Marine Nekton

• Fins: Shark vs Cetacean

  A) Horizontal tail fluke

  B) Vetical tail fin

  C) Blowhole

  D) Gills

  E) mammary glands

  F) additional fins

  G) flipper

  H) fin

  
• Nekton

  • Free-swimming organisms in the ocean
  • Can actively propel themselves through the water column, independent of currents or waves
• T or F: Nektons can actively propel themselves for transport, foraging, and predator avoidance

  True
• 3 Major taxa of marine nekton

  • chordates
  • molluscs
  • arthropods
• T or F: Osteichythyes, Chondrichthyes, Mammalia, and Reptilia are examples of Chordates


  True
• T or F: One of the key characteristics of chordates is having notochord. Sea turtles as well as rays are examples of animals belonging to chordates

  True
• Adaptations of marine nekton

  • streamlined bodies
  • fins
  • tail fins
  • gills
  • buoyancy control
  • sensory organs
  • warm blooded and insulated
  • facultative or obligate swimmers
  • breath-holding abilities
  • complex circulatory systems
  • sensory organs
• T or F: Fins minimize water resistance and provides propulsion, steering, and stability

  False
• T or F: Nekton have streamline bodies therefore they are able to move quickly underwater

  True
• T or F: Nekton cannot extract dissolved oxygen from the water column

  False
• T or F: Nekton are able to maintain their position in the water column due to their swim bladders or fat storage

  True
• T or F: As you go deeper into the water, color turns more monochromatic due to light being unable to penetrate, thus nekton do not rely on their eyesight for prey and predator detection rather they use smell and vibrations caused by moving underwater as sign of organisms swimming nearby

  False
• T or F: Mammals are unable to breath underwater, but they developed special abilities allowing them to hold their breath underwater. One of these are marine turtles

  True
• T or F: Beluga whales have specialized organs called watermelon by which they use for echolocation

  false
• Fins: Shark Vs Cetacean

  • Caudal fin vs tail fluke
  • Pectoral fins vs flippers
  • Dorsal fins
• Which fin minimizes rolling and aids in turning?

  dorsal fin
• Which fin aids in preicion swimming, steering, and depth control?

  Pectoral fin
• Which fin stabilizes fish and useful when resting on bottom?

  Pelvic fin
• Which fin aids in stability and swimming?

  Anal fin
• Which fin reduces drag, aids in controls vortices, and is for mechanosensors?

  Adipose fin
• Fin locations

  A) dorsal

  B) adipose

  C) caudal

  D) anal

  E) pelvic

  F) pectoral

  
• Examples of fin modifications

  A) dorsal

  B) pectoral

  C) pelvic

  D) pectoral

  E) pectoral

  F) pelvic

  
• Ecological Roles: Maintain balance by controlling prey populations

  Top predators
• Ecological Roles: Essential food source for other marine animals

  Prey species
• Ecological Roles: Clean up the ocean by consuming dead organisms

  Scavengers
• Ecological Roles: Carry nutrients between different parts of the ocean

  nutrient transporters
• Ecological roles: Disperse propagules

  Dispersal vectors
• Threats on nekton

  • overfishing
  • pollution
  • habitat destruction
  • climate change