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Chordates: basically- “animals with a notocord”

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1 Chordates: basically- “animals with a notocord”
Invertebrate Chordates Fish Amphibians Reptiles Birds Mammals

2 Chordata most familiar animal phylum
includes humans & other vertebrates. not all chordates are vertebrates. All chordates have 4 features at some point in their life in the case of humans and many other vertebrates, these features may only be present in the embryo

3 4 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


5 2 Invertebrate Chordates
Tunicates (Urochordata) Lancelets (Cephalochardata)

6 1. Urochordata "sea squirts" or tunicates larva, resembles a tadpole.
As it matures, the larva metamorphoses into a sedentary adult - losing its tail, its ability to move, and many of its chordate features. the adult form- a sack with two siphons for water to enter & exit. Reproduction may be asexual through budding, or sexual. (hermaphroditic)

7 White-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.

8 Sea squirts

9 Tunicates have barrel-shaped bodies & are abundant in the ocean.

10 The Georges Bank (New England) is the largest known infestation of colonial sea squirts in a major offshore fishing ground

11 -Open circulatory system with a tubular heart
-Open circulatory system with a tubular heart. -Also has a simple nervous system

12 Tunicates “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

13 Tadpoles & Adults of Stolonica socialis, photographed in Brittany, France

14 Taxonomy 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

15 2. Cephalochardata Lancelets found in coastal waters
Swims but no complex sense organs, so it burrows into the sand of shallow waters There 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.

16 A lancelet

17 A lancelet

18 A lancelet

19 Notochord in a lancelet

20 Embryonic Development
All chordates are deuterostomes, meaning that the anus develops before the mouth in early embryonic stages

21 Animals with a backbone

22 Most chordates are vertebrates
subphylum has over 50,000 species of animals

23 Subphylum: Vertebrate -Characteristics-
Vertebrae - bones or cartilage that surround the dorsal nerve cord and form the spine. Cranium - a skull that protects the brain highly cephalized well developed brain & sense organs Endoskeleton - internal skeleton made of bone or cartilage Closed circulatory system: heart, arteries and veins Also: Paired appendages, separate Sexes

24 Vertebrates are divided into nine classes:
Myxini - hagfishes Cephalaspidomorphi - lampreys Chondrichthyes - sharks, rays, skates Actinopterygii - ray-finned fishes Sarcopterygii - lobe-finned fishes Amphibia - frogs, toads, salamanders Reptilia - lizards, snakes, and turtles Aves - birds Mammalia - mammals

25 5 classes of fish Myxini Cephalaspidomorphi Chondrichthyes
Actinopterygii Sarcopterygii

26 1. Hagfishes (Myxini) never replace their notochord with a vertebral column, thus might seem not to qualify as vertebrates they share a number of other features with other vertebrates It is unclear if their evolution represents the most primitive vertebrates or are if they are simply degenerate vertebrates.

27 Phylogenic tree of vertebrates

28 Myxini (Hagfishes) Hagfish burrow into & eat dead fish
Also known as “slime eels” Hagfish burrow into & eat dead fish It slimes its enemies, has rows of teeth on its tongue, and feeds on the innards of rotting fish by penetrating any orifice

29 A single slime eel can turn a five-gallon bucket of seawater into a pool of goo in a matter of moments Cabria Colt / AP

30 Hagfish - 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 fish Mark 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

31 Eating Hagfish (
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.

32 2. Cephalaspidomorphi (Lampreys)
- Jawless, Parasitic Fish - Lampreys attach themselves to their host with disc-shaped mouth & feed on host’s blood.

33 Class Cephalaspidomorphi - The Lampreys

34 3. Cartilaginous Fish Chondrichthyes (sharks, rays & skates, ratfish)

35 Sharks 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.

36 Chondrichthyes Clearnose Skate Southern Stingray

37 Types of sharks Use dichotomous key shark activity


39 Feeding time ... Great White Great whites grow to 20ft long & can weigh 5,000lb.

40 Great white takes bite- seal gone

41 Feeding time: Whale Sharks
-feed on wide variety of planktonic (microscopic) and nektonic (larger free-swimming) prey, such as small crustaceans, schooling fishes, and occasionally on tuna and squids. Also, phytoplankton .

42 Food for sharks or sharks for food?
a swift, powerful predator and a fearsome menace to swimmers is now itself becoming prey to man’s insatiable appetite for exotic foods. several shark species are already endangered.

