Chap 15 Marine Life Classification

Chap 15 Marine Life - Marine Life Marine Chapter 15 I Monera bacteria that can photosynthesize above an image of blue­green algae(cyanophytes Many

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Unformatted text preview: Marine Life Marine Chapter 15 I. Monera bacteria that can photosynthesize: above, an image of blue­green algae (cyanophytes). Many cells are strung together into filaments. Many blue­green algae phosphoresce: they glow in the dark. They're especially noticeable in some waves breaking at night. II. Protista II. Protista Phylum Protozoa: animals of the Protist kingdom. Forams,note the tiny holes all over their shells (made of calcite) through which the cell extrudes as pseudopods (false feet). change shell type rapidly through time, making them useful for determining how old sediment is. The CaCO3 of their shells comes from CO2 in the water, so studying the C and O isotopes of the shells of these organisms tells us about temperature and salinity at different depths of water from ancient sediments. Radiolarians, their shells are made of silica. Phylum Chrysophyta: golden algae: diatoms, coccolithophores. They come in many shapes. These organisms prefer colder water and higher levels of nutrients than other floating plants. skeleton of silica (SiO2) bloom in areas of upwelling: cold water, nutrients one of 3 major sources for our petroleum form a brown foam at sea, a brown 'scum' in ponds; these are indicators that the water is clean­diatoms can't stand pollution Its shell is made of calcium carbonate. These prefer warm water and fairly low levels of nutrients. Very useful for determining age of sediment, Phylum Pyrrophyta: golden brown algae: dinoflagellates, zooxanthellae skeleton is an organic compound live in open ocean as well as coastal one of 3 major sources for petroleum blooms of certain species produce red tides; they exude a neuro (nerve) toxin that can produce paralysis, blindness, an inability to breathe These algal blooms can be deadly for animals: fish die off by the thousands, and swimming humans become very ill, paralyzed, or die from anaphylactic shock. blooms of Pfiesteria piscicida are now plaguing the Chesapeake Bay, MD, giving swimmers respiratory failure and memory loss Useful for age determination and water salinity, these are one of the few floating plants that live in very shallow water near the coast, where freshwater can reduce salinity. Zooxanthellae are the dinoflagellates that live inside coral animals. They help coral animals by providing them with food, III. Metaphytae III. Metaphytae Algae: 3 phyla of algae, each named for their color: red, brown and green. Very primitive red algae live in shallow water and may have a skeleton of calcite; brown algae include kelp; green algae may have a skeleton of calcite; include Penicillus, Halimeda Two forms of the red algae Goniolithon: encrusting on the left; upright, branching on the right. These organisms are adapted to low levels of nutrients and bright light. Red algae will only grow in very shallow, clear water. Kelp is a brown algae. Halimeda, a green algae with a calcite skeleton helping it 'stand up'. Phylum Tracheophyta: vascular plants: have some vessel (tube) that transports water from one place to another in the oceans, these live along the coast and include grasses and mangroves Mangroves grow in tropical climates The knotty mangrove roots help stabilize land by trapping sediment. Roots come down from its branches to help keep the plant supplied with oxygen (plants respire, too!). One of the few tracheophytes that can take being drowned part of the time and high and dry the rest of the time. IV. Metazoa IV. Metazoa Phylum Porifera: sponges The azure vase sponge and a brown, tubular sponge. suck water into their cells, remove any nutrients, and expel them back out through the large openings. a communal cluster of cells than a real, multicellular animal, but they can pump vast quantities of water through their bodies. Some sponges are predators. They slowly grow over a coral or other fixed animal and bore their way into the body. Phylum Ctenophora: combjellies Ctenophores or combjellies (above) look like jellyfish, but are a separate phylum because they have no stinging cells Not all have tentacles, but many bioluminesce (give off light, often as colors). Their colors flash on and off, through all the colors of the rainbow. They're often featured on TV shows about ocean life because of the beautiful color show they put on. Phylum Cnidaria: stinging tentacles: coral animals, jellyfish, sea anemones species of Acropora live communally with Zooxanthellae, a type of dinoflagellate, making the reef a sort of plant/animal organism. They continually grow upward Important requirements for healthy reef growth: 1) high levels of light (this means shallow water, clear water [no suspended mud]), 2) warm waters (tropics) and 3) low levels of nutrients. Remember what dinoflagellates do when they get high levels of nutrients. Coral animals and anemones live with their tentacles up; the jellyfish lives with its