Adaptations to the Marine Environment
• Ability to float (Zooplankton – some produce fats or oils to stay afloat)
• Ability to swim (Nekton – larger fish and marine mammals)
Propulsion and movement of fish - the body plan of fish reflect adaptations to feeding on prey and fleeing predators.
Tuna - .28
Dolphin - .25
Swordfish - .24
Whale - .21
Most efficient is about.25, but there is a size-scale factor.
Ratio produced from natural selection “the fittest survive and produce offspring”
Compare with Surfboard Design!
|Short Board||19 ¼"||6’4”||0.25||Small – medium waves|
|PT (Ebenizer Townsend, 1798)||19 ¼"||6'7"||0.24||Large waves|
|Average Long Board||22"||9'0"||0.20||Like a whale – scale factor|
|Average Surf Board||18 ¼"||6’2”||0.25||rapid turns, harder to control|
Kinds of Zooplankton
Includes organisms described as floaters and drifters. All forms are invertebrates.
Microscopic Zooplankton include:
Radiolarians, Foraminifers, Copepods
• Krill ( resemble mini shrimp or large copepods, critical in Antarctic food chains)
|Figure 16.43. Copepods||Figure 16.44. Krill|
Floating Macroscopic Zooplankton include:
• Portuguese man-of-war (have gas-filled float)
• Jellyfish (have soft, low-density bodies; there are hundreds of species)
Many species of portuguese man-of-war and jellyfish can sting or produce potent toxins.
|Figure 16.45. Portuguese man-of-war||Figure 16.46. Jellyfish|
Swimming (Nekton) Organisms
Includes all fish, squids, sea turtles and sea snakes, and marine mammals.
• Swim by trapping water and expelling it (squid, octopus)
• Swim by curving body from front to back (fish, etc.)
Adaptations for Finding Prey
• Lungers wait for prey and pounce (grouper).
• Cruisers actively seek prey (tuna).
|Figure 16.48. Groupers are lungers||Figure 16.49. Tuna are cruisers|
Adaptations to Avoid Predation
• Hiding: includes Transparency, Camouflage and Countershading
• Poison (to touch or eat: examples: sea snakes, blowfish, lion fish)
• Schooling (safety in numbers, appear as a larger unit, maneuvers confuse predators)
|Video: Schooling anchovies at Scripps Pier (Scripps Institute of Oceanography)|