| What
are Algae?
Algae are a large and successful group of organisms, which flourish
in the sea, in fresh-water and in damp places on land. Most algae
contain green chlorophyll, and can produce foods, such as sugars,
from the sun. Although they seem plant-like, scientists have classified
them in a group of their own, outside the plant kingdom. They have
been classified in a separate kingdom called Protista.
Whereas plants always have
specialised reproductive structures made up of many different types
of cell, algae do not.
Algae reproduce by using
little spores, or by growing copies of themselves from buds or broken-off
fragments.
Algae can be lively little
characters, even though they are not animals. Many are made of a
single cell, and cannot be individually examined without a microscope.
Many of these little algae can swim. Some, called Dinoflagellates
, have little whip-like structures (flagella), which pull them
through the water. Some algae squish part of their body forwards
and crawl along solid surfaces.
Some algae are made of fine
filaments, with cells joined from end to end. Some of them clump
together to form colonies. Others, like many seaweeds, are very
large and grow in the shape of tubes, clubs and trees. These large
algae have thick root-like structures, called "holdfasts"
which can cling onto rocks.
Are
Algae Important?
Algae are extremely important.
They produce more oxygen than all the plants in the world, put together.
They are also a very important food source for tiny animals such
as little shrimps and huge animals like whales.
Because algae are at the
bottom of the food chain many living things depend upon them.
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