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Lab 8: Lab 8: Animals II: Non-molting and Animals II: Non-molting and
Molting ProtostomesMolting 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 (2nd 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 CheliceriformesSubphylum 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 MyriapodaSubphylum 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 MyriapodaSubphylum Myriapoda
• One class (also called Crustacea)
• barnacles, crayfish, crabs, lobsters, shrimp, etc.
• on cephalothorax, starting at anterior end:
Subphylum CrustaceaSubphylum 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 CrustaceaSubphylum 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 HexapodaSubphylum 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 ANTODAY YOU WILL TAKE AN
EXIT QUIZ !!!EXIT QUIZ !!!