This lesson focuses on the topics of adaptation, habitat, and diversity as they apply to life in the ocean. During the activity the students will explore these important scientific concepts, as well as other important topics surrounding fish morphology, their defense strategies, general fish characteristics, and their ecosystems.

Fish morphology is a good starting place for this lesson. To appreciate, as well as to understand the diversity of marine fish, it is important to first be able to identify features that are common to most fish. Fish morphology is also especially important for the lab that accompanies this lesson, wherein the students will be asked to identify unique characteristics and adaptations for each fish. Without being able to identify a caudal fin for example, the students will not be able to attempt to explain what type of swimmer that fish is or what type of lifestyle that fish lives. When covering fish morphology include: (1) body forms of fish (2) fin function, location, and types-dorsal, caudal, anal, pelvic, pectoral (3) the operculum, nostril, gills, eyes, and lateral line (4) mouth shape, size, and location.

Once the students can identify the basic external characteristics of fish you are ready to introduce the major scientific concepts of this lesson; adaptation, habitat, and diversity. When introducing these concepts you might consider asking students, either by themselves or in small groups, to define these terms/concepts one at a time, following with a class discussion on each. This is a good way to uncover any misconceptions as well to stimulate participation. After discussing adaptation, take time to show a couple non-marine examples found possibly on your immediate campus or area (i.e.. overheads). Following the discussion on habitat, take time to come-up with examples of habitats, then introduce the marine habitats that will be referred to in lab-coral reef, sandy bottom, deep sea, and pelagic.

The next segment to this lesson is the exploratory lab. The lab itself can involve as many fish as you have specimens. It is a good idea however, to walk the students through an example or two in order to help them get started with what type of characteristics to be looking for as they explore and observe each specimen. It might also be a good idea to weave some drama into the lab by telling the class that they are all marine biologists that have just discovered some specimens of fish, and they are now studying them to try and identify their diets, their defense mechanisms, general habits, characteristics, possible lifestyles, their adaptations, and their habitats (it is during this part of the lesson where the students will need to use their knowledge of fish morphology to be able to come up with well educated ideas about the specimens).

Before the lab begins, pass out a lab worksheet with three columns; (1) Organism (2) Characteristics/Adaptations (3) Habitat. With this sheet in front of them, walk the students through an example having them fill in each of the categories as you do during your demo. Under the organism column the students will simply write down the name of the fish which is to be provided to them by the teacher. The column labeled Characteristics/Adaptations is where the students really need to do some exploring and reasoning in order to come up with ideas about the fish. It is in this column where they are to write down unique characteristics and adaptations that they identify, and anything else that they come up with. It is important for you the teacher, to explain to the students (marine biologists) that they are to feel free to inquire and write down any of their ideas, as the specimens in front of them are ÒnewÓ and ÒundiscoveredÓ to the scientific community. You may also want to take some time here to point out that science is not a perfect discipline, and that often it is only through much work and revision of a certain study that progress is finally achieved. Lastly the students are to determine, based on their observations, which of the marine habitats the fish resides in.

During the lab the students are to fill in the lab sheet for each specimen. Rotate the specimens from group to group every five to ten minutes. During the lab, go around the classroom and ask questions to challenge and extend the studentsÕ ideas to help facilitate their learning. After each group has seen every specimen, go over and discuss the specimens, keying in on adaptations and habitats unique to each. After each specimen has been discussed, have the students explore some other unique deep sea fish and their adaptations via overheads, pictures, and/or video.

The follow-up activity that helps to deepen understanding of this lesson is the fish of the future activity. In a nutshell, the students will be presenting and developing a fish that is an adaptation of a present day fish. This activity will be explained in detail in a later section labeled Beyond the Activity.

Morphological Terms

Operculum (gill cover)-flap of bony plates and tissue which covers and protects the gill cavity

Nostril-open to an olfactory pit and are used for scent, not for respiration

Gills-area where respiration occurs

Lateral Line-is a series of small canals containing pressure sensitive receptors, helps the fish to navigate even when vision is greatly impaired

Mouth Shape-related to the type of feeding and diet of the fish

(1)long, skinny bill(tweezerlike)-poking into crevices

(2)large mouth-swallowing/tearing large prey

(3)beaklike mouth-used to graze on small algea growing on hard surfaces

(4)downward-orientated mouth-useful to suck food up from bottom

Body Forms-directly related to the lifestyle of the fish

(1) streamlined-helps to lower frictional resistance, fast swimmers

(2) laterally compressed-tall, thin shape helps to enter vertical crevices, also good for leisurely swimming, but still efficient enough to allow for burst speed

