Fishes Moser and Hanson
Where exactly are they? Fish live in either fresh or salt water (some in anemones), depending on their specific group. Depending on their family, they eat anything from small underwater mollusks to other fish. http://www.nmfs.noaa.gov/habitat/habitatprotection/efh/
What is their importance? • Fish do not only pay an important food source for humans and other animals, fish also control the development of new and old underwater life forms.
How are they unique? • Their body structure, including being a vertebrate or not, is specified for their lifestyle. • i.e. small, flat fish typically dwell on the ocean floors, and longer fish swim faster because of their compressed body form.
Passage of Oxygen • Fish use osmosis; oxygen diffuses from water to blood and carbon dioxide diffuses from blood to water. • Almost all fish breathe with gills.
The Use of Gills • They exchange gases with water. • First, the gill slits close, the mouth opens, cheeks are pulled sideways, and volume of the mouth and the pharynx increases. • That entire process was just water being sucked into the fish. • The gills slits open, the mouth closes, and the volume decreases. • That process is water being pushed out of the slits.
Skeletal Structure • Fish are chordates and they have a • - notochord (long flexible rod typically developed in embryonic stage; becomes a backbone). • - hollow dorsal nerve chord (next to notochord, main nerve pass way from body to brain) • - Pharyngeal slits (slits in the pharynx and become featherlike structure for breathing; gills) • skeleton voice thread
Fish are Vertebrates • Organisms that posses a notochord in early development • Replaced by stronger support structure, backbone or vertebral column
Fish and Reproduction • There are two different ways to reproduce as a fish. These two include; • - external reproduction • - used by most fish. • - the male deposits sperm into the water and the female deposits the egg into the water. - fertilization occurs and the egg is hatched. • - Ovoviviparous reproduction. • - used by some sharks and bony fish. • - Eggs are retained in female until hatched, and embryos get their food from the yolk sac.
Nervous System • Fishes’ nervous system is set up similar to the human’s, except it is simpler. • There are five parts to their nervous system; • - Olfactory Bulbs • - Cerebrum • - Optic Lobes • - Cerebellum • - Medulla Oblongata
Olfactory bulbs Cerebrum Optic lobes Cerebellum Medulla Oblongata -sense of smell. -basic behaviors. -visual info. -body movement. -to maintain balance. Nervous System cont.
Sensory Structures • Chemical receptors are a good example of sensory structures; these are “smelling with lips and tasting with barbels [whiskers].” • Specialized cells which detect tiny electric currents to find hidden prey. • Some fish with specialized cells use them to navigate and communicate.
Fish Lateral Line System • The system is sensitive to changing water pressures. • The sensory unit is called “neuromast” • A bundle of sensory cells that hairs are included in a jelly-like cap. • It sends out nerve impulses through out the fish’s body. • When pressure waves bend with the body, it determines the frequency of nerve impulses.
Circulatory System • Single-looped system with two chamber heart. • This includes the atrium and ventricle. • Heart is near the respiratory organs. • Blood travels first to gills then rest of body.
Excretory System • Many fish rid of waste by allowing ammonia to diffuse through gills. • Simple kidney filters waste from blood, and also pass dilute urine. • Gills’ specialized cells can pump salts in/out of body fluids.
The Swim Bladder • Is a flexible-walled organ near the dorsal fin of dorsal fin. • Controls the fishes’ buoyancy in the water. • Depends of the amount of pressure in the fish. • i.e. if the fish becomes positively buoyant, it floats to the top and the gases escape from the swim bladder.
Digestive System • Is complete, with similar organs as humans have: • Stomach • Small intestines • Large intestines
Classes • There are three major fish classes. These include: • - Agnatha • - Chondrichthyes • - Osteichthyes • http://www.geocities.com/aquarium_fish/fishclasses.htm
Agnatha Class • Primitive jawless fish. • They have lost their bony skeletons. • They have no scales. • Examples: lampreys and hagfish.
Chondrichthyes • Fish with a jaw. • Cartilaginous skeletons. • Includes sharks, rays, and skates. • Plate-like scales. • There are 750 living species left. • Most are carnivores.
Osteichthyes • These are bony fish. • Skeletons made of strong, lightweight bone. • There are 30,000 species. • Biologists divide them into two subclasses; • Ray-finned fishes. • Fleshy-finned fishes (includes lobe-finned and lungfishes).
