The Water Pixies

THE LIFE CYCLE OF AQUATIC ANIMALS

Respect Rule: Look, Listen, Learn, and Leave Alone (until instructed).

Overview

Hands-on exploration of the creek environment engages students in learning first hand about aquatic animal life cycles.

Background

Animals have unique strategies for development that also applies to aquatic species. This great diversity in aquatic life teaches about life cycles. There are representative species of mammals, amphibians, insects, fish, and birds that live most or all of their lives in the water.

Aquatic insects exhibit two different types of life cycles. Many animals look significantly different in their early stages of development when compared to adulthood. This is often very true for aquatic insects. Many aquatic insects undergo metamorphosis, or change during growth. Some insects experience simple metamorphosis, while others undergo complete metamorphosis.

In simple metamorphosis, the insect egg develops into a nymph. Nymphs resemble adults, but they still vary considerably from their adult form. Many nymphs transform into adulthood by splitting open the exoskeleton so that the mature adult can emerge. This is true for dragonflies, damselflies, stoneflies, and mayflies.

In complete metamorphosis, eggs develop into larvae. The larvae grows through several stages and changes into pupae. Pupae are usually encased in a protective cover for their next stage of growth. From the pupae, emerge the soft-bodied, often pale-colored adults. They differ remarkably in appearance from earlier appearance, but are not yet completely formed. Gradually the soft pale bodies develop firmness and color. In complete metamorphosis, there is little resemblance between adults and larvae. Examples of this are caddis flies, most aquatic beetles and flies, as well as butterflies.

When a habitat changes, either slowly or catastrophically, the species of animals with adaptations (that allow them many options) are the ones most likely to survive. Some species have adapted to such a narrow range of habitat conditions that they are extremely vulnerable to change. These species are usually more susceptible than other animals to death or extinction. Each animal has its own unique physical adaptations to the watery world. Here are a few examples of adaptations to look for: streamlined body shape to move easily through the water; gills for underwater breathing; sharp hooks or claws to grasp the bottom in rushing water; camouflage colors for evading predators; dense fur to retain heat; webbed feet for more efficient paddling; and oil glands to repel water.

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Before-the-Field-Trip Activity

Activity: Are You Me?
Time: One or two 20-minute sessions in groups of 3 or 4 student each; preparation time for students to bring family pictures to class
Materials: Cardboard for making cards, Aquatic Animal Identification Cards, Aquatic Insect Life Cycle Stage Fact Sheet

Make pairs of cards of aquatic animals, such as a pair of beavers and a pair of pelicans, and so forth. One animal in the pair should be an adult; the other should be at a younger stage of development. The pairs might include adult, larva, nymph, hatchling, juvenile, infant and/or egg forms of aquatic animals.
Ask the students to bring two pictures from home, one of an adult, the other of a child. The pictures should be pictures of the same person as an adult and as a child.
Divide the class into small groups of three or four students and have them stand around a table. Have the students at each table place the adult-child pictures on the table and mix them randomly. Once the adult-child pictures are mixed at each table, have the entire group shift to another table so there will not be anyone at the table where their own pictures are placed.
At the new table, have the group attempt to match pairs of adult/child or student/infant photos.
When the students at each table have completed their efforts to match the pairs, ask all of the groups to return to the table where they started this activity. Are the matches correct? Ask the students to change any pairs that are not correctly matched. Talk about how difficult or easy it was to correctly match pairs. Introduce the idea that many animals look remarkably different as adults than they appeared in younger forms. (See the Aquatic Insect Life Cycle Stage Fact Sheet.) Tell the students that they are about to learn how to match young and adult forms of many different kinds of aquatic animals.
Introduce the Aquatic Animal Identification Cards and divide the class into groups. Designate one group as “adult” and the other half as “young animals.” Give each student in the adult group an adult animal image. Give each student in the young animal group a young animal image. Make sure there is a corresponding match, adult or juvenile, for each card given. Instruct the students to look for their match by pairing the appropriate adult and juvenile forms.
When all the students have made their choices, let the group ensure that the matches are correct. Teachers may show the students the matched images on the master.
Have all of the students examine the correctly matched pairs. Look for the similarities and differences in how aquatic animals grow and change.

Note: This activity can be repeated several times by shuffling the adult and young images so that each student becomes familiar with a wider array of animals.

Extensions

Research some of the habitats in which these animals live. If possible, visit some of the habitats where the animals are actually found.
Pick a pair of images and find out more about the life cycles of the animals shown.
Discuss and/or pantomime the concept of metamorphosis.

