Marb 435 1st Edition Exam 3 Study Guide Lectures Annelida 2 Deutersostomes Review Questions Annelida II Question 1 Give a definition of epitoky and two examples of polychaetes in which this phenomenon occurs be as specific as possible Epitoke formation of a pelagic reproductive individual from a benthic nonreproductive individual 4 Examples first 2 are families that have this phenomenon second 2 are more specific individual species 1 2 3 4 Family Nereididae Family Syllidae Odontosyllisenopla Palolaviridis Question 2 What type of cleavage is typical for polychaetes Spiral Cleavage Question 3 Spoonworms are not segmented but how can you tell that they are annelids The nervous system consists of a brain near the base of the proboscis and a ventral nerve cord running the length of the body this is a similar arrangement to that of other annelids Question 4 What is this larval form called and which taxon does it represent Pelagosphera Larva belongs to Sipunchula Question 5 Name three functions of the clitellum 1 Secretes mucus for copulation 2 Secretes nutritious albumen for eggs 3 Forms a cocoon in which eggs and albumen are deposited Question 6 Describe how earthworms reproduce The worms attach to each other on their ventral sides in opposite directions and the clitellum produces mucus to glue partners together The male gonopores release sperm to the seminal receptacles of the partner Question 7 What are giant axons In which taxon do they occur and where in the body What is their function Very large nerve cells and fibers found in Oligochaetes and Polychaetes Specifically for Oligochaetes they are located mid dorsal sensory input from the head quick reaction to danger and dorsal laterally sensory input from the body Question 8 How do leeches and oligochaetes differ from each other with respect to segmentation A leech does not have bristles and its external body segmentation does not match its internal organ segmentation Leeches always have 33 segments Oligochaetes are segmented from anterior to posterior Question 9 What are the benefits of using leeches for certain types of medical procedures such as re attachment surgery Components of their saliva particularly the hirudin functions as an anti coagulant vasodilator and anesthetic which allows the blood to continue flowing at a slow rate even after the leech has been removed Review Question Rotifera Chaetognatha Lophophorates Question 1 Describe the typical feeding mode of a rotifer Name the structures unique to rotifers that are involved in feeding Mostly suspension feeders on phytoplankton bacteria and small zooplankton Unique structures Mastax muscular modification of the pharynx Trophi used to grind food suck food in through the mouth or protrude from the mouth and pierce prey Question 2 Describe different modes of locomotion in rotifers They swim with a structure called a coronal some have spines in addition that are used in oar like motion They can temporarily or permanently attach with toes at the posterior end Also they can use looping to move Looping is interplay between circular and longitudinal musculature and posterior and anterior attachment Question 3 Describe the typical feeding mode of chaetognaths Raptorial feeders hang motionless in the water and dart forward to catch prey with grasping spines which surround the mouth Some use tetrodotoxin to subdue prey prior to ingestion Question 4 Which three phyla are traditionally combined as the lophophorates Why is lophophorates not considered a formal taxon name any longer Phoronida elongated tube dwelling worms 1mm 50cm long Bryozoa encrusting mossanimals Brachiopoda bottom dwelling marine organism with dorsal ventral shell arrangement With the advent of molecular taxonomies and 18 S RNA molluscs group more closely to brachiopods than with bryozoans meaning the lophophore evolved several times or that the molluscs evolved from a lophophorate and subsequently lost it Question 5 Name three features that all lophophorates have in common Lophophore a pair of spiral feeding structures located on the head superficially appearing like the feeding tentacles of a feather duster worm Sessile Suspension feeders U shaped gut Question 6 Brachiopods and bivalves both have bivalved calcareous shells How do they differ with regard to their body axes They have 2 coelomic spaces The Mesocoel inside the lophophore The Metacoel is the main body cavity Question 7 Fill in the blanks One of the lophophorate phyla the phylum Bryozoa consists almost exclusively of colonial species The individuals in a colony are called zooids Individuals that feed are called autozooids Individuals that performother functions in the colony are called heterozooids Some have beaklike structures called auicularia that are used to defend the colony Review Spiralia and Ecdysozoa Question 1 Which two major clades constitute the Protostomia For each name three phyla that belong to it Ecdysozoa Arthropoda Onychophora Tardigrada NematodaSpiralia Rotifera Platyhelminthes Phoronida Brachiopoda Nemertea Mollusca Annelida Bryozoa Question 2 What sources of data support these clades and which morphological features are characteristic for them Monophyly is supported by several molecular data sources SSU and LSU ribosomal RNA genes and other DNA sequence data Hox Genes Mitochondrial gene arrangement Phylogenomic data Question 3 What is the sister group to the Protostomia Deuterostomia mouth second Question 4 Why is the mitochondrial genome an important indicator for phylogenetic relationships The gene order and orientation on the circular mitochondrial genome vary among animal taxa Changes in gene arrangement are rare but can be important indicators for phylogenetic relationships Review Tardigrada Onychophora and Arthropoda I Question 1 What is cryptobiosis Name three invertebrates that can enter cryptobiosis Dormant state where the organism can survive extreme temperatures and desiccation Only Tardigrades can do this as far as we know Question 2 Describe how an onychophoran feeds Shoot jets of slime from oral papillae slime denatures into a sticky substance called a slime blob trapping prey items and does not stick to the onychophoran Question 3 Approximately what percentage of all living species and of all animals do arthropods represent 60 of all living species 75 of all living animals Question 4 Name five morphological synapomorphies for the Arthropoda 1 Segmented body with tagmatization 2 Chitinous exoskeleton that molts 3