Presentation on theme: "Chordates: basically- “animals with a notocord”"— Presentation transcript:
1Chordates: basically- “animals with a notocord” Invertebrate ChordatesFishAmphibiansReptilesBirdsMammals
2Chordata most familiar animal phylum includes humans & other vertebrates.not all chordates are vertebrates.All chordates have 4 features at some point in their lifein the case of humans and many other vertebrates, these features may only be present in the embryo
34 chordate features:pharyngeal slits - a series of openings that connect the inside of the throat to the outside of the "neck". These are often, but not always, used as gills.dorsal nerve cord - a bundle of nerve fibers which runs down the "back". It connects the brain with the lateral muscles and other organs.notochord - cartilaginous rod running underneath, and supporting, the nerve cord.post-anal tail - an extension of the body past the anal opening
61. Urochordata "sea squirts" or tunicates larva, resembles a tadpole. As it matures, the larvametamorphoses into asedentary adult - losing itstail, its ability to move, andmany of its chordate features.the adult form- a sackwith two siphons forwater to enter & exit.Reproduction may be asexual through budding, or sexual. (hermaphroditic)
7White-spotted Ascidians (Pycnoclavella diminuta) (Indonesian) sea squirts, are filter-feeding animals with one siphon to pull in water and another to discharge it.Adults remain rooted to the same spot their entire lives.
9Tunicates have barrel-shaped bodies & are abundant in the ocean.
10The Georges Bank (New England) is the largest known infestation of colonial sea squirts in a major offshore fishing groundsoundwaves.usgs.gov/2005/11/fieldwork2.html
11-Open circulatory system with a tubular heart -Open circulatory system with a tubular heart. -Also has a simple nervous system
12Tunicates “our distant cousins” Since the tadpole larva has a notochord, it is interesting to scientists.This tail can be thought of as ancestral to rings of cartilage or bone (vertebrae).They are thought to be vertebrate ancestors
13Tadpoles & Adults of Stolonica socialis, photographed in Brittany, France
14Taxonomy of some organisms continues to be debated: Some zoologists would put the Urochordata closer to the Echinodermata, instead of within the Chordata.Some would place the Echinodermata closer to or even with the Chordata
152. Cephalochardata Lancelets found in coastal waters Swims but no complex sense organs, so it burrows into the sand of shallow watersThere it rests with only the front end exposed to the water, using a row of tentacles to bring food into its mouth.The sexes are separate in this group; the sex organs produce gametes which are released into the water at maturity.
22Most chordates are vertebrates subphylum has over 50,000 species of animals
23Subphylum: Vertebrate -Characteristics- Vertebrae - bones or cartilage that surround the dorsal nerve cord and form the spine.Cranium - a skull that protects the brainhighly cephalizedwell developed brain & sense organsEndoskeleton - internal skeleton made of bone or cartilageClosed circulatory system: heart, arteries and veinsAlso: Paired appendages, separate Sexes
24Vertebrates are divided into nine classes: Myxini - hagfishesCephalaspidomorphi - lampreysChondrichthyes - sharks, rays, skatesActinopterygii - ray-finned fishesSarcopterygii - lobe-finned fishesAmphibia - frogs, toads, salamandersReptilia - lizards, snakes, and turtlesAves - birdsMammalia - mammals
255 classes of fish Myxini Cephalaspidomorphi Chondrichthyes ActinopterygiiSarcopterygii
261. Hagfishes (Myxini)never replace their notochord with a vertebral column,thus might seem not to qualify as vertebratesthey share a number of other features with other vertebratesIt is unclear if their evolution represents the most primitive vertebrates or are if they are simply degenerate vertebrates.
28Myxini (Hagfishes) Hagfish burrow into & eat dead fish Also known as “slime eels”Hagfish burrow into & eat dead fishIt slimes its enemies, has rows of teeth on its tongue, and feeds on the innards of rotting fish by penetrating any orificeoceanexplorer.noaa.gov/.../media/hagfish.html
29A single slime eel can turn a five-gallon bucket of seawater into a pool of goo in a matter of momentsCabria Colt / AP
30Hagfish - From MSNBC news “Bottom-feeder fish is foul-looking, but sold as an Asian aphrodisiac”Fishing hagfish is creating a business opportunity for struggling fishermen confronted restrictions on the catching of salmon and other fishMark Crossland, a state Fish and Game warden. “The product is difficult to deal with and handle —once it gets stressed it excretes this slime.”So ‘icky” it had a cameo on TV’s “Fear Factor.”two contestants sat in a vat of the creatures and had to push handfuls of them through holes. They described the experience as sticky, stinky and disgusting
31Eating Hagfish (msnbc.com) South Koreans drink in front of hagfish before it is broiled at a seafood restaurant in Seoul, South Korea. As if its looks weren’t enough of a turnoff, hagfish, when agitated, vomit and secrete a protein that reacts with seawater to create a thick mucus.
