Teacher Background

Investigation 1

This unit introduces the concept of habitat with a focus on aquatic habitats. Habitat refers to an organism’s environment—where it finds all that it needs to survive and where the conditions are suitable for staying alive.

Students at this grade level can begin by thinking in terms of a home. They can also begin with the concept of shelter, because many animals have a physical shelter that students can observe on the playground or on a field trip. In subsequent investigations in this unit, they will begin to conceptualize watery environments as a type of home or shelter where plants and animals can find what they need to survive (food, water, shelter in a suitable arrangement). Shelters also provide hiding places from direct threats to staying alive, like being eaten by a predator and also less obvious threats to survival like being too dry or too cold or too warm or being unable to breathe. They will also increase their awareness by observing life at various life stages in the water at a scale that cannot be seen by the naked eye. Finally, they will begin observing the unique characteristics, or adaptations, of animals that allow them to live in the water. 

Alaska has many types of aquatic habitats. These include

Marine or salt water:

• Ocean
• Intertidal beach
• Wetlands (examples: saltwater marsh, slough)

Freshwater:

• Stream
• Lake
• Pond
• Other wetland habitats (examples: bog, freshwater marsh, wet tundra)

The ocean is accessible from many communities, and inland communities have streams, ponds, or wetlands usually in close proximity to schools. This unit provides a combination of direct observation, an inquiry approach to defining the needs and thus, the habitat, of specific aquatic animals; and communication about observations, conclusions, and additional inquiries.

Print Resources

Videos

Web sites

Investigation 2

For this investigation, capitalize on students’ natural curiosity of aquatic creatures. The choices of animals to study may need to be driven by your local resources (books, video images, Zoobooks, experts library resources, etc.). Showing a local video clip and/or similar habitat video might be a way to engage interest in particular habitat. Your examples of aquatic animals can be those that spend their entire life cycle in the water (e.g., fish, whales, algae); those that spend part of their life cycle in the water (e.g., frogs, insects such as mosquitoes); or those that use shorelines and intertidal areas (e.g., shorebirds, sea stars, and other marine invertebrates).

Observing animals that live in water poses some obstacles, because the most common animals that can be found in abundance in water are small and their food sources even smaller or microscopic. This is where the What’s in the Jar? experiment from Investigation 1 will begin to uncover the mystery. Students should be encouraged to make predictions and pose questions throughout the research. Teachers can assist the students by modeling an "I wonder" type of question as students share their research with each other.

Pop-up Diorama. Examples of students that have used file folders to create dioramas.

Shoebox diorama

The Habitat Song by Bill Oliver. Listen to part of the song and see the words.

Investigation 3

To order brine shrimp:

(Triops is another kind of isopod that could be ordered. They grow larger and might be easier for younger children to see. Modifications would be required.)

Vernal Lakes
Debbie S. Miller, Author of Disappearing Lake

“Vernal lakes are temporary water systems created by rainwater or by snow melting in the spring. Disappearing Lake is one of many vernal lakes and ponds that are scattered across Alaska, and in many regions around the world. As temperatures rise and the snow vanishes, the lakes gradually disappear as the water seeps into the ground and evaporates. What once was a lake or pond, often becomes a meadow.”

“Vernal ecosystems provide important habitats for a fascinating web of life. Fairy shrimp thrive for a few brief weeks, laying their eggs before the water disappears. Migratory birds use vernal lakes as critical resting and feeding areas. Meadows provide foraging habitats for birds and for mammals such as caribou, moose, and voles. Each creature depends on this changing wilderness to meet its own special needs.”

Teacher Background Information on Sea Monkeys:
“Sea monkeys” is a common name for a type of brine shrimp, artemia, that have been studied for over a hundred years, and are currently used to study genetics, ecology, biochemistry, and more. They are used as a food source for fish in aquaculture and in home aquariums. The cysts were even carried to outer space both inside and outside the U.S. Apollo spacecraft to study the effects of ultraviolet radiation on living cells.

This tiny member of the crustacean family (which includes crabs and lobsters) has the unusual ability to survive for years in a dormant cystic state without water. This is because the eggs are coated with a self-made substance, called trehalose, that protects them from drying out, or getting too hot or cold.

