BIOL113 M3 Q1

• Name the annelid classes that indicate the relative number of bristles (chaetae) its members have. (x2)

  Oligochaeta, Polychaeta
• Which of the following is found only among annelids?

  a clitellum
• How many segments do true leeches have?

  34
• Which molluscan class includes organisms that are primarily suspension feeders? 

  bivalves
• The structure of molluscs that forms the shell and houses the gills is the

  Mantle
• The adaptation of bivalves to a sedentary, filter-feeding lifestyle that exploits the sand of a beach as a habitat, has lead to the loss of the ________ and the radula.

  head
• A terrestrial mollusc without a shell belongs to which class?

  Gastropods
• What is the role/function of the Ampullae of Lorenzini?

  To sense electrical fields
• What does viviparous mean?

  The organism births free-swimming young
• While most of the platyhelminths are free living or endoparasites, which one of the following taxa has an ectoparasitic life cycle?

  Monogenea
• Cestodes are monoecious and lack a digestive tract. The reproductive units of the cestodes are called


  Proglottids
• Cnidarians and ctenophorans differ from other eumetazoans by having

  Radial symmetry
• Do tapeworms feed by absorbing nutrients across their body walls?


  true
• what organisms have the most efficient respiratory system (in terms of oxygen uptake)?


  fish
• Why do we see tracheal systems in animals that breathe air, but not in those that live in water?

  because the oxygen diffusion rate through the air is 300,000 times faster than in water
• Why is cutaneous diffusion more efficient for oxygen uptake in air than in water?

  Because air has a higher oxygen content than water.
• Which of these characteristics of the human lung DOES NOT contribute to the efficiency of gas exchange:

  the residual volume of air in the lungs at expiration
• What are the air sacs of a bird used for?

  to create unidirectional flow of air across the lung
• Why is oxygen transport more efficient in animals with two closed circuits than one?

  Because blood pressure is lost as blood flows through a capillary bed, and two circuits allows blood to travel through the heart to be re-pumped after travelling through the gills/lungs
• Which of the following is NOT a characteristic of an artery:

  always carry oxygenated blood
• In vertebrates, why does a four-chambered heart deliver oxygen to the tissues more efficiently than a three chambered heart?

  Because a four chambered heart has complete separation of oxygenated and deoxygenated blood
• Insects have a very simple, open circulatory system because:

  They have low energy requirements
• In the frog heart, which of the following does NOT contribute to the separation of oxygenated and deoxygenated blood?

  The septum
• Compared to the seawater around them, most marine invertebrates are:


  hypoosmotic, isoosmotic
• What is the main function of an excretory system?

  to remove nitrogenous waste from the body
• What is the function of the loop of Henle in the vertebrate nephron?

  To create an osmotic gradient in the renal medulla, To reabsorb water to concentrate the final urine
• To maintain homeostasis, freshwater fish must:

  Excrete large quantities of water
• Which animals are the only animals apart from mammals that can produce urine significantly hyperosmotic to the blood (i.e. much more concentrated than blood/body fluid) out of: Insects, Earthworms, Salt-water fish, Amphibians, Reptiles, birds ?

  salt water fish and birds.