tentacles dangling down. The tentacles all have stinging cells at their tips. These all secrete a nerve toxin that stuns any animal. Some may have a hard hook that acts as a sting to inject the toxin. Humans are large enough that the small amount of nerve toxin doesn't stun us (unless we're already weakened by another condition), but it hurts pretty badly and leaves a red mark or a swollen welt if you get touched by one. The jellyfish moves about by floating, the coral animals and anemones are attached to the bottom. All cnidarians have a swimming larval stage. When the new organism is first born, it doesn't look anything like these, but looks like a tiny worm swimming about. After swimming to find food and growing for a while, it metamorphoses into the type of adult that gave birth to it: a floating jellyfish or it plants itself on the seafloor and becomes a coral animal or anemone These are all fairly primitive organisms (mouth=anus) but are advanced enough to fail the screen test, meaning they have real tissues: special tissues line the stomach and secrete enzymes that digest the captured prey. Even though stuck on the bottom, these are all meat­eaters. Phylum Bryozoa: a colonial organism Not nearly as abundant now as it was in the past,. The skeleton can grow to a foot or so, depending on the species. they have a digestive tract with a separate mouth and anus. They are found in cold to warm waters. In warm water areas they are minor components of the reef. In the Paleozoic, they were the reef, but those days are over for the bryozoan! 3 phyla of worms A tube worm, Protula tubularia,, and the brown­ banded social feather duster worm, Bispira brunnea, Some worms make a case or tube of calcite in which they live. Others burrow into the mud, while still others swim about and feed on other animals. The feather duster worms wave their feathery appendages in the water to trap whatever food particles happen by. It's better for them to live in a place with some current that helps bring food near. Worms can live just about anywhere. Some of them can even stand extremely low levels of oxygen. Phylum Brachiopoda: brachiopods look like clams superficially, but are more primitive. Brachiopods have a wave in their shell: the top half bows up, the bottom half bows in. This is how we tell their shells from clams. Phylum Mollusca: Phylum Mollusca: animals with a mantle, a thick, leathery skin. Class Gastropoda: snails. Some have shells, some don't. Those with shells have a coiled shell. Those without are either pteropods or slugs (called 'nudibranchs'). These have some of the most beautiful colors of any animal in the ocean. Snails and sea slugs exude a slime over which they crawl. Pteropods swim, There are 100s of species of sea snails, from abalone to limpets to whelks. Many snails eat algae by scraping it up with a tool in their mouths called a rasp. The rasp is a sharp object. Some snails are poisonous and use their rasp to inject poison into their prey. These snails are meat­eaters and are extremely dangerous to pick up. Conus is one species that has been known to kill humans who have picked it up. It's useful for you to know what these look like so you don't pick them up, even if you think they are dead! A sea slug or nudibranch (pronounced nude' eh brank). On the left are eyestalks, with eyes at the ends. On the right are a set of gills through which the animal breathes. Many of these are poisonous to the touch, as they secrete a toxin in their slime. Class Bivalvia: clams, oysters, mussels, scallops. "Bivalve" means 'two valves', or two shells hinged together. Bivalves dig into sediment, rest atop the sediment, attach themselves permanently to rock, or, in the case of scallops, they swim a bit. They generally have a tube (siphon) through which they pump water into their bodies and extract food particles from it. A few have the ability to bore their way into rock or even other clams. These may eat algae or are predators. They use the foot to dig themselves into soft sediment. Above, part of Tridacna, the so­called 'man­eating clam'. These grow in reefs, and the coral grow around them and cement them into place. They lie in the water with their 'mouth' permanently open, and they pump water through their bodies and extract food particles from it. How's a man supposed to get killed by this? Stick your head in it and get it stuck??? Their 'lips' (actually part of the mantle) are often colonized by algae, giving them lurid colors, such as purple or red. Class Cephalopoda: octopuses, squids, nautiluses These are all predators. These are all predators. They are among the smartest animals with the sharpest eyesight in the oceans. They grab their prey with their tentacles (which have suction cups on them) and bite them with a sharp, parrot­like beak. They change color rapidly. The octopus can also change shape rapidly and slither into very tight spaces. Some secrete nerve toxins!! Many of these are bioluminescent and live in deep, dark waters. Rumors have it these grow to enormous sizes, thanks in part to Jules Verne's 20,000 Leagues Under the Sea, in