Post on 18-Dec-2015
Fishes
Phylum Chordata Subphylum Vertebrata 3 Classes:
Class Agnatha (jawless fishes) Class Chondrichthyes (cartilaginous fishes) Class Osteichthyes (bony fishes)
Fishes - Anatomy Cartilaginous fishes:
Ventral mouth Heterocercal tail (caudal fin) Placoid scales
“dermaldenticles”
Bony fishes: Terminal mouth Homocercal tail Cycloid or ctenoid scales
cycloid
ctenoid
Fishes - Anatomy
Cartilaginous fish skeleton:
Fishes - Anatomy
http://www.marinebiodiversity.ca/shark/english/images/porbeagle%20skeleton%20for%20web.jpg
Bony fish skeleton:
Fishes - Anatomy
http://www.infovisual.info/02/img_en/034%20skeleton%20of%20a%20fish.jpg
Fishes - Buoyancy
Bony fish – swim bladder (gas) Cartilaginous fish –
Swim, get lift from stiff fins Large, oil-filled liver Cartilage half as dense as bone
Fishes - Locomotion
http://www.buschgardens.org/infobooks/BonyFish/images/muscle.gif
Muscle up to 75% of body weight Muscle bands – myomeres (flake when cooked) Red muscle – sustained swimming White muscle – burst swimming
http://www.earthlife.net/fish/muscles.html
Fishes - Locomotion
http://www.buschgardens.org/infobooks/BonyFish/images/caudalfi.GIF
Homocercal caudal fins by shape:
Slowest →
Fast → ← Fastest
← Slow
http://www.dfw.state.or.us/mrp/salmon/FishID/Heterocercal.jpg
Heterocercal caudal fins:
http://static.howstuffworks.com/gif/willow/flying-fish-info0.gif
Fishes - Respiration
Cartilaginousfish
Bony fish(more efficient)
5-7 pairs of gills Gill slit openings
4 pairs of gills Operculum gill cover
Fishes - Respiration
http://elasmodiver.com/images/Cortez-round-stingray-04.jpg http://blogs.southflorida.com/citylink_dansweeney/Southern_sting_ray.jpg
Spiracles important for rays when buried
Fishes - Respiration
Gills maximize oxygen diffusion: High surface area Counter-current flow (oxygen concentration of water always higher than blood)
Fishes - Respiration
“Warm-blooded” fish: Epipelagic sharks, tunas, billfishes Counter-current flow retains muscle heat Body surface stays water temperature Body core has elevated temperature
Fishes - Feeding
Large mouth, tear chunks or swallow fish whole Small mouth,
small prey
Small mouth, small prey
Hard beak, graze algae and coral
Large mouth, filter feeder (plankton)
Largest species: Whale sharks (up to 60 ft) Basking sharks (up to 50 ft) Filter feeders (eat plankton)
Whale (Rhincodon typus) Basking (Cetorhinus maximus)
Fishes - Feeding
Fishes – Sensory Organs Vision Taste buds Smell – olfactory sacs, nostrils Sound – inner ear, otoliths (bones)
http://www.ncdc.noaa.gov/paleo/pubs/andrus2002/otolith-md.gif
http://www.marinebiodiversity.ca/otolith/english/images/cod6oto.jpg
Fishes – Sensory Organs
Electroreception – ampullae of Lorenzini (cartilaginous fishes only)
small holes
http://www.seaworld.org/infobooks/Sharks&Rays/images/ampullae.gif
Fishes – Schooling
Use senses to coordinate (vision, sound, lateral line) Protection from predation
Safety in numbers Visual confusion
Feeding Mating Swimming efficiency
http://image14.webshots.com/14/5/22/94/170152294GjijRv_fs.jpg
http://image03.webshots.com/3/4/24/9/6942409XjGFEFguyY_ph.jpg
Fishes – Reproduction
Fertilization External – bony fishes Internal – cartilaginous
http://www.pbs.org/wnet/nature/files/2008/10/286_lifeed_behind1.jpg
http://www.gloversreef.org/grc/spawning.jpg http://www.flmnh.ufl.edu/fish/education/questions/claspers.jpg
http://www.charkbait.com/article/Scan5sm.jpg
Fishes – Reproduction
Development Oviparous (most bony fishes, some cartilaginous):
External eggs, yolk
http://www.ufz.de/data/bioindicator-fish-eggs2455.jpg
Fishes – Reproduction
Development Ovoviviparous:
Internal eggs, yolk, live-birth
Viviparous: Internal eggs, nutrition from mother, live-birth
http://www.west.asu.edu/achristie/hsw4kids/animals/sharks/birtha.jpg
Fishes – Reproduction
Asexual – parthenogenesis (“virgin births”)
Very rare Female sharks in captivity Female offspring (genetic clones)
http://www.sciencedaily.com/images/2008/10/081010173054-large.jpghttp://marinebio.org/upload/_05/Sphyrna_tiburo1.jpg
Bonnethead – 2001 Black-tip – 2008
Fishes – Reproduction
Strategies Many small eggs (tarpon – 100 million eggs each spawn) Fewer large eggs (more work)
http://www.soc.soton.ac.uk/GDD/hydro/atmu/ecology/chapter5/sgtmjr.jpg
Cartilaginous vs. Bony FishesCartilaginous Bony
Scales placoid cycloid, ctenoid
Mouth ventral terminal
Tail lobes unequal (heterocercal) equal (homocercal)
Gills 5-7 pairs, slits 4 pairs, covers
Position in water fins, lower density (cartilage and oily liver)
swim bladder
Osmoregulation urea (equal solutes), rectal gland
less solutes, gill excretion
Sensory ampullae of Lorenzini, lateral line
lateral line
Reproduction(fertilization, development, strategy)
internal, variety, fewer offspring
external, mostly oviparymore offspring