South Florida Science Museum Shark Dissection Program Curriculum
PROGRAM DESCRIPTION Dissection labs are designed to give students a hands-on approach to learning about anatomy, both externally and internally of various animal groups. Shark dissections allow students to discover the structures and functions of the spiny dogfish. Hand-outs, equipment, and specimens are all provided by the Museum. After having the chance to dissect a shark, students will be able to compare and contrast their body systems to ours.
SUNSHINE STATE STANDARDS SC.6.L.15.1: Analyze and describe how and why organisms are classified according to shared characteristics with emphasis on the Linnaean system combined with the concept of Domains. SC.6.L.14.5: Identify and investigate the general functions of the major systems of the human body (digestive, respiratory, circulatory, reproductive, excretory, immune, nervous, and musculoskeletal) and describe ways these systems interact with each other to maintain homeostasis.
MATERIALS - Dissection Trays - Shark specimen (1 per 4 students) - Dissection tools (scissors, forceps, probe, scalpel) - Gloves - Apron - Laminated anatomy worksheets
VOCABULARY Cartilage – a firm, elastic, flexible type of connective tissue Dorsal – situated on or toward the upper side of the body, equivalent to the back, or posterior, in humans Ventral - situated on or toward the lower, abdominal plane of the body; equivalent to the front, or anterior, in humans Pectoral Fins - either of a pair of fins situated just behind the head in fishes that help control the direction of movement Pelvic Fins - either of a pair of fins attached to the pelvic girdle in fishes that help control the direction of movement; correspond to hind limbs of a land vertebrate Gills – the respiratory organ of most aquatic animals that breathe water to obtain oxygen Spiracles - a small respiratory opening behind the eye of certain fishes, such as sharks, rays, and skates Dermal Denticles - a tooth like or plate like scale of cartilaginous fishes, such as sharks and rays Hydrodynamic - pertaining to, or derived from, the dynamical action of water of a liquid; of or pertaining to water power Endolymphatic pores – external opening which serves as ears in sharks Lateral Line - sense organs of fish and amphibians; believed to detect pressure changes in the water Nictating Membrane - a transparent inner eyelid in birds, reptiles, and some mammals that closes to protect and moisten the eye Ampullae of Lorenzini - small vesicles and pores found around the head of the shark that detect weak magnetic fields produced by other fishes, at least over short ranges Uterine Horn – reproductive organ in female sharks which houses shark pups Gestation Period - the period during which an embryo develops Oviparous – egg -laying Viviparous - bringing forth living young rather than eggs Ovoviviparous - eggs inside the mother and the baby is nourished by the egg but the mother still gives live birth
SCRIPT Good morning, everyone! I’m Ms./Mr. ______from the South Florida Science Museum and today we are going to do a shark dissection lab. You will be working with a group, the people sitting next to you. In your tray in front of you, you should see a pair of scissors, a pair of forceps (look like tweezers), a probe, and a scalpel. -Put gloves on -Pick up scalpel ~ (describe way to hold them -pointer finger lining it, pointed down) -Make sure diagram is external face up
SPINY DOGFISH SHARK -dogfish because they travel in huge packs - spiny because they have spines in front of each dorsal fin *Everyone locate the dorsal fin and point to it = chunk taken out of front of dorsal for packaging purposes ~ same reason its tail is like that = their spines can tell how old they are ~ the longer the spine, the older it is
PECTORAL MUSCLES - just like our pectoral muscles = chest muscles
PELVIC FINS -can determine sex by the pelvic fins ***draw diagram on board*** (males have claspers, females do not) -so, look for claspers on your sharks -if you think you have a male, raise your hand if you think you have a female, raise your hand
GILL SLITS -how many on each side? 5 -is it possible to have more? YES, but most have 5 - How do gills function? What do they do? -help them breathe -yes, almost 2x more efficient
SPIRACLES - purpose? = push water through and over the gills so they can remain sedentary and not have to keep moving - Rub from snout to caudal fin, and then rub back the other wayFeel a difference? -from snout => tail: smooth -from tail => snout: rough -roughness is why shark skin was once used as sand paper
SHARK SENSES What’s the first sense a shark uses to detect you in the water? - Hearing *Endolymphatic pores = act like our ears; located behind spiracles *Can hear a splash of a fin up to half a mile away *Sound travels 4x faster in salt water than in air *They also have lateral lines *sense motion and pressure *same way schools of fish all move together (they don’t talk so how do they all know how to move at the same time and don’t bump into each other? Their lateral lines sense each other) - Smelling *nares = nostrils *Have you heard sharks can smell a drop of blood a mile away? - smell is good, but not THAT good -more like a glob of blood, about ¼ mile away - Seeing *have excellent vision *sharks see 10x better in the dark than we do ~ most active during dawn and dusk (when it’s dark) ~ this type of shark lives in deep water and have dark eyes ~ nurse sharks live in coastal shallow waters and have light blue eyes Lens dissection (draw diagram of cuts on board) *have lens so they can have complex vision *use scissors to make cuts, use fingers of forceps to pull it out *squirts a little so be careful *lens is a little cream colored marble *(go around and help them) - Detecting Electricity *can detect electrical currents 2 feet away *what gives off electric current? Do we? - yes, everything that’s ALIVE gives off electric current *use their ampullae of lorenzini - Touching - *use their snout to bump into things - Tasting - *99% of shark bites are called exploratory bites = just trying to figure out what you are *Better chance of being struck by lightening or winning the lottery then of being bitten by a shark
INTERNAL ANATOMY
*Draw diagram of cuts on the board *have 1 person cutting, the rest can help hold it in place *cut up to the cartilage (where it’s tough and can’t cut anymore) *from armpits, diagonally up to a point
1) Locate liver (speckled marble looking thing) using diagram *3 lobes (2 are outer and long, 1 is inner and short) ~ lift up outer lobes and pull them out and to the side
*what’s a liver’s function? ~ do sharks always eat the healthiest fish? NO ~ liver helps them not get sick off of the bad fish ~produces red blood cells ~produces bile to help in digestion ~produces oil that helps keep them buoyant 2) Locate stomach *CUT STOMACH TO SEE if they ate before they were caught 3) Locate large intestine *spiral valve = spiral staircase ~slows down digestion ~better mineral consumption ~so they don’t have to eat that often (only 2 or 3 times a month) 4) Locate spleen *produces white blood cells
REPRODUCTIVE SYSTEM
*heart is in between testes/ovaries *testes/ovaries need to be near the heart because it’s a warm, constant temp *if they’re ovaries, they have unfertilized eggs inside of them = look like potato balls *if pregnant, have a uterine horn (where the shark pups are)
3 forms of birth: 1) Oviparous *like a chicken (lay eggs) 2) Viviparous *like humans (nutrition from mother while it’s growing, give live birth) 3) Ovoviviparous *combination of both = what spiny dogfish have *embryo grows inside an egg *derives all its nutrition from the yolk *when they hatch, female gives live birth
CLEAN UP
1 person = instrument person (bring up tools, put on paper towel in front) 2 people = tray people (come dump shark in bag) -be careful of blue mat (slips off) -one table at a time
*Once everything’s done, sit back down, THEN everyone can take their gloves off (show them how to pull their gloves off ~ inside out)
*Did you guys learn something? Did you have fun?
INTERNAL AND EXTERNAL DIAGRAM WORKSHEETS