Fish (bony and cartilaginous)

By Lilly Beyleri, Boris Konstantinov and

Veli Mincheva 10/8

Bony and cartilaginous fishes

Vertebrates are classified based on traditional interpretations of gross anatomical and physiological traits. Bony and cartilaginous fishes are clades of the different types of vertebrates:

• Osteichthyes (bony fishes) - Clades: Ray Finned Fishes (Actinopterygii) and

Lobe-Fins (Sarcopterygii and Dipnoi)• Gnathostomes (jawed vertebrates) - Clade: Chondrichthyes (cartilaginous fishes)*Note: Both bony and cartilaginous fishes share

the 4 derived characteristics of their common phylum: Chordata, which are:

- the notochord (dorsal stiffening rod) - a hollow dorsal nerve cord- pharyngeal gills- a post anal tail that includes the notochord and

nerve cord.

Osteichthyes (bony fishes) • Osteichthyes is a taxonomic group of fish which

means bony fish; the name was coined long before the advent of phylogenetic systematics.

• More than 29,000 species• Have bony (ossified), as opposed to cartilaginous,

skeleton =endoskeleton with a hard matrix of calcium

phosphate.• The group has bilateral symmetry • The phylum of Osteichthyes is Chordata (either

vertebrates or one of several closely related invertebrates);

• Domain Eukaryota ->Kingdom Animalia ->Phylum Chordata

• Amphibians are the most closely related group• The Phylum Chordata (vertebrates) dates

530.000.000 years ago and humans (from 200.000 years ago) originate from it.

Info for Osteichthyes (bony fishes)

• Characteristics of the clade:- Endochondral ("spongy") bone in the

endoskeleton- Ectothermic (cold blooded) = their body

temperature is dependent on that of the water.

- Dermal fin rays made up by lepidotrichiae (modified, tile-shaped scales)

- Some bony fish are hermaphrodites.- Can breathe through lungs or vascularized

swim bladders or through their skin, intestines or stomach.

- Three pairs of tooth-bearing dermal bones lining the jaws (dentary, premaxillary and maxillary)

Life of the Osteichthyes • Breathing: most fishes breathe by drawing water

over 5 pairs of gills, located in chambers, covered by a protective bony flap called the operculum. Water is drawn into the mouth, though the pharynx, and out between the gills by movement of the operculum and contraction of muscles surrounding the gill chambers.

• Movement: Fishes control their buoyancy with an air sac known as a swim bladder. Movements of gases from the blood to the swim bladder increases buoyancy and the animal rises, transfer of gas back to the blood makes the animal sink.

• Reproduction: the details vary extensively. Most species are oviparous, reproducing by external fertilization after the female sheds the large number of small eggs. Birthing and internal fertilization characterize other species.

• Adaptations: Glands in the skin secrete a slimy mucus over the skin to reduce drag during swimming

Chondrichthyes (cartilaginous fishes)• Cartilaginous = the skeleton of the

species in the clade is composed predominantly of cartilage, often impregnated with calcium. Also termed- elasmobranches = flexible endoskeleton.

• More than 750 species• Major group consist of sharks, rays and

skates; second of ratfishes and chimaeras.

• Have bilateral symmetry as most Chordates

• All information about the phylum (Chordata-vertebrates) of the clade is the same as for Osteichthyes.

Info for the Chondrichthyes (cartilaginous fishes)

• Characteristics of the clade:• Cartilaginous skeleton (derived

characteristic) • Jaws • Respiration through gills • Internal fertilization • May lay eggs or give birth • Acute senses, include lateral lines

Life of the Chondrichthyes (mainly sharks here)

• Movement: Sharks are swift swimmers; cannot maneuver vey well. Although a shark gains buoyancy by storing a large amount of oil in its liver, the animal is still more dense than water and if it stops swimming, it sinks. Continual swimming ensures the water flows into the shark’s mouth and out through the gills, where gas exchange occurs (because sharks do not have lungs)

• Feeding: Largest sharks and rays consume plankton. Most sharks are carnivores = swallow their prey whole with several rows of teeth and powerful jaws. Within a shark intestine is a spiral valve, a corkscrew-shaped ridge that increases the surface area =>makes longer the passage of food through the digestive tract.

• Adaptations: acute senses; sharp vision, but are color blind, have a pair of regions in the skin of their head that can detect el. Fields produced by muscle contractions of nearby animals.

• Reproduction: Sharks have a unique form of reproduction- internal fertilization. The male transfers the sperm into the reproductive tract of the female using its claspers on its pelvic fins. Depending on the species of shark, it can either be:

- oviparous (the eggs hatch outside the mother’s body)-ovoviviparous (the fertilized egg is retained in the oviduct)- viviparous (the young develops in the uterus and nourished by

the mother prior to birth).

