Bony Fish – Ch.8

Developed by • Dave Werner• OCC BIOL265

Intro to Chordates (fig. 7.51)Table 7.1

• dorsal hollow nerve cord

• notochord (dorsal, elastic supporting rod)

• paired pharyngeal gill slits

• post-anal tail

Chordates

• 3 sub-phyla under group Acrania (Protochordata)

1. Subphylum Urochordata (Tunicates, Sea Squirts)

2. Subphylum Cephalochordata (Lancelets)

3. Subphylum Vertebrata (Vertebrates) – cranium/brain• Chordates w/ a backbone, skull, brain, and

kidneys

Lanelet(amphioxus) & Tunicate

Phylum Chordata Subphylum Vertebrata

– class Agnatha (Lampreys)– Class Chondrichthyes (Elamobranchii)– Class Osteichthyes (Bony Fishes)– Class Amphibia– Class Reptilia– Class Aves– Class Mammalia

Classification p.152 (fig.8.1)

• Approx. 23,000 species

• 96% of all fishes and ½ of all vertebrates

• Kingdom Animalia--Phylum Chordata----Subphylum Vertebrata – Class Osteichthyes

• Subclass Actinopterygii (Ray-finned fish) • Subclass Sarcopterygii (Lobe-finned fish)

Coelacanth

Coelacanth Evolution

Characteristics of Fish

• Gills

• Backbone (vertebrae)

• Paired fins

• Single loop circulation

Respiration

• How do fish breathe?

Fish Respiration (fig. 8.17)

• Water flows over gills as the fish swims - this water is flowing in the opposite of the flow of blood (countercurrent flow). Oxygen diffuses from the water and into the blood

• Gills are made of thousands of gill filaments• When a fish opens its mouth, it "swallows"

water, water passes over the gills and then out the gill slits, which are covered by the fish's operculum. You can see the operculum opening and closing.

Fish Circulation (fig. 8.15)The fish heart is a single loop circulation

which has 2 chambers. Blood flows into the gills, picks up oxygen goes to the body and

then returns to the heart.

Maintaining Water Balance – HOMEOSTASIS (fig. 8.18)

• Remember that salt sucks?• Salt water fish have a tendency to lose

waterFresh water fish have a tendency to gain water (the fish is saltier on the inside)

• This is why you can't put a saltwater fish in fresh water - it is not adapted to it.

• Kidneys maintain homeostasis and water balance

Osmoregulation

• Freshwater take in water through body absorption and draw through mouth to breathe.

• Salt water fish take water through mouth salt leaves through gills and a small amount in urine as Urea.

Sensory organs

• An inner ear or Otolith is contained in teloests which detects sounds and balance.

• A lateral line controls impulse detections and low frequencies. This line contains ciliated nerve cells. (Fig. 8.19)

• Chemoreceptors are used for sensing smell

Swim Bladder

• Controls buoyancy in fish through oxygen filling the bladder or being released.

• Primitive fish have the bladder attached directly to the gills.

• Blood carries oxygen to and from the bladder.• The deeper a fish goes the more pressure on the

bladder. • The air becomes more dense in the bladder.• Gas is released through a gas duct.• What about benthic or deep sea species??? • Flounder and other bottom/deep sea dwelling fishes

have a reduced bladder.

Swim Bladder

How to Determine Age• Otoliths are commonly referred to as "earstones" or "fish ear bones." They

are hard, calcium carbonate structures located directly behind the brain of teleost (bony) fish. Otoliths help with balance, orientation, and sound detection-much like the inner ear of mammals. They are not attached to the skull, but "float" beneath the brain inside the soft, transparent inner ear canals.

• Thin sections of an otolith reveal bands of opaque and translucent material, sort of like the rings on a tree trunk. The growth of otoliths is a one-way process: new material (protein and calcium carbonate) is added to the exposed surface of the otolith over time, but existing material cannot be removed. The one-way growth process explains why otoliths can form and retain such delicate structures as daily rings, while bones cannot.

• http://elearning.uaf.edu/cc/otolith/index.htm

How to Determine Age

• Scales, bones, fin rays and otoliths have all been used to determine the age of fish, since these and other bony parts of fish often form yearly rings (annuli) like those of a tree. However, otoliths generally provide the most accurate ages, particularly in old fish.

• The easiest way to "read" an otolith is to take a slice, or cross section, out of the otolith with a special saw and then count the rings under a microscope. If the otolith is thin enough, it may be possible to count the annuli without having to slice it. If you can see alternating light and dark zones, you're probably looking at annuli. They probably won't be as clear as those in a cross section, but they should look roughly similar.

• Using Scales

• Image courtesy of www.marinebiodiversity.ca

Fish Reproduction

• Most fish fertilize their eggs externally

• Spawning - the process of fertilizing eggs (fish reproduction)Fry = baby fish

• Broadcast Spawning

2 Types of Bony Fish (Osteichthyes)

1. Ray-finned - majority of fish are this type, fins are supported by bony structures called rays.– Teleosts -most

advanced form of ray finned fish, symmetrical tales, mobile fins

Teleosts

• Advance dorsal fin is split into two regions; Anterior dorsal fin with spines, posterior dorsal with rays. Pelvic fin is ventrally located below pectoral.

2 Types of Bony Fish (Osteichthyes)

2. Lobe-Finned• Fins consist of long,

fleshy muscular lobe, supported by a central core of bonesThought to be the ancestors of amphibians

• Coelacanth• Lungfish

Fish Adaptations

• Scales• Lateral Line System - Used to detect vibrations,

orientate fish in the water. A line of cells running down the side of the fish

• Gill Cover (Operculum) - covers gills, movement of operculum allows more water to be drawn in

• Swim Bladder - a gas filled sac that helps the fish maintain buoyancy (sharks do not have swim bladders, they sink when they stop swimming)

• How do sharks maintain buoyancy w/o a swim bladder???

