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Biology 2201
Unit 1
Matter and Energy
Unit 1 Matter and Energy
1
Biology
• Definition:
– Biology is the study of living organisms – Divided
into many specialized fields that cover their
morphology, physiology, anatomy, behavior, origin
and distribution.
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2
Cells: An Introduction
HowStuffWorks "Cell Biology Videos"
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3
Unicellular organisms
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Multicellular
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Historical Development of Cell Theory
Cell Theory is composed of 4 main points:
1. All living organisms are composed of one or more cells.
2. Cells are the basic units of structure and function in
all organisms.
3. All cells are derived from pre-existing cells.
4. In a multicellular organism, the activity of the entire
organism depends on the total activity of its individual cells.
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6
Spontanteous Generation
(Abiogenesis)
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Biogenesis
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Significant Events in Biological History Relating
to Cell Theory
For hundreds of years a debate raged amongst scientists about
the origin of living things. The debate centered around two
theories:
1. Abiogenesis (Spontaneous Generation)
2. Biogenesis
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Abiogenesis
- The idea that living organisms can arise from
nonliving matter.
- Many examples are sited by early scientists:
- Appearance of mushrooms on logs
- Maggots forming on rotting meat
- Micro-organisms apprearing in a sterilized flask of meat
broth. (John Needham’s experiment)
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Evidence for Abiogenesis
Evidence that supported abiogenesis
•
•
•
•
Fact or Fiction
Maggots suddenly appeared on uncovered
meat after several days
Fiction – Maggots were present, but only after
the flies laid their eggs on the meat
Frogs and salamanders suddenly appearing
on or in mud
Fiction – These amphibians hibernate and
burrow into the mud and come to the
surface to eat
Jan Baptista van Helmont said that mixing
a dirty shirt with wheat grains would
produce adult mice that would then mate.
John Needham’s experiment with meat
broth teeming with microbes after being
boiled.
Fiction – The mice that were attracted to the
food source (wheat) arrived, and then
mated. They possibly hid in the mixture
Fiction – He did not boil the broth long enough
to kill all the bacteria in the broth, and so
they divided, making the broth cloudy.
Biogenesis
- The idea that living organisms can only come
from other living things.
- Scientifically shown to be correct by several
scientists.
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Activity #1
• Create a timeline that depicts the
accomplishments of the following scientists:
Aristotle
Redi
Needham
Spallanzani
Pasteur
Brown
Schleiden
Schwann
Braun
Virchow
Hooke
Leeuwenhoek
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Francesco Redi (1688) performs an experiment to
show that maggots will not appear on rotting meat if
flies are kept away.
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• Louis Pasteur (1860) designs and performs an
experiment that shows that micro-organisms that appear
in a sterilized meat broth actually come from microorganisms found in the air and do not
formspontaneously from the non-living broth.
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Other scientist who contributed to the
development of the Cell Theory:
Robert Hooke (1665) using a primitive set of
lenses to form a simple microscope, observes
“empty room like apartments” in samples of
once living tree bark. Hooke names these
compartments cells.
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Anton Van Leeuwenhoek (1667) designs his own
microscopes that are far more powerful than
any of the primitive forms at the time. Over
the next number of years Leeuwenhoek writes
extensively about is observations of tiny
organisms.
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Mathias Jacob Schleiden (1883) writes, “all plants
are made of cells”.
Theodor Shwann (1839) writes “all animals are
made of cells” and “cells are organisms and entire
animals and plants are collectives of these
organisms”.
Rudolph Virchow (1858) formulates the points of
the cell theory. Writes, “all cells come from preexisting cells”.
