Lab Quiz 3: Buoyancy, Swimming, Boney Fish, & Cladograms

• Cladistics: A method of classifying organisms according to their common characteristics
• Cladograms: Branching diagrams that show the relationship between clades
• Clades: The fundamental unit of phylogeny. These are groups of organisms believed to have evolved from a common ancestor
• Outgroup: Groups that serve as a useful comparison for the animals in ones study
• Sunapomorphies: Derived characteristics shared by all members of a clade
• What are the 4 strategies to control buoyancy?

  Low-Density Compounds

  Generate lift with fins

  Reduce heavy tissues

  Gas-Filled Spaces
• How do sharks create lift?

  Using a heterocercal tail and pectoral fins to balance against their heavy skull
• What are the two types of swim bladders?

  Physostomous

  Physoclistous
• What is the more ancient type of swim bladder?

  Physostomous
• What is the more evolved type of swim bladder?

  Physoclistous
• What goes in the pink box of this diagram of the Physoclistous gas bladder?

  Dorsal aorta

  
• What goes in the orange box of this diagram of the Physoclistous gas bladder?

  Posterior cardinal vein

  
• What goes in the yellow box of this diagram of the Physoclistous gas bladder?

  Oval body

  
• What goes in the green box of this diagram of the Physoclistous gas bladder?

  Gas Gland

  
• What goes in the blue box of this diagram of the Physoclistous gas bladder?

  Rete mirabile

  
• What goes in the purple box of this diagram of the Physoclistous gas bladder?

  Ceilacomesenteric artery

  
• What goes in the tan box of this diagram of the Physoclistous gas bladder?

  To Hepatic portal vein

  
• What goes in the red box of this diagram of the Physoclistous gas bladder?

  Red Body

  
• What are some groups of fish with Physostomus swim bladders?

  Osteoglossomorpha

  Elopomorpha

  Clupeomorpha

  Ostariophysi

  Protacanthopterygii
• What are some groups of fish with Physocloistous swim bladders?

  Stenopterygii

  Cyclosquamata

  Scopelomorpha

  Lampridiomorpha

  Polymixiomorpha

  Paracanthopterygii

  Mugilomorphia

  Atherinomorpha

  Percomorpha
• What group of fish did physoclistous swim bladders first evolve in?

  Neoteleost
• What are some notable features of physostomus swim bladders?

  Air taken from the surface

  Air volume reduced by half every 10 m of depth

  Cannot achieve neutral buoyancy at depth
• What are some notable features of physocistous gas bladders?

  Gas gland excretes lactic acid and makes CO2

  Hemoglobin loses O2 due to acidity

  O2 diffuses partly into the swim bladder

  Exceedingly high gas pressure

  Deflate by diffusing gas back into blood at vascular ovale
• Blood flowing back to the body first enters a rete where virtually all excess carbon dioxide and oxygen produced in the gas gland diffuses back into the arteries supplying the gas gland
• What species are least likely to have a swim bladder?

  Benthic

  Deep Water Dwelling
• What notable body forms reduce drag?

  Tapering tail

  Round front

  Hydrofoil head shape

  Mucous layer

  Plaquoid Scales

  Bill
• What are the best predictors of swiming performance in fish?

  Small caudal peduncle

  High aspect ratio (thin and deep tail)

  Long length
• Leptocercal: Modified diphycercal; vertebrae extend symmetrically to the tip of an expanded tail
• What are some fish with Leptocercal tails?

  Coelacanths

  Lungfish

  Ratfish
• Hetericercal: Unequal-lobed tail; vertebrae extend into upper lobe
• What are some fish with heterocercal tails?

  Sharks

  Sturgeon
• Homocercal: Equal-lobed tail; expresses asymmetry internally but symmetry externally; abbreviated heterocercal
• What are some fish with homocercal tails?

  Tuna

  Bangai Cardnalfish
• Isocercal: Resembles protocercal tails but retains asymmetrical internal structure of homocercal tails
• What are some examples of fish with Isocercal tails?

  Gadidae

  Notopteridae

  Gymnarchidae

  Macruridae

  Anguilliformes
• Hemihomocercal: An intermediate between heterocercal and homocercal
• What are some examples of fish with hemihomocercal tails?

  Amia calva - bowfin

  Gar
• Gephyrcercal: The calvus is the hardened bridge between anal and dorsal fins. Highly advanced
• What are some fish with Gephycercal tails?

  Molas

  Ocean Sunfish
• What kind of tail is the red arrow pointing to?

  Leptocercal