Science 8
Unit 1
1
Unit 1: Cells, Tissues, and Organ Systems
Intro: Getting Started
pages 14-15
Questions:
1. If you could see a cell in a lettuce leaf, could you tell it
apart from a cell in your arm?
Yes, they have a different shape. The human (animal cell) has
no chloroplasts, but the plant cell does.
2. What does it mean to say that blood is a living fluid?
Blood is made up of living cells, so it is a living fluid.
3. Is there any similarity between the roots of a tree which
must carry water to the tallest branch and the movement
of blood from your neck to your head?
Yes, just like your body has arteries to carry blood from your
heart to your head, a plant has a root system to carry water to
the top.
1.1: Characteristics of Living Things
page 16
Living things are known as organisms.
Before a living thing can be classified as an organism, it must
show all of the characteristics below:
1.
Living things are composed of cells. All cells are similar.
2.
Living things grow, repair, and reproduce. Cells grow by
dividing in two.
3.
Living things require energy. Plants get their energy from the
sun. Animals get their energy from plants or by eating other
animals that ate plants.
4.
Living things respond to the environment. It could be a
response to another organism or to many other factors.
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5.
Living things have a lifespan. Living things exist only for a
limited period of time.
6.
Living things produce waste. Your kidneys filter wastes from
your blood.
Understanding Concepts
page 17
2.
Are volcanoes living things?
No, because they are not made of living cells.
3.
Name at least one characteristic of living things shown
in each of the following examples:
a. A plant bends toward the light.
C: Living things respond to the environment.
b. A tadpole develops into a frog.
B: Living things grow.
c. Human lungs breathe out carbon dioxide.
F: Living things produce waste.
d. A blue jay feeds on sunflower seeds.
C: Living things require energy.
e. A cat gives birth to kittens.
B: reproduction.
4.
Characteristics of Living Things
6 Characteristics of Living
Things
Made of cells
Reproduce, grow, repair
Require energy
Respond to the environment
Have a life span
Produce wastes
5.
Non-living thing
comparison
Pencil
Volcano
Light bulb
Pieces of metal – corrodes
Tires
landfills
How do scientists determine if something is classified
as an organism?
Scientists determine whether something is classified as an
organism if it meets all 6 characteristics of living things.
Science 8
Unit 1
1.3: Plant and Animal Cells
3
page 20
Animal Cell Structures.
Design and label Figure 1 a and b on page 20.
(5 points: Color and shade in)
Most animal cells have these structures:
1.
Nucleus: The nucleus is the control center. It directs all the
cell’s activities.
2.
Chromosomes: They are found inside the nucleus and they
contain the genetic information for the cell.
3.
Cell membrane: Like a guard or gatekeeper, the cell
membrane controls the movement of nutrients and waste in
and out of the cell.
4.
Cytoplasm: Most of the cell is cytoplasm, a watery fluid,
which allows materials to be moved quickly around the cell. It
also stores wastes until they can be gotten rid of.
5.
Vacuole: Each one is filled with fluid and contains water and
nutrients such as sugar and minerals.
Plant Cell Structures
page 21
Plant cells have the same features as animal cells, but they have some
special structures.
The vacuole takes up a much larger part of the cytoplasm of a plant
cell.
First difference.
Cell wall: The cell wall protects and supports the plant cell. It is made
of cellulose, which provides the support. Gases, water, and minerals
can pass through the cell wall.
Second difference.
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Chloroplasts: The chloroplasts contain many molecules of a green
liquid (chemical) called chlorophyll, which, with light from the sun,
allows plant cells to make their own food. Animal cells cannot do this.
Unit 1 Understanding Concepts
Structure
Nucleus
Plant
Cell
Yes
page 21
Animal Function
Cell
Yes
 Control center.
 Directs cell’s activities.
Chromosomes Yes
Yes


Found inside the nucleus.
Contains genetic information.
Cell
membrane
Yes
Yes

Acts like a gatekeeper letting
in nutrients and letting out
wastes.
Cytoplasm
Yes
Yes

A watery fluid that allows
materials to be transported
quickly between cell
structures.
Also stores wastes for later.