which a giant squid grabs the submarine. Fact or Fiction? Both octopi and squids can change color rapidly to disappear into their surroundings­ masters of camouflage! Phylum Arthropoda: 'jointed legs', hard outer skeleton (land forms include spiders and insects). horseshoe crabs Horseshoe crabs are not Horseshoe crabs are not really crabs They are meat­eaters, feeding mainly on clams, and can go for a year without eating. crustaceans: most abundant: copepods ('fecal express'), barnacles, krill, shrimp, lobster, crabs copepods copepods Copepods are tiny creatures­a mm or two in length and voracious eaters of forams, and all the one­ celled algae. They also eat small particles of sediment. Their fecal pellets are larger than the particles they eat, so they settle to the seafloor faster than the particles would if they were not packed into fecal pellets. Great thicknesses of copepod fecal pellets occur in the rock record. We call this method of getting tiny particles of sediment to the seafloor the 'fecal express'. barnacles­ These are strange little organisms that attach their heads to an object, such as a rock, a ship, or a whale, grow a little house of calcite and stick their feet out the door. Their feet have feathery appendages on them which trap food particles from seawater. shrimp and krill­ These all have an elongate tail that contains a powerful muscle. The animal kicks the muscle to swim. Humans catch shrimp to eat the muscle. Shrimp feed on detritus (dead things). A few are predators. Krill are a kind of small shrimp eaten by the millions by certain kinds of whales (baleen whales). They live all over the world but tend to concentrate in colder, polar waters. lobsters, crayfish, crawdads: Lobsters and their cousins, the crayfish, are detritus feeders. Those living in cold water have large claws for protection. Floridian lobsters do not have claws. Lobsters and crayfish live in marine to brackish water, depending on the species. If you've never eaten lobster before, eat only a little bit the first time. Lots of people are allergic to them and break out in hives when they eat them. crab crab There are 100s of species of crabs. They are detritus feeders and sometimes eat living things: small crabs, clams, seaweed. Each island in the ocean has its own unique set of crabs. They are an important component of the clean­up brigade. With care, you can learn to pick up live crabs from the back without getting pinched. The Blue Crab of the east coast is popular food. Like all arthropods, crabs molt. This means they shed their old shell and hang around as soft­bodies animals for a few hours until the new shell hardens. This is how they can grow larger. During the few hours­days that they are soft­ shelled, they are particularly vulnerable to being eaten. Soft­shelled crab is a delicacy: the whole thing is fried and eaten. Male crabs are 'jimmys'; immature females are 'sooks'. hermit crab, these guys use the shells of dead gastropods (snails) as added protection from predators. They haul their little homes about wherever they go. If you pick up a seashell, be carefull one of these isn't in it. They pinch, or, if unnoticed for a few days, sitting someplace in your house, they can start to smell pretty strongly. Phylum Echinodermata: water vascular system­totally bizarre. The echinoderms have a system of vessels in the same way that we have vessels to move blood around. But the echinoderms' vessels are filled with seawater. They have an efficient system of applying pressure and releasing it that makes the vessels allow the animal to move and feed. These are called 'tube feet'. The first time you pick up a living echinoderm, it will feel pretty strange as all those wriggling tube feet move like mad to escape you. The vascular system is often supported by a skeleton of calcite. starfish: Starfish can move amazingly fast. They grab clams or other echinoderms and crush them with their strong arms. This fellow apparently lost a leg or two in some disagreement with intended prey. The legs are growing back. sea urchins (spines!!), sand dollars, echinoids Sea urchins are covered in spines, many of which Sea urchins have poison in the tips. If there's no poison, getting the spine caught in your flesh will doubtless lead to infection. Best not to touch them. They gouge their way into living coral and feed off them. The star­shaped groove on the top emits a series of tube feet that guide food to the mouth, located on the underside. Echinoids feed from particles floating in the water, or they live in burrows which they form by eating. They eat the sediment, digest what's available, and excrete the rest. sea cucumbers A really delightful organism, it is largely a sack that pumps water through it to remove floating food particles, or it eats sediment When startled, it turns inside­out. Most animals run away from such a sight. These are a delicacy in some parts of the world, including right here in the U.S. brittle stars Brittle stars are smaller and Brittle stars are smaller and more delicate­appearing than starfish. Many use feathery extensions of their legs