitin; used for protection, and for muscle attachments molting (ecdysis) – shedding of exoskeleton for growth; new exoskeleton later hardens Phylum Arthropoda – arthropods

very diverse group and successful group over 1 million named species, by far the most species of any phylum (in fact, 2/3 of ALL named species) estimates are as high as 30 million living species unnamed most of the species (well over half) are insects Phylum Arthropoda – arthropods

focus on both subphyla and classes for tests 4 subphyla, 6 selected classes to cover Subphylum Cheliceriformes Subphylum Myriapoda Subphylum Crustacea Subphylum Hexapoda Phylum Arthropoda – arthropods

body plan: cephalothorax and abdomen on cephalothorax, starting at anterior end: paired chelicerae paired pedipalps 4 pairs of legs selected classes: Merostomata – horseshoe crab Arachnida – spiders, scorpions, mites, ticks, etc. Subphylum Cheliceriformes

Body plan: head and multisegmented trunk on head: one pair of antennae paired mandibles Legs on trunk (either one or two per segment, depending on class) appendages are uniramous (unbranched) most have tracheal respiratory system Subphylum Myriapoda

Diplopoda (millipedes) two pairs of legs per trunk segment Chilopoda (centipedes) one pair of legs per trunk segment poison claws on trunk segment nearest the head Subphylum Myriapoda

One class (also called Crustacea) barnacles, crayfish, crabs, lobsters, shrimp, etc. on cephalothorax, starting at anterior end: Subphylum Crustacea two pairs of antennae (unique feature) paired mandibles (jaws) most then have 5 pairs of chelate appendages (pincher-like) swimmerets

appendages are biramous (two-branched; another unique feature) Subphylum Crustacea

Hexapoda – “six feet” One class to worry about: Insecta Body plan: head, thorax, and abdomen On head: one pair of antennae On head: paired mandibles On thorax: three pairs of legs On thorax: often two pairs of wings appendages are uniramous (unbranched) most have tracheal respiratory system Subphylum Hexapoda

arthropod box and displays: for all, note segmentation, head, exoskeleton, and paired jointed appendages items to note for each animal class (use Fig. 8-4 as a guide for structures): Merostomata – horseshoe crab large cephalothorax (from dorsal and ventral views) chelicerae, pedipalps, and legs book gills telson Task B-2:Phylum Arthropoda

arthropod box: Arachnida – garden spider chelicerae with fangs pedipalps (used by males in mating) 4 pairs of legs unsegmented abdomen with spinnerets for making silk Task B-2:Phylum Arthropoda

arthropod box: Crustacea barnacle – shell and holdfast blue crab – chelate appendages, mouth and feeding appendages, cephalothorax, abdomen (tucked under cephalothorax) crayfish – chelate appendages, mouth and feeding appendages, cephalothorax, gills, abdomen with swimmerets (note biramous nature) Task B-2:Phylum Arthropoda

arthropod box: Diplopoda – millipede head with mandibles, short antennae multisegmented trunk two legs per segment (key to identification) look for evidence that each “segment” is actually a fusion of two segments look for spiracles Task B-2:Phylum Arthropoda

arthropod box: Chilopoda – centipede head with mandibles, short antennae multisegmented trunk one legs per segment (key to identification) poison claws derived from first leg pair look for spiracles Task 3:Arthropods (Phylum Arthropoda)

arthropod box: Insecta – grasshopper and walking stick head with antennae, mandibles, and compound eyes thorax with three pairs of legs (note uniramous appearance of appendages) and two pairs of wings (grasshopper) segmented abdomen spiracles on sides in grasshopper, note the large tympanum (eardrum) on first segment Task B-2:Phylum Arthropoda

arthropod slides: tick, body louse, and water flea (Daphnia) for each, try to identify the class based on external features Task B-2:Phylum Arthropoda

TODAY YOU WILL TAKE AN EXIT QUIZ !!!