Vacuole
Yes
Yes


Cell wall
Yes
No



Filled with fluid, stores water
and nutrients such as sugar
and minerals.
Is larger in the plant cell.
Protects and supports the
cell.
Made of cellulose.
Gases, water, minerals pass
through small holes.
Chloroplasts
Yes
No

Contain green molecules
called chlorophyll, that allow
the plants to make their own
food from sunlight.
Flagellum
Yes
No

Whip-like tail that helps cells
to move.
Not found on all cells.

Science 8
Unit 1
cilia
5
yes
No

Tiny hairs that work together
to move a cell or the
environment around a cell.
Understanding Concepts
page 21
2.
Where is genetic information stored?
Genetic information is stored in the chromosomes, which are
found in the nucleus.
3.
What are some reasons a biologist might find 2 nuclei
in a cell?
There are 3 reasons:
1. A cell may be ready to divide.
2. A mutation (DNA damage).
3. The cell may be made that way. For example, cardiac cells
have 2 nuclei, and so do mould cells.
4.
What might happen if we covered a cell membrane with
a plastic coating that prevents molecules from entering
or leaving the cell?
The cell would die because no nutrients or water could get in
and wastes could not get out.
1.5: Technological Advances of the Microscope
1.
Who invented the microscope?
Anton Van Leewenhock invented the first microscope.
2.
What was it called and how did he make this
microscope?
It was called the single-lens microscope and he mad it by
using a single lens mounted between two brass plates.
3.
Explain how the compound microscope works. How
much greater is the magnification of this microscope?
The compound microscope was made by adding a second lens
to the microscope. An image magnified 10 x by the first lens
and 10 x by the second lens is viewed as 100 times larger.
4.
To make the image larger, what sort of adjustments are
made to the lenses?
To make images larger, lenses must become thicker.
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5.
What happens when you make the lens thicker?
As the lens becomes thicker, the images they produce begin
to blur.
6.
What is the magnification of the light microscope?
The light microscope is limited to about 2000 x magnification.
7.
What is the magnification of the electron microscope?
The electron microscope has a magnification of 2 000 000x.
8.
How does an electron microscope work?
Instead of light, transmission electron microscopes use a
beam of electrons that pass through the specimen mof cells
and tissues.
9.
What are electrons?
Electrons are tiny particles that travel around the nucleus of
an atom.
10.
What are the 2 major limitations of electron
microscopes?
Electron microscopes have 2 limitations:
1. Specimens that contain many layers of cells, such as blood
vessels, cannot be examined.
2. Mounting cells in plastic kills them.
Questions
page 25
1.
Why was the scanning electron microscope invented?
It was invented due to limitations of the transmission electron
microscope.
2.
How does it work?
It uses electrons to reflect off the specimen.
3.
What kind of image is created by this microscope?
It produces a 3-D image.
4.
What are 2 disadvantages of this microscope?
Two disadvantages are:
1. Only the outside of the specimen can be seen.
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2. It does not magnify as much as the transmission electron
microscope.
Understanding Concepts
page 25
Questions:
1. Give one advantage of a compound light microscope over
a single-lens microscope.
Two lenses give greater magnification without lowering clarity.
2. Give one advantage of a scanning electron microscope
over a transmission electron microscope.
Living objects may be viewed using the scanning electron
microscope. It also permits a wider view and objects don’t have
to be encased in plastic.
4. Which microscope would you recommend for viewing
each of the following? Give reasons for your choice.
a.
the detailed structure of a cell’s nucleus.
A transmission electron microscope, because the nucleus is
small and this one gives the greatest magnification.
b.
1.6
a single cell.
A light microscope. Slide preparation is quick and easy and
does not kill the cell.
Parts of a Cell Seen With a Microscope.

The cytoplasm contains special features called organelles.

The mitochondria provide the cells with energy. They do this by
combining sugar molecules with oxygen to form carbon dioxide
and water. This process is called respiration. This released
energy is used in almost every other function of the cell.

Proteins are put together on ribosomes using information from
the nucleus and molecules from the cytoplasm. Proteins are
Science 8
Unit 1
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large molecules and are needed for cell growth, repair, and
reproduction.