to trap particles of food from the water. crinoids: sea lilies a few dozen species, most of them discovered fairly recently. crinoids has the same legs as the starfish, but they extend upward into the water and have feathery tube feet that trap particles of food from the water. Most crinoids are anchored to the sea floor by a body part called the 'holdfast'. Phylum Protochordata: tunicates Most tunicates are small (a few inches at most) and swim or float. They filter food from the water. They have a notochord, a bundle of nerves that extends the whole length of the body. We also have a notochord that is protected by a hard part our bodies extrude: bone (the back bone). The back bone is made of separate units called vertebra. Tunicates probably gave rise to vertebrates. Phylum Chordata: animals with a notochord­ a long bundle of nerves. Most textbooks would split this group into two subphyla: those chordates without bone and those with bone. Those without bone include the lampreys and sharks. Fish: have gills Jawless fish: most primitive; Jawless fish: most primitive; lampreys This lamprey has no jaw, but he has a mouth. The mouth is a sucker and this fish attaches itself to other fish and sucks the life force from them. They were introduced into the Great Lakes by accident and have greatly reduced the numbers of native fish. Notice the row of holes along the side are the gills, through which this animal breathes. cartilaginous fish: sharks, skates and rays: these fish still have no backbone. There notochord is protected by a stiff substance called cartilage, the same stuff that makes up your ears and the soft part of your nose. This species can reach 4 m in length (that's 13 feet to you!). Shark must swim or they can't breathe. Their gills are fairly primitive, and only swimming pushes the water over them. Sharks depend on their teeth for survival, so it is important that the teeth stay sharp. Sharks have several rows of teeth, and are always growing new ones on the inside of the mouth, while teeth on the row on the outside are shed from time to time. Fossil shark teeth are fairly common in marine rocks. Sharks have a small bundle of nerves in their heads which passes for a brain. Sharks range in size from fairly small to the Great White, the biggest of which was 23 feet in length. Sharks really don't attack people, unless something strange has happened. Fear and overfishing have greatly reduced their numbers. Believe it or not, not all sharks are meat­eaters. Above is a nurse shark, which swims with its mouth wide open, filtering particles of food from the water, very much like crinoids, brachiopods, some clams, barnacles, and many other marine animals. It has no teeth. a relative of the sharks, a sting ray. These are predators. This particular one is electric, and stuns its prey with a touch of its barbed tail. Most rays (sometimes called 'skates') leave humans alone, except the ones humans feed regularly in the Bahamas. They are a nuisance there, always begging for handouts. This type of ray, the manta ray, is similar to the nurse shark. It swims with its mouth open and filters particles of food from the water. bony fish: 1000s salmon, tuna, seahorse, solefish, marlin, swordfish, etc etc etc a few important adaptations shared by all fish that have allowed them to become so successful in oceans (and freshwater) today: Fish have gills. Fish have Gills are organs used to extract oxygen from the water so the fish can respire underwater. What organ do we use to get oxygen? Fish actively suck water over the gills by opening their mouths, then when the water passes over the gill, it exits through gill slits. This is why fish swim with their mouths open. Jaws probably evolved from gills. In utero, humans pass through a development stage where we have gills on our necks. Fish have a lateral line system that helps them detect small changes in pressure. This is the way fish 'hear'. If you ever pick up a living fish, don't squeeze its lateral line, as you can damage this sensitive organ. The color of a fish above the lateral line helps the fish blend into its surroundings, so predators looking down on them can't see them as well. They don't bother to color their bellies, hence the term, 'fishbelly white'. Fish have a swim bladder. This is an internal organ that helps them keep the right position in the water (ie., the right water depth). Just as our heart beat speeds up or slows down when we need it to, without us thinking about it, the swim bladder responds to changes in pressure and helps the fish know where it is. The swim bladder is almost certainly the organ that evolved into lungs for higher organisms. Fish have body shapes that allow them to swim efficiently in water. Try running an eight­minute mile underwater and you will see that swimming is more efficient, and have a body shape like a fish is a major advantage. Fish move by flexing and releasing the major muscles that run the length of either side of the body. The more primitive fish, such as eels, move their entire body back and forth, pushing against the water. More advanced fish