The Great Barrier Reef
Australia's Great Barrier Reef is an amazing ecosystem. It is home to an immensely diverse range of creatures, including over 1,500 species of fish alone! One-third of the earth's soft coral inhabits the reef. Many types of endangered species find refuge in this thriving underwater metropolis. The Great Barrier Reef is the world's largest reef system, and can be seen from outer space!
Did You Know?
Clown fish sometimes live in sea anemones for protection, because the anemone is poisonous to all fish except the Clown fish!
The Ocean Floor
The ocean floor is a dark, gloomy place, but underneath the layers of inky black, a small population of animals thrive. For example, the Angler fish has a glowing membrane at the end of a stalk protruding from the fish's head. That fish has a built-in lamp! There is no sunlight this deep under the waves, and no sun means no photosynthesis.
Anatomy of an Ecosystem
An ecosystem is essentially a biological community. Two things define ecosystems: abiotic (non-living) things and biotic (living) things. An example of an abiotic entity is a mineral deposit. An example of a biotic entity is a deer.
Ecological Succession
When disaster strikes, such as a volcanic eruption or a forest fire, ecosystems can be completely wiped out. The result is a barren wasteland devoid of life. But then, after a few months, small changes occur. Lichens form on the rocks. Small tufts of grass spring up. Small flowers might even bloom. Eventually, small animals and birds arrive. Then small trees appear. A while later, the ecosystem is back as it was before the catastrophic event. This recolonization process is known as ecological succession.
Stages of Succession
Example of Succession
Imagine a volcano erupting on a small island. Days later, all that is left is a barren wasteland. It may seem like nothing will ever live there again, but that is not necessarily true. Fungus begins to grow on the rocks. A few weeks later, small patches of grass start to spring up. Soon large areas are covered. Some insects were hidden underground during the eruption, and they tunnel up and eat some of the grass. Birds fly over from neighboring islands to eat the insects. Small mammals hitch rides on sea creatures, and soon larger and larger animals are swimming over. Now the island is fully repopulated, bursting with trees, plants, and animals.
Food Webs
A food web is a group of food chains that makes up an entire ecosystem. A food web is the transfer of matter and energy between organisms, as well as the classic who-eats-who. Below is a food web diagram of a coral reef. The transfer of thermal energy and matter are shown in red and green respectively.