Summary: Wetlands Are Wonderlands! is actually five activities in one inquiry. In How Does Energy Travel Through Food Chains?, students use an Online Wetlands Ecosystem image to hypothesize food chain relationships within a wetland. In How Does Energy Travel through Food Webs?, students take the Food Chains activity one step further by creating, in teams, food webs that describe interdependence within a wetland ecosystem. In Can ONE change in a Food Web Affect the Entire Community?, students explore the story Wolf Island by Celia Godkin to better understand how one change in a food web can be felt throughout the community. In What Is the Pyramid of Energy?, students are introduced to the Pyramid of Energy. They learn how to identify consumer levels within a food chain/web. They also learn that most of the energy at each level is used for life processes and is not available to be passed on to the next level of consumer. In What Is the Role of Energy and Matter in an Ecosystem?, students learn that although an ecosystem constantly recycles its matter, it must also constantly receive new energy to remain in balance. In How Do Humans Fit into the Pyramid of Energy?, students connect the foods they eat to the Pyramid of Energy in order to discover their consumer level.
Topics: ecosystems, food chains, food webs, Pyramid of Energy, consumers,
producers, decomposers, consumer levels (primary, secondary, tertiary), the
Ten Percent Rule, energy, matter
Ohio Academic Standards Alignment: Click here to view content standards alignment to Science for Ohio by grade level.
- Wetlands. Wetlands,
transitional zones between land and water, tend to be relatively high in
species diversity. They are among the most biologically interesting and
productive, but least understood, habitats, ranging in diversity from prairie
potholes in Canada and the United States to papyrus swamps in Uganda. Many
wetlands have formed along riverbanks or near river deltas, including the
Mississippi in the United States, the Nile in Egypt, the Okavanga in Botswana,
the Rhone in France, and the Brahmaputra in India.
of water is the distinguishing characteristic of wetlands. It may vary from
standing water several feet deep to waterlogged soil without standing water.
The soil in wetlands differs from that of adjacent uplands; it is often saturated
long enough to become anaerobic. Wetland vegetation must be able to tolerate
both flooding and the lack of oxygen in the soil.
two major categories of wetlands: inland and coastal. Inland wetlands are
freshwater ecosystems and include marshes, swamps, riverine wetlands, and
bogs. Coastal wetlands may be either fresh or salt water and are affected
by tides. Examples include tidal salt marshes, tidal freshwater marshes, and
Biosphere 2000...Protecting Our Global Environment
by Donald G. Kaufman and Cecilia M. Franz, Copyright 2000.
- Wetlands and Ohio.
Wetlands are the most endangered ecosystem in Ohio. Human development (e.g.,
roads, industry, agriculture, housing) has resulted in the loss of over
90% of Ohio's original wetlands.
- Benefits to humans.
Wetlands benefit humans in countless ways. Among the most valuable are their
ability to filter and purify water. The U.S. government realized this after
an Army Corp of Engineers project to increase the flow of water in the Everglades
resulted in a decline in potable drinking water for the surrounding region
of Florida. Wetlands are also considered to be valuable carbon sinks.
As the name implies, they take in more carbon from the atmosphere than they
produce. This is an especially valuable trait in a world where humans continue
to increase carbon production through the burning of fossil fuels.
- Benefits to other
animals. Biodiversity is the key to a healthy ecosystem, and wetlands
are one of the most biologically diverse ecosystems on the planet. This
biodiversity supports not only year-round residents of wetlands, but seasonal
travelers as well. Many species of birds rely on wetlands in order to rest
and refuel during long seasonal migrations. Scientists and government officials
have recently come to the conclusion that the only realistic way to protect
endangered species is to protect and preserve ecosystems worldwide.
Producers are organisms that produce their own food. Most producers are
green plants that use the energy of the sun to make food through the process
of photosynthesis. (See Related Resources for an online
movie.) Producers support the rest of an ecosystem through the energy they
transform from the sun. Phytoplankton is listed under producers on the Online
Wetland Ecosystem. Phytoplankton is a generic term which refers
to the many microscopic plants (e.g., algae, diatoms) that live near the
surface in water ecosystems.