minimize the movement and just 'kick' the rear part of their bodies. A few key groups of the myriad fish in the world, that are better known because they are a source of food or have an unusual body shape include: sole fish (flounder, sole, turbot) metamorphose as adults to become bottom dwellers that can still swim Top side of a flounder. It lies on one side all the time, so both one eye has migrated to the other side of its head. Fins and gills have also migrated. the top side is colored so the fish is well­ camouflaged. It is a predator, waiting for prey to wander by. The bottom side of a flounder. Notice the hole where the eye used to be. Notice also there's no need to color the bottom side for camouflage. Barracuda have very sharp teeth and are attracted to shiny objects; common in the Caribbean and Gulf of Mexico. Barracuda are very fast swimmers and efficient predators of other fish American eel lives its adult life in rivers of the North Atlantic, then goes to sea to reproduce, which is the opposite behavior of the next group (salmon). Normally these live in brackish to fresh waters, and grow up to 1.5 m (about 5 feet). salmon, which live their adult lives at sea, then swim up freshwater streams around the Atlantic and Pacific to reproduce. tuna are the fastest swimmers in the ocean, often swimming in schools, and voracious predators They can grow up to 5 m (16 ft!) in length. They are extremely popular around the world as food. Huge nets set adrift to catch massive quantities of tuna also catch porpoises, sea birds, turtles, anything that happens by. How many tuna are there in the world? How do you count the fastest fish alive? Although we still don't know much about their numbers, reduced catch in the Pacific suggests they are being overfished. cod, mackerel, herring, anchovies, swim in schools, which helps protect them, partly by confusing predators, but also, 'there's safety in numbers'. They are omnivorous but prefer small fish, even of their own species. The white meat is particularly appealing to fish fans. Cod were available in great numbers around Scandinavia, and across the known North Atlantic, all the way to Greenland. They are easily dried and so keep for weeks. 3 feet was an average length, 10 pounds an average weight. It's suspected that Basque fishermen regularly visited the Grand Banks (the gravelly [thanks to glaciers] continental shelf off the coast of Newfoundland, Nova Scotia, and New England) centuries before Columbus, having followed the cod there. Leewenhoek, the inventor of the microscope, counted over 9 million eggs in one female. Cod were so numerous, it was believed they would multiply to the point that they would form a bridge across the North Atlantic upon which humans could walk. Today there is a ban on cod fishing because their numbers are enormously reduced. Former fishermen now collect cod for information on their comeback, and it doesn't look good. Average size is now around 20 inches, 4 lbs in weight. This is a direct result of massive overfishing with new methods that take in cod by the tens of thousands. Fish of the reefs: an enormous variety, many with beautiful colors. the scorpion fish. The spines contain a poison, so don't touch! a parrot fish, named for the fact that it's mouth looks and works like a parrot's beak. It crushes clams and eats the innards. a seahorse. Yes, these are fish, and yes, the male carry the young in a pouch until they're ready to leave home. a moray eel. Not poisonous or electric, but it's been know to bite and not let go of the hands and arms of people who go poking around into holes of the reef. a puffer fish puffed itself up with water to make it look less appealing as a meal. Not poisonous, but not fun to get stabbed by one of these. deep­sea fish live in the black 'deeps'. It's dark down there! No light means no plants. All of these fish, then, must eat either each other (carnivores) or dead things (detritus feeders). The lack of light means many of these fish are bioluminescent, many are blind, and all have bizarre adaptations in order to make a living down there: Above, a deep­sea gulper: all mouth and no body! By minimizing body volume, you need to eat less to stay alive. the deep­sea angler. has modified her nose into a protuberance that acts as a fishing lure that is bioluminescent. An unsuspecting fish goes to eat the thing dangling from her nose, and is instead, eaten. And if you think it's hard to find a mate, consider wandering the dark deeps of the world ocean when there are not many of you to begin with. The angler solves this problem by having a male greatly reduced in size and living as a parasite on her own body. He attaches himself to her, as shown, and they never have to worry about lonely nights again. the blind tripod fish. Although blind, this fish is a predator It's believed it can sense prey with its highly modified, antenna­like fins. Reptiles Reptiles lay eggs and have a leathery skin: turtles, snakes, lizards, marine crocodiles (extinct: plesiosaurs, mosasaurs, ichthyosaurs). Like all the animals discussed to this point, reptiles cannot