Warm-Up Write down five different characteristics of fish that you have observed. Once everyone is finished we will discuss them as a class.
Chapter 11:Fishes, Amphibians, and Reptiles SECTION 2: FISHES
A fish is avertebrate that livesin water and usesfins to move.Fish live inwater, havefins, obtain oxygenthrough gills, havescales, and most areectotherms.Fish are thelargest group ofvertebrates; almost Characteristics of Fishes50%.
Fish get oxygenfrom water. To getoxygen, they opentheir mouth, letwater in. The waterthen goes to thefish’s gills where itwill take the oxygenand spread it to therest of the fish.Then the water issent out of thebody. Characteristics of Fishes
Once oxygen hasentered the fish’sgills it will go in aloop through thefish’s body until ithas spread all of theoxygen evenly.A fish has a closedcirculatory systemlike mostvertebrates.The blood in afish goes from the Characteristics of Fishesgills to theheart, and backagain.
All fish have finsand these help fishto swim.A fin provides alarge surface topush against thewater; it’s kind oflike an oar.Each fin has thinmembranestretched acrossbony supports. Characteristics of Fishes
Most fishes haveexternalfertilization. Thismeans that they layeggs outside theirbody. Once the eggsare laid a male fishwill come andfertilize them byspreading a cloudof sperm over them.Some fishes, likesharks, haveinternalfertilization. This Characteristics of Fishesmeans they carrytheir young untilthey are born.
Fishes havenervous systemsand sense organsthat help them findfood and avoidpredators.Fish may havewhiskers that helpthemsmell, taste, andfeel. This can helpthem find food andit can help themknow when to avoid Characteristics of Fishesa dangerouspredator.
The major groupsof fishes are jawlessfishes, cartilaginousfishes, and bonyfishes.Jawless fishes areunlike other fishessince they have nojaws or scales.Cartilage is whatmakes up a jawlessfishes skeleton.Hagfishes andlampreys are theonly kinds of Jawless Fishesjawless fishes thatexist today.
Cartilaginousfishes have jawsand scales. Theyalso have skeletonsmade of cartilage.Sharks usecurrents andmoving to getoxygen whereasrays will move lessand get waterthrough holesbehind their eyes.Cartilaginousfishes are usually Cartilaginous Fishescarnivores.
A bony fish hasjaws, scales, a pocketon each side of thehead that holds thegills, and a skeletonmade of hard bones.Bony fish have aswim bladder whichis an internal gasfilled sac whichhelps the fish staystable at differentdepths in the water.95% of all fishes Bony Fishesare bony fishes.They can live insalt and fresh water.