322. Cephalaspidomorphi (Lampreys) - Jawless, Parasitic Fish- Lampreys attach themselves to their host with disc-shaped mouth & feed on host’s blood.
343. Cartilaginous Fish Chondrichthyes (sharks, rays & skates, ratfish) wdfw.wa.gov
35Sharks Shark cartilage- big medical controversy Has been “unconventional” cancer & prevention treatment.But sharks DO get cancer & treatment not effective.Shark has 6 to 20 rows of teeth.If lose a a replacement moves forward.may use more than 20,000 teeth over its lifetime.
41Feeding time: Whale Sharks -feed on wide variety of planktonic (microscopic)and nektonic (larger free-swimming) prey, such assmall crustaceans, schooling fishes, andoccasionally on tuna and squids. Also, phytoplankton .
42Food for sharks or sharks for food? a swift, powerfulpredator and afearsome menaceto swimmersis now itself becomingprey to man’s insatiableappetite for exotic foods.several shark species are already endangered.advocacy.britannica.com/.../page/4/
43Shark fin soup - a traditional dish for wealthy Chinese & served at Chinese weddings.
44Shark populations are declining Increased market demand, poor data on global shark populations, andsharks' inability to reproduce quickly have international conservation organizationsconcerned about the impacts of "finning“.
484. Sarcopterygii LOBE-finned fishes Have fleshy fins with bony axisExtinct lobe-fin fish may have been ancestors of amphibiansGroups alive today1 species coelacanth6 species lungfish(can gulp AIR into lungas Oxygen source)www2.dpi.qld.gov.au/far/12588.html
49COELOCANTH - SUBCLASS SARCOPTERYGII LOBE-FINNED FISH SINGLE SPECIES - LATIMERIA CHALUMNAE
51Evolution to first land vertebrates, the amphibians. Rare, modern lobe-finned fishes are survivors of groups that gave rise to four-legged vertebrates.Late Devonian (about 360 million years ago), the paired fins of some sarcopterygians moved under the body and developed limbs
53Bony fish anatomy & physiology Operculum -a hard plate that opens at the rear and covers & protects the gills.Closed circulatory systemheart has two chambered HEART
54Respiratory system Countercurrent flow. Gills for gas exchange. Water flows across the gill filaments in a direction opposite to blood flowCountercurrent flow allows more oxygen to diffuse into the blood than if blood and water flowed in the same direction.
58What is a swim bladder? Most boney fishes have a swim bladder Adjusts fish overall density by regulating gas in the swim bladder.Thin walled sac in abdominal cavityContains mix of gases (oxygen, CO2, Nitrogen) obtained from the Bloodstream.
59Excretory system The kidneys The gills Have nephrons filter chemical wastes from the bloodform urine, a solution containing ammonia, ions such as salts, and water.The gillsalso allow wastes to diffuse from the blood into the waterhelp regulate ion and water balance in fish.
602 methods of Reproduction spawning. -most bony fish reproduce by external fertilization (some internal)2. Some fish bear live young.Example- guppies-can store sperm & have up to 4 pregnancies from one deposit.
61Ray finned fish are a very diverse group Chondrostei : Sturgeons (think caviar…..)Atlantic Sturgeon - Eastern rivers in North America
62Paddlefish: 2 species (Mississippi River drainage andYangtze River drainage in China) - large bill used tostir bottom and expose food
64C. Fish & Humans Pollution/ poor water quality affect fish too. For list of Endangered & Threatened Species of Pennsylvania - Fish, Amphibians and Reptiles go toO2 is as important to fish as to terrestrial animalsIf Oxygen poor water, fish will die“Osmotically unfriendly”, (H2O is 800 times denser than air)Water is a “soup of pathogens” ocw.tufts.edu/Content/5/Lecturenotes/215706
65Can fish be trained? National Geographic Video-Over Fishing National Geographic Video-Over FishingHow to Help: Safe, Sustainable Seafood:
69Pennsylvania FishesPennsylvania is home to many popular game fish, including trout, bass, musky, walleye, steelhead, panfish and many more!
