Marb 435 1st EditionExam # 3 Study Guide Lectures: Annelida 2- DeutersostomesReview Questions – Annelida IIQuestion 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. Family Nereididae2. Family Syllidae3. Odontosyllisenopla4. PalolaviridisQuestion 2. What type of cleavage is typical for polychaetes?Spiral CleavageQuestion 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 annelidsQuestion 4. What is this larval form called and which taxon does it represent?Pelagosphera Larva, belongs to SipunchulaQuestion 5. Name three functions of the clitellum1. Secretes mucus for copulation2. Secretes nutritious albumen for eggs3. Forms a cocoon in which eggs and albumen are depositedQuestion 6. Describe how earthworms reproduce.The worms attach to each other on their ventral sides in opposite directions, and the clitellumproduces 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 istheir 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 internalorgan 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, suchas 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 removedReview Question – Rotifera, Chaetognatha, LophophoratesQuestion 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 zooplanktonUnique structures:Mastax: muscular modification of the pharynxTrophi: 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 "graspingspines" which surround the mouth. Some use tetrodotoxin to subdue prey prior to ingestionQuestion 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 moss-animals Brachiopoda - bottom-dwelling marine organism with dorsal-ventral shell arrangementWith 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 gutQuestion 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 lophophoreThe Metacoel is the main body cavityQuestion 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 beak-like structures called auicularia that are used to defend the colony.Review –Spiralia and EcdysozoaQuestion 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, BryozoaQuestion 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 dataQuestion 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 IQuestion 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 onychophoranQuestion 3. Approximately what percentage of all living species and of all animals do arthropodsrepresent?60% of all living species, 75% of all living animalsQuestion 4.