They can also be found in rivers, lakes,
and swamps. Only the yellow-bellied sea
snake swims hundreds of miles out into
the ocean. This sea snake is also the only
known reptile that spends its entire life
in water.
Most sea snakes are 3 to 5 feet (0.9 to
1.5 meters) long. Many have lightcolored
bodies with dark rings. Sea
snakes have short, hollow fangs that
contain venom, or poison. This venom
attacks the nervous system (nerves and
brain) and can be deadly. Sea snakes eat
eels, fish, and fish eggs.
Sea snakes are specially made for the
water. They have a flat tail that is shaped
like an oar. The snakes swim by moving
the tail from side to side. Their lungs
can also hold extra oxygen. This allows
them to stay underwater for long periods.
Some sea snakes have very small
belly scales. These scales make them
unable to crawl on land.
#More to explore
Cobra • Snake
Season
As a year passes, regular changes occur
in the weather. This cycle of weather
The banded sea krait is a sea snake of the
Pacific Ocean.
60 Sea Serpent BRITANNICA STUDENT ENCYCLOPEDIA
The North and South poles are the farthest
points from the equator. Therefore
temperatures stay cold throughout the
year. During the winter it is dark even in
the daytime. In the summer the sun
shines late at night. However, this “midnight
sun” is not strong enough to give
the poles hot weather.
Between the poles and the equator, temperatures
may vary greatly from one
season to the next. During winter, the
weather is generally cold and often
snowy. Some animals hibernate, or sleep
for a long time. Many birds have
migrated, or moved to warmer places for
the season. Some plants die, and others
stop growing.
When spring arrives temperatures
become warmer. Plants and trees produce
new leaves and flowers. Birds
return from their winter homes, and
animals come out of hibernation.
During the summer, temperatures reach
their highest levels. There are more
hours of daylight, and the sun is more
intense. This extra sunshine helps plants
to grow.
Temperatures fall again as autumn
begins. Some trees and plants lose their
leaves. Animals with fur grow thicker
coats to keep them warm during the
coming winter. Many birds travel to
warmer places.
#More to explore
Earth • Equator • Hemisphere
•Weather
Seed
Most plants begin life as seeds. Plants
form their seeds inside flowers or cones.
In flowering plants a fruit often surrounds
the seeds.
Seeds need the right conditions to germinate,
or grow into a new plant. They
need air, water, the right temperature,
good soil conditions, and the right
amount of light.
Features
A seed contains a miniature plant, called
an embryo, that can develop into a fully
grown plant. The outer shell of a seed,
called a seed coat, protects the embryo.
Inside the seed a nutritious material
provides food to the embryo. In flowering
plants this material is called
endosperm.
Germination
Once a seed has formed, it leaves its
parent plant. Seeds often can stay
dormant, or inactive, for many years
before they germinate, or grow. Because
of this, people can store seeds and plant
them later. A seed will germinate once
it is in the ground and the conditions
are right.
As germination begins, parts of the
embryo break out of the seed coat. One
part grows downward. It becomes the
plant’s roots, which take in water and
food from the soil. Other parts grow
upward. They become the plant’s stem
and leaves, which absorb sunlight.
Winter is an
old Germanic
word meaning
“time of
water”—of
rain and
snow.
62 Seed BRITANNICA STUDENT ENCYCLOPEDIA
How Seeds Travel
It is important that seeds travel away
from their parent plant. If the seeds land
nearby, they compete with the parent for
light and water. This means that they are
less likely to survive.
Seeds travel in many ways. Some plants
have fruits or pods that burst open to
scatter the seeds inside. The wind blows
lightweight seeds. Some seeds, such as
those of dandelions, have fluffy parts
that help them to drift through the air.
Some plants, such as coconut palms,
drop their seeds in nearby water. These
seeds have waterproof coverings that let
them float far away.
Animals also carry seeds to other places.
Seeds with sticky or prickly seed coats
stick in the fur of animals. The seeds
drop to the ground later. When birds
and other animals eat fruit, the seeds
pass through their bodies and often end
up far from where they ate the fruit.
Uses
Seeds are an important source of food
for people and animals. Seeds used for
food are often called grains or beans.
People also use seeds to make oils,
spices, fabric dye, and jewelry.
#More to explore
Bean • Flower • Fruit • Grain • Plant
Seminole
The Seminole are Native Americans
who were once part of the Creek tribe of
the U.S. state of Georgia. In the 1700s
they broke away from the Creek and
moved southward into northern Florida.
The name Seminole probably came
from the Spanish word cimarron, which
means “wild” or “runaway.”
BRITANNICA STUDENT ENCYCLOPEDIA Seminole 63
The Seminole lived in villages. A chief
ruled each village. The Seminole made
their homes by covering wooden frames
with roofs of branches, grass, and bark.