Osteichthyes: Ray-finned Fishes • Includes nearly all of the bony fishes. • Many perform feats that you wouldn’t imagine. • Includes: guppies, groupers, blue fish, flounders, anchovies, eels, salmon, and more. Above is a flying fish
Osteichthyes: Fleshy-finned Fishes • Lobe-finned fishes. • - Today, the only living species is the Latimeria (also known as Coelacanth). • - These fish live in deep sea. • - These are closest to the common ancestor of all four-limbed vertebrates.
Latimeria Coelacanth Replica of most famous Latimeria Visit: http://nature.ca/discover/treasures/anim/tr3/coe_e.cfm or http://sacoast.uwc.ac.za/education/resources/fishyfacts/coelacanth.htm
Fleshy-finned Fish • Lungfish • They have retained their primitive lung. • Is an air-filled sac connected to the gut. • Fills its lung by swallowing air and empties by belching.
Works Cited (pictures) • National Geographic. 2008. National Geographic Society. 31 March 2008. <http://animals.nationalgeographic.com/staticfiles/N GS/Shared/StaticFiles/animals/images/primary/parro t-fish.jpg>. • College of Sciences. 2008. San Diego State University. 2 April 2008. <http://www.sci.sdsu.edu/classes/bio100/Lectures/Le ct16/Image266.gif>. • Kimball, John W. “Kimball's Biology Pages.” Biology Pages. 14 March 2008. 3 April 2008. <http://users.rcn.com/jkimball.ma.ultranet/BiologyPa ges/F/fish_heart.gif>. • University of Aberdeen. 20 March 2008. King’s College. 3 April 2008. <http://www.abdn.ac.uk/ ~nhi708/images/coelacanth.jpg>.
Works Cited (pictures) • “Archives.” Tomorrow Yesterday! 2008. 2 April 2008. <http://www.tomorrowyesterday.com/archives/nemo.j pg>. • “Fish Biology.” National Aquarium of New Zealand. 2008. National Aquarium of New Zealand. 1 April 2008. <http://www.nationalaquarium.co.nz/docs/ programmes/Fishbiol.pdf>. • “Fish.” Sportsman Choice. 27 Feb 2008. 3 April 2008. <http://www.sportsmanschoice.com/A%20Note%20 Worth%20Reading/encyclopedia/lr000531.gif>. • “Latimeria Coelacanth.” PALAEOS: The Trace of Life on Earth. 2008. 3 April 2008. <http://www.palaeos.com/Vertebrates/Units/ 140Sarcopterygii/Images/LatimeriaPhoto.jpg>. • “Latimeria.” Practical Fishkeeping. 2008. 4 April 2008. <http://www.practicalfishkeeping.co.uk/pfk/images/ latimeria_chalumnae_cc.jpg>.
Works Cited (websites) • “Modern Coelacanth.” Our Amazing Treasures. 22 June 2006. Canadian Museum of Nature. 4 April 2008. <http://nature.ca/discover/treasures/ anim/tr3/coe_e.cfm>. • “The Coelacanth.” Coastcare: South African Coastal Information Centre. 2008. Department of Environmental Affairs and Tourism. 4 April 2008. <http://sacoast.uwc.ac.za/education/resources/fishy facts/coelacanth.htm>. • “Fish Classes.” Hand Made. 3 March 2006. 2 April 2008. <http://www.geocities.com/aquarium_fish/ fishclasses.htm>. • “Essential Fish Habitat.” Habitat Protection Division. NOAA Fisheries. 3 April 2008. <http://www.nmfs.noaa.gov/habitat/ habitatprotection/efh/>.
Works Cited (websites) cont. “Fish Lateral Line System”. Lateral System. 8 April 2008. http://www.lookd.com/fish/laterallinesystem.html
Works Cited (books) • Filisky, Michael. Peterson First Guides: Fishes. Boston, Mass: Houghton Mifflin Company, 1989. • Miller, Kenneth and Levine, Joseph. Biology: The Living Science. Upper Saddle River, NJ: Prentice-Hall, 1998.
Works Cited (videos) • “Videos.” Discovery Education Streaming. 2008. Discovery Communications, LLC. 2 April 2008.<http://streaming.discovery education.com>.