Hatfield Visitor Center

The Animal Adaptations program at Hatfield Marine Science Center is a 50-minute lab-based program for 3-12 grade students. Students examine marine organisms from three different habitats (sandy beach, rocky shore and estuary) and explore the many ways they adapt to their particular environment. This lab focuses on the adaptations of several groups of marine animals, including mollusks, crustaceans, and echinoderms. It investigates how they differ depending on whether they are in a sandy beach, rocky shore, or estuary environment. Students will work in small groups with various live animals, studying individual characteristics and how these organisms interact with their environment and one another.

Background Information

The Oregon Coast is made up of a series of rocky shores, sandy beaches, and estuaries, all of which are greatly affected by fluctuating tides. Many of these areas are intertidal and are alternately inundated by seawater and exposed to air, wind, and dramatic changes in temperature and salinity. High tide floods these areas with cold, nutrient-laden seawater, bringing food to organisms that live there in the form of plankton and detritus. Low tides often expose these organisms to the dangers of predation and desiccation.

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In addition to tidal effects, organisms that inhabit sandy beaches and rocky shores also have to deal with the physical stresses of pounding waves. Because of these harsh conditions, organisms have developed unique adaptations that not only help them to survive but thrive in these environments.

An adaptation is a physical or behavioral trait that helps a plant or animal survive in a specific environment or habitat. Although many marine organisms may be closely related and share many characteristics or behaviors, each has its own unique set of adaptations that make it suited to a particular environment. One example of an adaptation to their environment that many marine organisms possess is camouflage that makes them virtually undetectable to predators and prey alike.

In this lab, we will examine various organisms found on rocky shores, sandy beaches, and estuary and investigate how they adapt to their particular environment.

Most rocky shores are composed of impenetrable rock that most organisms cannot bore into to seek protection. As a result, many organisms found here seek shelter from the elements and predators by hiding in rock crevices or withdrawing into hard shells. Rocky shore inhabitants are often sessile or attached to rocks to resist wave action and maintain advantageous positions for feeding and reproduction. Some examples of rocky shore creatures are sea stars, barnacles, limpets, urchins, and anemones.

Sandy Beaches

Sandy beaches are composed of tiny bits of weathered rock (sand) that are constantly being shifted by the wind and waves. Many organisms found in this environment are streamlined and/or possess shells to protect them from pounding waves. Because the sand is in constant motion, organisms that live here have nothing to attach to and may burrow in the sand to seek shelter from the elements. These animals usually possess specialized structures that enable them to dig quickly and obtain oxygen and food beneath the surface. Some examples of sandy beach animals are mole crabs, razor clams, and sand dollars.

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Estuaries are environments that form at the mouth of rivers where they meet the sea. Rivers erode their banks as they travel across the land, carrying sediment that is then deposited when waters come in contact with the force of the ocean and river flows slow. The sediment in estuaries tends to be finer than that of sand beaches, consisting primarily of mud. It can be difficult for organisms and water to move through and is often anoxic (devoid of oxygen). Organisms found here, including mud shrimp, polychaete worms, and cockles, create burrows in the mud and have specialized structures for obtaining oxygen and food below. Predators, such as crabs, fish, and birds, feed on these burrowing organisms as the tide moves in and out of the estuary.

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Create a Critter

Discuss one (or more) of the marine environments above then have students create a critter with multiple adaptations to that particular environment. Adaptations might include coloration, means of defense, feeding or reproduction. Have students create a picture of their critter in the appropriate environment and present it to the class, explaining how it is adapted to that environment. Discuss the concept of limiting factors and how they determine what organisms can survive in an area. For example, organisms found in mudflats must be able to deal with all of the challenges listed below. Have students create a similar diagram of limiting factors for Rocky Shore and Sandy Beach environments.

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Visit the Tide Pool Scientist lesson from the Monterey Bay Aquarium to learn an interactive game, the Rocky Shore song, and other activities.