Chapter 16Chapter 16

Marine Animals - VertebratesMarine Animals - Vertebrates

Phylum ChordataPhylum Chordata

All members of the phylum (the most advanced of the All members of the phylum (the most advanced of the animal phylum) have a stiffening animal phylum) have a stiffening notochord.notochord.

Notochords are stiff rods of connective tissue.Notochords are stiff rods of connective tissue.

The also have The also have a tubular dorsal nervous systema tubular dorsal nervous system and and gill gill slitsslits behind the oral opening at sometime during their behind the oral opening at sometime during their development.development.

The notochord serves as a rigid support and a The notochord serves as a rigid support and a foundation for muscles and bone.foundation for muscles and bone.

5% of 45,000 species of chordates lose their notochord 5% of 45,000 species of chordates lose their notochord as they develop.as they develop.

These are invertebrate chordates.These are invertebrate chordates.

95% retain the notochord or the vertebral column that 95% retain the notochord or the vertebral column that forms around it.forms around it.

These are called These are called Vertebrate ChordatesVertebrate Chordates..

Classification of Groups Classification of Groups Within the Phylum ChordataWithin the Phylum Chordata

Phylum ChordataPhylum Chordata Subphylum Urochordata – TunicatesSubphylum Urochordata – Tunicates Subphylum Cephalochordata – AmphioxusSubphylum Cephalochordata – Amphioxus Subphylum Vertebrata:Subphylum Vertebrata: Class Agnatha (jawless fish) – Hagfish; lampreyClass Agnatha (jawless fish) – Hagfish; lamprey Class Chondrichthyes (cartilage skeleton) – Sharks; Class Chondrichthyes (cartilage skeleton) – Sharks;

Rays; SkatesRays; Skates Class Osteichthyes (bony skeleton) – tuna; seahorse; Class Osteichthyes (bony skeleton) – tuna; seahorse;

pufferspuffers Class Amphibia – frogs; salamandersClass Amphibia – frogs; salamanders

Class Reptilia – crocodiles; turtles; snakesClass Reptilia – crocodiles; turtles; snakes Class Aves – gulls; penguins; ternsClass Aves – gulls; penguins; terns Class Mammalia – Whales; sealsClass Mammalia – Whales; seals

FishesFishes Vertebrates that usually:Vertebrates that usually: Live in waterLive in water Possess gillsPossess gills Have finsHave fins

There are more species of fish and more There are more species of fish and more individuals than species and individuals of all other individuals than species and individuals of all other vertebrates combined.vertebrates combined.

Fish range in size form 10 millimeters to over 20 Fish range in size form 10 millimeters to over 20 meters (.4 inches to 60 feet)meters (.4 inches to 60 feet)

Fish weigh from 0.1 gram to 41,000 kilograms. (.004 Fish weigh from 0.1 gram to 41,000 kilograms. (.004 ounces to 45 tons)ounces to 45 tons)

Fish are Ectotherms – cold blooded – can not maintain Fish are Ectotherms – cold blooded – can not maintain a steady internal temperature.a steady internal temperature.

40% of species live all or part of their life in freshwater.40% of species live all or part of their life in freshwater.

60% live exclusively in salt water.60% live exclusively in salt water.

Class AgnathaClass Agnatha

(a = lacking; gnathos = jaw)(a = lacking; gnathos = jaw)

Examples – Hagfish and LampreysExamples – Hagfish and Lampreys

Lack jawsLack jaws No paired appendagesNo paired appendages Have gill slitsHave gill slits Have openings to slime glandsHave openings to slime glands Have round sucking mouths surrounded by organs sensitive to Have round sucking mouths surrounded by organs sensitive to

touchtouch Tails are flattened Tails are flattened Eye are covered by thick skinEye are covered by thick skin

Hagfish:Hagfish: PinkPink Live in coloniesLive in colonies Feed on the inner tissues and internal organs of its Feed on the inner tissues and internal organs of its

preyprey

Lamprey; Lamprey; Have a toothed, funnel-shaped mouthHave a toothed, funnel-shaped mouth Rasps through scales and skin to get nutrients from Rasps through scales and skin to get nutrients from

bloodblood

Class ChondrichthyesClass Chondrichthyes

(chondros = cartilage; ichthys = fish)(chondros = cartilage; ichthys = fish)

The skeleton is made of cartilage. Some calcification The skeleton is made of cartilage. Some calcification is present, but is present, but true bones do not exists.true bones do not exists.

