Osteichthyes
Description
To help you with the dissections, the anatomy terms list, a series of dissection videos, and a dissection primer have been made available for this dissection. Please make sure to review all the materials before beginning your dissection. To receive full credit, you must submit four photographs that clearly identify 16 of the anatomical features from the terms list for that animal. The number of labeled terms per photo can vary; however, no more than four labels can be external anatomical features. Each correctly identified structure will be worth 0.5 points. Please do not label more than 16 as only the first 16 will be graded.
We recommend that you insert your labeled photos into a single document that can be uploaded easily to Canvas. Also, when composing your photos, try to zoom in on the areas of interest. Caption your photographs within the document so that your TA will be able to recognize these areas even when the structures are extremely magnified or positioned in an uncommon orientation. Additionally, rather than submitting a single photo, you will need to take four separate images that show different regions of the body. At least one of the body cavity photos for each animal needs to show a physical signature card.
Osteichthyes In this module, we will dissect the perch, a member of Osteichthyes, Actinopterygii, and Teleostei. Yellow perch FWS 1.jpg by Otis Maha/U.S. Fish and Wildlife Service is in the public domain Osteichthyes Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer. Osteichthyes “Oste” = bone “Ichthyes” = fish Osteichthyes includes all bony vertebrates (not just fish!) and are split into two clades: Sarcopterygii and Actinopterygii. Major traits for Osteichthyes 1. Endochondral bone: replaces cartilage during development 2. Gas bladder: derived from the gut; ancestrally, this evolved as a lung or lungs for breathing air. It was later modified to form a buoyancy control device (gas or swim bladder) in the Actinopterygii. 1. Endochondral bone Coleman, W. M. (1921). Beginners Zoology. MacMillan. 2. Gas bladder Note: The gas bladder is often torn like this upon dissection. Sarcopterygii Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer. Sarcopterygii “Sarx” = flesh “Pteryx” = fin Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer. Lung Fish Fins.jpg by Patty Jansen is in the public domain Sarcopterygii includes all vertebrates with fleshy, lobelike limbs. The major extant groups include coelacanths (Actinistia), lungfish (Dipnoi), and tetrapods. The major trait in this group is the presence of paired fins that are “fleshy” (lobed) and have a bony central axis. Ray-finned fishes (Actinopterygii) Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer. Actinopterygii “Actina” = ray “Pteryx” = fin Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer. Yellow perch FWS 1.jpg by Otis Maha/U.S. Fish and Wildlife Service is in the public domain Actinopterygii includes all fish with bony or horny projections (“rays”) connected by a thin web of skin. The most extant species within this clade are in Teleostei. The major trait in Actinopterygii is the presence of these ray fins as opposed to the fleshy lobed limbs of Sarcopterygii. Teleostei Pough, F. H., Janis, C. M. (2018). Vertebrate Life (10th ed.). Sinauer. Teleost fish (Teleostei) Major trait = Operculum The operculum is a bony covering that protects the gills. Rapid expansion creates negative pressure and allows fish to ‘suck’ in prey items. Opercular pumping aids respiration (don’t have to be swimming rapidly to move H2O over gill filaments). Underneath the operculum… Gill filaments: where gas exchange occurs Gill rakers: protect the delicate gill filaments from food and other particulates passing through the pharynx Gill (branchiostegal) arches: support the gill filaments and rakers External Anatomy • Branchiostegal rays – support the floor of the opercular chamber • Maxilla – upper jaw bone; acts as a lever for the jaw muscles in helping to protrude the premaxilla (upper jaw bone) forward and the mandible (lower jaw bone) downward; participates in “gulping” action for sucking in prey • Naris – opening that allows water to flow into the olfactory sacs • Lateral line – senses pressure and vibrations • Anus – exit for intestinal excreta • Urogenital aperture – exit for urinary and reproductive excreta Digestive System • Pharynx – opening inside the mouth that acts as both leads to the esophagus and contains the internal gill structures • Esophagus – tube carrying food to stomach • Stomach – chemical digestion • Small intestine – nutrient absorption • Pyloric ceca (singular: cecum) – extensions of the intestine that secrete digestive enzymes and add extra surface area for nutrient absorption • Pancreas – secretes digestive enzymes and some hormones (e.g. insulin); note: will not be visible in perch specimens • Liver – stores energy, metabolizes waste, breaks down toxins (like alcohol), produces blood clotting factors, and produces bile • Gallbladder – stores and secretes bile to break down fats Urogenital System • Kidney – removes nitrogenous waste from blood for temporary storage in urinary bladder and eventual excretion into urogenital aperture • Urinary bladder – temporary storage for nitrogenous waste before exit through the urogenital aperture • Testes (male) – produce sperm • Ovaries (female) – produce eggs/ova Cardiovascular System Deoxygenated blood from the body enters the sinus venosus and fills the atrium which empties the blood into the muscular ventricle. The ventricle pumps blood through the bulbus arteriosus to the gill capillary beds to become oxygenated then the body tissues to distribute the oxygen. Two chamber heart.svg by Ahnode CC BY SA 3.0 Other Structure-Function Relationships • Spleen – produces white blood cells, destroys old red blood cells • Transverse septum – thin membrane separating the head/heart cavity from the body cavity Perch Anatomy Terms List External Anatomy Branchiostegal rays Lateral line Naris Operculum Anterior dorsal fin Pectoral fin Pelvic fin Anal fin Posterior dorsal fin Caudal fin Anus Urogenital aperture Gallbladder Liver Esophagus Transverse septum Pharynx Intestine Pyloric ceca Testes Ovaries Sinus venosus Atrium Ventricle Bulbus arteriosus Internal Anatomy Gill filaments Gill arches Gill rakers Swim bladder Kidney Urinary bladder Spleen Stomach