Download From Cells to Organisms

8
From Cells to Organisms
Understanding Life Systems
Enduring Understandings
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All living things are made of cells.
Processes witnessed on the cellular level are also witnessed in more complex multicellular
organisms.
For every function or need, specific structures are present at both the unicellular level and
the multicellular level to complete the function or meet the need.
Understanding the structures, functions, and interdependence of human organ systems can
result in improvements in human health.
Essential Guiding Questions for Unit Design
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What advancements in medicine have led to improvements in human health?
What is the advantage of being made of one cell instead of many?
What is the advantage of being made of many cells instead of just one?
How can a microorganism or a tree be as “alive” as a human being?
Why do we breathe (eat, etc.)?
My car is alive! Prove me wrong?
Important for Students to Know
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that living things can be unicellular or multicellular;
the differences/similarities between plant and animal cell;
the main parts of the plant and animal cell which can be identified under a microscope (e.g.,
nucleus, cell membrane, cell wall, cytoplasm, vacuole);
that specialization exists on a cellular level and a systems level;
the hierarchical organization in multicellular organisms;
the processes of diffusion and osmosis; and
how water and nutrients are moved through a plant.
Important for Students to Do..
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use the microscope to identify plant and animal cells and some of the key structures;
investigate the properties of cells and/or the functioning of plants through experimentation.
Life Systems-Grade 8-Cells, Tissues, Organs, and Systems
Students focus on the structure and function of cells in plants and animals and on the
organization of cells into tissues, organs, and organ systems.
Teacher Background
Student Vocabulary
Ion - charged atom or molecule.
unicellular
amoebae
Cell - the microscopic units sometimes called building
blocks, that make up all living things including the human
body. A typical cell consists of a cell membrane
surrounding numerous organelles suspended in a fluid
substance called cytoplasm.
multicellular
organelles
vacuole
nucleus
chloroplast
tissue
organ
system
Unicellular - an organism consisting of a single cell,
they include protists and bacteria (amoebae, paramecia,
euglena and some fungi (e.g.,yeast).
diffusion
osmosis
selectivity
permeable membranes
Multicellular - having more than one cell, some fungi
(mushrooms, plants and animals).
How The Body Works
From Body To Atom
Bacteria cells - prokaryotic containing no nuclear
membrane or no membrane bound organelles. It is the
smallest type of organism.
System
Cell membrane - 2 layers of oily molecules with proteins
and carbohydrates attached. It allows the passage of food
and structural materials to enter and wastes to pass out.
Found in all cells.
Organ
Cell wall - found only in plants; thicker dead covering
around the cell membrane; supports the cells so the plant
can stand upright.
Tissue
Organelle - a tiny structure inside a cell.
• Nucleus - the control centre or brain of the cell. It
contains the cell’s genetic information in the form of
DNA packaged into chromosomes.
• Chloroplast - contains chlorophyll (green pigment)
which traps the sun’s energy and uses it to make
glucose through photosynthesis.
• Mitochondria - organelle where (ATP) energy is
produced by cellular respiration. The powerhouse of
the cell. It releases energy from glucose and sugar.
• Ribosome - organelle where proteins are made.
• Vacuole - clear fluid filled sacs that store water and
other materials giving shape and support in plants and
in animals.
Cell
Organelle
Molecule
White Blood Cells - blood cells that have no hemoglobin
and migrate into the tissue to fight off infection and digest
cell debris.
Atom
Red Blood Cells - a hemoglobin (red pigment) containing
cell with no nucleus, that carries oxygen from the lungs to
body tissue.
continued…
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Basic Concepts
Life Systems-Grade 8-Cells, Tissues, Organs, and Systems
Continued 2. . . . .
Teacher Background
Cells in Animals - in multi cellular organisms cells are
organized into tissues, tissues into organs and organs into
organ systems. Each tissue is composed of a group of cells
that work together to perform a specific function.
Cells and Tissues in Plants
• Guard cells - control the entry and exit of gasses in the
underside of leaves.
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Epidermis cells - outer layer on the upper and lower
surface. In some species they may be covered by a
waxy cuticle which functions to prevent water loss.
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Palisade mesophyll cells - long, thin cells that contain
chlorophyll and perform photosynthesis.
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Spongy mesophyll - cells that contain chlorophyll and
perform photosynthesis.
