Shark! Marine Biology - Conrad. Superclass Agnatha The first chordates with a notochord. This lovely...
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Transcript of Shark! Marine Biology - Conrad. Superclass Agnatha The first chordates with a notochord. This lovely...
Shark!
Marine Biology - Conrad
Superclass Agnatha• The first chordates with a
notochord.• This lovely looking, fish-
like organism is jawless and lack most fins.
• They are parasites on fish.• They are called hagfish or
lamprays belonging to class agnatha.
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Class Chondrichthyes: Sharks and Rays• Skeletons composed of cartilage. • Sharks have jaws of replaceable
rows of teeth to injure prey.• Gill slits lack operculum
(covering).• Sharks have tiny scales, electric
sensors, and internal fertilization.• The tail/fin design and large, oily
liver provides buoyancy.• Osmosis is controlled through the
urea concentration in the blood.• The spiral intestine increases SA.
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Class Chondrichthyes: sharks, rays, skates, and ratfish
• Rays have flat teeth and are bottom eaters.
• Hide in sand. • Barb on tail for defense.• Since their mouth is ventral they
need to take in water from spiracles (gill openings) that are located on their dorsal surface to avoid breathing mud.
• Was is released through gill slits near the mouth.
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Shark attack• Only 12 of the 375 species of sharks have ever attacked humans.
50 attacks world wide per year. • Watch out for the tiger, bull, and great whites.
– Stay in groups– Stay close to shore, but away from drop offs (they hide there)– Stay out of cloudy water or night (they are nocturnal).– Avoid swimming when bleeding (distinct smell (olfactory)– Avoid shiny jewelry (resembles fish scale shine).– Avoid “fishy” areas used for fishing or diving birds.– Avoid bright clothing because they are keen to contrast.– Avoid splashing and pet movements. Stay calm when shark
arises. Move away from it and towards shore.
Sharks attack each other too!• Here is the cookie-cutter shark. Its round
jaws attach with great suction, twist, and pull out a chunk of flesh.
Sensory Structures• Sharks are far sighted, but otherwise see like us (color and
focus). They also have a tapetum lucidum to reflect additional light.
• A nictitating membrane is a clear eyelid to protect their eye.• A cartilaginous tongue, called a basihyal, is used to tear food.• Taste buds are on the papillae of the mouth.• Sharks have ears and lateral lines that detect vibrations in the
water • The ampullae of Lorenzini on their chin sense electrical
impulses from the muscles of prey and for navigation.• Sharks have excellent smell (olfactory senses) in their nostrils. • Eels are fish that use electric sensors to communicate to each
other, locate prey, and to navigate. Eels also generate electricity to communicate, zap their prey, and for defense.
Shark Swimming• Sharks lack a swim bladder so they need a lighter skeleton,
oils, and tail/pectoral fin design to prevent sinking. • The dorsal, anal, and pelvic fins maintain balance.• The caudal fin (tail) creates lift and pushes fin through the
water.
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Shark Reproduction• Male sharks have claspers for internal fertilization• Sharks may be oviparous (lay eggs) or Viviperous
gestate eggs either maternally or using a yolk sack inside the mother giving live birth.
• The hard (horny material?) egg case of sharks, rays, or skates is called a mermaid’s purse, which contains the developing embryo enough yolk to sustain the nutritional needs of the embryo until it hatches.
• The corner tendrils wrap around rocks or kelp for anchor.
• If 2 sharks share the same yolk, one will eat the other (adelphophagy
Image courtesy of encarta-msn (2007 and the Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Shark Facts quoted from http://www.kidzone.ws/sharks/facts4.htm
• Existing for 400 million years, sharks came before dinosaurs!
• These good survivors have not evolved in the last 150 million years.
• Sharks have the most powerful jaws on the planet. Unlike most animals' jaws, both the upper and lower jaws move.