A series of folded membranes, called endoplasmic reticulum,
carry materials through the cytoplasm.

Proteins are stored inside the Golgi Apparatus.

This organelle puts protein into packages called vesicles.

Vesicles carry the protein molecules to the surface of the cell,
where they are released to the outside.

Lysosomes patrol the cytoplasm, cleaning up. They contain
special proteins that are used to break down larger molecules
into many smaller molecules.

The smaller molecules are also used to kill and digest invading
organisms in humans and other animals.
Understanding Concepts
page 27
1.
What are organelles?
Organelles are tiny cell structures within the cytoplasm that
are specialized to carry out a function.
2.
Predict what would happen to a cell if its mitochondria
stopped working.
If the mitochondria stopped working, they wouldn’t be able to
provide the cells with energy, so the cells would die.
3.
Cells living in the stomach release enzymes that aid
digestion. Digestive enzymes are protein molecules.
Explain why many Golgi Apparatuses are found in
stomach cells.
Many Golgi Apparatuses are found in stomach cells because
they contain a protein digestive enzyme to help our bodies
digest food.
Understanding Concepts
1.
page 29
Explain in your own words the process of diffusion.
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Unit 1
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In diffusion, molecules move from a crowded area to a less
crowded area. Molecules move form an area of high
concentration to an area of low concentration.
2.
Explain what is meant by impermeable, semipermeable, and selectively permeable materials.
 Impermeable: not permitting passage.
 Permeable: permitting passage.
 Selectively permeable: letting some things pass through
while not allowing others to pass through the membrane.
3.
What type of membranes do cells have? Why?
Cells have selectively permeable membranes that allow
certain substances to pass through the membrane, but not
others.
4.
Hypothesize why the pores in the cell membrane are of
different sizes.
They are different sizes to allow only certain things to pass
through the membrane.
Page 33
1.
How are osmosis and diffusion different? How are they
the same?
Diffusion moves water from a higher concentration, but in
osmosis, it is achieved by passing through a selectively
permeable membrane.
With diffusion, there is no selectively permeable membrane.
2.
What determines the direction of water movement into
or out of cells?
The direction of the water movement depends on the
concentration of water inside the cell compared with the
concentration outside the cell.
3.
What prevents a plant from bursting when it is full of
water?
The cell wall prevents a plant from bursting when it is full.
4.
Explain why animal cells are more likely than plant
cells than plant cells to burst when placed in distilled
(pure) water.
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Animal cells are more likely to burst when placed in distilled
(pure) water because they don’t have a cell wall.
5.
Describe Turgor Pressure in your own words.
Turgor pressure is the pressure exerted on a cell wall.
Unit 1.12
page 40-41
Questions:
1.
Define tissue, organ, and organ system.
 Tissues are a group of cells that are similar in shape
and function.
 Organs are tissues which are organized into larger
structures.
 Organ systems are groups of organs that have related
functions. Example: The heart and the circulatory
system.
2.
What two purposes does epithelial tissue serve for our
bodies?
The 2 purposes that epithelial tissues serve for our bodies
are:
1. It covers both the outside and inside surfaces of our
bodies.
2. It provides support and protection for the body.
3.
What function does the heart serve in the body?
It pumps blood through your entire body.
4.
What is included in the circulatory system?
The circulatory system includes the heart and arteries that
carry blood from the heart to the tissues. It also includes
capillaries where nutrients and wastes are exchanged and
veins that carry blood and wastes from the tissues back to
the heart. Nerve tissue, blood, epithelial tissue, connective
tissue, and muscle tissue are all found in the circulatory
system.
Unit 1.13
1.
pages 42-43
What is a microorganism?
A microorganism is an organism that is so small that it is only
visible under a microscope.
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2.
What are bacteria?
Bacteria are among the most primitive and also the most
plentiful organisms on the planet.
3.
What are protists?
Protists are microorganisms that live in moist areas, they have a
nucleus, mitochondria, ribosomes, and lysosomes.
4.
What are diatoms?
Diatoms are found in both fresh and salt water. They contain
chlorophyll and can make their own food. They are encases in
two thin shells joined together.
5.
What is a euglena?