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Xylem - tubes that carry raw materials such as water
and minerals throughout the plant
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Phloem - tubes that carry food throughout the plant
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Cortex - stores food; photosynthesis can also occur
here.
Diffusion– molecules or ions moving from a region of high
concentration of the molecules or ions to a region of low
concentration of the molecule.
• Passive Transport - movement of solutes not requiring
the cells energy (e.g., diffusion), also known as passive
permeability.
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Osmosis - diffusion involving moving water molecules
across a membrane.
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Facilitated Diffusion - involving larger ions or
molecules as they move through protein channels in
the cell membrane. Molecules move more quickly with
help from protein molecules.
Active Transport - movement of ions or molecules from a
region of low concentration to a region of higher
concentration. Requires energy from the cell.
Insulin - produced in the pancreas; to maintain the proper
level of glucose in the blood. Used in the control of
diabetes.
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Basic Concepts
8
Systems at Work
Understanding Structures and Mechanisms
Enduring Understandings
When designing, producing and testing mechanisms and systems, they should be efficient in
their ease of use, energy demands and cost.
• The needs of the consumer drive the design and manufacturing or products.
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Essential Guiding Questions for Unit Design
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What makes a mountain bicycle “good”?
What are the essential qualities of a good off-road vehicle? A good dishwasher?
Through the use of machines (mechanical systems), how have humans made life easier?
Have there been any social or environmental costs to mechanization?
Are machines more efficient than humans? If so, how?
What is “ergonomics” and what role does it play in your life?
Important for Students to Know
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that efficiency is a comparison of the useful work energy provided by a device or system to
the work energy applied to the device or system;
that the formula for efficiency is as follows:
Efficiency = Energy output x 100%
Energy input
that the components chosen for a mechanical system and the ways in which they are connected effect the efficiency of the system;
that the velocity ratio is a comparison of the distance a load moves to the distance traveled
by the force (effort) required to move it; and
that various forces, such as friction, affect the movement of an object.
Important for Students to Do
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measure forces that affect movement of objects;
determine velocity ratios through direct observation of devices using pulleys and gears;
investigate the mechanical efficiency of different mechanical systems through experimentation;
research the kinds of information gathered from consumers prior to and during the design
of a product;
through technological design, investigate the concept of mechanical efficiency by designing a device that uses a mechanical system which is operated by hydraulics or pneumatics.
Structures and Mechanisms-Grade 8 – Mechanical Efficiency
Students develop their understanding of the efficient operation of mechanical systems. Special
attention is given to the use of hydraulic and pneumatic power.
Teacher Background
Pneumatics- any machine that uses compressed air to
transmit force from one place to another is called a
pneumatic system. Compressed air leads to a lag in the
time between the force being applied and the output or the
resulting force.
• Compressed Air - air that has been forced into a small
space (such as blowing up a balloon or pumping up a
bicycle tire).
ergonomic design
mechanical efficiency,
velocity/velocity ratio
hydraulic/pneumatic power.
Hydraulics - any machine that uses a liquid to transmit
force from one place to another is called a hydraulic
system. To overcome the lag of a simple air filled system,
fluids are incompressible and therefore, transmits a force
immediately.
• Pascal’s Law - pressure exerted on a contained fluid is
transmitted in all directions throughout the fluid and
perpendicular to the walls of the container.
Syringe - a plastic tube with a plunger attached at
the end. When the plunger is pulled out either air or water
can fill the cavity of the tube. When the plunger is pushed
in the air or water is forced out. Syringes can be attached
to tubing and other syringes to produce either pneumatic
or hydraulic systems. The size of the sending and
receiving syringes will determine the amount of input and
output movement.
Ergonomics - designing products and structures to match
human needs.
Feedback - information coming back into a system about
the way it is changing. One example is a thermostat,
which shuts down the central heating system when the
temperature rises above a certain level.
continued…
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Basic Concepts
Structures and Mechanisms-Grade 8 – Mechanical Efficiency
Continued 2 . . . .
Teacher Background
Mechanical efficiency - the comparison of the useful work
or energy provided by a machine or system with the actual
work or energy supplied to the machine or system.
Efficiency is usually stated as a percentage. The formula is
as follows:
• efficiency = energy output x 100%
energy input
Mechanical advantage - The advantage of the work done
by a simple machine can be determined by comparing the
load to the effort required to move or lift that load. The
formula is as follows:
• Mechanical Advantage = load
effort
(See page 108, Ontario Curriculum Science and
Technology)
fig. 1
Mechanical Advantage
Less effort needed to lift
load
Velocity - rate of motion (speed) in a particular direction.
