Britannica Student Encyclopedia - 2010

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

enemies to attack.

The earliest Anasazi survived by hunting

and gathering wild plants. By about

700, however, they had learned to grow

corn, beans, squash, and other crops. As

their farming methods improved, their

food supply grew. Their population

grew, too, and they built large permanent

settlements.

No one knows why, but by about 1300

the Anasazi had mostly abandoned their

multistoried buildings. They broke into

smaller groups and moved south and

east where they built new villages.

The Anasazi’s descendants are the

Pueblo Indians. They established smaller

villages, mostly clustered in the Rio

Grande Valley of New Mexico and Arizona.

At the end of the 20th century

there were about 60,000 Pueblo Indians

living in the United States.

#More to explore

Native Americans • Pueblo Indians

Cliff Palace is an ancient Anasazi building

at Mesa Verde National Park in Colorado.

114 Anasazi BRITANNICA STUDENT ENCYCLOPEDIA

 

Anatomy

Anatomy is the study of the structures

that make up the bodies of living

things. It is a branch of the science of

biology.

Scientists learn about body structures

mainly by dissecting, or cutting apart,

bodies. They may dissect human or animal

bodies, plants, or other life-forms

such as bacteria. Scientists identify the

structures inside the life-form and how

they are put together.

Importance of Anatomy

Scientists study anatomy to learn about

the size, shape, and position of different

body parts—for example, the skin,

muscles, bones, and organs of humans.

The study of human anatomy is

important in medicine. Medical

students learn how the parts of a

healthy human body fit together and

how they function. This helps them

treat bodies that are not functioning

properly.

Scientists also compare the anatomies of

different types of living things. They

observe the similarities and differences

of their structures. This helps them

determine how different types of living

things are related to one another and

how they developed over time.

History

An ancient Greek doctor named Herophilus

is often called the Father of

Anatomy. He performed dissections of

human bodies, sometimes in public, in

about the 300s BC. The ancient Greek

doctor Galen later wrote many books

about human anatomy. They were a

major source of anatomy information in

Europe for centuries. However, they

contained many errors. Many of his

ideas were not based on direct observations

of the human body.

The modern science of anatomy began

to develop in the 1500s. In 1543 a

doctor named Andreas Vesalius wrote

the first detailed and illustrated

anatomy textbook based on observed

facts. He performed careful dissections

of human bodies in order to study

them.

The first powerful microscopes were

developed in the late 1600s. These

instruments allow scientists to study tiny

structures in the body such as cells and

their parts. As technology has improved

Students study a model of a human body.

Anatomy models can help students understand

how the human body is made up and

how its different parts work together.

The most

famous book

about human

anatomy is

called Gray’s

Anatomy.

Henry Gray

wrote the first

edition in

1858. Other

scientists have

kept it up to

date.

BRITANNICA STUDENT ENCYCLOPEDIA Anatomy 115

 

over the years, scientists have been able

to learn more and more about anatomy.

#More to explore

Biology • Medicine • Microscope

Andersen,

Hans Christian

The fairy tales of Hans Christian Andersen

are popular today, just as they were

when first published in Denmark in the

mid-1800s. His stories include such

favorites as “The Ugly Duckling” and

“The Emperor’s New Clothes.”

Hans Christian Andersen was born on

April 2, 1805, in a Danish fishing village

called Odense. Andersen’s family was

very poor. As a boy, he attended school

only occasionally. He visited the theater

and found that he loved performing.

When Andersen was 11 years old, his

father died. Shortly after that, Andersen

began working in various trades.

At age 14 Andersen moved to Copenhagen,

the capital of Denmark, to try to

become an actor or dancer. But he did

not have much success. Andersen later