|
Ecosystems
What is an ecosystem?
An ecosystem is defined as a self-sustaining
community of organisms living in a physical environment. Part
of what sustains an ecosystem
is the constant interchange of matter between its living
and physical components. This is the focus of Session 8: Material
Cycles in Ecosystems.
Ecosystems can be vast, like the tropical rainforests
that
occur along the equator. They can also be very small, like
the ecosystem inside the leaves of pitcher plants discussed
by Dr. Aaron
Ellison
in the video.
Coniferous forest, a North American
ecosystem
An ecosystem is shaped by physical factors such
as rainfall, temperature, humidity, sunlight, and soil type.
The interaction of these factors determines the types of organisms
that live
there. Scientists
classify larger terrestrial ecosystems into several major
types that occur over wide geographical areas. They are
recognized by their
distinctive
climates and are given their names from the dominant plant
life.
The ecosystems listed below are found in North America,
including Hawaii. Which ecosystem do you live in?
| Ecosystem type |
Average Precipitation |
Average Temperature |
Dominant Plant Life |
| Tropical rain forests |
250+ cm
(100+ in.) |
20 - 28°C
(68 - 82°F) |
Broad-leaved trees; dense undergrowth; more species
than any other ecosystem |
| Deserts |
2 - 20 cm
(1 – 8 in.) |
10 - 32°C
(50 - 90°F) |
Cactus; shrubs with thick leaves that store water |
| Temperate grasslands |
10 – 60 cm
(4 – 24 in.) |
8 - 20°C
(46 - 68°F) |
Tall, dense grasses in rich soil; few trees |
| Deciduous forests |
75 – 250 cm
(30 – 100 in.) |
5 - 20°C
(41 - 68°F) |
Broad-leaved trees that drop their leaves in winter |
| Coniferous forests |
20 – 60 cm
(8 – 24 in.) |
-5 - 5°C
(23 - 41°F) |
Trees with needles and cones |
| Tundra |
25 – 50 cm
(10 – 20 in.) |
-15 - -5°C
(5 - 23°F) |
Mosses and lichens; some dwarfed trees; permanently
frozen ground |
|
What is an Ecosystem
prev:
a closer look intro