(3) broad and flat (bottom-dwellers)-adapted to lying on or below surface of sand

(4) elongated (eel-like)-facilitates maneuvering in crevasses, often live in narrow spaces in rocks or coral reefs

Fin Function-related to the maneuverability of the fish

(1) Caudal fin-provides the main thrust used in swimming

rounded caudal fin-slow swimming, has effective acceleration and maneuvering, but is inefficient for prolonged continuous swimming

truncated caudal fin (triangular shape)-turning quickly

lunate caudal fin(moon-shaped)-high propulsive efficiency for continuous long-distance swimming, but less maneuverable

forked caudal fin-produces less drag and is efficient for rapid swimming

(2) Pelvic fins-help the fish to turn, balance, and brake

(3) Dorsal and Anal fins-used to stabilize and steer, and help prevent rolling over while turning at high speeds

(4) Pectoral fins-help to keep balance and can help provide lift

Scientific Concepts

Habitat-the area or natural environment in which an organism normally lives or grows

Adaptation-to adjust or becoming adjusted to new or different conditions

Diversity-the total number of species inhabiting a particular environment

Marine Habitats

Coral Reef-the fish that are found living in and around the coral reef, coral reefs are made of calcium carbonate (CaCO3), limestone, which is deposited by reef-building corals (not all corals build reefs)

Deep Sea-the portion of the ocean in which there is not light at all, the deep sea includes the bathypelagic (ranges from 1,000-4,000m deep) and the abyssopelagic (ranges from 4,000-6,000m deep)

Pelagic-refers to the free swimming fish that are found in the open ocean Benthos-those organisms that live on the bottom

Sandy-Bottom-these organisms are benthic, but are specifically adapted (i.e.. camouflage) to inhabit the sandy ocean floor

Defense Strategies

Cryptic Coloration-form of camouflage, colored to match background/surroundings

Countershading-dorsally darkened and ventrally whitened, dark helps fish to blend in with the dark bottom when viewed from above whereas the white belly helps them to blend with the sky or clearer waters above when viewed from below

Disruptive Coloration-another form of camouflage, colors and patterns (i.e.. presence of color stripes or bars) that break up the outline of a fish making it harder to see

Eye Spot (false eye)-black spot located near base of the tail used to confuse predators

Thickened Scales-protective covering making their hard carpace relatively immune to predation

Spines-for defense and protection from predators, may be venomous

Schooling-fish swimming in schools may have a greater chance to survive than if by themselves because an individual fish in a school may be harder to pick out by a predator

The idea for this lesson originally stemmed form one of the workstations, which I used to present in Marine Discovery. The workstation was a kind of touch tank with various fish available for the students to explore and observe. The station focused on the diversity of some of the fishes of the sea, and introduced some unique characteristics of each. This station was presented in 10-15 minutes and was quite brief. I have since then developed this lesson, including the exploratory type lab incorporating the original fishes from the touch tank, as well as numerous additions. This developed lesson extends three to five class periods and addresses some essential concepts and topics of science.

Fish Diversity was developed by Ben DeGain as an undergraduate in Marine Discovery in 1997. He developed it as a 30 minute station for the Marine Discovery workshop whose purpose was to illustrate form and function of fish and adaptations to catch prey and to escape being eaten.

dishes or trays to put the specimens in

organism/adaptation/habitat handout

overheads, video, or pictures showing example adaptations and habitats

possible specimens-scorpionfish, moray eel, butterfly fish, stingray, lionfish, beaked leatherjacket herring, surgeonfish, catfish, triggerfish, clownfish, porqupinefish, angelfish, ribbon eel, seahorse

Triggerfish:

Family: Baelistida

Triggerfish can be found in the Atlantic, Pacific, and Indian oceans. They inhabit coral reefs. They have a compressed body covered with large plate-like scales (protection from predation). Their first dorsal spine can be locked into an erect position by second dorsal spine. They can also flare out their pelvis to appear larger in size. When the triggerfish senses danger, it often quickly retreats to a crevice in the reef and erects the dorsal spine and the pelvis, helping to wedge itself into shelter. They are gentle swimmers, but can swim fast if threatened using their tail. They posses a relatively small mouth with powerful jaws and strong incisor-like teeth. They feed mainly on mollusks, echinoderms, and crustaceans.