70Northern Snakehead Snakeheads are native to parts of China, Russia, and Korea- alien to PAThe air-breathing, land-crawling, voracious predator found in a pond in Crofton, Maryland, is now multiplying into PA.The fish's ability to breathe out of water and travel across land has increased the sense of urgency among wildlife officials.IF YOU CATCH ONE-dispose of them properly. Anglers suspecting they have caught a snakehead are encouraged to NOT release it, and report it to theCommission at or via . PA REGULATIONSIt is unlawful for a person to possess, sell, purchase, offer for sale or barter live snakehead species in Pennsylvania.
71Red Bellied Piranha Serrasalmus nattereri By Pittsburgh Zoo StaffWeight -up to three poundsLength -8 to 15 inches in length.Can live up to 8 years.Red-bellied piranhas live in the warm fresh water regions of South America.Feed on fish, birds, reptiles, rodents, and small mammals.The name South American native language Tupi-guarani and means “cuts the skin.”It is illegal to keep piranhas in 21 states of the United States.''A school of these 8- to 12-inch fish, have been observed gnawing a 400-pound hog to the bone in minutes''(from the “Book of Facts”)
72Photo in the News: Century-Old Fish Caught in Alaska April 6, 2007—A handful of Christians preparing rockfish as part of their traditional fish dinner this Good Friday might be feasting on one of the oldest creatures ever to live in Alaskan waters.Commercial fishers in the Bering Sea recently hauled in the female shortraker rockfish seen above, which scientists say was between 90 and 115 years old.Researchers at the National Oceanic and Atmospheric Administration (NOAA) used growth rings in the fish's ear bone, or otolith, to make their age estimate.
73Commonly eaten fish: http://www. eatwell. gov Oily / fatty fishWhite / non-oily fishSalmon Trout Mackerel Herring Sardines Pilchards Kipper Eel Whitebait Tuna (fresh only) Anchovies Swordfish Bloater Cacha Carp Hilsa Jack fish Katla Orange roughy SpratsCod Haddock Plaice Coley Whiting Lemon sole Skate Halibut Rock salmon/Dogfish Ayr Catfish Dover sole Flounder Flying fish Hake Hoki John Dory Kalabasu Ling MonkfishParrot fish Pollack Pomfret Red and grey mullet Red fish Red snapper Rohu Sea bass Sea bream Shark Tilapia Turbot Tinned tuna MarlinOily fish are all rich sources ofomega 3 fatty acids, which helpprevent heart disease.
74Would you eat FUGU???Puffer fish (genus-Takifugu)(“Fugu” in Japanese) is an expensive delicacy.But more than just the money- it could cost your life!It has a deadly poison (tetrodotoxin) in its organs.Chefs must take intensive courses & pass exam to become licensed. Only 30% of the applicants pass the test!Several people die each year from eating this fish. If an ingested dose of the fugu's poison is lethal, as more and more muscles are paralyzed, symptoms may include dizziness, exhaustion, headache, nausea or difficulty breathing. For 50 to 80% of the victims, death follows within four to 24 hours.To learn more on FUGU
75Eating Fish Is eating fish healthy? What is mercury and methylmercury? Fish and shellfish are an important partof a healthy diet.Contain protein & omega-3 fatty acids, are low in saturated fatHowever, nearly all fish and shellfish contain traces of mercury.What is mercury and methylmercury?Mercury occurs naturally in the environmentCan be released into air by industrial pollution. Mercury falls from the air and can accumulate in streams and oceans and is turned into methylmercury in the water.This type of mercury can be harmful to unborn babies & young child.Fish absorb methylmercury as they feed & it builds up in them. It builds up more in some types of fish and shellfish than others.
76Recommendations for eating fish to reduce exposure to mercury. Do not eat Shark, Swordfish, King Mackerel, or Tilefish because they contain high levels of mercury.Eat up to 12 ounces (2 average meals) a week of a variety of fish and shellfish that are lower in mercury.Five commonly eaten fish that are low in mercury are shrimp, canned light tuna, salmon, pollock, and catfish.Albacore ("white") tuna has more mercury than canned light tuna..Check local advisories about the safety of fish caught by family and friends in your local lakes, rivers, and coastal areas.