These small arthropods are found naturally in 250 locations around the world, including tidal pools, estuaries, and salt lakes. In the Great Salt Lake in Utah, the life cycle of this brine shrimp begins when the eggs hatch in early spring. Next, the larvae go through 15 molts, outgrowing each shell or exoskeleton, and quickly growing a larger, harder one. The adults start dying by October, and most are gone from the lake by December. From May to December, the females give birth to live embryos (nauplii) unless all conditions are not suitable for survival. In that case, they will lay cysts which can be carried to shore by wind and waves. Later, spring rains will bring the cysts back to the lake, where they will hatch when the temperature, salinity, oxygen, and seasonal conditions are optimal.

Things to Look for During Observations:
Males are smaller than females and will have pincers under their "chins" when full grown. Females are larger and will carry a brown egg sac on their "stomachs" when they mature. Both males and females have a third eye, which disappears when they are full size (measuring about 3/4 inch long). Both perform acrobatics as they swim, and are attracted to and move toward light.

Web sites with information about brine shrimp and/or raising them:

Investigation 4

Underwater Viewer Instructions
An underwater viewer can easily be made from a coffee can (small or large). Cut out both ends of the can. Make sure the edges are smooth, and file as necessary with a metal file. Use rubber bands to secure a piece of plastic wrap over one end. Students can place the covered end in the water and observe!

Timed Counts
This activity should be done after you and your class have spent at least 15 minutes doing a general exploration of the habitat that is the focus of the field trip. Following this initial exploration, the class can help choose the animal groups to count based on what they saw in their explorations. They should search for animals in areas where they are thought to be abundant.

Timed counts are a way to count one species (or animal group) at a time, in a defined area, for a specific time period (e.g., 10 minutes). The goal is to count as many of the animals as possible to give an idea of the overall abundance of the organisms.

Depending on the animal selected and the type of habitat, rules for “what counts” will be required. For example, on a rocky beach students should only count the animals they can see on the surface and should not turn over rocks or search under seaweed. Timed counts can be modified for ponds or other bodies of water to the number of scoops of a net of a specified size.

If you have a large class, pairs of students can count the same animals but search in different areas of the field trip site. The numbers can then be combined for data analysis.

1. Assign a student or the teacher to give the signal for starting and stopping the counts.
2. Count only one category of animal at time.
3. Select areas where you know the animal occurs and define the area of the count by using landmarks.
4. Do at least three counts by assigning the same animal to three different students or teams of students.
5. Students can use a sampling tool for animals that are very abundant, such as barnacles or mussels on a rocky beach. This can be as simple as a string of a specific length that is used to make a circle. Coat hangers bent into circles provide an area of about 100 square centimeters. You can also construct ¼ square meter quadrats from PVC pipe and joints. The students using the sampling frame should do as many counts as possible during the period of time at different areas within the overall count area.
6. Have the students calculate the average count for each species.

If this timed count method is repeated in the same area at different seasons, monthly, or annually, it can be used to provide evidence of a trend in numbers upward or downwards in abundance.

The following may be too advanced for 2nd grade:

Timed Counts—scientific conference
The best way to illustrate your findings after conducting timed counts is to make graphs or charts of organisms counted. A pie chart can also show the percentages of organisms found in the area and can help students to visualize the diversity of animals on your beach. Have students work in groups or pairs to compile the information you have collected.
For example, all students who counted sea stars should work together to compile their data. Groups can do individual graphs showing species breakdown as well. As a class, draw a large graph on the board and have a representative from each help graph the results as a class. (A simple bar graph with the name of the organism on the x-axis and the “average count” on the y-axis.)

Some questions to ask might be:

Adapted from CoastWatch Curriculum. Center for Alaskan Coastal Studies.

Investigation 5

It is helpful for the teacher to think about the presentation of information. Modeling the presentation will be useful for students, starting with the engagement activity of describing a habitat. Teacher modeling of answering questions, defending thinking, and accepting appreciations of the presentation will assist students in understanding the expectations.

Understanding that children learn through questioning, exploring, and exchanging ideas is very important. Rather than gathering facts, memorizing habitat characteristics and regurgitating from books, students are connecting to prior knowledge or notions of the world around them. The field experience is a key part of this entire unit in that children need to experience and explore the natural world to make connections with stories, nonfiction text, and their own ideas and possibly correct misconceptions along the way.

Additional Resources

Print

Web sites

Curricula and Teaching Guides

Videos