• Each type of shark has a different shaped tooth depending on their diet (sharp, pointy teeth for carnivores!). They go through over 20,000 teeth in a lifetime!
• Even their skin is made of small, teeth (denticles) instead of ordinary fish scales. They are hydrodynamic, and feel like sand paper. They protect the shark from injury.
• Great whites can detect one drop of blood in 25 gallons (100 liters) of water and can sense even tiny amounts of blood in the water up to 3 miles (5 kilometers) away. They have 3,000 serrated teeth!
Nice Sharks• Harmless sharks tend to be the largest! • The 1. basking shark, 2. whale shark, and 3.
megamouth sharks eat plankton by swimming forward with their mouths wide open.
• "Gill rakers" at the back of their throat strain the food from water.
Quoted from http://www.kidzone.ws/sharks/facts4.htm
1.
2.
3.
Swim or Die. Swim or Die.• Sharks have to force water over their gills in order
to breathe. Gas exchange is better the faster the faster the shark moves "ramjet principle” forces more gas into the water.
• Some sharks have to keep moving to breathe. If they stop they die from suffocation (this accounts for the majority of the big predators caught in beach-defense nets being brought up dead).
• Some bottom dwelling species (dogfish, carpet, and nurse sharks), can stay docile (lazy), because they pump water by rhythmically contracting the muscles that control the inlet and outlet valves of the gill system.
• The Tiger shark and the Grey Nurse Shark are able to make use of both pumping and ramjet, achieving a real saving in energy. Nurse sharks use this pump to create a strong suction for feeding on conch.
Nurse Shark
Shark Blood• To ensure a good transfer of oxygen from the gills to
the muscles and other organs, a maximum percentage of red corpuscles in the blood (haematocrit) is needed.
• A final parameter for good oxygen transfer is the cardiac pump. Larger sharks have larger hearts.
• Sharks have only 2 chambers in their heart.• The image of the aortas leaving the shark’s heart.
Mean Sharks• The most dangerous sharks are the 1. Great White
shark, 2. Tiger shark, 3. Hammerhead shark, 4. Mako shark, and 5. Bull shark.
• There are only about 100 shark attacks each year and only 10 of those result in a human death. However, people kill thousands of sharks a year for sport and
food.
1.
3.
5.
2.
4.
To a shark, a surfer paddling on a surfboard can look a lot like its typical prey.
Dangerous Sharks• Great White: cool, coastal waters. They are
endangered due to over-fishing (no food), net by-catch, and hunting. They are 20ft. Long.
• Tiger shark: identified by dark, vertical stripes found on juveniles. They do not have a picky palate, so the are not likely to swim away after biting a human, as great whites do. They have excellent senses of sight and smell. Strong jaws can crack turtle shells. Stomach contents may include license plates and old tires. They are heavily harvested for their fins, skin, and flesh, and their livers contain high levels of vitamin A. Their repopulation rates is very low.
• Bull Shark: can go into fresh water and beaches.• Nurse Sharks: are nocturnal. Docile during the
day, but will attack when bothered. Bulldog jaw.
The Maugean Skate
Ventral cut to remove the lobed liver, vertebrae, and egg cases in this female.http://www.marinebiodiversity.ca/skatesandrays/internal%20anatomy.htm
http://www.playpark.net/lifestyle/view/what_do_stingrays_eat/
http://aquaticpredators.com/forums/index.php?showtopic=35745
http://jeb.biologists.org/cgi/reprint/202/24/3523.pdf
Sting rayhttp://www.mesa.edu.au/comets/resguide01.asp
http://www.youtube.com/watch?v=Jdsof8ip7H4&feature=fvw
Lamprey http://www.cumberland.k12.il.us/schools/chs/Starwalt%20Projects/Lamprey%20Dissection/lamprey_dissection.htm
http://hs.riverdale.k12.or.us/~simonew07/Lamprey%20Dissection.pdf
Fish - Class Osteichthyes• Bony endoskeleton• Excellent sense of smell but not eyesight• Swim bladder• Operculum• Scales• Pyloric cecum• Paired ray fins*• Lateral line• 2 chambered heart• Cold blooded
* one living specie has lobed fins
Image courtesy of National Geographic (2006).
