Biology: The Study of Life
CHAPTER 1
1.1 WHAT IS BIOLOGY?
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1.1 BIOLOGISTS STUDY THE DIVERSITY OF LIFE
Biology = the study of life
 Interactions of Life

 Living
things do not exist isolated from other living
things.
 Living things interact with other living and non-living
things within their environment.
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1.1 BIOLOGISTS STUDY THE DIVERSITY OF LIFE
Biologists study the diversity of life…
 Learning about the world of living things in our
environment…
 Biologists study the interactions of the
environment.
 Since no living thing exists in isolation, we must
study their interactions with other living things and
non-living components in their environment.
Population of rabbits: what they eat, and what eats
them
 Humans? What are our interactions within our
environments?

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1.1 BIOLOGISTS STUDY THE DIVERSITY OF LIFE
Biologists study problems and propose solutions.
 Water pollution
 Air pollution
 Over-fishing
 Deforestation
 Acidity of our water
 Illness
 Etc...
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1.1 CHARATERISTICS OF LIVING THINGS
All living things:
 Have
an orderly structure
 Produce offspring
 Grow and develop
 Adjust to changes in the
environment
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1.1 CHARACTERISTICS OF LIVING THINGS
Living things are organized.
 Orderly structure = organization
 1+ cells
 Each cell contains the genetic material (DNA),
which provides all the information necessary to
control the life processes of an organism.
 Living things are unified in having cellular
organization.
 All
of the parts of a cell, whether single cell, or
multi-cell, function together in an orderly, living
system.
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1.1 CHARACTERISTICS OF LIVING THINGS
Living things make more living things.
 Reproduction = the production of offspring
 Organisms do not live forever.

For life to continue, they must replace themselves.
Reproduction is not essential for the survival of an
individual organism, but it is essential for the
continuation of the organism’s species.
 A species is a group of organisms that can
interbreed and produce fertile offspring in nature.
 If a species did not reproduce, it would mean the
end to that species’ existence on Earth.

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1.1 CHARACTERISTICS OF LIVING THINGS
Living things change during their lives.
 An organism’s life begins as a single cell.
 Over time, it grows and takes on the
characteristics of its species.
 Growth = increase in the amount of living
material and the formation of new structures
 Development = all of the changes that take
place during the life of an organism

 Embryo
– baby – toddler – child – adolescent –
teenager – adult
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1.1 LIVING THINGS ADJUST TO THEIR SURROUNDINGS
Organisms live in a constant interface with their
environment.
 The environment includes other living things,
and also non-living things, such as:

 Air
 Water
 Earth
 Weather
 Temperature
 Etc…
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1.1 LIVING THINGS ADJUST TO THEIR SURROUNDINGS
Stimulus = anything in an organism’s external
or internal environment that causes the
organism to react
 Response = is a reaction to a stimulus

 i.e.,
The fox responds to the presence of a rabbit
(the stimulus) by quietly moving toward it.
 If the rabbit spots the fox (now the fox is the
stimulus), the rabbit will respond by hopping away…
very quickly.
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1.1 CHARACTERISTICS OF LIVING THINGS
Homeostasis = regulation of an organism’s
internal environment to maintain suitable
conditions for its survival
 Water/mineral content within their cells
 Blood pressure
 Internal temperature
 pH
 Without the ability to adjust to internal
changes, an organism would die.
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1.1 CHARACTERISTICS OF LIVING THINGS
Living things reproduce themselves, grow &
develop, respond to external stimuli, and
maintain homeostasis by using energy.
 Energy = is the ability to cause change.
 Organisms get their energy from food.

 Plants
make their own food.
 Animals, fungi, other organisms get their food from
plants or other organisms that consume plants.
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1.1 CHARACTERISTICS OF LIVING THINGS
Living things adapt and evolve.
 Adaptation = any inherited structure, behavior,
or internal process that enables an organism to
respond to environmental factors and live to
reproduce
 Adaptations are inherited from previous
generations.
 There are some differences in the adaptations
of individuals within a population of organisms.
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1.1 CHARACTERISTICS OF LIVING THINGS
As an environment changes, some
adaptations are better suited to the new
conditions than others.
 Organisms with better suited adaptations are
more likely to survive and reproduce.
 Individuals with these adaptations become
more numerous in the population.

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1.1 CHARACTERISTICS OF LIVING THINGS
Evolution = gradual change in a species through
adaptations over time
Clues to the diversity of life may be understood by
the study of evolution.
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