43 Shark fin soup - a traditional dish for wealthy Chinese & served at Chinese weddings.

44 Shark populations are declining
Increased market demand, poor data on global shark populations, and sharks' inability to reproduce quickly have international conservation organizations concerned about the impacts of "finning“.

45 Shark steaks- (from Vietnam)

46 Samui Honey Cottage's Lunch (Shark Steak)

47 Asian “box” lunch- featuring skate

48 4. Sarcopterygii LOBE-finned fishes
Have fleshy fins with bony axis Extinct lobe-fin fish may have been ancestors of amphibians Groups alive today 1 species coelacanth 6 species lungfish (can gulp AIR into lung as Oxygen source)



51 Evolution 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

52 5. Actinopterygii RAY-Finned Fishes
Have thin, non-fleshy & flexible fins Includes most familiar fish: Yellow perch, trout, salmon, guppies, goldfish, herring,& eels.

53 Bony fish anatomy & physiology
Operculum -a hard plate that opens at the rear and covers & protects the gills. Closed circulatory system heart has two chambered HEART

54 Respiratory system Countercurrent flow. Gills for gas exchange.
Water flows across the gill filaments in a direction opposite to blood flow Countercurrent flow allows more oxygen to diffuse into the blood than if blood and water flowed in the same direction.


56 Skeleton: The major parts of a fish’s skeleton are the skull, spinal column, pectoral girdle, pelvic girdle, and ribs

57 Internal structures:

58 What 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 cavity Contains mix of gases (oxygen, CO2, Nitrogen) obtained from the Bloodstream.

59 Excretory system The kidneys The gills Have nephrons
filter chemical wastes from the blood form urine, a solution containing ammonia, ions such as salts, and water. The gills also allow wastes to diffuse from the blood into the water help regulate ion and water balance in fish.

60 2 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.

61 Ray finned fish are a very diverse group
Chondrostei : Sturgeons (think caviar…..) Atlantic Sturgeon - Eastern rivers in North America

62 Paddlefish: 2 species (Mississippi River drainage
andYangtze River drainage in China) - large bill used to stir bottom and expose food


64 C. Fish & Humans Pollution/ poor water quality affect fish too.
For list of Endangered & Threatened Species of Pennsylvania - Fish, Amphibians and Reptiles go to O2 is as important to fish as to terrestrial animals If Oxygen poor water, fish will die “Osmotically unfriendly”, (H2O is 800 times denser than air) Water is a “soup of pathogens”

65 Can fish be trained? National Geographic Video-Over Fishing
National Geographic Video-Over Fishing How to Help: Safe, Sustainable Seafood:



68 Stay tuned for some interesting fish:

69 Pennsylvania Fishes Pennsylvania is home to many popular game fish, including trout, bass, musky, walleye, steelhead, panfish and many more!

70 Northern Snakehead Snakeheads are native to parts of
China, Russia, and Korea- alien to PA The 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 REGULATIONS It is unlawful for a person to possess, sell, purchase, offer for sale or barter live snakehead species in Pennsylvania.

71 Red Bellied Piranha Serrasalmus nattereri
By Pittsburgh Zoo Staff Weight -up to three pounds Length -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”)

72 Photo 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.

73 Commonly eaten fish: http://www. eatwell. gov
Oily / fatty fish White / non-oily fish Salmon Trout Mackerel Herring Sardines Pilchards Kipper Eel Whitebait Tuna (fresh only) Anchovies Swordfish Bloater Cacha Carp Hilsa Jack fish Katla Orange roughy Sprats Cod Haddock Plaice Coley Whiting Lemon sole Skate Halibut Rock salmon/Dogfish Ayr Catfish Dover sole Flounder Flying fish Hake Hoki John Dory Kalabasu Ling Monkfish Parrot fish Pollack Pomfret Red and grey mullet Red fish Red snapper Rohu Sea bass Sea bream Shark Tilapia Turbot Tinned tuna Marlin Oily fish are all rich sources of omega 3 fatty acids, which help prevent heart disease.

74 Would 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

75 Eating Fish Is eating fish healthy? What is mercury and methylmercury?
Fish and shellfish are an important part of a healthy diet. Contain protein & omega-3 fatty acids, are low in saturated fat However, nearly all fish and shellfish contain traces of mercury. What is mercury and methylmercury? Mercury occurs naturally in the environment Can 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.

76 Recommendations 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.


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