“When we share the outdoors with others, we receive much more than we give. Sharing intensifies our won, inner experiences. Enjoying nature with others reveals the aspects of the outdoors that we love most. Sharing nature’s serenity and joy with others, we absorb the same qualities in increased measure ourselves.”

—Joseph Cornell, Listening to Nature

Field Trip Activity

Activity: Observe Aquatic Life Cycles
Time: 1 to 1.5 hours
Materials: Aquatic Animals Fact Sheets, Aquatic Animal Habitats Student Worksheet, collecting cups and nets, large collecting containers, magnifiers, water quality test kit, thermometer, stereomicroscope, Stream Ecology Exploration Kit (STE Lending Library)

Preparation for Field Trip

Select a small, shallow, slow-moving stream or pond as the sampling site. Be sensitive to the impact students may have on stream bands and beds, spawning and nesting sites, and vegetation.
Have students establish ethical guidelines for their sampling activities.
Advise students to dress for trip: old “tennies” or water socks and shorts are best.

At the Site

Remind students of their ethical guidelines for sampling. Instruct them on how to minimize the potential for damaging the habitat and encourage care in their collecting techniques. Emphasize that all wildlife is to be returned to its habitat unharmed.
Establish boundaries and a group signal for announcements and safety.
Give each student a collecting cup and net.
Place larger collecting containers, Aquatic Animals Fact Sheets, and magnifiers in the shade near the water.
Begin by having students observe the water. Identify organisms on the surface and in the depths.
Using the sampling equipment, instruct students to move slowly into the water, collecting as many different forms of animal life as possible. Instruct them to explore the many micro-habitats within the aquatic environment: slow-moving pools, riffles, shade, sun, under rocks, and on the surface. While they will find mostly aquatic insects, be sure to look for other types of animals as well.
Place small animals in the large collecting containers for all to observe. Water should always be in all the collecting containers. In the shade, use the magnifiers to see more detail.
Using the Aquatic Animal Identification Cards, Aquatic Animals (1) (2) Fact Sheets, and the Aquatic Animal Habitats Student Worksheet, have each student or team of students identify and draw the animals they observed and where they found them.

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After-the-Field-Trip Activity

Activity: Create the Life Cycle
Time: 45 minutes
Materials: Materials for different art mediums

Have each student choose two aquatic animals they observed on the field trip.
Construct and describe in writing the life cycles of those animals. Use different mediums to produce the life cycle.
Have students review Aquatic Animals Fact Sheets for detailed information (pages 15, 16, 25–35).

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Objectives

Students will describe the life cycles of two forms of aquatic life.

Grade Levels

Adult/Student Ratio

10 students to 1 adult

Location

Riparian habitat: small, shallow, streams or ponds where students can access the water safely and with minimal impact to the streamside vegetation.

Skills

Observing, collecting, describing, classifying, identifying, cooperative learning

Key Words

Adaptation, Aquatic, Complete metamorphosis, Life cycle, Macro invertebrates, Metamorphosis

Downloads [PDF]

Lesson
Worksheets:
- Aquatic Animals 1
- Aquatic Animals 2
- Aquatic Animal Identification Cards
- Aquatic Animal Habitats
- Aquatic Insect Life Cycle Stage
- Scud (Sideswimmer) Fact Sheet
- Crayfish Fact Sheet
- Waterstrider Fact Sheet
- Water Boatman Fact Sheet
- Net-Spinning Caddisfly Larvae Fact Sheet
- Stonefly Nymph Fact Sheet
- Water Penny Beetle Fact Sheet
- Mosquito Larvae Fact Sheet
- Mayfly Nymph Fact Sheet
- Dragonfly Nymph Fact Sheet
- Case-Building Caddisfly Fact Sheet
View all Circles and Cycles PDFs

Resources

For the Teacher

A Beginner’s Guide to Fresh-Water Life. Leon Hausman. Putnam’s Sons.
Golden Guide to Pond Life. George K. Reid, Herbert S. Zim. Western Publishing Company.
Water Insects. Sylvia Johnson. Lerner Publications.
A Handbook of Hatches. Dave Hughes.
Dragonflies, a WILD Guide. Berger.

Videos

Ecosystem of a Pond. Chatsworth, California: AIMS Media, 1992.
Wonders in A Country Stream. Los Angeles: Churchill Media, 1992.

Source

Adapted with permission from “Are You Me,” Project WILD Aquatic, 1992.

