section
1.1 The Study of Life
Teacher Notes and Answers
SECTION 1
Instant Replay
1. at the equator
Vocabulary Check
1. Biology
2. Biodiversity
3. species
4. biosphere
5. science
The Big Picture
6. cell, species, biosphere
7. the discovery and study of cells and
microorganisms
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section 2A, 3D, 3F
1.1 The Study of Life
Key Concept Biologists study life in all its forms.
Earth is home to an incredible
diversity of life.
Living things are found almost everywhere
on Earth. There is life in the deepest parts
of the ocean, in hot springs, and even in
Antarctic ice. Living things can be all shapes
and sizes. The blue whale is the largest
animal living on Earth. Other living things
are so small they can only be seen through This organism is made
of a single cell and is too
a microscope. small to be seen with
just the human eye.
The Biosphere
Everything that lives on Earth, and every place where those things
live, is part of the biosphere. Prairies, forests, deserts, and other land
environments are all part of the biosphere. Oceans, lakes, and other
water environments are also part of the biosphere. Even the inside of
your nose, where bacteria and fungi live, is a part of the biosphere.
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Biodiversity
The word diversity means “variety.” If you have lots of VISUAL VOCAB
different kinds of t-shirts, you have a variety of t-shirts, Across the biosphere, the variety
or a diversity of t-shirts. The word part bio- means of life is called biodiversity.
“related to life.” Biodiversity is the variety, or all the
different types, of life on Earth. There is more biodiver-
sity in warm areas of Earth. More living things can sur- Biodiversity is
greater closer to
vive in consistently warm areas. These areas have a larger the equator.
food supply for more forms of life. The region around
the equator* has the most consistently warm tempera- biosphere = everywhere life exists
tures on Earth, so there is the greatest biodiversity near
the equator.
* Academic Vocabulary
equator the imaginary circle around the middle of the Earth
2 Holt McDougal Biology
These are all different species
of North American birds.
Cardinal Peregrine falcon
Screech owl Brown pelican
Snowy egret
A species is a particular type of living thing that can breed and
reproduce. Humans are one species, and monarch butterflies are another
species. About 2 million different living species have been identified.
Biologists think that there could be millions more species that have not
yet been discovered. Over half of all known species are insects.
Where on Earth would you find the greatest variety
of species?
Biology is the scientific study of all forms of life.
Biology, or life science, is the scientific study of living things and their
interactions with their environment. Biology is one of three basic areas
of science: life science, earth science, and physical science.
The study of living things helps us to better under-
© Houghton Mifflin Harcourt Publishing Company
stand ourselves and our world. For example, high intel-
ligence and the ability to make and use tools were con-
sidered to be strictly human traits until chimpanzees
were observed using sticks and other tools to hunt
insects and other organisms. Science is knowledge
gained by observing natural events and conditions.
Observations help scientists to discover facts or to
perform experiments to test theories or formulate laws.
® Frank Lukasseck/Corbis
Humans have studied living things throughout
history.
The study of living things began long before the invention of computers,
microscopes, or other scientific tools and techniques. Prehistoric cave
paintings show that early people were interested in the animals they
observed and used as food. Ancient civilizations used herbal remedies,
domesticated animals, and grew crops. The ancient Egyptians mummified
their royalty, nobility, and the wealthy. All of these things taught ancient
civilizations much about living organisms and their surroundings.
Scientists during any time period are limited by the demands and rules
of society. Changes in politics and governance also influence the progress
of science.
Interactive Reader 3
The ancient Greek and Roman societies are known for their milestones
in science and philosophy. There was not as much scientific development
in Europe during the Middle Ages as in places such as India and China.
The Scientific Revolution (1450s–1700s) gave rise to a renewal of
interest in art and science. Leonardo da Vinci made close studies of animal
and human anatomy and used this knowledge in his art. He introduced
methods of observation and documentation that are still used today.
Scientific understanding is always limited by available technology.
Advances in biology and other areas of science are made possible by the
use of new technologies. For example, the invention of the microscope
allowed for the discovery and study of cells and microorganisms.
1.1 Vocabulary Check Mark It Up
Go back and highlight
biosphere science
each sentence that
biodiversity
has a vocabulary
species
word in bold.
biology
Fill in the blanks with the correct term from the list above.
1. is the scientific study of all living things.
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2. describes all of the different types of living organisms
in a given area.
3. A is a particular type of living thing that can breed and
reproduce.
4. All living things and the places where they are found on Earth make up
the .
5. Knowledge that is gained by observing natural events and conditions is
known as .
1.1 The Big Picture
6. Put the following three terms in order from smallest to largest: species,
biosphere, cell.
7. List two advances in biology that were made after the m
icroscope was
invented.
4 Holt McDougal Biology