Supports 1/2 the load
Supports 1/2 the load
Velocity ratio - The ratio between the distance moved by
effort and the distance moved by the load. Whenever you
gain in one movement you lose in the other. The formula is
as follows:
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Velocity Ratio = distance moved by effort
distance moved by load
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Basic Concepts
8
Fluids
Understanding Matter and Energy
Enduring Understandings
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Fluids have specific properties (e.g., viscosity, density, buoyancy) that affect their
behaviour and their use in natural (e.g., human body) and human-made (e.g., automobile
engine) systems.
Fluids under pressure exert forces that can be used to do work.
Essential Guiding Questions for Unit Design
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How does an artificial heart function? How does it compare with a real heart?
How do devices that you use in your daily life make use of the properties of fluids?
How is a mechanic able to lift a car?
If the viscosity of oil is so important to the protection of engine parts, why not make oil
extremely viscous?
Important for Students to Know
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that fluids consist of both liquids and gases;
that fluids can be compared according to their physical properties (e.g., viscosity, density
and buoyancy);
that some fluids (gases) can be compressed while others (liquid) cannot;
that the particle theory can be used to describe the relationship between mass, volume and
density; and
that some properties of fluids (e.g., viscosity, density) are affected by changes in temperature.
Important for Students to Do
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use measuring devices correctly while investigating the properties of viscosity, density and
buoyancy through experimentation;
use the concepts of density and buoyancy to design and calibrate a hydrometer;
apply the concepts of hydraulics and pneumatics through technological design.
Matter & Materials-Grade 8 – Fluids
Students are introduced to Fluid Mechanics. Fluids including air and water form the basis of
hydraulic and pneumatic devices. Students will explore Archimedes’ principle by investigating
and measuring buoyant forces on different objects.
Teacher Background
Student Vocabulary
Matter - anything that has mass or takes up space
(volume).
Material - the parts or substances of which a thing is
made.
viscosity
density
pneumatic
hydraulic
particle theory
flow rate
compressibility
Properties - (i) Physical - characteristics that can be
described using the senses. (ii) Chemical - the way in
which matter and materials behave under different
conditions of light, heat, pressure, or chemical reaction.
Fluid - anything that flows. It could be a gas or liquid (air
and water).
• Flow rate - the speed at which a liquid substance,
moves from place to place.
Viscosity - the property of fluid that describes how easily it
flows. Force can decrease viscosity (e.g., margarine is
affected by a knife as it is being spread).
Law of Viscosity - Isaac Newton stated that the viscosity
can be changed only by altering the fluid’s temperature.
(e.g., honey as it is warmed flows more easily, therefore, it
is less viscous).
Density - the ratio of an object’s mass to its volume. The
greater the viscosity the greater the density.
Emulsion - the mixture of liquids that do not dissolve in
each other .Tiny blobs of one liquid floating in another
liquid, such as oil droplets floating in water.
continued…
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Basic Concepts
Matter & Materials-Grade 8 – Fluids
Continued 2 . . . .
Teacher Background
Particle Theory - the fundamental theory that is used to
explain matter. fig. 1, The theory states:
• All substances are composed of tiny particles called
atoms, molecules and ions and the tiny particles that
have spaces between them. Spaces are very small in
solids and very large in gasses (ions carry either
positive or negative charges).
Particle Nature
of Solids, Liquids, and Gases
fig. 1
Decreasing Temperature
Solid Particles
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The particles are in constant state of motion and the
amount of motion increases from solid to liquid to gas.
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The motion of particles is temperature dependent, that
is, the higher the temperature the faster the particles in
any state of matter will move.
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There are forces of attraction between particles in
solids liquids and gasses. These forces are strongest
in solids, fairly strong in liquids, and very weak in gas.
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Liquid Particles
Archamedies’ Principle - the buoyant force on an object
in a fluid is equal to the weight of the fluid displaced by the
object. fig. 2
fig. 2
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Gas Particles
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Increasing Temperature
See The Way Things Work CD
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Basic Concepts
8
Water Systems
Understanding Earth and Space Systems
Enduring Understandings
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Water in all its forms shapes the environment (including climate) and is critical to the survival of plants and animals.