Lateral Line (fig. 8.19)

Lateral Line

Fins

Fin Shape

• Fin shape and functional diversity in fish (and compared to a shark). Show are: a. sea robin (Dactylopterus volitans): b. catfish (Corydoras aeneus); c. piked dogfish (Squalus acanthias); d. mosquito-fish (Gambusia affinis); e. anglerfish (Lophius piscatorius); f. lumpfish (Cyclopterus lumpus).

• Barbels – taste and sense food on bottom

Locomotion (fig 8.11)• Fish move through the water with movements of their tail, here

different kinds of fish locomotion are illustrated: A. A crucian carp's fin action for stabilizing and maneuvering. a. Anguilliform locomotion (eel); b. Carangiform locomotion (tuna); c. Ostraciform locomotion (boxfish). The blue area on these fish shows the portion of the body used in locomotion.

Do all fishes have scales?

• No. Many species of fishes lack scales.

• All the clingfishes (family Gobiesocidae) for example, are scaleless. Their bodies are protected by a thick layer of mucous.

Mucous• Some species like blennies, don't

have scales, but a slimy skin with brown and black spots: see picture below. These spots are of a size which can probably fluctuate according to nervous stimuli (like in squids): if the black spots are enlarged, the skin become darker to conceal itself on the dark sea bottom thus escaping its predators. If the red spots become enlarged its color mimics a brown sandy color ...It's for the same reason that fishes have a pale coloured belly: they escape predators coming from below, because they are less visible against the silvered surface of the sea.

Scales: 4 types (fig. 8.8)

• 1. Ganoid: Bony scales found in oldest known species including sturgeon.

• 2. Cycloid: Simple thin disc lik escales with smooth surface which have circular rings to determine growth.

• 3. Ctenoid: same as cycloid, but have been found in most advanced teleosts which have posterior spikes from scales. Perch

• 4. Cosmoid: Similar to placoid scales and probably evolved from the fusion of placoid scales.

Ganoid

• Ganoid scales of the Florida Gar, Lepisosteus platyrhincus. Photo: C. Bento © Australian Museum

Ctenoid & Cycloid Scales

Sturgeon

Cycloid

• Cycloid scales of Jungle Perch, Kuhlia rupestris. Photo: C. Bento © Australian Museum

CycloidRainbow Trout on lower left

Ctenoid

• Dried scale of a Barramundi showing the growth rings, or annuli

• Ctenoid scales of the Paradise Fish, Macropodus opercularis. Photo: S. Lindsay © Australian Museum

Ctenoid ScalesSole & Sea Perch

Cosmoid

• Cosmoid scales of the Queensland Lungfish. Photo: C. Bento © Australian Museum

Red muscles

• Game fish have large amounts of red muscles which contain more blood vessels = more energy and O2.

• Red muscles produce greater heat energy b/c separate smaller blood vessels carry oxygenated blood to muscles and not dorsal aorta. The blood vessels are close to the veins which are 10 degrees warmer, thus heating the blood, producing more power.

Red Muscle - Myomeres

Body Design (fig. 8.9)

• Fish possess a dorsal, ventral, posterior, and anterior symmetry

• Fish are attenuated, compressed, depressed, or fusiform in shape

Attenuated

• American Eel

Depressed

• Dorsoventrally

Flattened

Laterally Compressed

• Squished – side to side

Fusiform

• Torpedo Shaped = very fast

Guess Who???

• What species & shape???

Guess Who???

• What species & shape???

• Male or Female? Why?

Guess Who???

• What species & shape???

Guess Who???

• What species & shape???

• Left or Right Handed???

Guess Who???

• What species & shape???

• Left or Right Handed???

Guess Who???

• What species & shape???

Who am I???

Cryptic coloration (fig 8.10a)

• a pattern of pigmentation that allows an organism to blend into the background of its preferred habitat.

Disruptive Coloration(fig.8.28, 14.30)

• Color stripes, bars, or spots

Warning Coloration(fig.8.10c)

• Dangerous, poisonous, or taste bad

Countershading

• Dark top, light bottom

Symbiotic Relationships

1.Several species of small bony fishes, such as the cleaner wrasse (Labroides dimidiatus), are "cleaners" that eat debris and parasites from the skin and scales of larger fishes.

Symbiotic Relationships

2.Remoras (family Echeneidae) commonly attach themselves to sharks or other large fishes, whales, and sea turtles using a modified dorsal fin. They eat scraps left over from the meals of their hosts. They may eat parasites as well.

Symbiotic Relationships

3.Some bony fishes have symbiotic relationships with nonfish species. Clownfishes (family Pomacentridae) live unharmed among the venomous tentacles of sea anemones, which protect the clownfish from potential predators

Commensalism

• a situation in which two organisms are associated in a relationship in which one benefits from the relationship and the other is not affected much. The two animals are called commensals.

• The word derives from the Latin com mensa, meaning sharing a table.

• + and 0 = Commensalism.

Mutualism

• + and + = Mutualism. Both species benefit by the interaction between the two species.

• Examples???

• Cleaner Shrimp Video

Parasitism

• When one organism, usually physically smaller of the two (the parasite) benefits and the other (the host) is harmed.

• + and - = One species benefits from the interaction and the other is adversely affected. Examples are predation, parasitism, and disease.

• Examples???