Swordfish are found in oceans around
the world. They are mainly pelagic. This
means that they live out in the open sea.
Swordfish grow to about 15 feet (4.6
meters) long. They can weigh as much
as 1,000 pounds (450 kilograms).
Swordfish are purplish blue in color. The
sword is almost black. Unlike most
fishes, the adult swordfish does not have
scales. It also does not have teeth.
The swordfish has a powerful body that
is shaped like a torpedo. Its sword is
actually a bony extension of the top jaw.
The swordfish eats smaller fishes and
squid. It uses its sword to slash through
schools of fishes.
Swordfish reproduce by laying eggs. The
young swordfish hatch after about two
and a half days. They have teeth and
scales but not a sword-shaped snout. By
the time a swordfish is about 2 to 4 feet
(0.6 to 1.2 meters) long, it has lost its
teeth and scales. It also has grown a
sword.
Swordfish are important to the fishing
industry. They are also popular with
people who fish for sport. When caught,
a swordfish will use its sword to defend
itself.
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Fish
Sydney
Population
(2006
estimate), urban
area,
4,293,100
Sydney is a major city in Australia, a
country in Oceania. The greater Sydney
area is Australia’s largest metropolitan
area. Sydney has a huge and magnificent
harbor. It is one of the most important
ports on the South Pacific Ocean. The
city is also one of Australia’s main centers
of business and culture.
Places of Interest
The Sydney metropolitan area stretches
across a large section of land. The city
center lies along the harbor. The Sydney
Harbour Bridge is one of the longest in
the world of its kind. The city’s most
famous landmark, the Opera House, is
A swordfish swims in the Pacific Ocean
near Costa Rica.
220 Swordfish BRITANNICA STUDENT ENCYCLOPEDIA
also on the waterfront. It has several
white roofs shaped like shells. Sydney is
also home to a large aquarium.
Many beaches and parks surround Sydney.
The city is famous as a place for
sailing, swimming, surfing, and other
sports and recreation.
Economy
Sydney is Australia’s main center of
banking and business, especially computer
and communications services.
Tourism, education, entertainment, and
trade are also important. Many large
companies have headquarters in Sydney.
Manufacturing is a smaller part of the
city’s economy.
History
The people called Aborigines have lived
in Australia for many thousands of years.
The British began settling in Australia in
1770. Great Britain’s rulers decided to
use the island as a prison colony, where
they could send convicts to serve their
sentences. Sydney was founded as a
prison colony in 1788.
Sydney soon became a major trading
center. It continued to be a home for
British convicts until 1840. The city
grew rapidly in the late 1800s. By 1930
more than 1 million people lived in the
metropolitan area. Sydney and its
economy continued to grow throughout
the 1900s. Sydney hosted the Summer
Olympic Games in 2000.
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Australia
Symbiosis
Symbiosis is a close relationship between
two different kinds of organisms, or
living things. There are three basic types
of symbiotic relationships: mutualism,
commensalism, and parasitism.
Mutualism is a relationship in which
both organisms benefit. For example,
bacteria live in the digestive system of
cows. The bacteria help the cows by
breaking down plants that the cows eat.
In turn, the cows provide a place to live
and a source of food for the bacteria.
The Sydney Opera House is a distinctive
feature along the city’s waterfront.
Remora fish have a symbiotic relationship
with sharks and other larger sea animals.
BRITANNICA STUDENT ENCYCLOPEDIA Symbiosis 221
Commensalism is a relationship in
which one organism benefits but the
other is neither helped nor harmed.
Remora fish and sharks have a commensal
relationship. Remora fish attach
themselves to sharks. The fish eat scraps
left over by the sharks. But the fish do
not affect the sharks.
Parasitism is a relationship in which one
organism benefits but the other is
harmed. The organism that benefits is
known as a parasite. Parasites live on
organisms known as hosts. Hosts are
usually larger than their parasites. Ticks
and fleas are examples of parasites. They
attach themselves to a dog, a cat, or
another host and feed off its blood. This
can cause itching, pain, or even disease
in the host.
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Living Thing • Parasite
Synagogue
A synagogue is a place of worship for
people of the Jewish religion. Jews also
use synagogues as places to meet and
study. Synagogues have played an
important role in preserving the Jewish
religion and culture throughout history.
A synagogue is sometimes called a
temple or a shul. (Shul is a word in the
Jewish language called Yiddish.)
The layout and design of synagogues can
vary greatly. Older synagogues were
often built in small streets near a marketplace,
in a courtyard, or on the top
floor of a building.
The most important thing inside a synagogue
is the ark, or cabinet, that holds
the Torah scrolls. The Torah is a holy
book of Judaism. There is also a platform
called a bimah, where a reader