Fins and Swimming• The air filled swim bladder prevents sinking. • Fins are lobed or spiny.• Rigid, streamlined body shape to be pushed through the water
using myomer muscle contractions and fins (caudal fin).• Caudal fin: Tail fin. Forked tail for speed; flat tail for speed
quick bursts of speed; and round tails are slow swimmers.• Pectoral fins turn and stop and other fins are for balance.
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
External Anatomy of Bony Fish
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Fish Skin• Fish scales provide protection and
calcium storage. Growth rings.• scales: ganoid, cycloid, placoid & ctenoid• Fish are covered in large scales that
are covered by mucus/slime.• The slime coat prevents infection and
skin can be used for excretion, breathing, and regulating osmoregulation.
• Melanophores add dark color, chromatophores add light color, and iridophores add iridescence by having tiny crystals inside the cell.
Image courtesy of M
ills (2000).
I’m Hot!
• Parrotfish make their own sleeping bag out of mucous.
Image courtesy of L
auterman (2005).
Coloration1. Camoflague with colored pigment cells.
2. Disruptive patterns break up and disguise their outline (cryptic coloring).
3. Counter shading is dark on top and light on bottom. When looking up the water appears light like their underside, but looking down they blend into the dark.
4. Bright colors to warn “I’m poisonous” or “Ladies come and get me”.
A.
B.
C.
D.
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Other Tricks• Cryptic coloring with light
breaks up silhouette in deep sea fish using bioluminescent bacteria or photophore cells.
• Deep Sea anglers use the light to lure prey or mates.
• Stingrays, catfish, and others may have stinging spikes with venom (but don’t kill humans).
• Barbles are used to feel and sort food.
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Image courtesy of Florida Museum of Natural History. Retrieved on 1/8/07 from www.flmnh.ufl.edu/fish/Education/education.htm
Feeding
Phillips (2006) jeb.biologists.org/cgi/content/full/209/14/iii
• Fish do not chew, but pharyngeal teeth and tongue can grind.
• They have taste buds.
• Teeth are used to hold onto food
• Food is sucked into the mouth when the operculum (gill covering) is closed.
Mouth Morphology Determined by Diet
Image courtesy of Castro and Huber (2000).
Surface Feeder (insects)
Downward mouth: benthic feeding scavengers
Break off pieces of coral. Their poop makes the coral sand.
Terminal: feed at all levels and variety foods.
carnivorous fish have strong suction and closes using teeth to hold prey.
Fish Digestive System• Fish eat a variety of foods because they can not produce
their own amino acids. • The stomach stores large infrequent meals, grinds, and
chemically digests food with enzymes.• The pancreas and small int. make enzymes too. Bile
from the liver digests oils (other human functions).• The small intestine has pyloric ceca pouches to increase
surface area for absorption.• The large intestine reabsorbs water
and vitamins• Some fish lack a stomach (parasites).• Undigested food exits the anus.
Images courtesy of High Country Sailing (2006).
Gas Exchange in Fish• The 2 chambered heart pumps blood to the gills. • Blood flows through the gills in the opposite direction of
the water (countercurrent) to maximize gas exchange.• The gills pick up oxygen and emit CO2 by way of
diffusion.• Water has less dissolved oxygen than air especially
warmer water.• Oxygen binds to the hemoglobin in blood and is carried
to the cells. • The closed circulatory system (blood) transports and
exchanges waste, food, and gases throughout the body .
Dery (2006). www.infovisual.info/02/img_en/033%20Internal%20anatomy%20of%20a%20bony%20fish.jpg
Gill Mechanisms
• The gills are contained within a common chamber that is covered with an operculum.