They have jaws with teethThey have jaws with teeth They have paired finsThey have paired fins

Sharks and Rays tend to be larger than either Sharks and Rays tend to be larger than either Agnathans or bony fish.Agnathans or bony fish.

Only a small fraction of all fish species are members of Only a small fraction of all fish species are members of this group.this group.

Nearly all are marine; a few species will inhabit Nearly all are marine; a few species will inhabit estuaries and very few are found in fresh water.estuaries and very few are found in fresh water.

Skates and Rays have flattened bodies with spreading Skates and Rays have flattened bodies with spreading pectoral fins – They move by flapping of thes fins.pectoral fins – They move by flapping of thes fins.

Neither sharks or rays have gas bladders and both are Neither sharks or rays have gas bladders and both are slightly negatively buoyant; they sink if they stop slightly negatively buoyant; they sink if they stop swimming.swimming.

Rays have smooth skinRays have smooth skin Sharks are covered with a tooth-like placoid scale.Sharks are covered with a tooth-like placoid scale.

Rays:Rays: Some have a defensive barb Some have a defensive barb

on their tailon their tail Some grow to 7 meters Some grow to 7 meters

across (giant Manta)across (giant Manta) Some have the ability to Some have the ability to

shock their prey.shock their prey.

Sharks:Sharks: 80% are less than 2 meters 80% are less than 2 meters

longlong Not very intelligentNot very intelligent Hunt prey by vibrations in the Hunt prey by vibrations in the

water and also by smell.water and also by smell.

Largest – Whale shark; 18 meters (60 feet), 41,000 Largest – Whale shark; 18 meters (60 feet), 41,000 kilograms (90,000 pounds); feed on planktonkilograms (90,000 pounds); feed on plankton

Carcharodon (Karcharos = sharp; odontos = tooth) Carcharodon (Karcharos = sharp; odontos = tooth) Great White Shark; 7 meters, 1,400 kilogramsGreat White Shark; 7 meters, 1,400 kilograms

Other “dangerous” species: Mako; Tiger; Hammer Other “dangerous” species: Mako; Tiger; Hammer headhead

Class OsteichthyesClass Osteichthyes

(osteum = bone; ichthys = fish)(osteum = bone; ichthys = fish)

27,000 + species of bony fish27,000 + species of bony fish Success due to light, hard, strong skeleton that Success due to light, hard, strong skeleton that

supports them.supports them. Most numbers and successful of all vertebrates.Most numbers and successful of all vertebrates.

Representatives of this class are found in every marine Representatives of this class are found in every marine habitat.habitat.

90% of all fish belong to the Xlass Osteichthyes and 90% of all fish belong to the Xlass Osteichthyes and the Order Teleostei (teleos = perfedt; osteon = bone)the Order Teleostei (teleos = perfedt; osteon = bone)

This group contains the most familiar of the fish; perch, This group contains the most familiar of the fish; perch, tuna, flounder,etc.tuna, flounder,etc.

They have a gas filled swim bladder to help maintain They have a gas filled swim bladder to help maintain neutral buoyancy.neutral buoyancy.

They have independently movable fins for well They have independently movable fins for well controlled swimming.controlled swimming.

The are capable of great speed for pursuit or The are capable of great speed for pursuit or avoidance of predators.avoidance of predators.

They have effective camouflage.They have effective camouflage.

They have social organizationThey have social organization They have an orderly pattern They have an orderly pattern

of migration.of migration. They have the ability to They have the ability to

cluster together in defensive cluster together in defensive schools.schools.

Over 77 million tons of Over 77 million tons of bony fish are taken bony fish are taken annually form the ocean for annually form the ocean for consumptionconsumption..

Movement, Shape & Movement, Shape & PropulsionPropulsion

A fish’s resistance to movement (drag) is determined A fish’s resistance to movement (drag) is determined by the frontal area, body contour and surface drag.by the frontal area, body contour and surface drag.