A euglena is like both a plant and an animal cell. If there is
enough sunlight, it acts like a plant and makes its own food. If
there is not enough sunlight, it acts like an animal and begins
feeding on smaller cells.
1.13
pages 44-45
1.
What is an amoeba?
The amoeba is a single animal cell that feeds by wrapping itself
around food.
2.
How does an amoeba move?
Amoeba move by stretching out a branch of cytoplasm called a
pseudopod (false foot) that anchors itself to an object and the
rest of the cell is dragged toward it.
3.
What other cell moves this way?
Animal white blood cells also move this way.
4.
What is a paramecium?
The paramecium is a single animal cell that must perform most
of the functions that your body performs.
5.
What two functions do the cilia perform for the
paramecium?
1.
The cilia beat together to create water currents to move
the paramecium.
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Unit 1
2.
12
There are also cilia around the oral (mouth) groove that
draw food into the groove.
6.
What are fungi?
Fungi include many organisms that are multi-cellular.
7.
Give examples of fungi.
Bread, mould, mushrooms, and puff balls are all examples of
fungi.
8.
Give examples of 3 harmful fungi.
Three harmful fungi are:
1. ringworm
2. Dutch elm disease
3. athlete’s foot
9.
What are yeast?
Yeast is one of the few unicellular fungi. There are many
different species.
10.
What do yeast do for food?
Like animal cells, yeast cells do not have chlorophyll and must
rely on other organisms for food.
1.14 The Need for Cell Division
Pages 46-47
1.
How does the size of a cell affect the speed at which it can
send a message to the nucleus?
The bigger the cell is, the longer it takes for messages to reach
the nucleus.
2.
Look at and read Figure 1 on page 46 and explain what
would happen to the child’s skin if it took a long time for
the nuclear message to reach the ribosomes?
The body would not get the message to release melanin to
protect the skin, and the child’s skin would begin to burn
immediately.
3.
What does the sunlight do in Figure 1?
Sunlight triggers a chemical message that travels to the nucleus.
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4.
What does the nucleus do in Figure 1?
The nucleus sends a message to the ribosomes telling them to
make melanin.
5.
What does melanin do in Figure 1?
The melanin blocks sunlight, preventing sunlight from damaging
cells below.
6.
Why are fat cells bigger than a lot of other cells in the
body?
Fat cells are larger than other body cells because they are not as
active.
7.
Give 2 characteristics of active smaller cells.
Active smaller cells take in more nutrients and produce more
wastes.
8.
Why are many small cells together more efficient than one
large cell?
A group of small cells have a greater surface area than a single
large cell.
Understanding Concepts
page 49
1.
What are the advantages of cell specialization for an
organism?
They have more than one cell which has to do all the functions of
life. Therefore, an organism that has more than one cell can
have separate cells performing different tasks. Specialization
allows cells to develop the specialized structures to take on a
particular shape to do the job well.
3
What is the advantage of a highly folded cell membrane?
A highly folded cell membrane increases the surface area,
allowing more cell membrane for absorption.
4.
What advantage does a thick, flexible plant cell wall
provide over a thick, rigid cell wall?
It allows the plant to bend and move in the wind without
breaking in two.
Science 8
Unit 1
1.15 Cell Specialization
14
page 48
1. Specialization allows cells to develop the specialized
structures or take on a particular shape required to do the
job well. Cells required to do multiple jobs must have
structures and a shape that permit diversity.
2. Plant cells would no longer stay attached to each other if
the pectin were digested. Multi-cellular plants would
appear like a group of building blocks. They would topple.
3. A highly folded membrane increases the surface area,
allowing more cell membrane for absorption.
4. Flexible cell walls allow the plant to bend,. In a high wind,
or under a load of snow, the plant will bend rather than
break.
Understanding Concepts
page 51
1.
Explain what disease is in your own words.
Disease is a long-term illness that can have a negative effect
on your life.
2.
What types of invaders cause infection in humans?
Some of the invaders are living things such as bacteria, fungi,
or parasitic worms. Others are viruses or toxic chemicals.
3.
Identify 2 ways in which white blood cells protect the
body from disease.
White blood cells produce antibodies that attach themselves
to foreign invaders. White blood cells also engulf antigens.
4.
How does your body benefit when a white blood cell
kills a cell that has been infected with a virus?
