Teacher Background Information:

Outcome: 6-1-03: Develop a system to classify common objects or living things into groups and subgroups, and explain the reasoning used in the system s development. Materials: highlighter or writing utensil Teacher s Instructions: 1. Make a class set of pages 3 and 4. Hand out page 3 to each student. 2. Review the different external features of fish and discuss the uses of some of the more unusual features. 3. Hand out page 4 to each student and ask them to complete the word search puzzle to help them remember some of the fish terminology that they will use in some of the other activities available for this outcome. An answer key is provided on page 5. Teacher Background Information: Fish are animals - they move, they have sensory organs (eyes, mouth, barbels), and they have body structure (skeleton, skin). They eat other organisms to survive. They also breathe oxygen, however they "breathe" by inhaling water through their mouths. The water is then passed over special structures called gills. The gills absorb the oxygen from the water as it flows over the gills and then exits the fish's body. The gills are protected and covered by a gill cover or operculum, just behind the cheek (yes, fish have cheeks!). While they do not use them to breathe, fish do have nostrils that they use to smell. Fish have fins to help them swim. They may have one or two dorsal fins (fins on top of the fish's back). If they have two, they may be separate or joined together. Some fish have an adipose fin on their back, which is actually a fleshy lobe that is a "leftover" of a more developed dorsal fin that was lost as the particular fish species evolved. Fish have pectoral fins (fins along the side of their body where their "arms" would be) and pelvic fins (fins underneath their bodies). They also have an anal fin just behind the vent where they excrete wastes. Their tail fin or caudal fin may be lobed or club-shaped. Depending on what they eat, fish may or may not have teeth. Fish that are carnivores or piscivores (i.e. they eat other fish) will have well-developed teeth (like a northern pike). They will likely have mouths at the end of their snout, or even above it, which helps them grasp their prey. Fish that feed off the bottom of a lake or river often do not have teeth. Their mouth may be located underneath their head to help them "vacuum" up their food (like a sucker). Some fish have barbels or fleshy feelers ("whiskers") that hang in front of the mouth (such as the catfish). These barbels are sensory structures that help the fish detect its food as it swims along the bottom of a river or lake. Continued on page 2... 1 of 5

Teacher Background Information (Cont d.): Fish have a lateral line. This is a system of holes along the sides of a fish that is actually a sensory organ. Similar to sonar, fish use it to detect vibrations and sense what they cannot see. Manitoba has many different species of fish. Some of them look very unusual and are easy to distinguish, such as the prehistoric-looking lake sturgeon. Sturgeon have an outer armour of bony plates called scutes and a heterocercal (shark-like) tail which are vestiges of earlier times. These features have disappeared in most modern-day freshwater fish. Other Manitoba species look very much alike, such as the various species of trout. All of these species have adipose fins and are distinguished from each other primarily by their body colouration. Other species also have adipose fins but can be distinguished from trout because they lack teeth (such as the whitefish). Other species with adipose fins are obviously different from trout because they have barbels (like the bullhead). Some fish have spines while other species have no spines. Fish may have spines in their dorsal fins, like a walleye, or along the leading edge of their pectoral fins, like a catfish. Goldeye and northern pike do not have any spines. Fish have scales, which may be very large or barely visible to the naked eye, depending on the species of fish. For example, goldeye scales are very large. On the other hand, catfish scales are so small, these fish look like they have a smooth skin. Some fish do not have scales, such as a burbot. All of these features - spines, teeth, barbels, tail shape, fins - can be used to help classify and identify fish species found in Manitoba. The size and shape of the mouth, body colouration, and markings (spots or stripes) can also be used to sub-classify similar species. 2 of 5

Dorsal Fin Adipose Fin Tail Fin Anal Fin Pelvic Fin Pectoral Fin Catfish Walleye Dorsal Fin Spines Gill Cover Nostral Pectoral Fin Lateral Line Pelvic Fin Anal Fin Tail Fin 3 of 5

Find the 15 words listed below and decode the secret message using the letters that remain on the first two lines (hint: start from left to right) C N A S F I S H I L N S A V E R A I T E E B R A A O T E N U S H U F J L N X Q S S S M Y S F Z V D L W A S N R T N Y N K J S O Q A I L C R O R I M B T T U E N T L A P S D I F N N Z K U F Y I G E T T M L U E A A H A O G E C E N I P S V X V Q Y G M N T O O V E V C F F H B Q J C O S Z A V P V A J T M Z W A R H I Q Z A M O U T H U G C A S L E B R A B Q B H U S U L N A M F E B A Q M J F H F H H N I X X W K E Y C I V D M N P G H X Y Q Y R Y P C C S L S Dorsal Gills Pectoral Spine Caudal Eyes Mouth Scales Tailfin Hidden Message Cheek Fins Nostrils Snout Vent 4 of 5