The Amount of the earth’s water that is “drinkable” is a very small percentage; therefore,
humans must use and manage water resources carefully.
Essential guiding Questions for Unit Design
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Why did the Walkerton, Ontario water tragedy occur (summer of 2000)?
How does construction (e.g., development of the Oak Ridges Moraine for a housing
complex) affect water systems and resources?
The search for landfill sites is a continuous problem as the amount of waste produced by
our society increases. Why would you not want one in your backyard?
Should Canada be involved in the bulk export of its water resources?
Important for Students to Know
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that water exists naturally in all three states on Earth (students should be able to give examples of conditions/locations for each state);
that water is distributed unevenly about the world and circulates via the water cycle;
that large bodies of water have an affect on global and regional climate and weather (e.g.,
moderation of temperature, changes in precipitation);
that land formations affect water systems and water affects the creation of landforms, including waterways (e.g., Grand Canyon, Bay of Fundy); and
that humans use, abuse and manage water resources in a variety of ways.
Important for Students to Do
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investigate some of the physical properties of water (e.g., buoyancy in fresh and salt water)
through experimentation;
investigate needs of events relating to the earth’s water (e.g., changes in the world’s water
distribution over time, ways in which humans use water and manage water resources)
through research.
Earth and Space Systems-Grade 8 – Water Systems
Students learn the important role that water systems play in global ecosystems. They come to
understand that large bodies of water influence climate and weather of the region in which they
are located and that lakes and oceans interact with the atmosphere through a water cycle. They
learn the importance of fresh and salt water to the sustainability of life on earth.
Teacher Background
Student Vocabulary
States of Water fig. 1
• Solid - water exists as glaciers, snow mountains, and
polar ice caps.
sea mounts
continental shelves
sustainability
trenches
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Liquid - water exists as oceans, lakes, rivers, and
groundwater.
continental divide
glacier
ice caps
salinity
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Gaseous - water exists as part of the atmosphere
currents
basins
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Evaporation - the change in state from a liquid to a
gas.
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Sublimation - the change in state from a solid directly
to a gas or from a gas directly to a solid.
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Condensation the change in state from a gas or vapor
to a liquid.
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Solidification (freezing) - the change in state from
liquid to solid.
fig. 1
Three States of Water
Geological Features of the Ocean’s Floor
• Ocean - large body of salt water.
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Sea mounts - under water mountains.
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Continental Shelves - areas near landforms where the
ocean is relatively shallow (e.g. the Grand Banks of
Newfoundland). Oceans tend to moderate climate
since the water is warmer in the winter.
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evaporation
condensation
Liquid
melting
freezing
Solid
Trenches - valleys where the ocean is deepest.
Physical Characteristics of Salt Water:
• Movement
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Density - the amount of mass per unit volume
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Buoyancy - the tendency to float or rise in a fluid.
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Salinity - the amount of salt per unit volume.
continued....
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Basic Concepts
take away heat to change state
Water Cycle - the recycling of water. Water evaporates
from the oceans and falls as precipitation becoming
surface run-off, ground water, or part of a water table. If it is
not evaporated from lakes or rivers, then it returns to the
ocean to repeat the cycle again.
add heat to change state
Gas
Earth and Space Systems-Grade 8 – Water Systems
Continued 2 ...
Teacher Background
Formation of Lakes and Rivers • Basin - relatively shallow depression in the land that
contains water.
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Water Shed - Area from where all rivers flow to a
certain place. The Great Lake’s Water shed refers to all
the land where the rivers flow into the Great Lakes e.g.,
the Grand River water shed).
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Continental Divide - the watershed boundary for North
America e.g., the Rocky Mountains.
Climate - the temperature, humidity, precipitation, winds,
radiation, and other meteorological conditions
characteristic of a locality or region over an extended
period of time.
Currents - the movement of water in the ocean caused by
differences in temperature & the movement of the earth.
Circulating currents are one way to cool off the planet. The
sun warms water at the equator and water is transported to
colder regions. As the water gets colder it sinks. Colder
water then circulates back to regions where they can be
warmed again. This pattern takes more than a 1000 years
to complete.
Desalination - the removal of salt from water through
either reverse osmosis or distillation
• Reverse Osmosis - pressure is applied to intake
water, forcing water molecules through a semipermeable membrane which does not allow salt
molecules through.
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Distillation - the intake water is heated to produce
steam and then condensed as drinkable water.
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Basic Concepts