Transcript Chapter 3

Chapter 3
Cells: The Basic Units of
Life
Organization of Life
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All living things have one or more cells
Not all of our cells look the same
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Humans have over 2oo types of cells each
specialized for different jobs
Tissues
 A group
of
similar cells that
work together to
perform a
specific job in
the body
Organ
 A combination
of two or more
tissues that
work together to
perform a
special function
in the body
Organ System
 A group
of
organs that
work together to
perform body
functions
Organism
 Anything
that can
independently carry on life
processes
Unicellular vs. Multicellular
 Unicellular-
organism made
of one cell
 Multicellularorganism made
of many cells
Population
 A group
of
individuals of
the same
species that live
together in the
same area at
the same time
Community
 All
of the
populations of
different
species that
live and
interact in an
area
Ecosystem
 A community
of organisms
and their
nonliving
environment
Robert Hooke
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English scientist
1665  cut a thin slice
of cork and observed
with a microscope
Hooke saw small
boxes resembling the
small rooms monks
live in  cells
Anton van Leeuwenhoek
Dutch microscope
maker
 1675  first
person to see
living cells under
the microscope
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150 years later…..
 Matthias
Schleiden (1838)
 German botanist
 Concluded that all plants are
composed of cells
 Theodor Schwann (1839)
 German zoologist
 Concluded that all animals are
composed of cells
Rudolph Virchow
 1858,
German doctor
 Saw cells couldn’t develop
from anything other than other
cells
Collectively known as
the Cell Theory
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2.
3.
All living things are composed of
one or more cells
Cells are organisms’ basic units of
structure and function
Cells come from existing cells