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Table of Contents, Subconcepts & Storyline:
Grade Level Concept: Where water and land meet, a changing aquatic environment exists in which organisms strive to succeed
1995 DRAFT Version
Storyline for Unit......3
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The first subconcept: The movement of water affects landforms, creating a variety of changing environments creates a background of information for the students relating to the interactions between the land and water. The first series of lessons teaches the students about the effects of erosion on the landforms. In Lesson 2, Make-A-River, the effects are seen when they make a model of a hillside and watch as the water erodes the hill creating rivers. The idea of water acting as a force on landforms is further seen in Lesson 3, Melting Snow & Ice, in which the effects of both snow and glaciers are modeled. Each of these lessons has shown that while water may destroy some of the landforms, it also creates new environments. The next Lesson 4, Make-A-Lake, examines the creation of lakes and their drainage systems. These environment create habitats for living things.
Each of these habitats have a characteristic range of physical and chemical conditions that are imposed on it. Some of those conditions are the amount of light, the average temperature, and the type of soil. However, the most important component of the aquatic environment is the presence of water. Thus the physical properties of water and its interaction with soils become important characteristics. This leads to the second subconcept, Physical properties of water and soils and affect their interactions. Lesson 5, Water Chemistry, examines several properties of water; hardness & surface tension, salinity, and evaporation rate. These properties not only affect water and soil interactions, but also affect the living organism which habitate the aquatic environment. Lesson 6, Sedimentation & Water Holding Capacity, investigates both the layering of different soils and the amount of water these soils can hold. Coupled with lesson 7 below, this lesson in its examination of the idea of silting and ability to hold moisture, introduces some of the challenges to living organisms explored in the next subconcept, Subconcept three, Aquatic environments present challenges to living organisms.
A study of niches and some of the special problems created by the conditions imposed by the interactions of land and water are seen in the next few lessons. Another area of interactions between water and land are the areas affected by the changing tides. The tides present many challenges to organisms; swift powerful onrushing waves, times of total submersion and other times when there is no water at all, and the abiltiy to survive on salt water rather than fresh water. Add to that the shifting sands along beaches and at the mouths of rivers. These problems can be even more severe in estuaries where the delicate balance between the exchange of river's fresh water and ocean's salt water is extremely important. Lesson 7, Shifting sands, Changing Tides, shows the relationship of the tides to the shape of the channels of estuaries or bays and the resulting movement and layering of sand, due to wave and current action, which again points out to the students the interactions between the land and the water can have long lasting effects not only on the landforms, but also for the organisms. It also highlights the concept that the changing level of water is significant along rocky coasts and within bays, and that this change will affect the life within this band. This important effect of the tide can be seen more fully in Lesson 8, Who Gets Wet & Salty? in which the students learn about the organisms that live in the different tidal zones, and examines to what degree organisms which live in the splash zones receive moisture and salt. Lesson 9, The Year of the Lake and Stream explores the life forms which live in the lake/stream environment and their dependence upon its seasonal changes. As new environments are created, organisms come to live within them, creating predator/prey relationships within their habitat. This lesson begins with a card game, "Who lives at the Lake and Stream?" This game gives an introduction to the organisms that live in the particular habitats created in and near the aquatic environment. The second part of the lesson is a play that summarizes many of the problems faced as organisms deal with the challenge of their river drying up, changes in salinity and water temperature, as well as silting. Lesson 10, Run, Salmon, Run, examines how this unique fish faces the challenges and obstacles of rivers during their lifetime. The affect of both human created obstacles or hazards and more natural enemies and barriers are observed in this interactive board game.
The uniqueness of solutions in overcoming challenges by organisms is fascinating, as we have seen in the previous lesson. Many of the solutions were physical adaptations. Each of the organisms that live within the aquatic environment is adapted to those conditions in terms of its morphology, physiology, and behavior. Many of the adaptations are unique to a particular species, while other adaptations are wide-spread among many organisms. The adaptations that have evolved in terms of an organism's morphology and physiology are due because of natural selection. The saying that "only the strong survive" is a truth that becomes apparent and understandable to the students only with many explanations and explorations. The final subconcept for this unit, Subconcept four, Living organisms within an aquatic environment have physical adaptations which help in survival, goes into greater depth in examining some of the adaptations, which are modifications of simple machines. These adaptations often can be better understood and appreciated when when viewed from more than one perspective. For this reason, the next series of lessons present adpatations that are viewed from the mechanical prespective as well as the biological. As the adaptations are studied, comparisons of the organism's anatomy to those of simple machines are made. Lesson 11, Waterstrider Race, emphasizes how the waterstrider uses surface tension to escape from frogs and captures insects in a pond environment.
A tidal zone is shown is Lesson 12, Hold on! In this lesson, the various ingenious manners in which organisms hold on to their rocky substrate in the turbulent world of the surf is examined. The limpet's, the starfish's and abalone's suction , the kelp's holdfast, the mussel's threadlike webbing, are among those modeled. Lesson 13, Webbed to Work, show how this adaptation of fish, birds and turtles and frogs, all of which have webbed appendages, help power their movement. The final lesson, Lesson 14, Aquatic Environments Near Our Home, is a culminating field trip to a local area that points out the interactions between the land and water. Further there will be on site exploration of the various unique organisms that survive there, their niches and some of their adaptations.
"Run, Salmon, Run!"
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