Drag increases geometrically with increasing speed. Drag increases geometrically with increasing speed. Faster swimming fish must be highly modified to Faster swimming fish must be highly modified to minimize drag.minimize drag.

The most effective antidrag shape is a tapering The most effective antidrag shape is a tapering torpedo-like body plan.torpedo-like body plan.

This shape produces This shape produces minimum drag when they are:minimum drag when they are:

A. circular in cross-sectionA. circular in cross-section B. greatest width is ¼ the B. greatest width is ¼ the

lengthlength C. the point of max width C. the point of max width

occurs about 2/5 the occurs about 2/5 the distance from the leading distance from the leading tiptip

Thrust come from a combines effort of the body and Thrust come from a combines effort of the body and fins.fins.

Muscles in slender flexible fish (eels) create S-shaped Muscles in slender flexible fish (eels) create S-shaped waves along the body. The body pushes against the waves along the body. The body pushes against the water.water.

This movement is not efficient; body length to width This movement is not efficient; body length to width ratio must be too high (this increases the surface area ratio must be too high (this increases the surface area that creates drag)that creates drag)

More efficient forms have shorter less flexible bodies More efficient forms have shorter less flexible bodies that undulate more rapidly and a hinged tail to transfer that undulate more rapidly and a hinged tail to transfer muscular energy to the water.muscular energy to the water.

How Efficient?How Efficient? In the fastest fish 60-80% of In the fastest fish 60-80% of

muscle force delivered to the muscle force delivered to the tail results in forward tail results in forward movement.movement.

Marlin & swordfish can travel Marlin & swordfish can travel 33 meters/second (75 mph)33 meters/second (75 mph)

Maintenance of LevelMaintenance of Level

The density of a fish’s tissue is greater than The density of a fish’s tissue is greater than surrounding water. surrounding water.

This difference is offset by propulsive forces and by This difference is offset by propulsive forces and by buoyant gas or fat-filled bladders (buoyant gas or fat-filled bladders (swim bladderswim bladder))

The quantity of gas is controlled by:The quantity of gas is controlled by: A. secretion and absorption of gas from the bloodA. secretion and absorption of gas from the blood B. muscular contraction of the bladder.B. muscular contraction of the bladder.

Fast predators lack a swim Fast predators lack a swim bladder. The volume would bladder. The volume would have to change too rapidly have to change too rapidly and the chance of rupture and the chance of rupture is great.is great.

OsmosisOsmosis

(Random movement of water molecules from areas of (Random movement of water molecules from areas of greater concentration to areas of lesser concentration greater concentration to areas of lesser concentration across a semi-permeable membrane)across a semi-permeable membrane)

Primitive vertebrates and marine invertebrates have an Primitive vertebrates and marine invertebrates have an internal salt content almost identical to sea water.internal salt content almost identical to sea water.

Advanced vertebrates tissue contains fluid ½ as saline Advanced vertebrates tissue contains fluid ½ as saline as sea water. They are Hypotonic to their as sea water. They are Hypotonic to their surroundings.surroundings.

The cells of marine fish contain a lower concentration The cells of marine fish contain a lower concentration of solutes (salts) than its surroundings.of solutes (salts) than its surroundings.

Because of this fact, water is lost constantly to the Because of this fact, water is lost constantly to the environment, by osmosisenvironment, by osmosis

Ton control the loss of water from the body marine fish:Ton control the loss of water from the body marine fish: A. make smaller amounts of urineA. make smaller amounts of urine B. actively drink waterB. actively drink water C. eliminate excess salts through special salt secreting C. eliminate excess salts through special salt secreting

cells in the gillscells in the gills

The process of adjusting internal salt concentration is The process of adjusting internal salt concentration is call call Osmoregulation.Osmoregulation.