regulate their internal body temperature. They are the temperature of the water they live in (or the rock they sun themselves upon). most reptiles live in tropical or warm temperate areas. Reptiles have lungs and breathe air. sea turtles must come to the surface for air. This clearly limits the depth at which they might live. A green sea turtle eat mostly vegetables (algae and sea grasses). They've streamlined their shells to the point that there is no room to retract their head or limbs into the shell as land turtles do. However, their only predator is the human. Sea turtles must come ashore to lay their eggs. They usually return to the place they were born to lay their eggs and bury them in the sand. The warmer the temperature of the eggs, the more males are produced. they are endangered now because of housing and other development at the beaches where they must breed, and they become trapped in fishing nets. Another threat to them is plastic bags at sea. These look like the jellyfish they like to eat, and when they ingest them, the bag clogs their digestive tract and they slowly starve to death. The only truly marine crocodile lives in the western Pacific, on islands and in northern Australia. They can grow up to 23 feet, weigh over a ton, and hunt in packs. They are very fast and usually take down a human or two each year. The crocodiles and aligators of Florida and Louisiana are smaller and live in fresh to brackish water. They were nearly driven to extinction to make purses and shoes and belts, but having been protected for the last 20 years, they have made a smashing comeback, and there is now a legal hunting season for them. Their thrashing about in the swamps keeps pools of water open during drought, so other animals in their communities benefit by their presence. Crocs differ from 'gators by the following: crocodiles lower teeth stick out when the mouth is closed; their snouts are long and narrow (the 'gators is stouter and no teeth stick out) Sea snakes and lizards are closely related: The one marine lizard we know of is the marine iguana of the Galapagos Islands. They eat algae. Sea snakes are most abundant in the warm tropical waters of the western Pacific and Indian Oceans. Several dozen species are known. these are meat eaters. The Australian Brown Snake (Pseudonaja textilis) has such powerful venom that it can kill a human in a few minutes after the bite. There are antivenom injections available now, but you have to get to a hospital that has it within 30 minutes. This sea snake of Australia is only a few inches long, but its bite kills. Rumors that its mouth is too small to bite effectively are wrong. Another good reason not to stick your hand into cracks and crevices of the reef! Birds Birds feathers, lay eggs: pelicans, albatross, penguins, puffins, etc etc. Sea birds may live essentially on land and feed at sea (sea gulls, pelicans, puffins, penguins, terns, etc.), or they may live most of their lives at sea and only rarely return to land (albatross). All birds can regulate their body temperature (i.e., they are 'warm­blooded'). The feathers are excellent insulators, so birds can be found from the tropics (frigate birds, for example) to the poles (penguins in the southern hemisphere; puffins in the northern). Of all the birds on the planet, only a few percent are seabirds. They are all predators (carnivores). the albatross, the most marine­type bird of all. It only goes on land to breed, and then, only in isolated area. The wingspan can reach 12 feet, they can fly 50 mph, and can travel 100s of miles without resting. They can smell fish from 10s of kms and dive for fish as well as squid, catching their prey in flight. "A marvelous bird is the pelican, his beak can hold more than his bellycan" wrote Ogden Nash. Relatives of the pelican include cormorants and frigate birds: all have a pouch at the throat that holds the fish they intend to swallow whole. Penguins live only in the southern hemisphere. They cannot fly, but are excellent swimmers. They can dive to almost 1000 feet and stay underwater up to 10 minutes. They have a more varied diet in that they eat clams, crustaceans, and larger zooplankton as well as fish. Puffins live in the northern hemisphere and are relatives of seagulls and terns. Most birds in this group have long legs and can run as well as fly and swim. The puffin neither runs nor flies very well. Most of these birds feed on fish. Mammals Mammals only a few of us warm­blooded hairies have made it back to the sea. The word "mammal" comes from the mammary glands which these (us) organisms evolved to feed milk to young born live and/or helpless (one group of animals still lays eggs: Australia's platypus and echidna). Whales and porpoises are closely related to each other. They appear to have evolved from a hooved ancestor that also gave raise to the horse. Seals, otters and walruses appear to have evolved from dogs. Both of these groups are carnivores. The manatees or dugongs (sea cows) are herbivores and probably evolved from a hooved ancestor. Mammals are warm­blooded: they can regulate their body