In the second phase the larva develops
into the adult form. In most species, the
animal loses its gills and develops lungs.
It is then capable of living on land at
least part of the time. The animals body
structure may change in many other
ways, too. For example, a tadpole grows
legs and loses its tail. The change from
larva to adult is called metamorphosis.
However, some species do not have separate
larva and adult forms. They are
born in the same form as adults, only
smaller.
..More to explore
Animal Frog Hibernation
Metamorphosis Poison Salamander
Toad
Amsterdam
Population
(2008
estimate), urban
area,
1,482,287
Amsterdam is the largest city in The
Netherlands, a country in northwestern
Europe. It is the official capital of The
Netherlands. However, the government
offices are in the city of The Hague.
Amsterdam is a historical city as well as
the countrys major economic center. It
is also famous as a place of freedom and
tolerance. Tourists go to Amsterdam to
see its scenic canals and collections of
great art. Museums in the city display
the works of important artists from The
Netherlands, including Rembrandt and
Vincent van Gogh.
The Amstel River flows through Amsterdam.
The city also lies on a body of
A boat travels down a canal in Amsterdam.
BRITANNICA STUDENT ENCYCLOPEDIA Amsterdam 111
water called the IJ (pronounced eye).
A canal connects the IJ with the North
Sea. Amsterdam is a major port.
Part of Amsterdams land used to be
underwater, but people drained the
land. A system of pumps, barriers, and
canals keeps the water from rushing in
again. Boats travel through the city
along a cobweb pattern of canals. More
than 1,000 bridges provide land connections
over the canals.
Economy
For seven centuries Amsterdam has been
a center of international trade and transportation.
Other important industries
include banking, insurance, and tourism.
Industries that provide services to
businesses also bring money to the city.
History
Amsterdam began as a fishing village in
the 1200s. By the 1400s it was an
important port.
During the 1500s many Jews and Protestants
fled religious wars in other parts
of Europe. Many settled in Amsterdam
because it was known for its religious
freedom.
The 1600s were Amsterdams golden
age. The city grew wealthy as a center of
trade and banking. Amsterdam declined
somewhat in the 1700s.
Nazi troops from Germany controlled
Amsterdam in the 1940s, duringWorld
War II. The Nazis murdered most of
Amsterdams Jews.
After the war Amsterdam began to
thrive again. Its economy grew greatly in
the late 20th century.
#More to explore
Canal Hague, The Netherlands, The
Rembrandt Van Gogh, Vincent
Amundsen,
Roald
The Norwegian explorer Roald Amundsen
was one of the most important
people in the history of polar exploration.
He traveled to both the Arctic and
the Antarctic, and he was the first person
to reach the South Pole.
Roald Engelbregt Gravning Amundsen
was born in Borge, Norway, on July 16,
1872. His father, a shipowner, died
when Roald was 14. Young Amundsen
always wanted to be a polar explorer, but
to please his mother he studied medi-
A young Jewish
girl named
Anne Frank
and her family
hid from the
Nazis in
Amsterdam for
two years. The
building
where they hid
is now a
museum.
Roald Amundsen
112 Amundsen, Roald BRITANNICA STUDENT ENCYCLOPEDIA
cine. When his mother died, Amundsen
left school and went to sea.
At age 25 Amundsen made his first
voyage to the Antarctic, as part of a
Belgian expedition. Then in 1903 he
set out with his own ship and crew to
explore the Arctic. By the end of this
expedition, in 1906, Amundsen had
become the first navigator to find his
way through the Northwest Passage
from the Atlantic to the Pacific Ocean.
This had been a dream of explorers for
400 years.
In 1909 the explorers Robert Peary and
Matthew Henson became the first
people to reach the North Pole. Amundsen
then decided to try to be the first to
reach the South Pole. He set out with
four men, 52 dogs, and four sleds and
reached the pole on December 14,
1911.
In 1918 Amundsen tried to drift across
the North Pole in a boat, but the ice was
too thick. In 1926, with two companions,
Amundsen flew over the North
Pole in a dirigible, a lighter-than-air
craft. Amundsen died near the Arctic
island of Spitsbergen on June 18, 1928.
#More to explore
Henson, Matthew Northwest Passage
Peary, Robert E. Polar Exploration
Anaconda
Anacondas are huge, nonpoisonous
snakes. They live in or near water in
warm parts of South America. Anacondas
are constrictors. This means that
they usually kill their prey by coiling
their body around it and squeezing until
the animal can no longer breathe. Anacondas
are one of the two largest types
of snakes in the world. Certain pythons
grow longer, but anacondas are much
heavier.
Anacondas are members of the boa family.
There are two species, or types, of
anaconda: the giant, or green, anaconda
and the yellow, or southern, anaconda.
The giant anaconda is the larger species.
It is usually brown or olive green with
oval-shaped black spots. The yellow anaconda
is tan or greenish yellow with
overlapping black spots.
The largest anacondas reach about 30
feet (9 meters) in length, but most grow
only to about 16 feet (5 meters). Some
anacondas weigh as much as 550
pounds (249 kilograms). Their thick,
bulky bodies may measure 12 inches (30
centimeters) or more around.
Anacondas usually hunt at night for
mammals, reptiles, and birds. Although
The giant anaconda is one of the largest
snakes in the world.
BRITANNICA STUDENT ENCYCLOPEDIA Anaconda 113
anacondas constrict larger prey, they
may kill turtles, birds, or other small
animals by using their mouth and sharp
teeth alone. Sometimes they may pull
their prey underwater to drown it. After
killing their prey, anacondas swallow it
whole.
Nine months after mating, female anacondas
give birth to large litters of live
young. A litter has 14 to 82 young. Each
young measures more than 2 feet (0.6
meter) long.
#More to explore
Boa Constrictor Python Snake
Anasazi
The Anasazi were a Native American
people whose civilization developed
beginning in about AD 100. They are
also known as the Cliff Dwellers because
of the great buildings they constructed
along the sides of cliffs. They lived in the
area where the present-day states of Arizona,
New Mexico, Colorado, and Utah
meet.
Early Anasazi houses were underground
pits lined with stone walls. In time,
these pit houses developed into kivas,
or structures where religious ceremonies
were performed. Then the Anasazi
began to live aboveground in simple,
one-story houses made from mud and
wood or stone.
Probably by about the mid-800s, the
Anasazi began constructing multistoried
structures that resembled modern apartment
buildings. The Anasazi built some
of these buildings into the sides of cliffs,
where they were difficult for their