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Early Use of Microscopes
• Tendency to look at the known world
• Magnified up to 50x the actual size
• Most microscopes had 2 lenses doubling
the distortion of the poor quality lenses
• Van Leeuwenhoek mastered lens craft in
is single-lens scopes achieve
magnifications as high as 500x with little
distortion
Van Leeuwenhoek’s
microscope
Microscopes
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Microscope Imaging of Today
• Compound light microscopes
–
–
–
–
Max. magnification of about 2000X
Can see most but not all cells, and cell structures
Resolution limited to about 0.2 µm
Resolving power is limiting, so the light source must be
changed to accommodate this
• Electron microscopes
– Use a beam of electrons instead of light to magnify objects
– Use electromagnets to focus beams instead of lenses
Using a Microscope to Explore the Cell
• Resolution or Resolving power
– The ability of the eye, or other instrument, to distinguish
between two objects that are close together
High resolution
Low resolution
Compound Light Microscope
Completely
Label the
microscope
using pg.
16 in your
textbook.
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Compound Light Microscope Parts
See page 16 in your
textbook
Condenser lens
Viewing Prepared Slides
1. Put low power objective lens in place
2. Lower the stage with coarse adjustment.
3. Adjust the diaphragm for brightest light.
4. Place the specimen on the stage and clip in place.
5. Focus with course adjective.
6. Change to Med. Power and focus with fine
adjustment.
7. Change to high power and focus with fine
adjustment only.
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Biological Drawing
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Transmission Electron Microscopes
(TEM)
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Transmission Electron Microscope
• Directs a beam of tiny particles (electrons)
through an object.
• It uses magnets rather than lenses and the
result is shown or projected on a screen
because the eye cannot respond to electrons.
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Transmission Electron Microscope
• The problem with this microscope is that the
object being viewed must undergo extensive
preparation.
• It must be very thin and as it is prepared, it is
sliced frozen and treated with chemicals which
may distort the image.
• The magnification is 1,000,000 x.
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Scanning Electron Microscope
(SEM)
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Scanning Electron Microscope
(SEM)
• Takes pictures rather than slices. It is
almost three dimensional. In many
cases , whole organisms are used.
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Light Vs Electron Microscopes
Type
Light Source
Magnification
Resolution
Specimen Prep
Compound
Light
Visible Light
(light bulb)
Up to 2000x
Aprox 0.2
micrometers
Killed, fixed
and stained
Electron
Beam of
electrons
10 000-500 000 o.2 nm (TEM)
x (TEM)
1000- 10, 000
x (SEM)
Unit 1 Matter and Energy
Killed, dried an
fixed (TEM)
1- 10 nm (SEM) Killed, fixed,
cleaned and
coated with
metal
32
Caring For and Using a Microscope
• LAB ACTIVITY  PAGE 15 – 19
This must be completed in the class time
provided
• Techniques covered in this lab will be on the
test / exam
Magnification
• Multiply the power of the ocular lens by the
power of the objective lens in place.
Low power mag = ________________
Med power mag = ________________
High power mag = ________________
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Field of View (F of V)
Field of view is the size of the
area you see when looking
down a microscope.
For low power: place a ruler
across the field of view and
measure the diameter in
millimeters.
F of V (low) =
Fof V (med) =
F of V (high) =
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Characteristics of Living Cells:
1. obtain food and energy
2. convert energy from an external source into a form
that the cell can use
3. construct and maintain the molecules that make up
cell structures
4. carry out chemical reactions
5. eliminate wastes
6. reproduce
7. keep records of how to build structures
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Cells
• KNOW Figure 1.11 in your text – you will be
expected to label either the animal cell or
plant cell (coming up later)
• You will also be expected to know the
functions of all the parts of the cell and how
they work together to help the cell function
Cells
There are two types of cells:
1. Prokaryotic cells- cells that have no nucleus
or membrane bound organelles. They are
smallest in size and are characteristic of the
simplest type of living things, bacteria.
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Prokaryotic Cells
• Since they do not have a nucleus, all the genetic information
is concentrated in an area called the nucleoid. Some
prokaryotic cells also have a small ring of DNA called a
plasmid
• Prokaryotic cells move using flagella
• See Fig. 1.22 on page 33
Prokaryotic Cell (Bacterial)
Draw this!
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2. Eukaryotic Cells – cells that contain a distinct
nucleus and have membrane bound organelles.
