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Hagfish . Bottom dwellers in cold marine waters Unique: they don’t have vertebrae Unique: their body fluids have nearly the same ion concentration as sea water L ack jaws : within mouth are 2 movable plates & a rough tonguelike structure that it uses to pinch off chunks of flesh.
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Hagfish • Bottom dwellers in cold marine waters • Unique: they don’t have vertebrae • Unique: their body fluids have nearly the same ion concentration as sea water • Lack jaws : within mouth are 2 movable plates & a rough tonguelike structure that it uses to pinch off chunks of flesh • often burrow into the body of a dead fish thru gills, skin, or anus • once inside, they eat the internal organs
Hagfish • http://www.youtube.com/watch?v=bqk0mnMgwUQ • http://www.youtube.com/watch?v=pmaal7Hf0WA
Lampreys • Class Cephalaspidomorphi *3-17 years • Found along Atlantic Coast of Europe & North America , western Mediterranean Sea, & Great Lakes • About half of the species are free-living (non-parasitic) • Other half are parasites as adults & feed on the blood/body fluids of other fishes • SEE
Lamprey finds a suitable host & uses its disk-shaped mouth to attach • Scrapes a hole in the host with its rough tongue & secretes a chemical that keeps the host’s blood from clotting • After feeding, the lamprey drops off • Host may recover, bleed to death, or die from infection
Lampreys • http://www.youtube.com/watch?v=x-KJZ22-wTQ • http://www.youtube.com/watch?v=eqoT8tcZq6k • http://www.youtube.com/watch?v=iWtt-BUCaJg • http://www.youtube.com/watch?v=CscE2XyrBFU&feature=fvsr • http://www.youtube.com/watch?v=nQJFoA_6mJQ&feature=related LONG
CLASS CHONDRICHTHYES • Cartilaginous fishes because of cartilage skeleton • Sharks, rays, & skates • Cartilage- flexible, lightweight material made of cells surrounded by tough fibers of protein • Notochord of juveniles turns to cartilage in adults • Tough skin is covered with dermal denticles (placoid scales)-makes them feel like sandpaper • Breathe thru 5-7 gills • Sharks and rays reproduce by passing sperm from male to female, male using modified fins called claspers • Some species produce large egg cases while others produce live young
Ray Skate Skates give birth to young in eggcases – sometimes called mermaid’s purses (via oviparity) each pelvic fin divided into 2 lobes tail relatively stocky, without a stinging spine • give birth to live young (via ovoviviparity) • pelvic fin with 1 lobe • tail relatively slender to whip-like, usually with a saw-edged stinging spine midway along its length • **BIGGEST DIFFERENCE IS IN BREEDING
Chondrichthyes • http://www.youtube.com/watch?v=z3LnYqtjlVQ&feature=related sharks • http://www.youtube.com/watch?v=NNG5l1K9jLk&feature=related
SUPERClassOsteichthyes • Of 25,000 fish species, about 95% are bony fishes • Group accounts for most of the vertebrates living in aquatic environment • EXAMPLES: lungfishes, coelacanth, trout, salmon, perch, guppies, bass, herring, goldfish, eels, etc.
3 characteristics of bony fish • BONE: Material is typically harder and heavier than cartilage • LUNG or SWIM BLADDER: early bony fishes had lungs (internal respiratory organs in which gas is exchanged b/w air and blood - today most bony fishes have a swim bladder that controls buoyancy • SCALES: protect the fish & reduce friction when swimming
2 main groups of bony fishes • Class Sarcopterygii: lobe-finned fishes • Have fleshy fins supported by a series of bones • 2 groups exist today • 6 species of coelocanths & 1 species of lungfish • Lungfishes live in shallow tropical ponds that periodically dry up • Coelocanths live deep in the ocean • Coelocanth lungfish
Ray-finned Fishes • Class Actinopterygii • Contain majority of species of fish (96% of 25,000 species) • Divided into 46 orders • They have an upper jaw that consists of 2 bones & fins with bony spines (which differ from those with lobed-fins) • Inhabit a wide range of habitats..salt & freshwater…shallow to great depths