Fish Lecture Related to Swimming

Fish Lecture Related to Swimming

5/29/2018 Student Learning Outcomes • Define “vertebrate” and list their features. • Make comparisons between agnathans and jawed fishes. • Discuss the main features of chondrichthyans. • Describe and compare three osteichthyes orders. • Understand different aspects of fish adaptations Fish Lecture related to swimming. • Discuss the reason some fish go to school. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Vertebrate Features Oral hood with tentacles Notochord Phylum Chordata Dorsal nerve cord • Includes fishes, amphibians, reptiles, birds and mammals. Several invertebrates also in this group e.g. Sea squirts During some phase of their lives, all Chordates have: Pharynx • Notochord —dorsal rod-like structure that serves as an Muscle blocks embryonic skeleton Pharyngeal slits • Pharyngeal gill slits • Dorsal hollow nerve cord —a tube that runs beneath the dorsal surface above the notocord Intestine • Post-anal tail Anus • Bilateral symmetry • Segmented body , including segmented muscles Postanal tail 4 1 5/29/2018 Vertebrate Features Fish General Features • All chordates with a vertebral column are in the • Extremely diverse in form and function subphylum Vertebrata. • Most basic description of a fish—live in water, swim with fins, • Vertebral column replaces the notochord. and use gills for oxygen and CO 2 exchange. • May be made of cartilage or bone. • Have a single loop closed circulatory system – with Heart. • Those that do not have vertebrae are invertebrates. • Very prehistoric—fossil record goes way back! • Invertebrate chordates have all of the chordate features Conodonts – discovered in 1983 from Cambrian. at some point in life…………………just no vertebrae. Why do fish fossilize well? Lancelets Tunicates (sea squirts) Three classes of fishes- vary greatly. 1) Agnatha - jawless 2) Chondrichthyes - cartilagenous 3) Osteichthyes – bony (aka Teleost) https://www.seeker.com/photos-the-surprising-world-of-sea- squirts-1768678963.html I. Agnatha: The Jawless Fishes II. Chondrichthyes: • Very different from other fish classes Sharks, Rays, Chimaeras • Only two orders exist: lampreys and • Almost all marine, a few notable exceptions hagfish e.g. Sharks in Lake Nicaragua • Very primitive and simple https://www.animalanswers.co.uk/animals/how-do- hagfish-defend-themselves/ • Larger in body size than other fish classes • Slender, eel-shaped body • Largest living animals besides whales • Seven external gill openings • Range from <20 cm to 15 m long – whale sharks • Notochord persists in the adult. • Skeleton composed of cartilage • Lack many fish-like features • Salts in body are less than seawater, so must maintain osmotic balance. • No paired fins • No biting jaws • Accumulate high concentrations of urea to aid in salt • No scales balance Isotonic with water • Able to maintain an internal ion concentration equal to that Detritivores live in burrows. outside the body (in seawater) Direct development from eggs. Renown for slime. 2 5/29/2018 II. Chondrichthyes: Sharks 7.3 Chondrichthyes: Rays Sharks Rays – Batoid fish • Almost all are fierce predators. • Spines used for defense • Few are filter feeders (e.g. • Some are poisonous, whale shark). others sharp and painful. • Adapted for speed, maneuverability, and strength • Used for defense only, • Teeth are modified scales. not to capture prey • Numerous rows of teeth attached Example: stingray at their bases by connective • Countershading tissue • Several rows of replacement • Swim with pectoral fins teeth continually develop behind • Gill slits on ventral/belly side the outer rows of functional teeth • Eat a variety of food including mollusks, fish. (c) cbpix/Shutterstock https://www.aquariumdomain.com/adSocial/index.php/nurse-shark/ • Manta rays - planktivorous © Matt9122/Shutterstock 7.3 Chondrichthyes: Chimaeras Chondrichthyes Fish Reproduction Chimaeras (a.k.a. ratfish, elephant fish, rabbit fish) • In Greek mythology, chimaera is a monster. • Oviparous —lay eggs/spawn with no support to young • Very few species and rare in the world’s oceans unless they lay a nest and tend to it e.g. rays • Have long, rat-like tails • Viviparous —live bearers; the ultimate support to • Glide through the water with large pectoral fins extended young. E.g. Hammerhead sharks • Very different look from all other fish • Ovoviparous —store eggs in body, but do not provide • Skin is smooth & without any other nutritional support; support developing young scales. e.g. Mako shark • Primarily forage on invertz on floor of sea. • Young called a “pup” http://galleries.neaq.org/2011/06/just- biofacts-shark-egg-cases.html 3 5/29/2018 Osteichthyes – Bony fish Yellow-tail Snapper The most abundant ray-finned fishes are the group Teleostei - Class: Actinoptergygii • In the ocean there are 26 orders, hundreds of families, and thousands of species. • Traits • Bony skeletons (calcified) • Thin and flexible scales • A gas-filled organ (swim bladder) • Low concentrations of salt in the body Seahorse Mola - Sunfish 4 5/29/2018 Circulation in Fish The art of swimming Mechanism: pressure of fish fins against water is used to swim through water. • Muscles/myomeres contract and relax forming a wave-like motion. I. Most fish are generalist swimmers. II. Some fish are specialized swimmers, influenced by food choice, habitat, and lifestyle. • Barracuda sprints (ambush predator). Long body - bursting • Butterfly fish finely maneuver (hover and pick off small prey items). • Tuna cruise at high speeds to find prey (transit large areas). Tuna torpedo-shaped & thick with muscles for long endurance swimming Body Shape Specialization Caudal fin – provides a clue Tail (caudal fin) shape • Determines amount of forward thrust • Can be measured by the aspect ratio = (fin height 2) / fin area • Higher aspect ratio is ideal for fast, long-distance swimming. 5 5/29/2018 A remarkable fish Schooling Behavior • Opah Fish schools vary in size few – innumerable (over several sq kms) • A unique and fully endothermic fish Usually all of the same species. • Specialized gills to warm the blood Safety in numbers approach. May confuse potential predator • Spend time in cold, deep water Spatial arrangement • The only nonmammal or > Visual cues bird species to exhibit > Vibrational cues full endothermy Broadcast spawning – reproductive advantage Can you think of any disadvantages? NOAA/SWFSC 6.

View Full Text

Details

  • File Type
    pdf
  • Upload Time
    -
  • Content Languages
    English
  • Upload User
    Anonymous/Not logged-in
  • File Pages
    6 Page
  • File Size
    -

Download

Channel Download Status
Express Download Enable

Copyright

We respect the copyrights and intellectual property rights of all users. All uploaded documents are either original works of the uploader or authorized works of the rightful owners.

  • Not to be reproduced or distributed without explicit permission.
  • Not used for commercial purposes outside of approved use cases.
  • Not used to infringe on the rights of the original creators.
  • If you believe any content infringes your copyright, please contact us immediately.

Support

For help with questions, suggestions, or problems, please contact us