They are found in more complex unicellular
organisms and all multicellular organisms.
Eukaryotic cells have distinct parts that are
responsible for carrying out certain functions
within the cell. These are called organelles.
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Organelles work together to carry out basic life
processes. Eukaryotic cells display what is
known as a division of labour.
Within all eukaryotic cells, there are several
distinct areas:
- The cell membrane
- The nucleus
- The Cytoplasm
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The Eukaryotic Animal Cell
(DRAW THIS!)
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The Eukaryotic Plant Cell
(Draw This)
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Plant Cells vs. Animal Cell
•
Plant cells contain many of the same structures
as animal cells, but there are some differences:
plant cells have an outer cell wall made of
cellulose; animal cells do not
•
–
•
Provides rigidity and protection
Plant cells have one large central vacuole;
animal cells have several vacuoles
–
•
Provides rigidity and stores wastes, nutrients and
is filled with water
Animal cells have a centrosome; plant cells do
not
–
•
Involved in animal cell division
Plant cells have chloroplasts; animal cells do not
–
chloroplast – plastid that gives green plants their
colour and transfers energy in sunlight into stored
energy in carbohydrates during photosynthesis
1. The Cell Membrane“The Control Gate”.
-
Composed of a double layer of lipids (fats), with proteins
embedded in these layers.
-
The cell membrane is selectively permeable. This means
that some substances can pass through it and enter the cell,
while other substances cannot pass through. This allows the
membrane to maintain homeostasis- keeping the internal
physiological environment of the cell constant.
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2. The Nucleus-
“ The Command Center”. It controls most activity in the cell.
The nucleus contains chromatin- uncoiled chromosomes
that contain DNA. The DNA contains the information
required for proper functioning of the cell.
The nucleus also contains a darkened structure known as
the nucleolus- responsible of production of ribosomes.
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• The nuclear envelope surrounds the nucleus and has
pores that allow materials to enter and leave the
nucleus.
3. The CytoplasmThe gel-like portion of the cell that contains each of the
cells organelles. The liquid of the cytoplasm also contains
many dissolved substances that creates a chemical
environment necessary for proper functioning of the cell
structures.
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Organelles in BOTH plant and
animal cells
-Ribosomes- spherical two-part
structures that play a role in the
production of proteins. Located on the
E.R or the cytoplasm.
-Endoplasm Reticulum (E.R)- These
structures are involved in the transport of
proteins through the cell. It’s made of
folded membrane. May be rough, which
means it is covered with ribosomes, or
smooth, which means it has no
ribosomes
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The proteins that are made from the
ribosomes on the rough ER are transported
from rough to smooth ER then forms a bubble
and pinches off, forming a vesicle. This vesicle
transports the protein to the Golgi Apparatus.
- Vesicles- small transport sacs.
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• Golgi Apparatus- These structures are involved in
the refinement, packaging and shipping of
proteins for the purpose of excretion.
• Mitochondria- The “power house”. These
structures break down simple carbohydrates in
order to release their energy. This is called
cellular respiration.
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• Vacuoles- areas of storage within the cell for
water and other substances. In plants, these
can be quite large.
- Centrioles- involved in cell reproduction. They
ensure even distribution of cell components
when the cell divides. Located in centrosome.
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- Lysosomes- “The Recycling Center”. These
structures are involved in the breakdown of
large particles as well as warn out cell parts.
Organelles found ONLY IN PLANT CELLS:
- Cell Wall- This structure is composed of
cellulose and surrounds the cell membrane.
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The function of the wall is to give support and
shape to plant cells.
- Plastids, including chloroplasts and
chromoplasts, are involved in the trapping of
sunlight and the process of photosynthesis.
-Central Vacuole- Provides support and storage
for food, water and toxins. It’s large and fluidfilled.
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The Cell Membrane
• In order for a cell to carry out its life functions,
it must be able to get raw materials from its
environment and regulate the movement of
materials into and out of the cell.
• Recall: the cell membrane is SELECTIVELY
PERMEABLE!!!