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THIS LESSON: Downloads Objectives Grade Levels Adult:Students Location Skills Key Words Worksheets Resources EXPLORE SITE: Home Appendices Activities Lessons	Water \| Energy \| Air \| Land The Water Pixies THE LIFE CYCLE OF AQUATIC ANIMALS Respect Rule: Look, Listen, Learn, and Leave Alone (until instructed). Overview Hands-on exploration of the creek environment engages students in learning first hand about aquatic animal life cycles. Background Animals have unique strategies for development that also applies to aquatic species. This great diversity in aquatic life teaches about life cycles. There are representative species of mammals, amphibians, insects, fish, and birds that live most or all of their lives in the water. Aquatic insects exhibit two different types of life cycles. Many animals look significantly different in their early stages of development when compared to adulthood. This is often very true for aquatic insects. Many aquatic insects undergo metamorphosis, or change during growth. Some insects experience simple metamorphosis, while others undergo complete metamorphosis. In simple metamorphosis, the insect egg develops into a nymph. Nymphs resemble adults, but they still vary considerably from their adult form. Many nymphs transform into adulthood by splitting open the exoskeleton so that the mature adult can emerge. This is true for dragonflies, damselflies, stoneflies, and mayflies. In complete metamorphosis, eggs develop into larvae. The larvae grows through several stages and changes into pupae. Pupae are usually encased in a protective cover for their next stage of growth. From the pupae, emerge the soft-bodied, often pale-colored adults. They differ remarkably in appearance from earlier appearance, but are not yet completely formed. Gradually the soft pale bodies develop firmness and color. In complete metamorphosis, there is little resemblance between adults and larvae. Examples of this are caddis flies, most aquatic beetles and flies, as well as butterflies. When a habitat changes, either slowly or catastrophically, the species of animals with adaptations (that allow them many options) are the ones most likely to survive. Some species have adapted to such a narrow range of habitat conditions that they are extremely vulnerable to change. These species are usually more susceptible than other animals to death or extinction. Each animal has its own unique physical adaptations to the watery world. Here are a few examples of adaptations to look for: streamlined body shape to move easily through the water; gills for underwater breathing; sharp hooks or claws to grasp the bottom in rushing water; camouflage colors for evading predators; dense fur to retain heat; webbed feet for more efficient paddling; and oil glands to repel water. [Back to top] Before-the-Field-Trip Activity Activity: Are You Me? Time: One or two 20-minute sessions in groups of 3 or 4 student each; preparation time for students to bring family pictures to class Materials: Cardboard for making cards, Aquatic Animal Identification Cards, Aquatic Insect Life Cycle Stage Fact Sheet Make pairs of cards of aquatic animals, such as a pair of beavers and a pair of pelicans, and so forth. One animal in the pair should be an adult; the other should be at a younger stage of development. The pairs might include adult, larva, nymph, hatchling, juvenile, infant and/or egg forms of aquatic animals. Ask the students to bring two pictures from home, one of an adult, the other of a child. The pictures should be pictures of the same person as an adult and as a child. Divide the class into small groups of three or four students and have them stand around a table. Have the students at each table place the adult-child pictures on the table and mix them randomly. Once the adult-child pictures are mixed at each table, have the entire group shift to another table so there will not be anyone at the table where their own pictures are placed. At the new table, have the group attempt to match pairs of adult/child or student/infant photos. When the students at each table have completed their efforts to match the pairs, ask all of the groups to return to the table where they started this activity. Are the matches correct? Ask the students to change any pairs that are not correctly matched. Talk about how difficult or easy it was to correctly match pairs. Introduce the idea that many animals look remarkably different as adults than they appeared in younger forms. (See the Aquatic Insect Life Cycle Stage Fact Sheet.) Tell the students that they are about to learn how to match young and adult forms of many different kinds of aquatic animals. Introduce the Aquatic Animal Identification Cards and divide the class into groups. Designate one group as “adult” and the other half as “young animals.” Give each student in the adult group an adult animal image. Give each student in the young animal group a young animal image. Make sure there is a corresponding match, adult or juvenile, for each card given. Instruct the students to look for their match by pairing the appropriate adult and juvenile forms. When all the students have