Lab Practical

• What kind of characters does cladistics use to determine evolutionary relationships?

  Synapomorphies
• Synapomorphies

  Shared derived characteristics
• Clade

  A grouping on a cladogram based on shared characteristics from a common ancestor (the more recent the better)
• Primative Characters

  a character that is shared among members of a large group (clade) and is thought to have arisen early in the evolution of the group
• What larva does this diagram represent?

  Urochordate larva

  Tunicate Larva

  
• In this diagram of a urochordate larva what is the pink line pointing to?

  Notochord

  
• In this diagram of a urochordate larva what is the orange line pointing to?

  Dorsal Nerve Chord

  
• In this diagram of a urochordate larva what is the yellow line pointing to?

  Pharyngeal Gill Slits

  
• What type of larva is this?

  Cephalochordate

  Lancelet

  
• What does the purple line on this lancet larval diagram point to?

  Dorsal Nerve Chord

  
• What does the blue line on this lancet larval diagram point to?

  Notochord

  
• What do the green lines on this lancet larval diagram point to?

  Pharyngeal Gill Slits

  
• Larval Lamprey

  Ammocoetes
• Larval Lancelet

  Amphioxus
• What are the differences between the skeletal structure of a perch and shark?

  Perch

  Shark
• What are the differences between the skeletal structure of a perch and shark?

  Perch

  • Fins supported by thin bone with thin membrane
  • Stiff spine & soft ray dorsal support
  • Uroneural present
  • Operculum
  • Girdles non-free floating
  • Head comprised of many bones

  Shark

  • Tesserae endoskeletal ossification
  • Fins supported by radial cartilage in fleshy tissue
  • Most lack any fin spine
  • Free-floating pelvic & pectoral girdles
  • Operculum absent
  • Dermatocranium only of teeth
  • Uroneruals absent
• Spiral Valve Intestine

  Seen in sharks and other basal fishes.

  Increases surface area for nutrient absorption as the liver of a shark takes up a large amount of space
• Pyloric caeca

  Floods the stomach with enzymes to further breakdown food for increased nutrient absorption

  Used as they have no need to increase surface area of the digestive track

  
• Ampullae of Lorenzini

  Shark sensory system

  A grouping of pores around the head that are filled with a conductive jelly.

  Important for passive electroreception to find & consume prey

  May be involved in migration

  
• Lateral Line System

  Seen in bony fishes

  A series of pores with neuromasts to sense changes in the water around a fish

  Important in avoiding predation & navigating habitat changes

  Can be lost or expanded on based on habitat

  
• What are some similarities between ammocoetes & amphioxus?

  Notochord

  Dorsal Nerve Chord

  Caudal Fin

  Myotomes

  Fusiform Body

  Laterally Compressed

  Poorly Defined Head

  Oral Hood

  Atrium
• What are some traits unique to a tadpole tunicate?

  Attachment Discs

  No Caudal

  Incurrent Siphon

  Eye Spot

  Longitudinal bar in pharynx wall
• What are some traits unique to ammocetes?

  Cloaca

  Gallbladder

  Kidney

  Centeralized Nerve Center

  Lateral Eye
• What are some traits unique to amphioxus?

  Frontal Eye

  Hepatic caecum

  Atriophore
• What kind of circulatory system do fishes have?

  Single loop system
• Single Loop System

  Circulatory system works that works by pumping blood from the heart to the rest of the body through blood vessels. The blood carries oxygen and nutrients to the cells and tissues and picks up waste products, which are then transported back to the heart.

  
• Describe the steps of circulation in a fish's circulatory system

  1. Counter current exchange in gill capillaries to get oxygen and remove carbon dioxide
  2. Blood travels through body exchanging gasses and collecting waste
  3. The Sinus Venous collects blood from the body
  4. The atrium transfers blood to the ventricle
  5. The ventricle pumps blood to the gills
  6. The bulbous arteriosus prevents backflow into the ventricle and sends blood to the gills
• What is the black line towards the head pointing to?

  Eye

  
• What is the lavender arrow pointing to?

  Nostril

  
• What is the turquoise line pointing to?

  Maxilla

  
• What is the blue arrow pointing to?

  Mouth

  
• What is the purple arrow pointing to?

  Mandible

  
• What is the lime arrow pointing to?

  Anterior Dorsal Fin

  
• What is the yellow arrow pointing to?

  Posterior dorsal fin

  
• What is the peach line pointing to?

  Anal fin

  
• What is the coral arrow pointing to?

  Anus

  
• What is the pastel tangerine arrow pointing to?

  Pelvic fin

  
• What is the pastel green line pointing to?

  Pectoral fin

  
• What is the pastel yellow-orange line pointing to?

  Caudal fin

  
• Cycloid Scale

  A type of elasmoid scale that is notably rounded and lacks ctenii

  Found in some basal teleosts