Functions of the Cell Membrane
1. Transport raw materials into the cell.
2. Transport manufactured products and
wastes out of the cell.
3. Prevent entry of unwanted materials into
the cell.
4. Prevent escape of matter needed to perform
cellular functions.
Cell Membrane function:
A living cell must maintain a good internal environment or homeostasis. This
homeostasis refers to maintaining nearly constant internal conditions so that
the cell can perform its life functions. It is a process of keeping a balance of
solutes and solvent within a cell. The environment of the cell interior is kept at
a steady state despite changes in the conditions of the external environment.
Materials have to pass into or out of the cell membrane. The cell membrane is
said to be selectively permeable, allowing some molecules to pass through it
while preventing others from doing so. The cells of a multicellular organism
are bathed in a thin layer of extracellular fluid, containing a mixture of water
and dissolved materials. Dissolved materials such as nutrients and oxygen can
enter into a cell while other materials such as wastes and carbon dioxide can
leave a cell.
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Cell Membrane Structure
• The cell membrane is a DOUBLE LAYER of
PHOSPHOLIPIDS with PROTEINS embedded
throughout.
THE FLUID-MOSAIC MEMBRANE MODEL
The phospholipid bilayer contains a mosaic of
different components scattered throughout it,
like raisins in slice of bread. But, the proteins
that are embedded are able to drift sideways,
hence the term fluid-mosaic.
Components of the Cell Membrane
• Phospholipid Bilayer- Contains a phosphate
“head” that is water-loving or hydrophillic,
and two fatty acid “tails” that are
hydrophobic, or water-hating. The heads are
soluble in water while the tails are insoluble.
• Draw:
Components of Cell Membrane
con’t
• The Proteins are used mainly for transporting
various materials in and out of cells.
• Cholesterol- is a lipid that is also embedded
throughout the membrane allowing the cell to
funtion in a wide range of temperatures.
• Carbohydrate Chains- like the “fingerprint” of
the cell, it distinguishes one cell from another.
Drawing of a Cell Membrane
Transport Across the Cell
Membrane
There are two broad categories of transport
across the cell membrane:
• Passive Transport (Requires NO ENERGY)
• Active Transport (ENERGY REQUIRED)
Passive Transport:
Three ways this occurs:
– Simple Diffusion
– Facilitated Diffusion
– Osmosis
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Simple Diffusion
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Diffusion Examples
Diffusion of oxygen into
the cell
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Facilitated Diffusion
• Diffusion of substances that need to be
“helped” across the membrane! Sugars and
charged iors like sodium and chloride.
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Osmosis
• The diffusion of water across the cell
membrane. Results in three conditions:
1. Isotonic Conditions
2. Hypotonic conditions
3. Hypertonic conditions
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Isotonic conditions
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Hypotonic conditions
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Hypertonic Conditions
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Overview of Osmosis
effect on cells
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Active Transport
• When a cell must spend energy in order to
move materials against the concentration
gradient.
• Active transport involves moving materials
from areas of low concentration to high
concentration through a transport “pump” in
the membrane. Energy in the form of ATP is
used to work the pump.
Active Transport
Examples of Active Transport
• At rest, 40% of your energy is being used to
perform active transport!
• How?
– Kidney cells move glucose (sugar) and amino acids
(building blocks of proteins) into the bloodstream.
– Intestinal cells move nutrients in from the gut.
More examples…
• Root cells of plants move nutrients from soil
into the plant cells.
• Gill cells of fish pump out sodium ions.
Compare Active and Passive
Transport
Active Transport
Passive Transport
Similarities
particles enter and exit the particles enter and exit the
cell
cell
proteins in the membrane proteins in the membrane
act
act
as “doorways”
as “doorways” for some
particles
Differences
particles move against the
concentration gradient
cellular energy is used to
move particles
particles move with the
concentration gradient
no cellular energy is
needed
to move particles
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Bulk Membrane Transport
• Occurs by active transport.