Examples• Osteichthyes- Dwarf pygmy goby (Pandaka pygmaea)*Elongated body that is nearly transparent; dark spots;

large head; females larger than males; curved profiles; two rows of teeth.

*only found in tropical freshwater conditions with temperature range between 24 and 30 degrees Celsius

*eats mainly plankton*found in river banks around the Philippines, Indonesia,

Singapore and imported to Germany.- Ocean Sunfish (Mola Mola)* Heaviest known; undetermined lifespan (up to 10 years

in captivity); undetermined growth rate; gentle, slow-moving giant, round, flattened bodies for movement

*Native to tropical and temperate waters (more than 10degress Celsius) all over the world, mainly between the Atlantic and Pacific

*Extended dorsal and ventral fins=>tall*It consumes: jellyfish, salps, comb jellies, zooplankton,

squid, small fishes and eel grass;

More Examples• Chondrichthyes-Great White Shark (Carcharodon Carcharias)*family: Lamnidae*immense size and girth- the largest predator on Earth;

conical snout with broad jaw; large, triangular teeth; upper body is gray or blue with white or pale underside;

*encountered in 12-16 ft range; Sizes exceed 7 metes and 2300kg.

*lifespan of 30 to 100 years; becomes sexually mature at 15

*Eats dolphins, porpoises, whale carcasses and pinnipeds like seals.

*Only surviving species of the genus Carcharodon. *Found in coastal surface waters in all major oceans.

(with temperature between 12 and 24 degrees Celsius)

*Their dies is composed mainly of fish*Great white sharks are ovoviviparous, but their birth

has never been observed

Interactions with Humans

• More than 100 million metric tons of bony fishes are harvested every year for human consumption

• Bony fishes are also used to feed livestock, make fertilizer, and produce fish oil and production of metallic paints, leather, glue, and medicines

• Sharks can and do attack humans, although the risk of dying from a shark bite is about 1 percent of the risk of being killed by lightning. Only about one to two dozen deaths by shark attack occur annually.

• In contrast, an estimated 30,000 human illnesses occur each year when people eat poisonous fish.

• we eat a whole lot of fish!!!

Vocabulary:• Chondrichthyans- cartilaginous fishes • Osteichthyans- bony fishes• Oviparous – type of reproduction among fish (internal

fertilization), where the eggs hatch outside the mother’s body

• Ovoviviparous- type of reproduction among fish (internal fertilization), where the fertilized egg is retained in the oviduct.

• Viviparous- type of reproduction among fish (internal fertilization), where the young develops in the uterus and nourished by the mother prior to birth

• Cloaca- a common chamber, that has a single opening to the outside

• Operculum- protective bony flap that covers the chambers where the pairs of gills of the Osteichthyans.

• Swim bladder- air sac, with which fish control their buoyancy.

• Cartilage- A tough, elastic, fibrous connective tissue which is a major constituent of the embryonic and young vertebrate skeleton

• Buoyancy- ability to float on water

Fun Fact• Goldfish have been pets over 1000

years

• Goldfish can actually see ultra-violet and infra-red colors

• Goldfish can live up to over 20 years more than most cats and dogs

• The oldest Goldfish recorded was 49 years old

Works Cited Page•  "Fishes, Cartilaginous - Depth, Largest, Salt, Marine, Human." Water:

Science and Issues. Web. 22 Mar. 2010. <http://www.waterencyclopedia.com/En-Ge/Fishes-Cartilaginous.html>.

• "Osteichthyes." Fernbank Science Center. Web. 22 Mar. 2010. <http://fernbank.edu/STT/VertBio/pages/Osteichthyes/osteichthyes.htm>.

•  "CHONDRICHTHYES." University of Miami Department of Biology. Web. 22 Mar. 2010. <http://www.bio.miami.edu/sharks/shark.htm>.

• BioMEDIA ASSOCIATES. Web. 22 Mar. 2010. <http://ebiomedia.com/prod/BOchordates.html>.

•  "Chondrichthyes -." Wikipedia, the Free Encyclopedia. Web. 22 Mar. 2010. <http://en.wikipedia.org/wiki/Chondrichthyes>.

•  "Osteichthyes -." Wikipedia, the Free Encyclopedia. Web. 22 Mar. 2010. <http://en.wikipedia.org/wiki/Osteichthyes>.

• "8 Fun Goldfish Facts | Freshwater Aquariums." Freshwater Tropical Fish | Freshwater Aquarium Care - Freshwater-Aquariums.net. Web. 22 Mar. 2010. <http://freshwater-aquariums.net/8-fun-goldfish-facts.html>.

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