Consumers are organisms that must consume food energy in order to survive.
Consumers are generally considered to be animals. In a wetland ecosystem,
consumers range greatly in size from tiny zooplankton (e.g., copepods,
daphnia) to large fish, birds, and mammals.
- Consumer Levels.
There are three basic consumer levels that will be discussed in
this inquiry. These are primary, secondary, and tertiary consumers.
Their meanings are listed below.
- Primary consumer:
an animal that eats mainly plants in order to get energy. It is
the first consumer on a food chain.
consumer: an animal that eats plants and/or animals in order to
get energy. It is the second consumer on a food chain.
- Tertiary consumer:
an animal that eats mainly other animals in order to get energy.
It is the third consumer on a food chain.
Decomposers are consumers such as fungi or bacteria that feed on dead
or decaying matter in order to get energy. They are in a separate category
from the consumers listed above because:
- they are
not animals, and
- they digest
food outside of their bodies using enzyme
are responsible for breaking down plant and animal waste into nutrients
(e.g., nitrogen, carbon, phosphorus) that are returned to the soil, air,
and water where they can be used by plants.
Chains/Webs. A food chain shows the connections between individual
organisms that depend on each other for energy. (See
example.) A food web shows all of the energy connections among living
things within a community or ecosystem. (See example.)
- Observation vs Inference.
Observation is the process of gathering information using the five senses
(sight, smell, etc.). Inference is the ability to use observations to make
informed decisions. For example, a group of students working on the Wetlands...
inquiry observe that the red-tailed hawk is larger than most birds, has a
hooked beak, and sharp claws. They infer that the hawk is a carnivore based
on these observations and consequently place the hawk at the top of several
food chains they are brainstorming in their group.
Pyramid of Energy and the Ten Percent Rule. The Pyramid of Energy is
a model which illustrates the availability of energy at each level of a
food chain or web. In any ecosystem, the producer level has the most energy
and is therefore at the bottom of the pyramid (largest part). As producers
are consumed, roughly 10% of the energy at the producer level is passed
on to the next level (primary consumers). The other 90% is used for life
processes (e.g., photosynthesis, respiration, reproduction, digestion) and
ultimately transformed into heat energy before the organism is ever consumed.
This phenomenon is known as the Ten Percent Rule. This pattern of energy
transfer continues with each successive level of the pyramid. Secondary
consumers receive 10% of the energy available at the primary consumer level
(1% of the original energy). Tertiary consumers receive 10% of the energy
available at the secondary level (0.1% of the original energy). As a result,
tertiary consumers have the least amount of energy and are therefore at
the top of the pyramid (the smallest part). On the What
is the Pyramid of Energy? 3D Model, energy at each level is illustrated
in calories since this is the standard unit for food energy. These numbers
are not reflective of every ecosystem. Rather, they are intended to illustrate
the total amount of energy available at each level of the Pyramid of Energy.
For comparison, it might be helpful to remind students that they consume
between 1,500 and 2,500 calories of food energy each day. For more information,
see the What is the Pyramid of Energy? Student
Flows and Matter Cycles. Two of the great laws of nature are energy
flows and matter cycles. Energy is constantly flowing into a system,
such as a wetland, as radiant energy from the sun. This energy is then transformed
into the energy needed to sustain life for organisms such as plants and
animals. This energy is used for life processes such as respiration, photosynthesis,
digestion, and reproduction. Once used, it is transformed into heat energy
and leaves the system. This heat energy is then dispersed into the atmosphere
and, in time, into space. As this energy is lost to the system, new energy
flows in to replace it. Matter, on the other hand, is constantly cycling
within a system. Plant and animal waste products, as well as dead plants
and animals, are broken down by decomposers and returned as nutrients to
the soil, air, and water. As these nutrients are used by plants, they cycle
back to the living part of the system once again.
Misconception: Heat energy that leaves a system and eventually the Earth
returns to the sun and is recycled. Fact: This energy is dispersed into
space and does not return to the sun.
Results. Expect students to have a strong understanding of food
chains, food webs, the Pyramid of Energy, and the Ten Percent Rule.