Download Characteristics of Life 1.01

Biology and You
Chapter 1
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Overview
The purpose of this chapter is to
introduce you to characteristics shared
by all living organisms, including
yourselves. During your study of this
chapter, you will learn how your own
lives relate to the study of biology, and
how biologists approach the study of
living organisms. These themes will
recur throughout the course.
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Section 1: Themes of Biology
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Section 1 Objectives
Relate the seven properties of life to a living
organism.
 Describe seven themes that can help you
organize what you learn about biology.
 Identify the tiny structures that make up all
living things.
 Differentiate between reproduction and
heredity and between metabolism and
homeostasis.

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Characteristics of Living Organisms
The photo at the right
shows an orphaned
rabbit.
 Imagine that you are
holding and feeding the
rabbit.
 How do you know that
it is alive?
 What does the rabbit
need to stay alive?

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Characteristics of Living Organisms
[Organism = living thing]
Defining life is difficult, many
nonliving things display some
characteristics of life.
[Biology = the study of life]
All living things share certain general
properties that separate them from
nonliving things.
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Characteristics of Living Organisms
PROPERTIES OF LIFE
• Cellular organization
• Reproduction
• Metabolism
• Homeostasis
• Heredity
• Responsiveness
• Growth and development
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Characteristics of Living Organisms
 Cellular organization - every living thing is composed of
one or more cells
 Reproduction - all living things are able to reproduce
 Metabolism - all obtain and use energy to run the
processes of life
 Homeostasis - living organisms maintain a consistent
internal environment
 Heredity - living things pass traits to offspring
 Responsiveness - all living things respond and adjust to the
environment
 Growth and development - all living things grow and
develop
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Unifying Themes in Biology
 In
the study of Biology, broad themes
emerge that:
 Unify living things – explain the
similarities among organisms despite
their great diversity.
 Explain Biology as a science, a
systematic process of inquiry
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Unifying Themes in Biology
The themes include:
 Cellular structure and function
 Reproduction
 Metabolism
 Homeostasis
 Heredity
 Evolution
 Interdependence
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Unifying Themes in Biology
Theme #1--Cellular structure and function
 All living things are made of one or more
cells.
 Cells are the smallest units capable of all
life functions.
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Unifying Themes in Biology
Theme #2—Reproduction
 Reproduction = the process by which
organisms make more of their own kind.
 All living things reproduce.
 Though life spans vary, no organism lives
forever.
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Unifying Themes in Biology
Theme #3—Metabolism
 Metabolism is the sum of all chemical
reactions carried out in an organism.
 These chemical reactions occur in order to
obtain and use energy for all life processes
(growth, movement, etc.)
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Unifying Themes in Biology

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Energy flow
 Energy is captured from sunlight by
plants, algae, and some bacteria through
photosynthesis
 This energy is used to build complex
molecules.
 Complex molecules serve as sources of
energy (food) for other organisms
Unifying Themes in Biology
Theme #4—Homeostasis
 Refers to the maintenance of stable
internal conditions regardless of external
change.
 All organisms must be able to maintain
stable internal environment in order to
function properly.
 Example: Mammals maintain a fairly
constant body temperature regardless of the
environment
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Unifying Themes in Biology
Theme #5—Heredity
 Refers to the ability to pass traits from
parent(s) to offspring each generation.
 The basic units of heredity are the genes,
coded segments of a deoxyribonucleic acid
(DNA) molecule.
 Mutation is change in the DNA of a gene
 Only mutations that occur in sex cells
(egg, sperm) are passed on
 Most mutations that cause change are
harmful, but some are beneficial
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Unifying Themes in Biology
Theme #5—Heredity (cont.)
 Examples of mutations
 Sickle-cell disease
 Affects hemoglobin, the oxygen transporting
protein in red blood cells.
 Causes red blood cells to become distorted
into irregular shapes that do not travel
through tiny capillaries.
 A positive effect of the mutation is resistance
to Malaria
 Cancer may result from mutations in body cells
that disrupt the control of cell reproduction.
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Unifying Themes in Biology
Theme #6—Evolution
 Refers to change in the inherited
characteristics of species over
generations.
[species = a group of genetically similar
organisms that can interbreed and produce fertile
offspring]
Occurs by the process of natural selection
 Provides a consistent explanation of life’s
diversity—it unifies all branches of biology.

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Unifying Themes in Biology
Theme #7—Interdependence
 Organisms live and interact with
other organisms.
 Ecology is the study of interactions of
organisms with one another and with the
nonliving part of their environment.
 Interdependence within biological
communities is the result of a long history
of evolutionary adjustments.
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Review
A change in the DNA of a gene is called a
mutation
____.
2. The many different species of organisms
evolution
on Earth today are the result of _____.
3. The maintenance of a stable internal
environment is called homeostasis
_____.
1.
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