Marine ReptilesMarine Reptiles

Each of the 3 main groups within the Class Reptilia have marine Each of the 3 main groups within the Class Reptilia have marine representatives:representatives:

A. turtlesA. turtles B. sea snakes B. sea snakes C. marine lizardsC. marine lizards

Each of these groups:Each of these groups: 1. are ectothermic1. are ectothermic 2. breathe air using lungs2. breathe air using lungs 3. are covered with scales and an impermeable skin3. are covered with scales and an impermeable skin 4. have salt glands that concentrate and excrete salt4. have salt glands that concentrate and excrete salt

Marine TurtlesMarine Turtles

Most successful living marine reptileMost successful living marine reptile 8 Species8 Species More streamlinedMore streamlined Shell lacks enough internal space for head and limbsShell lacks enough internal space for head and limbs Forelimbs are modified as flippersForelimbs are modified as flippers Hind limbs act as ruddersHind limbs act as rudders Most abundant and wide spread are the 2 species of Most abundant and wide spread are the 2 species of

green sea turtlesgreen sea turtles

The largest of the turtles is the Atlantic LeatherbackThe largest of the turtles is the Atlantic Leatherback Have a skin covering the shellHave a skin covering the shell Reach 2 meters in lengthReach 2 meters in length Weigh more than 6oo kilograms (1300 pounds)Weigh more than 6oo kilograms (1300 pounds)

All marine turtles are in danger of extinction:All marine turtles are in danger of extinction: 1. breeding beaches are being developed 1. breeding beaches are being developed 2. Their eggs and shells are in demand2. Their eggs and shells are in demand 3. They drown in fishing nets3. They drown in fishing nets 4. Feeding areas are polluted4. Feeding areas are polluted 5. Floating plastic bags are mistaken for food and 5. Floating plastic bags are mistaken for food and

eateneaten

Marine CrocodilesMarine Crocodiles

One living speciesOne living species Lives in mangrove swamps and isolated Lives in mangrove swamps and isolated

mainland shores in the tropical western mainland shores in the tropical western Pacific Pacific

Very aggressive and hunts in packsVery aggressive and hunts in packs 7 meters long7 meters long Weighs over 2.000 poundsWeighs over 2.000 pounds

Marine LizardsMarine Lizards

One surviving species – Galapagos Marine Iguana.One surviving species – Galapagos Marine Iguana. Live among the intertidal rocks and beaches of the Live among the intertidal rocks and beaches of the

Galapagos IslandsGalapagos Islands Grow to more than 1 meter in length Grow to more than 1 meter in length Weigh 9 kilograms (20 pounds)Weigh 9 kilograms (20 pounds) Swim by undulating body and tailSwim by undulating body and tail Live in colonies and feed on off-shore seaweeds.Live in colonies and feed on off-shore seaweeds.

Sea SnakesSea Snakes

50 species of sea snakes50 species of sea snakes

Most are native to the Indian Ocean and the western Most are native to the Indian Ocean and the western Pacific areasPacific areas

There are none in the AtlanticThere are none in the Atlantic They hunt among the coral headsThey hunt among the coral heads

Sea snakes must return to the surface to breatheSea snakes must return to the surface to breathe The young are born alive in the water The young are born alive in the water

Venom is among the most powerful animal poison Venom is among the most powerful animal poison known.known.

Prey is held in the mouth until saliva which contains the Prey is held in the mouth until saliva which contains the neurotoxin enters wounds and takes effect.neurotoxin enters wounds and takes effect.

Marine BirdsMarine Birds

Marine birds:Marine birds: A. are endotherms – they generate and regulate A. are endotherms – they generate and regulate

metabolic heatmetabolic heat B. have thin hollow bones without fatty insulationB. have thin hollow bones without fatty insulation C. have light weight beak replacing jaws and teethC. have light weight beak replacing jaws and teeth D. 4 chambered heart to circulate blood under high D. 4 chambered heart to circulate blood under high

pressurepressure E. have a respiratory system that can accept large E. have a respiratory system that can accept large

quantities of oxygenquantities of oxygen

F. all birds lay eggs on landF. all birds lay eggs on land

Only 3% of known birds are classified as sea birds.Only 3% of known birds are classified as sea birds.

Sea birds have salt secreting glands in their head like Sea birds have salt secreting glands in their head like marine reptiles.marine reptiles.