Beaked Leatherjacket:

Family: Monacanthidae

The beaked leatherjacket is found in the Great Barrier Reef and throughout S.E. Asia and Indo-W. Pacific. They inhabit coral reefs, and are closely related to triggerfishes but are laterally more compressed. They are slow swimmers, using their dorsal and anal fins, yet can achieve rapid bursts by vigorous tail movement. They feed on benthic invertebrates. They posses a unique tubular snout, orange spots (disruptive coloration), a sharp dorsal spine (defense), and eyespots located on the caudal fin.

Black Anemonefish:

Family: Pomacentridae

The black anemonefish is found in the Great Barrier Reef and throughout S.E. Asia and the C. Pacific. They inhabit lagoons and reefs. They feed on a wide variety of plant and animal material, mainly planktonic copepods and benthic algae. They have commensal with sea anemones and have distinguishing single white bar behind the eye.

Emperor Angelfish:

Family: Pomacentridae

The angelfish is found in the Great Barrier Reef and throughout S.E. Asia and the Pacific. They inhabit coral reefs and have unique black band through eye and narrow yellow stripes on side (disruptive coloration). Their diet includes sponges, tunicates, gorgonians, zooantharians, algae, hydroids, and sea-grasses. Depend upon coral crevices and caves for protection.

Zebra Lionfish:

Family: Scorpaenidae

The zebra lionfish is found in tropical waters and inhabits coral reefs. Their elaborate dorsal, anal, and pelvic spines are venomous and serve as a warning to potential predators. They have bands on pectoral fins and distinct bars on side which help to provide camouflage (disruptive coloration).

Moray Eel:

Family: Muraenidae

The moray eel can be found in tropical and subtropical seas all over the world. They typically inhabit coral reefs and can be found living in coral or rock crevices. They are scale-less and their dorsal fin is continuous along the entire length of their body. They have needle-sharp teeth and well developed olfactory senses, usually only coming out at night to feed.

Porquipinefish:

Family: Diodontidae

The porquipinefish can be found in the Atlantic, Pacific, and Indian oceans, as well as tropical seas worldwide. They inhabit the coral reef and vicinity, and have long spines on their head and body. When threatened, they inflate their bodies with air or water, causing their spines to stick out serving as a deterrent to potential predators. The flesh of the porquipinefish contains a potent toxin which provides further protection. They are slow swimmers and their tooth plates are fused into two teeth.

Ribbon Eel:

Family: Muraenidae

The ribbon eel can be found in tropical seas worldwide. They inhabit sandy burrows or rubble patches on the edge of coral reefs. The males are bright blue and yellow with elaborate nostril flaps, whereas the females are yellow except for a black anal fin. They feed on fishes and crustaceans. When threatened, they retreat into their burrow.

Scorpionfish:

Family: Scorpaenidae

They can be found in tropical and temperate waters all over the world, and inhabit coral and rocky reefs. Their diet includes crustaceans and fishes. They posses an excessively spiny body, and their dorsal, anal, and pelvic spines are venomous. They are bottom living fishes and exhibit color patterns that blend in well with their surroundings (cryptic coloration). Using their natural camouflage they lay still until a meal comes too close, then, they quickly snatch it with their large mouth. Their pectoral fins can be used for rapid bursts.

Seahorse:

Family: Syngnathidae

They are found in the Atlantic, Indian, and Pacific oceans. They inhabit reef environments. They posses an elongated snout used to poke into crevices while creating a suction to slurp up food. Seahorses are often found hiding in sea-grasses where their unique body shape serves as a form of camouflage. Their tail can be used to act as an anchor by wrapping around coral or sea-grass.

Stingray:

Family: Dasyatidae

Stingrays are found in the Atlantic, Pacific, and Indian oceans. They are most commonly found inhabiting sandy bottom environments. They have a large, circular disk-shaped body with a long slender tail. Their tail has a serrated spine with a venom gland inside. If stepped on, they will whip their tail up and deliver a painful sting. They do not posses a dorsal fin. They use their continuous pectoral fins to propel themselves through the water in an undulating motion.

Introduce fish morphology. This can be done in several ways. If you have access to a textbook with illustrations and descriptions, you may choose to use this as a starting place. If not, you can put up an overhead, drawing, or a poster to introduce the various morphological features. It also may helpful to use a fish morphology worksheet, I found that page 35 of The Marine Biology Coloring Book by Thomas M. Niesen to be very useful when introducing and discussing fish morphology. Introduce fin function, location, and types (see Background Information-Morphological Terms-Fin Function, Type, and Location). Introduce body forms (see Background Information-Morphological Terms-Body Forms).