temperature. a thick layer of fat beneath the skin that serves as a great insulator. In whales, this layer is called 'blubber' and is the reason they were hunted to near­extinction before humans figured out how to use fossil fuels instead of melted whale blubber to keep the lights burning. All the mammals have lungs and must reach the surface of the ocean to breathe. whales and porpoises There are two groups of whales: 1. the baleen whales are filter feeders, just like brachiopods, crinoids, and many clams! They have a jaw with a huge fringe of baleen, hairy material that traps krill and other small plankton. They cruise through the water with their mouths open and the baleen hanging in front of the mouth, then like their lips and get all the trapped krill off the baleen. 2. the toothed whales includes porpoises and dolphins. These are carnivores, with big teeth to grab fish, squid, and the occasional human. Whales have a highly modified nose that has migrated to the top of their heads where we see it as a blowhole. They must come to the surface to the breath, and having your nose on the top of your head minimizes how much of you gets exposed when you breathe. The Baleen Whales The Baleen Whales The Blue Whale is the largest mammal on Earth. It can reach up 110 tons in weight and 110 feet in length. They live for about 30 years. They need about 1 million calories a day, about 3 tons of krill per day. Baleen whales like to swim in schools. Because krill are most abundant in cool polar waters, they migrate to the Southern Ocean in the southern winter (our summer) and back to the cool North Pacific waters in the northern hemisphere summer. The humpback whales are the singers When a whale reaches the surface and throws his body into the air, its called breaching. Humpbacks are the most spectacular breachers­ all the great photos you see of whale tails (the fins on the tail are called 'flukes') are most likely Humpbacks. The Toothed Whales The Toothed Whales This is the 'Moby Dick' whale, as sperm whales are the largest of the toothed whales All the toothed whales can swim very fast and capture fish, squid, seals, and killer whales When we go whale­watching at sea, it's safest to watch baleens! Porpoises and Dolphins: what's the differnce? Above, a harbor porpoise: note Above, a harbor porpoise: note the blunt nose and flat teeth. Above, a spotted dolphin: pointed nose, sharp teeth. Above, happy dolphins playing in the wake of a ship. In the States, we don't really worry about the difference between porpoises and dolphins. It can get confusing because there are a few blunt­ nosed dolphins! Hard to make these guys hang while you check out their teeth to make sure. Killer whales and pilot whales are also members of the Dolphin family. "Whale" is informally a size term. manatees, dugongs, or sea cows As the As the name implies, these are the herbivores of marine mammals. Rumor has it that these are the singing sirens of Greek mythology. The guys who mistook these beasts for beautiful women were obviously at sea way too long! Manatees are gentle animals that feed on algae and marsh vegetation. They live in estuaries, lagoons, marshes, and the like. Individuals may live as long as 60 years, but much more study is needed on these creatures. Some species have been driven to extinction already by humans; the manatee of Florida (the West Indian Manatee) is endangered, with only about 1000 individuals left. At least 25% of all manatee deaths each year are caused by recreational boats colliding with them, crushing their heads or cutting them mortally with inboard or outboard boat propellers. Sleeping with her nostrils above Sleeping with her nostrils above the waterline... seals, sea lions, otters, walruses ­ these are all members of the Carnivore order of mammals, just as dogs, cats, weasels and bears are. This is why seals sound like dogs, and why many members of these families have elongate snouts with whiskers. Clearly seals, otters, and walruses are highly modified pups. Their forelegs have evolved into flippers, and their rear legs have fused to become flippers, and in many cases, vastly reduced in size. Like their doggy and catly cousins, they are meat eaters, preferring fish. Otters like clams and snails. Sea lions are different from seals in that they have an external ear. seal have no external ear. Nothing personal...seals and sea lions are favored prey of larger sharks and killer whales. Seen from below, couldn't one of these be a human? How would the poor shark or killer whale know the difference? Sea otters are most closely related to weasels, ferrets and badgers (Mustelid family). They are the smallest of marine mammals and were hunted to near­extinction for their wonderful fur pelts. One small group of 32 remained in California, and under heavy protection has expanded to over 2,000 individuals. ...
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This note was uploaded on 09/24/2011 for the course OCE 1001 taught by Professor Staff during the Spring '11 term at Broward College.

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