4 Groups of sea birds:4 Groups of sea birds: 1. Tubenoses1. Tubenoses 100 species – world’s most oceanic birds; examples – 100 species – world’s most oceanic birds; examples –

albatrosses, petrels and shear watersalbatrosses, petrels and shear waters

Albatross;Albatross; Wingspan of 12 feetWingspan of 12 feet Weighs 22 poundsWeighs 22 pounds Wings are aerodynamic; can soar at high speeds using Wings are aerodynamic; can soar at high speeds using

very little energyvery little energy

2. Pelicans2. Pelicans This group includes pelicans, cormorants, frigate birds, This group includes pelicans, cormorants, frigate birds,

and Boobiesand Boobies

All have throat patchesAll have throat patches All have webbed feetAll have webbed feet They do not spend much time over open oceanThey do not spend much time over open ocean The frigate can not walk or swim; its skeleton weighs The frigate can not walk or swim; its skeleton weighs

less than its feathersless than its feathers

4. Penguins4. Penguins Have lost the ability to flyHave lost the ability to fly Excellent swimmersExcellent swimmers Have fatty insulation making Have fatty insulation making

feathers greasyfeathers greasy Neutrally buoyant; can dive to Neutrally buoyant; can dive to

depths of 875 feet and stay depths of 875 feet and stay submerged for 10 minutessubmerged for 10 minutes

Marine MammalsMarine Mammals

3 Living groups3 Living groups 1. Cetacea – Porpoises, dolphins, and whales1. Cetacea – Porpoises, dolphins, and whales 2. Carnivora – seals, sea lions, walruses and sea otters2. Carnivora – seals, sea lions, walruses and sea otters 3. Sirenia – manatees and dugongs3. Sirenia – manatees and dugongs

All exhibit mammalian characteristics:All exhibit mammalian characteristics: A. endothermicA. endothermic B. breathe airB. breathe air C. give birth to living youngC. give birth to living young

D. young suckle milk produced in mammary glandsD. young suckle milk produced in mammary glands E. have hair at some time during lifeE. have hair at some time during life

All marine mammals have 4 common features:All marine mammals have 4 common features: 1. Streamlined body shape with limbs adapted for 1. Streamlined body shape with limbs adapted for

swimming (drag is reduced by a slippery skin or hair swimming (drag is reduced by a slippery skin or hair covering)covering)

2. They generate internal body heat through high 2. They generate internal body heat through high metabolic rate and conserve the heat by layers of metabolic rate and conserve the heat by layers of insulation (fat or fur)insulation (fat or fur)

3. A respiratory system modified to collect and retain 3. A respiratory system modified to collect and retain large amounts of oxygen.large amounts of oxygen.

4. Many osmotic adaptations allow marine mammals to 4. Many osmotic adaptations allow marine mammals to do away with the need for fresh water.do away with the need for fresh water.

Order Cetacea (whales)Order Cetacea (whales) 90+ species90+ species Range in size from 6 feet to 110 feetRange in size from 6 feet to 110 feet Can weigh up to 110 tonsCan weigh up to 110 tons

Suborder Odontoceti (toothed whales)Suborder Odontoceti (toothed whales) Have teeth and are active predatorsHave teeth and are active predators Have a high brain weight to body weight ratioHave a high brain weight to body weight ratio Use echolocation (biological answer to sonar) to find Use echolocation (biological answer to sonar) to find

preyprey

Suborder MysticetiSuborder Mysticeti Baleen whales – have no Baleen whales – have no

teeth; filter feedersteeth; filter feeders (blue whales, humpback, and (blue whales, humpback, and

grey whales)grey whales)

Order CarnivoraOrder Carnivora

Suborder PinnipediaSuborder Pinnipedia (seals, sea lions, and walruses)(seals, sea lions, and walruses)

True seals – smooth head, no external earsTrue seals – smooth head, no external ears

Elephant seals have diving record of 5,120 feet.Elephant seals have diving record of 5,120 feet.

Suborder FissipediaSuborder Fissipedia Sea Otter Sea Otter

Order SireniaOrder Sirenia

Bulky, small brained manatees and dugongsBulky, small brained manatees and dugongs Herbivores 15 feet; 1500 poundsHerbivores 15 feet; 1500 pounds