Activity 1: Aquatic vs Terrestrial Ecosystems
Name ______________________________
6th Grade PSI Science
Score: _____ / 16 points
Ecosystems include all of the biotic and abiotic components of a community. A variety of
ecosystems cover Earth and can be broken down into two different types: aquatic and
terrestrial.
Although all ecosystems contain a variety of species that interact with each other and their
environment, different types of ecosystems usually have different limiting factors that lead to
adaptations in the organisms that live there. For example, the only plant life in the grasslands
ecosystem is grasses and small shrubs because there is not enough rainfall to sustain the
growth of trees. A limiting factor for the grasslands ecosystem, then, is water.
Read the information about aquatic and terrestrial ecosystems and then compare and contrast
them by answering the questions that follow.
Terrestrial Ecosystems
In terrestrial ecosystems, water is not always readily available. This means that
organisms often have adaptations to allow them to conserve water. Plants, for example,
often close their stomata (pores in a leaf) during the day in order to minimize
transpiration. The terrestrial environment can experience large fluctuations in
temperature. In some desert ecosystems, daytime temperatures can reach 100⁰F while
falling to below 50⁰F at night. The organisms that live in this ecosystem need to have
adaptations for both hot and cold temperatures. Another important aspect about living
on land is the effect of gravity. Because gravity constantly pulls organisms downwards,
they must have a support system. For many animals, this takes the form of a skeleton.
Plants have strong cell walls that offer support and allow them to grow upwards, against
the pull of gravity.
Aquatic Ecosystems
In aquatic ecosystems, water is everywhere. Many organisms have adaptations to allow
excess water to be pumped out of their bodies. Organisms must also adapt to the
salinity level of the water. Because only 70% of sunlight penetrates the water’s surface,
light is an important resource. Most producers must live at the surface of the water in
order to maximize their light intake. Organisms that live in the deep water have
adaptations to living without light. Water is much more supportive than the air on land.
While some aquatic organisms have skeletons, many do not. They are able to float in
the water. Some areas of the ocean have very low oxygen content. In these areas,
organisms have special adaptations to maximize oxygen in the water.
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6th Grade PSI
Ecosystem Dynamics
1. List three abiotic factors for terrestrial ecosystems.
2. List three abiotic factors for aquatic ecosystems.
3. What is a limiting factor for each ecosystem?
a. Terrestrial ecosystem:
b. Aquatic ecosystem:
4. In your quest to study ecosystems throughout the world, you discover several new
species. Listed below are partial descriptions of each new species. Determine if each
was discovered in a terrestrial or an aquatic ecosystem. Below each description, explain
your reasoning.
a. ____________________ A short plant that is covered in tiny hairs that insulate
against extreme cold and heat.
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b. ____________________ An organism that looks like a gelatinous blob with
seemingly no structure.
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c. ____________________ An organism that has very large eyes but is essentially
blind. Its other senses, such as touch and smell, are
highly developed.
__________________________________________________________________
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6th Grade PSI
Ecosystem Dynamics
__________________________________________________________________
d. ____________________ A small animal that buries itself under the ground.
When water is present, it comes out and lays eggs.
When water disappears, it goes back underground.
__________________________________________________________________
__________________________________________________________________
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6th Grade PSI
Ecosystem Dynamics