made their choices, let the group ensure that the matches are correct. Teachers may show the students the matched images on the master. Have all of the students examine the correctly matched pairs. Look for the similarities and differences in how aquatic animals grow and change. Note: This activity can be repeated several times by shuffling the adult and young images so that each student becomes familiar with a wider array of animals. Extensions Research some of the habitats in which these animals live. If possible, visit some of the habitats where the animals are actually found. Pick a pair of images and find out more about the life cycles of the animals shown. Discuss and/or pantomime the concept of metamorphosis. “When we share the outdoors with others, we receive much more than we give. Sharing intensifies our won, inner experiences. Enjoying nature with others reveals the aspects of the outdoors that we love most. Sharing nature’s serenity and joy with others, we absorb the same qualities in increased measure ourselves.” —Joseph Cornell, Listening to Nature Field Trip Activity Activity: Observe Aquatic Life Cycles Time: 1 to 1.5 hours Materials: Aquatic Animals Fact Sheets, Aquatic Animal Habitats Student Worksheet, collecting cups and nets, large collecting containers, magnifiers, water quality test kit, thermometer, stereomicroscope, Stream Ecology Exploration Kit (STE Lending Library) Preparation for Field Trip Select a small, shallow, slow-moving stream or pond as the sampling site. Be sensitive to the impact students may have on stream bands and beds, spawning and nesting sites, and vegetation. Have students establish ethical guidelines for their sampling activities. Advise students to dress for trip: old “tennies” or water socks and shorts are best. At the Site Remind students of their ethical guidelines for sampling. Instruct them on how to minimize the potential for damaging the habitat and encourage care in their collecting techniques. Emphasize that all wildlife is to be returned to its habitat unharmed. Establish boundaries and a group signal for announcements and safety. Give each student a collecting cup and net. Place larger collecting containers, Aquatic Animals Fact Sheets, and magnifiers in the shade near the water. Begin by having students observe the water. Identify organisms on the surface and in the depths. Using the sampling equipment, instruct students to move slowly into the water, collecting as many different forms of animal life as possible. Instruct them to explore the many micro-habitats within the aquatic environment: slow-moving pools, riffles, shade, sun, under rocks, and on the surface. While they will find mostly aquatic insects, be sure to look for other types of animals as well. Place small animals in the large collecting containers for all to observe. Water should always be in all the collecting containers. In the shade, use the magnifiers to see more detail. Using the Aquatic Animal Identification Cards, Aquatic Animals (1) (2) Fact Sheets, and the Aquatic Animal Habitats Student Worksheet, have each student or team of students identify and draw the animals they observed and where they found them. [Back to top] After-the-Field-Trip Activity Activity: Create the Life Cycle Time: 45 minutes Materials: Materials for different art mediums Have each student choose two aquatic animals they observed on the field trip. Construct and describe in writing the life cycles of those animals. Use different mediums to produce the life cycle. Have students review Aquatic Animals Fact Sheets for detailed information (pages 15, 16, 25–35). [Back to top] Objectives Students will describe the life cycles of two forms of aquatic life. Grade Levels 2 Adult/Student Ratio 10 students to 1 adult Location Riparian habitat: small, shallow, streams or ponds where students can access the water safely and with minimal impact to the streamside vegetation. Skills Observing, collecting, describing, classifying, identifying, cooperative learning Key Words Adaptation, Aquatic, Complete metamorphosis, Life cycle, Macro invertebrates, Metamorphosis Downloads [PDF] Lesson Worksheets: Aquatic Animals 1 Aquatic Animals 2 Aquatic Animal Identification Cards Aquatic Animal Habitats Aquatic Insect Life Cycle Stage Scud (Sideswimmer) Fact Sheet Crayfish Fact Sheet Waterstrider Fact Sheet Water Boatman Fact Sheet Net-Spinning Caddisfly Larvae Fact Sheet Stonefly Nymph Fact Sheet Water Penny Beetle Fact Sheet Mosquito Larvae Fact Sheet Mayfly Nymph Fact Sheet Dragonfly Nymph Fact Sheet Case-Building Caddisfly Fact Sheet View all Circles and Cycles PDFs Resources For the Teacher A Beginner’s Guide to Fresh-Water Life. Leon Hausman. Putnam’s Sons. Golden Guide to Pond Life. George K. Reid, Herbert S. Zim. Western Publishing Company. Water Insects. Sylvia Johnson. Lerner Publications. A Handbook of Hatches. Dave Hughes. Dragonflies, a WILD Guide. Berger. Videos Ecosystem of a Pond. Chatsworth, California: AIMS Media, 1992. Wonders in A Country Stream. Los Angeles: Churchill Media, 1992. Source Adapted with permission from “Are You Me,” Project WILD Aquatic, 1992. [Back to top]
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