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The virus will be destroyed along with the cell. The virus can
no longer spread beyond the single cell and you can recover if
only a few cells are destroyed.
Questions
page 58
1.
What main function do leaves serve for the plant?
Leaves use energy from the sun to combine water from the
soil and carbon dioxide from the air to form sugars and
oxygen.
2.
What is a cuticle?
The cuticle is a coat of wax that covers the leaf.
3.
What 2 functions does the cuticle perform?
1. The wax stops water from evaporating from the cells
below.
2. It keeps the leaf from drying out.
4.
What purpose does the epidermis serve on a leaf?
The epidermis protects the cells below.
5.
Since epidermis cells usually have no chloroplasts.
What is it they cannot do?
They cannot perform photosynthesis.
6.
Where is the palisade located?
The palisade is located just under the cuticle and the
epidermis.
7.
What does the palisade contain and what does this
enable them to do?
The palisades contain many chloroplasts to trap light for
photosynthesis.
8.
Explain what is meant by the vein in a plant.
The vein is a combination of xylem and phloem vessels.
9.
What is found under the palisade cells?
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Under the palisade cells is a spongy area with few cells and
many air spaces.
10.
What do photosynthesizing cells do?
They absorb carbon dioxide from the air spaces and release
oxygen into these spaces.
Understanding Concepts
#1, 2, 3.
1.
Why is the ability to move water important to the
survival of plants?
Plants move water into their leaves to perform
photosynthesis.
2.
What structures in plants help them move a. water b.
sugars?
a. The xylem vessels move water.
b. The phloem vessels move sugars.
3.
List 3 forces that may help plants move water.
a. Root pressure: Water in the soil enters the roots by
osmosis. This produces a pressure that moves the water
into the xylem vessels.
b. Capillarity: Liquid tends to cling to the side of narrow
tubes, which helps the water move up into the narrow
xylem tubes.
c. Transpiration: Water evaporates from the leaves. Since
water molecules are attracted to each other, they pull
other water molecules with them, forming a long chain
through the xylem vessels.
Understanding Concepts
1
page 57
a. air space
b. xylem vessels
c. stomates
d. guard cell
e. palisades
f. phloem vessels
g. cuticle
page 59
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3. The air spaces allow for more rapid diffusion of gases. Gases
move slowly in liquids.
Questions
page 60, 61.
1a.
What happens to the size of plants as you move south?
Plants get taller as you move south.
2b.
How does the size of the plant root system change as you
move south?
Root systems become more developed or the root extends
further into the soil as you move south.
3c.
How might permafrost affect plant growth?
The frozen ground doesn’t allow roots to penetrate and take up
water.
4d.
Why wouldn’t you expect an apple tree to grow in Inuvik?
Apple trees have a deep root system that could not grow into the
permafrost.
5e.
Speculate about why more soil is found in southern
forests than northern forests.
In southern forest. Plants produce leaves that in turn fall and
decompose. The decomposed plant material contributes to the
soil.
6f.
Why don’t mosses grow as tall as spruce trees?
A poorly developed root system without transport vessels (xylem
vessels) means that water transport is limited.
7g.
Why would you find a large number of moss plants in a
northern ecosystem during the summer months?
A great deal of water is found along the soil surface from melting
snow and it is prevented from entering the soil by the frozen
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permafrost. Moss plants are well adapted to absorb surface
water.
8h.
Why can’t spruce trees compete with maple trees in more
southern forests?
Maple trees have a better developed system than spruce trees
and can absorb water from greater depths.
What advantages do the maple trees have?
The leaves from the maple trees are much larger and therefore
capable of capturing sunlight for photosynthesis.
9i.
Why are spruce trees more likely to survive in areas with
extreme changes in climate?
A protective cuticle and smaller surface area of the leaf prevent
water loss.
10j. Why can’t maple trees compete with the black spruce in
northern forests?
The larger leaves of the maple provide too much surface area for
water loss.
Understanding Concepts
oage 61
1. Hypothesize or guess why trees don’t grow to the top of a
mountain.
Like the tundra, harsh conditions with frozen soil or no soil are
found at the top of a mountain.
2. What advantage does the maple tree gain with its thick,
broad leaves?
More surface area is available for photosynthesis.
3. Why can’t moss compete with large trees in southern
forests?
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19
