Chapter 1
• 40 million Species of organisms.
• About 2 million have been identified and
named, only a few thousand have been
studied.
• All living things are called Organisms.
• The first life form arose more than 3.5
BILLION years ago. (Single Celled
organism.)
• Over time Organisms Change (Evolution)
• Organisms also inhabit extreme locations
on Earth:
-Antarctic Ice
-Hot vents on the ocean floor
-Inside of other organisms
• Each organism is adapted to the specific
features of its environment.
• BIOLOGY - the Science of Life - is The
Study of ALL Living Things.
SIX UNIFYING THEMES OF
BIOLOGY
A. Cell Structure and Function
B. Stability and Homeostasis
C. Reproduction and Inheritance
D. Evolution (Change)
E. Interdependence of Organisms
F. Matter, Energy, and Organization
CELL STRUCTURE AND
FUNCTION
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THE CELL IS THE BASIC UNIT OF LIFE.
UNICELLULAR ORGANISMS - ONE CELL
MULTICELLULAR - MORE Than One Cell
Cells are Highly Organized.
Specialized Structures called
ORGANELLES.
• Cells go through DIFFERENTIATION.
STABILITY AND HOMEOSTASIS
• Living Things Maintain Very Stable
Internal Conditions such as Temperature,
Water Content, and even Food Intake.
• Maintaining this Stable Level of
INTERNAL CONDITIONS is called
HOMEOSTASIS and is found in all Living
Things, including single cells.
• Examples??
REPRODUCTION AND
INHERITANCE
• REPRODUCTION process in
which Organisms produce new
organisms like themselves by
transmitting hereditary information
to their offspring.
• The Hereditary Information is in a
form of a large molecule called
DEOXYRIBONUCLEIC ACID OR
DNA.
• A short segment of DNA that contains the
instructions for the development of a
SINGLE TRAIT is called a GENE.
• The DNA of every body cell is
IDENTICAL. Each cells uses CERTAIN
GENES from the complete set.
ASEXUAL REPRODUCTION
• Used by Unicellular Organisms
• Hereditary Information from different
organisms IS NOT COMBINED. One Cell
gives rise to TWO NEW CELLS. Each of
the TWO Cells contains an IDENTICAL
COPY (Clones) DNA from the Original
Cell.
SEXUAL REPRODUCTION
• used by Multicellular organisms
• Hereditary Information from TWO
Organisms of the SAME SPECIES
Combine.
• Female EGG
• Male SPERM.
• The Joining of Egg and Sperm produces a
FERTILIZED EGG CALLED A ZYGOTE,
• It contains Hereditary Information from
both the Parents.
EVOLUTION
• Populations of organisms EVOLVE, or
CHANGE over Generations (TIME).
• NATURAL SELECTION - driving force in
Evolution - Organisms that have certain
Favorable Traits are Better able to
Successfully Reproduce - SURVIVAL OF
THE FITTEST.
• The survival of organisms with Favorable
Traits causes a gradual Change in
populations of organisms over many
generations.
• Modern Day Horse - 57 Million Years.
INTERDEPENDENCE OF
ORGANISMS
• ECOLOGY is the study of Interactions of
Organisms with one another and with their
Environment.
• THE PASSING OF ENERGY FROM ONE
ORGANISM TO ANOTHER.
• Grass (Producer) to (Consumer) Herbivore
(plant eater) to (Consumer) Leopard.
• Nonliving factors (Abiotic) are also
necessary for survival of organisms…
A. Air
B. Water
C. Energy (THE SUN)
D. Minerals
• BIOSPHERE - The part of the Earth that
supports life.
• Includes all the LAND, WATER, and AIR,
where organisms live.
• Organisms respond to their environment
by either:
A. Adapting
B. Fleeing
C. Or Dying
• Most organisms can survive a temporary
change.
• Permanent change can lead to extinction.
• Main cause - Human Interference?
MATTER, ENERGY, AND
ORGANIZATION
• ALMOST ALL THE ENERGY FOR LIFE
ON EARTH COMES FROM THE SUN.
• PHOTOSYNTHESIS - plants and
Unicellular Organisms capture the energy
from the Sun and change it into a form of
energy that can be used by living things.
• Converts Water and Carbon Dioxide into
Sugars and Starches
• Organisms that make their own food, like
plants, are called AUTOTROPHS
(Producers).
• Organisms that must take in FOOD to
meet their Energy needs are called
HETEROTROPHS (Consumers).
• Includes all Animals and Fungi as well as
many Unicellular Organisms and a few
Plant Species.
CHARACTERISTICS OF LIFE
1. CELLS - All organisms are
COMPOSED of
CELLS. Unicellular or
Multicellular
2. ORGANIZATION - Living
things are HIGHLY
ORGANIZED at both the
Molecular and Cellular Level.
3. ENERGY USE - All organisms USE
ENERGY for GROWTH AND REPAIR in a
process called METABOLISM.
• Which is the sum of all the Chemical
Processes that occur in the organism.
4. HOMEOSTASIS - All Living Things
maintain stable internal Conditions HOMEOSTASIS. All organisms
RESPOND to the
ENVIRONMENT.
5. GROWTH - All organisms GROW and
DEVELOP.
• Single celled organisms grow and develop
into mature cells.
• Multicellular organisms - Growth is an
Increase in Size. Development is a change
in Shape or Form.
6. REPRODUCTION - REPRODUCTION IS
NECESSARY FOR THE SURVIVAL OF A
SPECIES.
7. ADAPTATION - SPECIES of organisms
ADAPT to their ENVIRONMENTS
through EVOLUTION.
Molecular Level
• The simplest part of a living system are the
atoms and molecules from which the
organisms are made.
• An example is DNA. DNA is a very complex
molecule made of thousands of atoms.
Cellular Level
• In a cell many different molecules
interact with one another. The cell is
the smallest unit of life capable of
carrying out all the functions of living
things.
Tissue Level
• Tissues are a group of cells that
perform a specific function in an
organisms
– Ex. Muscles
Organ Level
• An organ is made of several different
types of tissues that function together
for a specific purpose.
– Ex. Heart, liver
Organ System Level
• An organ system is
made of several organs
working together to
perform a function.
– Ex. Circulatory,
digestive,
reproductive
Population Level
• A group of organisms of the same
species that lives together in a particular
location.
Community Level
• A community includes all the populations
of different kinds of organisms living in the
same place.