Identify, define, and discuss the operculum, nostril, gills, lateral line, mouth shape, size and location (see Background Information-Morphological Terms). Once the students can identify the basic external characteristics of fish you are ready to introduce the major scientific concepts of this lesson. Ask students, either by themselves or in small groups, to define adaptation. After giving them some time to think and exchange ideas, engage in a short five minute discussion. After discussing, take time to show a couple non-marine examples of adaptations via overheads. Ask students, either by themselves or in small groups, to come-up with five to ten examples of habitats. After giving them a couple of minutes, engage in a class discussion listing the habitats that the students came up with. Following the discussion, introduce the marine habitats that will be referred to in the lab-coral reef, sandy bottom, deep sea and pelagic (see Background Information-Marine Habitats).

Exploratory lab introduction. Optional: explain to the class that they are all marine biologists that have just discovered many new marine specimens and are now studying them to try and identify their diets, their defense mechanisms, general habits, characteristics, possible lifestyles, their adaptations and their habitats. Now ask the students what type of questions they should be asking themselves, as scientists, about the specimens they are studying. Have small discussion to seen what kind of ideas get brought up, then put up on the overhead or on the board:

Questions to keep in mind!

(1) What do fish do?

(2) How do fish defend themselves?

(3) How do fish get food?

(4) Where do fish live in the water?

(5) How do fish swim?

Pass out lab worksheet with columns; (1) Organism (2) Characteristics/Adaptations (3) Habitat. With this sheet in front of them, walk the students through an example having them fill in each of the columns as you do during the demo (see examples below). Under the organism column the students will simply write down the name of the fish which is to be provided to them by you, the teacher. The column labeled Characteristics/Adaptations is where the students really need to do some exploring and reasoning in order to come up with ideas about the fish. It is in this column where they are to write down unique characteristics and adaptations that they identify, and anything else that they come up with. It is important for you to explain to the students (marine biologists) that they are to feel free to inquire and write down any of their ideas, as the specimens they are exploring are new to the their scientific community (for the purpose of the lab). It is critical that students gain an understanding that science is not perfect and many mistakes/false inquiries are often made in science, even by notable scientists, before anything of any merit is ever discovered or uncovered. Lastly the students are to determine which of the marine habitats each fish resides in.

Examples:

Exploratory Lab. Students should be in small cooperative learning groups of three or four. Rotate the specimens from group to group every five to ten minutes. During the lab, walk around the classroom and ask questions to challenge and extend the students' ideas. After each group has studied every specimen, discuss the specimens highlighting the unique adaptations, defense mechanisms, habitats, characteristics, etc. of each (see Background Information).

Explore some unique deep sea fish (i.e. anglerfish, flashlight fish, hatchetfish) and their adaptations via overheads, pictures, and/or video.

Follow-up activity: Fish of the Future Activity (see Beyond the Activity).

Lab Worksheet Handout:

1st question:

A fish, new to science, is collected for the first time. The specimen is studied in detail, but its stomach is empty. How could you get an idea of its feeding habits?

2nd question:

Do you think that the adaptations of organisms may be a force that drives evolution? Why or why not? Explain.

3rd question:

What effect does habitat have on the diversity of organisms?

Fish Of The Future-this is a fun activity that can be implemented after the above lesson has been completed. This activity helps the students to reflect, discuss, and apply what they have learned.

The year is 9999, and environmental conditions on Earth and in the oceans have changed dramatically. The fish that live in the ocean waters face major challenges. You and your partner are Ichthyologists and will be presenting a fish to the International Ichthyology Conference in the country of Oceanus. Your fish is an adaptation of a present day fish. It has acquired some unique abilities and adaptations that are different from the fish of 2000.

Your presentation will be both written and oral. You will also present a large color drawing or picture of your fish. After your oral presentation, be prepared to turn in your written description and your picture.

Presentation should include:

identify the problem your fish encounters what is the Earth like? the oceans?

common, scientific name, and class

composition of skeleton/support system

size of fish/body shape

habitat

swimming ability and speed

mouth location

body parts and fins

adaptations and coloration

unique abilities

defense mechanisms/protection techniques

enemies

food source

location and number of species

be creative!!!