Phylum: Chordata - Laboratory Work #8 | BIO 1301, Lab Reports of Biology

Download Phylum: Chordata - Laboratory Work #8 | BIO 1301 and more Lab Reports Biology in PDF only on Docsity! -1- BIOLOGY OF ANIMALS LABORATORY LAB # 8-A(Supplement Spring09) (Written and provided by Dr. Olson; Modified by J.D. Wilhide and Dr. Alan D. Christian) PHYLUM: CHORDATA ("chordates") LAB. MAN.: EXERCISE #18-A; Pages 275-280. THE "HIGHER CHORDATES" (Early-vertebrate chordates) The higher chordates are often called the "vertebrate chordates" because the possess vertebrae at some time. They also are called the "craniata" because they possess a partial, or complete cranium (skull). SUBPHYLUM: VERTEBRATA (vertebr = ="vertebrae") a . Common names: "Fishes", "Amphibians", "Reptiles", Birds", and "Mammals". b . In most adult vertebrates (except hagfish and lamprey) the larval notochord is replaced by vertebrae in the adult stage. c . Vertebrates possess all 4 major chordate characteristics at some time in their life (especially in the embryo stage). d . Vertebrate evolution has been guided by the following major adaptations: • Living Endoskeleton: Grows with the body and thus is not size-limiting. Provides more surface area for muscle attachment...leads to more body bulk...means all systems must be improved...means a more active and aggressive lifestyle. An important chain-of-events for vertebrate success! • Muscular Pharynx with Improved Blood Supply: The ciliated pharynx of tunicates and lancelets is an inefficient filter-feeding and breathing device. The vertebrate pharynx is more muscular (moves more water) and has a much better blood supply (better oxygen pickup). As a result, vertebrates are able to have higher metabolism and activity levels. • Advanced Nervous System: A more active, predatory life required -2- centralization of the nervous system (brain/spinal cord) and considerable improvement of sensory structures (eyes, ears, chemo/mechano-receptors.) • Paired Limbs: Most "higher vertebrates" possess pectoral (fore-limb) and pelvic (hind-limb) appendages, either in the form of paired fins (swimming stabilizers) or jointed legs (for support/ locomotion on land). SUPERCLASS: AGNATHA (a = "without"; gnatha= "jaw") This superclass (in the subphylum Vertebrata) includes the most primitive of the living vertebrates. All "agnathans" lack a jaw, and lack paired appendages and lack supporting limb girdles. Their notochord persists into the adult stage, even if the beginnings of vertebrae are present. CLASS: MYXINI (Myx = "slime" or "mucus") • Common name: "Hagfishes". • All hagfishes are benthic (bottom-dwelling) marine scavengers that feed on dead, decaying, worms, fish, whale bodies, etc. • Hagfishes possess numerous mucus glands in their skin which form enormous amounts of "slippery slime" when they are "disturbed". CLASS: CEPHALASPIDOMORPHI (cephal = "head; aspido = "shield"; morph= "form") • Common name: "Lampreys". • Most lampreys are marine and parasitic on fish. The "marine lamprey" (Petromyzon marinus) has been especially damaging to commercial fishes in the Great Lakes. • A few "freshwater lampreys" (Ichthyomyzon) live only in freshwater, are not parasitic, and do not even feed as adults. • All lampreys in North America (marine or freshwater) spawn in the Spring in sandy or gravel-bottomed freshwater streams. • The larval stage of lampreys is called the ammocoete ("ammo-seat"). It lives most of its life (3-7+ years) burrowed into the sandy stream bottom where it filters food from the water. After metamorphosis, the adult may either remain in -5- e. Scales placoid (are modified to form teeth). f. Pelvic fins of males modified to form claspers (aid internal fertilization of eggs) g. Swim (air) bladder lacking: Unable to regulate buoyancy. CLASS : ACTINOPTERYGII (actino = "ray"; ptery= "fin") -The "ray-finned fishes" (including perch, catfish, crappie, etc.) are the "most-successful vertebrates" and occur in both fresh and marine waters. Their paired fins are supported by dermal rays and they exhibit an amazing variety of body styles and food habits. -Major Class Features:.....