Fundamentals of Biology
Chapter 4
Levels of Organization
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Atom Level
Tissue Level
Ecosystem Level
Molecule Level
Individual Level
Organelle Level
Organ System Level
Cell Level
Community Level
Population Level
Organ Level
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Atom Level
Molecule Level
Organelle Level
Cell Level
Tissue Level
Organ Level
Organ System Level
Individual Level
Population Level
Community Level
Ecosystem Level
Atom
The fundamental unit of
all matter
Molecule
Combinations of atoms
that are bonded together
Organelle
A subcellular membranebound compartment
Cell
The basic unit of life
Tissue
Group of similar cells that
perform a common function
Organ
Two or more different tissues
that perform a common
function
Organ
System
Group of related organs that
have a common function
Individual
A single organism
All individuals of the
Population same species that
occupy a given area
All the species in an
Community ecosystem that can
interact
Ecosystem
A community and its
physical environment
The Ingredients of Life
• Elements- substances composed of only one type of atom.
– 94 naturally occurring.
– Carbon, Nitrogen, Hydrogen, and Oxygen account for 90% of the
elements in living things.
The Building Blocks
Cells and
Organelles
Eukaryotic vs. Prokaryotic Cells
Feature
Eukaryotic
Organisms
Animals, plants
Size
10-100 µm
Organelles
Yes
DNA form
Coiled, linear
DNA location
Nucleus
Internal membranes
Yes
Cytoskeleton
Yes
Prokaryotic
Bacteria, Archaea
1-10 µm
No
Circular
Cytoplasm
No
No
Robert Hooke (1635-1703)
Cell Theory
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CELL THEORY- proposed in 1839 by Schleiden
and Schwann.
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All living things are composed of cells.
The cell is the basic unit of life.
New cells arise only from preexisting cells.
Cells contain hereditary information which is passed
from cell to cell during cell division.
5. All cells are similar in chemical composition.
6. All of the energy flow of life occurs within cells.
Invention of the Microscope
• Invented circa 1595 AD by
Zacharias Janssen (15801638), a spectacle maker
from Holland.
4 Types of Microscopes Used to Study Cells
• Dissecting microscope- 4-50X.
– Light is passed through or reflected on a specimen.
– Focus with a set of glass lenses.
• Compound light microscope- 1,000X.
– Light is passed through a specimen.
– Focus with a set of glass lenses.
• Transmission electron microscope- 50,000X.
– Electrons are passed through a specimen.
– Focus with a set of magnetic lenses.
• Scanning electron microscope- 10,000X.
– Electrons are scanned over the surface of a specimen that has
been coated with a metal.
– No Focus, produces a three-dimensional image collected from
electrons that are emitted from the metal.
Dissecting Microscope
Diffusion
• Diffusion- the
spontaneous tendency of
a substance (solute or
solvent) to move from a
more concentrated to a
less concentrated area.
– T or F. Diffusion results in
the uniform distribution of a
substance.
Osmosis
• Osmosis- the diffusion of water through a selectively
permeable membrane from a region of higher
concentration to a region of lower concentration.
When referring to two solutions that are separated
by a selectively permeable membrane:
• Isotonic solutions have the same
concentration of solute as the cell.
• Hypotonic solutions have lower solute
concentrations than the cell.
• Hypertonic solutions have higher solute
concentration than the cell.
3 Domains and 6 Kingdoms
Classifying Living Things