• Molecules that are too large are moved across
the membrane by way of the membrane
folding in on itself to create a membraneenclosed, bubble-like sac, called a vesicle
• Draw…
Bulk Membrane Transport
Bulk Membrane Transport
• When materials enter the cell in this manner,
it’s called Endocytosis.
• When materials exit the cell in this manner it’s
called Exocytosis.
Three kinds of Endo/Exocytosis
1. Pinocytosis- “Cell drinking”. Here, the cell
takes in extracellular fluid that has dissolved
particles, as if drinking.
2. Phagocytosis- “Cell eating”. Here, the cell
takes in extracellular fluid that contains
particulate or organic matter in it.
3. Receptor-Assisted/Mediated- The cell
membrane has receptor proteins that attaches
to specific molecules to transport. Like a lock
and key, the molecules must match the
receptor site.
Why are cells so small?
• EFFICIENCY!
• It is more efficient for cells to diffuse materials
across the cell membrane over short
distances. So, having trillions of small cells (as
opposed to one large one) provides the best
amount of cell membrane over which to
transport materials in and out of the cell.
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Surface Area: Volume
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One Large Cell VS Many Small Cells
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Cells, Matter and Energy
• All organisms are composed of cells. They all
need food to provide the energy and matter
they need for growth and reproduction.
The energy that is utilized by a cell has to come from an
outside source. In terms of the makeup of feeding
relationships for organisms, the basis of all energy will be
the SUN. In an ecological relationship, the sun is needed to
provide the energy that producers need to make their own
food by the process of PHOTOSYNTHESIS. The producers
( green plants, algae and some kinds of bacteria) undergo
photosynthesis and are known as AUTOTROPHS .
Autotrophs become food for other organisms known as
HETEROTROPHS — obtain food from other sources.
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Chemical Energy in Cells
• Cells control the chemical reactions occurring
within. With every chem rxn, there is an
energy transformation (a change from one
form to another).
• The total of all the chemical reactions that
occur within a cell is known as its
METABOLISM.
METABOLISM
• Includes all the building up and breaking down
of substances in a cell in addition to the
energy transformations that occur
simultaneously.
TWO MAJOR PROCESSES THAT
PROVIDES CELLS WITH ENERGY:
• 1. Photosynthesis
• 2. Cellular Respiration
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Energy Transformations in Cells
• 1. Photosynthesis:
– Occurs in chloroplasts of plant cells. The
chlorophyll absorbs light energy and give leaves
their green colour.
– Light energy is used to transform carbon dioxide
and water into energy-rich food.
CO2 + H2O
C6H12O6 + O2
Energy Transformations con’t
• 2. Aerobic Cellular Respiration:
– A series of chemical reactions that break down
(metabolize) carbohydrates and other molecules
in order to release the energy they contain.
– Occurs in the MITOCHONDRIA of cells.
PS and CR are COMPLEMENTARY!
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Comparison of PS and CR
Process
Raw Materials
Products
photosynthesis
carbon dioxide
sugar
water
oxygen
Location
Chloroplasts of Plant
Cells
energy
respiration
sugar
oxygen
carbon dioxide
water
Mitochondria of
Animals and plants
energy
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Global Implications of Photosynthesis
(PS) and Cellular Respiration(CR)
•
The energy transformations that occur in PS
and CR are important for several reasons:
1. Autotrophs- manufacture their own food through PS.
They form the basis of all food chains.
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2. Heterotrophs- These organisms must eat to
obtain nutrients, therefore they depend
indirectly on PS for food. They also depend on
CR to release energy from their food.
3. Environment- PS and CR are important parts of
the carbon cycle that recycles carbon
throughout the land, water and atmosphere.
4. Industry- The economy is driven mainly by
agriculture, fishing, forestry and mining. PS
and CR play key roles in each.
Agriculture and forestry- depend on plants to provide
food, construction materials, fabrics,and
pharmaceuticals.
Fishery- The fish depend phytoplankton to perform
PS to provide food. The fishers in turn catch the fish.
Mining- The fossil fuels being mined today were once
ancient forests and oceanbeds.