© 2014 Pearson Education, Inc. Chapter 14 Lecture Animals of the Pelagic Environment

© 2014 Pearson Education, Inc. Pelagic animals use a variety of adaptations to help them survive. Marine mammals share similar characteristics with land mammals. Chapter 14 Overview

© 2014 Pearson Education, Inc. How Are Marine Organisms Able to Stay Above the Ocean Floor? To avoid sinking animals may use the following methods to increase buoyancy: 1.Rigid gas containers

© 2014 Pearson Education, Inc. How Are Marine Organisms Able to Stay Above the Ocean Floor? To avoid sinking animals may use the following methods to increase buoyancy: 2.Swim Bladders 3.Fats or oils Swim bladder used by slow moving fish

© 2014 Pearson Education, Inc. How Are Marine Organisms Able to Stay Above the Ocean Floor? To avoid sinking animals may use the following methods to increase buoyancy: 4.Spines to increase surface area

© 2014 Pearson Education, Inc. Floating Zooplankton Sizes of floating zooplankton range from microscopic to large organisms like jellies. Microscopic zooplankton have shells or tests. The zooplankton can be herbivores or omnivores. Highly abundant in oceans

© 2014 Pearson Education, Inc. Floating Zooplankton – three important microscopic zooplankton 1.Radiolarians –Silica tests –Intricately ornamented –Spikes on test increase organism’s surface area

© 2014 Pearson Education, Inc. 2.Foraminifers –Very small –Planktonic most abundant, benthic most diverse –Calcium carbonate tests that are chambered Floating Zooplankton – three important microscopic zooplankton

© 2014 Pearson Education, Inc. 3.Copepods –Microscopic –Shrimplike crustaceans –Segmented bodies, jointed legs –Most of ocean’s zooplankton biomass Floating Zooplankton – three important microscopic zooplankton

© 2014 Pearson Education, Inc. Floating Macroscopic Zooplankton Cnidarians – soft bodies, stinging tentacles –Hydrozoan (Portuguese man-of- war) gas-filled float –Scyphozoan (jellyfish) Soft, low-density bodies Jellies move by muscular contractions. Water enters under the bell and muscular contractions of bell force water out.

© 2014 Pearson Education, Inc. Macroscopic Zooplankton Krill –Crustaceans –Resemble mini shrimp or large copepods –Abundant near Antarctica –Critical in Antarctic food chains

© 2014 Pearson Education, Inc. To avoid sinking many organisms will swim –Nekton – squid, fish, sea turtles and marine mammals that swim How Are Marine Organisms Able to Stay Above the Ocean Floor?

© 2014 Pearson Education, Inc. Swimming Organisms Nektonic Squids-swim by drawing water into body cavity and expelling it out the siphon.

© 2014 Pearson Education, Inc. Swimming Motion and General Fish Features Swim by curving body from front to back

© 2014 Pearson Education, Inc. Fin Designs in Fish Vertical fins (dorsal and anal) as stabilizers Paired pelvic fins and pectoral fins for “steering” and balance Tail fin (caudal) for thrust Dorsal fin Anal fin Pectoral fin Pelvic fin Caudal fin

© 2014 Pearson Education, Inc. Fin Designs in Fish Rounded caudal fins –Flexible –Maneuver at slow speeds Truncate fins and forked fins –Useful for both maneuvering and thrust

© 2014 Pearson Education, Inc. Fin Designs in Fish Lunate fins –Rigid, little maneuverability –Efficient propulsion for fast swimmers Heterocercal fins –Asymmetrical –Lift for buoyancy (shark)

© 2014 Pearson Education, Inc. What Adaptations Do Pelagic Organisms Possess for Seeking Prey? 1.Mobility Lungers wait for prey and pounce (grouper). –Mainly white muscle tissue Cruisers actively seek prey (tuna). –Mostly red muscle tissue (contains high amounts of myoglobin) Myoglobin is an oxygen storing pigment in the muscles. –The red muscle tissue allows the fish to have the endurance needed to actively seek prey.

© 2014 Pearson Education, Inc. Lungers and Cruisers Grouper waiting to lunge at prey

© 2014 Pearson Education, Inc. Lungers and Cruisers Tuna swim constantly in search of prey

© 2014 Pearson Education, Inc. 2.Swimming speed Speed generally proportional to size Can move very fast for short time (mainly to avoid predation) Tuna can reach speeds up to 90 miles per hour. What Adaptations Do Pelagic Organisms Possess for Seeking Prey?

© 2014 Pearson Education, Inc. Most fish are cold-blooded – poikilothermic –Bodies same temperature as environment –Not fast swimmers Some are warm-blooded – homeothermic –Found in warmer environments –Helps them capture prey because they can get the maximum power out of the muscles. What Adaptations Do Pelagic Organisms Possess for Seeking Prey?

© 2014 Pearson Education, Inc. Mainly fish that consume detritus (dead and decaying organic matter) or each other Limited numbers of organisms because of lack of abundant food What Adaptations Do Pelagic Organisms Possess for Seeking Prey? Adaptations of Deep-Water Nekton Bioluminescence- produce light from special cells called –photophores

© 2014 Pearson Education, Inc. Adaptations of Deep-Water Nekton Large, sensitive eyes Large sharp teeth Expandable bodies Hinged jaws Sensitive lateral line Counterillumination

© 2014 Pearson Education, Inc. Deep Sea Nekton

© 2014 Pearson Education, Inc. Adaptations of Deep-Water Nekton Ways that bioluminescence is useful: 1.Searching for food in the dark 2.Attracting prey with bioluminescent lure 3.Communicating or seeking a mate 4.Escaping from predators by using flash of light 5.Avoiding predators with displays of bioluminescence 6.Camouflaging-belly light that matches the color of dim light filtered from above- counterillumination

© 2014 Pearson Education, Inc. What Adaptations Do Pelagic Organisms Possess to Avoid Being Prey? 1.Schooling –Safety in numbers –School may appear as single larger unit –Schooling maneuvers confuse predator

© 2014 Pearson Education, Inc. Symbiosis – two or more organisms associate in a way that benefits at least one of the organisms. There are three types of symbiotic relationships What Adaptations Do Pelagic Organisms Possess to Avoid Being Prey? 1.Commensalism – less dominant organism benefits without harming host Remora benefits and the shark is not harmed.

© 2014 Pearson Education, Inc. Adaptations to Avoid Predation 2.Mutualism – both organisms benefit Example: clown fish and anemone 3.Parasitism – parasite benefits at expense of host Example: Isopod attached to soldierfish