A poor root system and a lack of water transportation vessels
(Xylem vessels) mean the moss is unable to secure water below
the soil surface.
4. How does the root system of a plant determine where it
grows best?
Plants compete for water in the soil. Better developed root
systems are able to get at water at lower levels in the soil.
Fibrous roots are better able to secure surface water. Plants with
many tissues, like the maple tree, require more water and a
better developed root system.
5. If you cut into a pine tree, the sap that begins to flow
hardens very quickly. What advantage does this give to
the tree?
Pine trees grow in areas in which conditions can be very dry.
Hardening of the sap prevents excessive loss of sap (water).
Questions
Read pages 72 and 73.
1.
What is the result if sperm from one species is used to
fertilize an egg from another species?
2.
How can genetic information be transferred from one
organism to another?
1.21 Animal Organ Systems Working Together pages 62, 63.
Questions:
1.
Why does the circulatory system need the respiratory
system?
The circulatory system relies on the respiratory system for
oxygen and to get rid of carbon dioxide.
2.
Is the circulatory system important to the digestive
system?
The digestive system provides nutrients to the circulatory
system.
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3.
Would the circulatory system be able to do is job
without the digestive system? Explain.
No, because it wouldn’t get any nutrients and would slowly
shut down.
4.
How does the excretory system help the circulatory
system do is job?
The excretory system receives waste from the circulatory
system.
5.
What would happen to the skin cells if the circulatory
system failed to work?
The skin cells would not receive oxygen, so they would die.
6.
Why is a circulatory system necessary for skin cells?
To receive oxygen.
7.
What does the endocrine system do?
The endocrine system produces chemical messengers called
hormones that travel to organs and tell them how to adjust to
internal and external cues.
8.
What is the main job of the nervous system?
The nervous system detects what is going on inside and
outside of the body and sends electrical messages throughout
the body.
9.
Give an example of when the nervous system and the
endocrine system work together.
Your eyes detect the stimulus and send an electrical message
from your brain to your muscles. The signals cause the
muscles to contract and you run. Other nerves carry
messages from your brain to your endocrine glands which
respond by pumping a chemical called adrenaline into your
blood. Your heart beats faster and your lungs take in more
oxygen. Your muscles have more nutrients available and you
run faster.
10.
What is the small gland near the top of your kidneys
called and what does it do?
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It is called the adrenal gland and it secretes adrenaline.
Regulating Your Body
Page 68
Questions:
1. Which system, the nervous system or the endocrine
system, is best suited to detect danger? Explain why.
The nervous system is best suited for detecting danger. The
senses, such as vision, hearing, taste, and touch, used to detect
dangerous situations, all produce signals.
2. What is the difference between a response by the nervous
system and a response by the endocrine system? Explain
why.
The nervous system allows the body to adjust quickly to
changes. The endocrine system maintains control over a longer
duration.
3. If you stepped on a tack, how would your nervous system
respond? What other organ systems would be signaled?
Your nervous system would send a message to the central
nervous system, which would signal the muscle system to move
the foot.
4. Categorize the following organs as either:
1. supplying organs and removing wastes or
2. regulating the body
heart (1)
artery (1)
kidney (1)
eyes
brain (2)
stomach (1)
(2)
5. How do nerves and muscles work together?
Nerves signal the muscles to contract.
6. Explain why organ systems that regulate or control other
body systems are important.
The organ systems of the body are interdependent. They all live
closely together in a common environment. A malfunction in one
system affects all the other systems.
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7. How would the health of an animal be affected if disease
damages an organ that:
a.
delivered nutrients:
The body cells would die.
b.
removed wastes:
The body cells would die.
c.
informed it about environmental change:
Permanent damage could occur to body cells.
d.
controlled other organ systems
They all function together, so the cells would
become ill or die if the organs that controlled
systems were damaged.
8. How does the statement “all for one and one for all” apply
to large multi-celled organ systems?
No organ can function properly without all the other organ
systems.