(compare with Chondrichthyes features) a. Bony Endoskeleton: In fishes, a bony skeleton is considered to be a "primitive condition" because bone originated first, before cartilage. b. Mouth terminal (anterior): Lower jaw highly mobile. c. External gill slits: 1 pair and with an operculum. d. Caudal (tail) fin homocercal (upper/lower lobes equal). e. Scales (3 types): Ganoid, Cycloid, Ctenoid. f. Pelvic fins of males not modified to form claspers (result is external fertilization of eggs). g. Swim (air) bladder present: Can regulate buoyancy. SUBCLASS: CHONDROSTEI = "primitive" ray-finned fishes. Ex.: "sturgeon" and "paddlefish" SUBCLASS: NEOPTERYGII = "intermediate" and "modern" ray- finned fishes. Ex.: "gar", "bowfin", and "teleosts" CLASS AMPHIBIA: (am-fib’e-a) (Gr. Amphi = both or double; bios = life) -6- Characteristics: a. Respiration by lungs, gills or skin b. 3 chambered heart c. Development through larval stage d. Skin moist • containing mucus glands • lacking scales ORDER URODELA (CAUDATA): salamanders ORDER ANURA: frogs and toads CLASS REPTILIA ((rep-til’e-a) (L. repere, to creep) the Reptiles. Snakes, lizards, turtles and crocodiles Characteristics a. Mostly a 3 chambered heart b. Respiration by lungs c. Embryo develops within shelled egg d. No larval stage e. Skin dry Lacking mucus glands Covered with epidermal scales ORDER TESTUDINES: turtles ORDER SQUAMATA: lizzards, snakes and lizard worms ORDER CROCODILIA: alligators and crocodiles CLASS AVES (ay’veez) (l. pl of avis = bird) The birds Characteristics a. 4 chambered heart b. Respiration by lungs c. Forelimbs usually modified for flying d. Embryo develops within shelled egg e. Body covered with feathers f. Legs covered by scales CLASS MAMMALIA (ma-may’lee-a) “ l. mamma = breast” the mammals Characteristics 1. 4 chambered heart 2. Respiration by lungs 3. Embryo develops in uterus 4. Body mostly covered with hair 5. Mammary glands LABORATORY EXERCISES: **Observe preserved male and female "dogfish sharks".** Know their external anatomy (Figure 18-4) (as explained and diagramed on page 280 - 281 of -7- lab manual) (Figure 18-4: nostril, rostrum, eye, spiracle, lateral line canal, anterior dorsal fin, posterior dorsal fin, dorsal and ventral lobes of caudal fin, pelvic fin, pectoral fin, external gill slits). **See demonstration slide of placoid scales (Figure 18-5 a and b). Be able to identify a placoid scale. **See preserved cartilage skeleton of dogfish shark. **Observe demonstration specimens representing this class and take special note of their distinct class features (listed above). **Do Perch dissection.** **Learn external and internal anatomy of the freshwater perch by reading and following lab manual instructions for Exercise 18C which begin on page 286. (For dissection know: Figure 18-9: Mouth, nostril, eye, first dorsal fin, second dorsal fin, lateral line, caudal fin, anal fin, pelvic fin, pectoral fin, operculum; Figure 18-10: Neocranium, premaxilla, operculum, dentary, maxilla, fin ray, anterior dorsal fin, posterior dorsal fin, vertebra, vertebral spin, caudal fin, anal fin, pectoral fin, ribs, pelvic fin, pelvic girdle, pectoral fin, pectoral girdle;18-12a: gills, brain, spinal chord, kidney, liver, heart, spleen, swim bladder, ovary, bladder, cardiac portion of stomach, pyloric ceca, duodenum) . **See demonstration slides of Ganoid, Cycloid and Ctenoid scale types and be able to identify each type. ** Observe demonstration specimens representing this class and take special note of their variety and distinct class features (listed above). AMPHIBIA DEMONSTRATIONS Observe demonstration specimens representing these class and take special note of their variety and distinct class features (listed above) and be able to know what common group names go with which the 2 different Order names. REPTILIA DEMONSTRATIONS Observe demonstration specimens representing thisclass and take special note of their variety and distinct class features (listed above) and be able to know what common group names go with which the 3 different Order names. AVES DEMONSTRATIONS Observe demonstration specimens representing this class and take special note of their variety and distinct class features (listed above). MAMMALIA DEMONSTRATIONS Observe demonstration specimens representing this class and take special note of their variety and distinct class features (listed above)