Is Fire Alive?
Reproduce?
Breath?
Growth?
Development?
Life Cycle?
Waste?
Eat?
Cells?
Introduction to Biology
What is Biology?
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“Bios” means life
“logy” means the study of
What do we get when we put the two words
together?
“Biology” = the study of life
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The science that seeks to understand the living world
A biologist uses scientific methods to study living
things
What is life?
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Life extends much further than what you
can see. Everywhere around you, all over
your desk, the walls, the floor, the ceiling,
your clothes, and even your skin, you can
find billions and billions of tiny microscopic
life forms.
What kinds of things are alive?
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Living things are called
organisms.
There are many different
types of organisms
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Animals (humans, insects,
birds, mammals, fish,
reptiles, amphibians)
Plants (trees, grasses,
bushes, shrubs)
Fungi (mushrooms, mold,
yeast)
Bacteria
Protists (algae)
What are some things that living
things have in common?
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Made up of units called cells
Reproduction
Based on a genetic code
Growth and development
Obtain and use materials and energy
Response to the environment
Maintaining stable internal balance
Evolution
Living things are made of cells
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Cells are the basic building units of all forms of life.
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a collection of living matter enclosed by a barrier that separates
the cell from its surroundings
Example: a sandcastle looks “smooth” but on closer
examination, it is made up of millions of tiny grains of
sand.
An elephant also looks “smooth,” but if you could get
close enough and if your eyes were powerful enough,
you would realize that the elephant is really made up of
many billions of cells.
Cells make up every part of a living thing. For example,
skin, blood, bones, nerves, and muscles are all made up
of cells.
Living things reproduce
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Reproduction is the process of organisms
producing new organisms similar to themselves
There are two kinds
Sexual reproduction- process by which cells from
two different parents unite to produce the first cell of
the new organism
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Example: union of female egg cell with male sperm cell
Asexual reproduction- process by which a single
parent produces a new organism by itself
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Example: splitting of bacteria cells
Living things are based on a
genetic code
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A molecule called
DNA carries the
genetic code which
determines the
inherited traits of
every organism.
Living things grow and develop
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To grow means to get larger in size.
To develop means to change shape &
structure throughout life.
Examples:
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Frogs begins life as tadpoles and then change
into an adult frogs.
Butterflies start life as caterpillars before
maturing into full grown butterflies.
Living things need materials &
energy
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Most of us call this eating!
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But then we have to be able to convert our food, a
form of energy, to chemicals our cells can use
through metabolism.
Metabolism is the combination of chemical
reactions through which an organism builds up
or breaks down materials as it carries out its life
processes.
Photosynthesis is when plants convert the
sun’s energy into stored chemical energy.
Living things respond to the
environment
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Organisms can detect stimuli from the
environment.
A stimuli is a signal to which an organism
responds.
Examples:
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Reflex of quickly removing your hand from a
hot stove
Leaves and stems of a plant grow toward light
Living things maintain an internal
balance
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Organisms must keep their internal conditions stable
with a changing external environment.
Homeostasis is the process by which organisms
maintain a relatively stable internal environment.
Example: Humans have an internal "thermostat" that
helps us maintain a body temperature of about 98.6
degrees F.
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To keep body temperature up when the weather gets cold, your
body shivers
To keep body temperatures down when the weather gets hot,
you sweat
As a group, living things change
over time
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Evolution is a change in a kind of
organism over time.
So again…What is life?
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Defining "life" is a very difficult task, and
scientists don’t all agree on a common list of the
characteristics of life.
Many of the characteristics of life are not limited
to living things. For example, is fire a living
thing?
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It uses energy, grows, and can reproduce…
But it is not considered to be living because it is not
made of cells, lacks a genetic code, & cannot evolve
In order to be considered a living thing, something
must have all of the characteristics.
Biology in Everyday Life
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Helps you understand and appreciate other
organisms
Provides information about food and methods
for sustaining world’s food supplies
Describes conditions of good health & behaviors
& diseases that can harm you
Diagnose and treat medical problems
Identifies environmental factors that can
threaten you