• Water is sucked in when the mouth opens and operculum closes. When the mouth closes the water is forced over the gills and through the operculum. This can also be used to swim faster.
• Gill arches of cartilage support the gill fillaments. There are many rows of feathery filaments with blood containing lamellae to increase SA.
• Gill rakers rake debris from the gills and can filter feed.• Gills are cleaned with cilia and mucous located on their
surface
Chordate Species
Images courtesy of Miller and Harley (1996).
Fish Excretion• Marine fish are osmoregulators that
excrete salty urine.• They drink a lot of water and their kidneys pull
out the salts and save the water. • Chloride cells in the gills help remove salt and
waste. • Kidneys are also used to make blood cells and
hormones.
Fish Nervous System and Senses• They have a brain and can sense pain.• They can remember/make mental images.• Eyes focus differently and they lack lids.• Fish can “hear” vibrations with their lateral line
and create sounds with their swim bladder.
Reproduction• Fertilization can be internal or external.• Some can store sperm for months.• Some males will turn into females if absent.• Some males are small parasites on females.• Some females produce males or sometimes eat them.• If a male with a harem dies, the largest female undergoes
“gender reassignment”. • Some fish are born males and mature into females.• Some lay eggs randomly or in layers on rocks. Some
form bubble nests of saliva or hold onto them in brood pouches. Some nests are guarded.
Ladies! There’s no need to fight!
Image courtesy of Murch (2006).
References• Castro, P. and Huber, M. (2000). Marine Biology, Third Edition. Dubuque: Iowa. McGraw Hill Companies • Dery. (2006). Internal Anatomy of Bony Fish. [On-line]. Available http://www.infovisuals.com• Friedl, C. (2000).The Answer. [On-line]. Available http://hoopermuseum.earthsci.carleton.ca/aquatic/ans.htm• Gillis, R. (2002) Zoo Lab: A Website for Animal Bioloy. [On-line]. Available
http://bioweb.uwlax.edu/zoolab/Table_of_Contents/Lab-9b/Perch_Mount_1/perch_mount_1.htm• Heatherwick, P. (2006). Reefpix. [On-line]. Available http://www.reefpix.com.au/welcome.html• High Country Sailing. (2006). Sailing, St. John. [On-line]. Available http://www.highcountry-sailing.com/• Image Quest Marine 3D. (2005). Image Quest Marine. [On-line]. Available
http://www.imagequest3d.com/pictures/krill/• Lauterman, W. (2005). Gallery. [On-line]. Available http://www.creativeparagons.com/wyant_gallery_01.html• Lee. (2006).Divebums. [On-line]. Available http://photos.divebums.com/slideshow.php?set_albumName• Miller, S. and Harley, J. (1996). Zoology. Dubuque: Iowa. Wm. C. Brown Publishers.• Mills, R. (2000). Rendezvous Discos. [On-line]. Available http://www.disco.co.nz/djrichard.htm• Ministry of Fisheries (2006). Fish Characteristics. [On-line]. Available
http://www.starfish.govt.nz/science/facts/fact-fish-chars.htm• Murch, A. (2006). BC Marinelife. [On-line]. Available.
http://www.elasmodiver.com/BCMarinelife/BCML%20Chordata.htm• National Geographic. (2006). Angelfish. [On-line]. Available http://www.nationalgeographic.com• NOAA. (2006). NOAA Magazine. [On-line]. Available http://www.magazine.noaa.gov/stories/mag141.htm• Rattner, R. (2000). The West Indian Manatee. [On-line]. Available http://www.thewildones.org/Animals/manatee.html.• U.S. Navy's Marine Mammal Program. (1998). Marine Mammal Training. [On-line]. Available
http://www.spawar.navy.mil/sandiego/technology/mammals/Images_animals/4053p.jpg• Wilson. (2005).Divebums. [On-line]. Available http://photos.divebums.com/slideshow.php?set_albumName