Studying Life
Chapter 1.3
What is “Biology”
• Biology is the science that seeks to understand
the living world
• “The study of life and how they interact”
Interactions
With each other
With other animals
With people
Characteristics of Life
• What is life? What is needed to “be alive”??
• How can you classify all living things?
– What must they do or have the ability to do?
Living things share the following eight
characteristics:
1. Living things are made up of units called cells
2. Living things reproduce
3. Living things are based on a universal genetic
code
4. Living things grow and develop
5. Living things obtain and use materials and
energy
6. Living things respond to their environment
7. Living things maintain a stable internal
environment
8. Taken as a group, living things change over time
1. Made up of Cells
• Small units that make up life
• A Cell is a collection of living matter enclosed
by a barrier that separates the cell from its
surroundings
• Can be unicellular (made up of only one cell)
or multicellular (made up of many cells)
2. Reproduction
• Must be able to produce new organisms
• Can be done using:
– Sexual Reproduction where two parent cells unite
to form offspring
or
– Asexual Reproduction where the new organism
has a single parent
3. Based on a Genetic Code
• Offspring usually resemble their parents
• Inherit these traits in the reproduction process
• Passed on through DNA using their genetic
code to produce the offspring
4. Growth and Development
• All living things grow during at least part of
their lives
• For many organisms, development includes
periods of rapid and dramatic change
5. Need Materials and Energy
• Organisms need materials to stay alive
• The combination of chemical reactions
through which an organism builds up or
breaks down materials as it carries out its life
processes is called metabolism
6. Response to the environment
• Organisms detect and respond to stimuli from
their environment
• A Stimulus is a signal to which an organism
responds
– Can be external (from the environment like light
or temperature) or it can be internal (from inside
the organism like sugar levels in the blood)
7. Maintaining Internal Balance
• Things are always changing around us but we
need to maintain a constant set of conditions
• Homeostasis is maintaining a fairly constant
set of internal conditions, such as
temperature, water content, salinity, and pH
• Think about sweating and shivering… think
about the “Homeostasis of the Eye Lab” that
we did
8. As a group, we change over time
• Organisms will always grow and change over
time to make the best of their surroundings
and conditions
• Species will evolve to be better suited for their
climates, food selection, and availability of
other necessary resources (water, mating
patterns, habitat, etc.)
Midway “checkpoint” questions
• Lets discuss and answer the following questions:
1. Describe 5 characteristics of life
2. Compare sexual and asexual reproduction
3. What biological process includes chemical
reactions that break down materials?
4. What is homeostasis?
5. Give two examples of homeostasis and explain
how the organism maintains this “happy balance”
Branches of Biology
• Living things come in many different shapes,
sizes, and habits
• Living systems also range in size from groups
of molecules that make up structures inside
cells to the collections of organisms that make
up the biosphere.
• No single biologist could study this diverse
What CAN we study??
•
•
•
•
Molecules
• The biosphere (the
part of the earth
Cells
that contains all
Organisms
ecosystems
Populations of a single
kind of organism
**REALLY,
we
can
• Communities of
study
the
smallest
different organisms in
thing
all
the
way
up
an area
to the largest groups
Copy the Following Table in Your Notes
Levels of Organization
INCREASING IN SIZE
Biosphere
Ecosystem
Community
Population
Organism
Groups of Cells
Cells
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Copy the Following Table in Your Notes
Levels of Organization
INCREASING IN SIZE
Biosphere
Ecosystem
Community
Population
Organism
Groups of Cells
Cells
Smallest functional Units of life
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Copy the Following Table in Your Notes
Levels of Organization
INCREASING IN SIZE
Biosphere
Ecosystem
Community
Population
Organism
Groups of Cells
Tissues, organs, and organ systems
Cells
Smallest functional Units of life
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Copy the Following Table in Your Notes
Levels of Organization
INCREASING IN SIZE
Biosphere
Ecosystem
Community
Population
Organism
Individual living things
Groups of Cells
Tissues, organs, and organ systems
Cells
Smallest functional Units of life
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Copy the Following Table in Your Notes
Levels of Organization
INCREASING IN SIZE
Biosphere
Ecosystem
Community
Population
Group of organisms of one type
that live in the same area
Organism
Individual living things
Groups of Cells
Tissues, organs, and organ systems
Cells
Smallest functional Units of life
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Copy the Following Table in Your Notes
Levels of Organization
INCREASING IN SIZE
Biosphere
Ecosystem
Community
Populations that live together in a
defined area
Population
Group of organisms of one type
that live in the same area
Organism
Individual living things
Groups of Cells
Tissues, organs, and organ systems
Cells
Smallest functional Units of life
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Copy the Following Table in Your Notes
Levels of Organization
INCREASING IN SIZE
Biosphere
Ecosystem
Community and its nonliving
surroundings
Community
Populations that live together in a
defined area
Population
Group of organisms of one type
that live in the same area
Organism
Individual living things
Groups of Cells
Tissues, organs, and organ systems
Cells
Smallest functional Units of life
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Copy the Following Table in Your Notes
INCREASING IN SIZE
Levels of Organization
Biosphere
The part of earth that contains all
ecosystems
Ecosystem
Community and its nonliving
surroundings
Community
Populations that live together in a
defined area
Population
Group of organisms of one type
that live in the same area
Organism
Individual living things
Groups of Cells
Tissues, organs, and organ systems
Cells
Smallest functional Units of life
Molecules
Groups of atoms; smallest unit of
most chemical compounds
Biology in Everyday Life
• In this class, you will see that more than any
other area of study, biology touches your life
every day
• In fact, its hard to think of anything you do that is
not affected by it
• Biology can help people understand that humans
are capable of predicting and trying to control
their future and the future of the planet
What do we NOW know??
1. Describe the AT LEAST 5 of the 8 characteristics
of life
What do we NOW know??
2. What topics might biologists study at the
“community” level of organization?
3. How about at the “groups of cells” level?
What do we NOW know??
4. What is the difference between “asexual
reproduction” and “sexual reproduction”?
5. What is homeostasis? Give two examples of
how homeostasis is maintained.
What do we NOW know??
6. What biological process includes the chemical
reactions that break down materials??
Test Thursday!!
Keep Studying!