Nov. 29 – Ecosystems Services and Equilibrium

A schedule for the remainder of this unit:

• Monday, Dec. 2 – Assignment
• Wednesday Dec. 4 – Research Period
• Thursday Dec. 5 – Guest Speaker
• Tuesday Dec. 10 – Assignment Due
• Thursday Dec. 12 – Unit Test

After Dec. 12 we will begin our final unit on Space!
Back to what we did today...

Learning Goals: 

• Understand the different types of services that ecosystems provide for us.
• Understand ecological equilibrium and how succession works.

Success Criteria:

• You can describe different ecosystem services and what broad categories they fall under.
• You can describe what equilibrium is and the process of primary and secondary succession.

Handout:

• Ecosystem Services
• Equilibrium and Succession

We started today by asking this question: How does the ecosystem benefit humans?

You guys came up with many great answers which I put on different parts of the board.  You were able to then come up with some ideas about what the different categories meant.

Cultural Services –  They are benefits relating to our enjoyment of the environment. They include the recreational, aesthetic, and spiritual experiences we receive when we interact with our natural surroundings.

Ecosystem Products – These refer to goods that are provided by the ecosystems, such as food, medicine, building materials, rubber, fibres, dyes, etc.

Regulating Services – The ecosystem also regulates temperatures, weather, disease, animal populations, purifies water, etc.  All of which can benefit humans.

Ecotourism is an example of a cultural service.

Next we discussed what is meant by equilibrium.

Equilibrium describes the state of an ecosystem with constant abiotic and biotic conditions over a period of time. Equilibrium is maintained when abiotic conditions are stable. 

Succession is the process by which an ecosystem can recover or be replaced if after a disturbance such as a fire or human made changes.

Primary succession is the process in which bare rocks can grow into a forest.  The process can take hundreds of years. 

Homework: Continue to catch up on questions from previous days.

• P. 41 # 1, 2, 5, 9, 11
• P. 47 # 2, 4, 5, 6, 8
• P. 51 # 2, 3, 5, 6, 7, 8
• P. 55 # 2, 3, 4, 7

Nov. 28 – Terrestrial and Marine Ecosystems

Learning Goals: 

• Understand the major terrestrial biomes in Canada.
• Understand the different types of aquatic ecosystems.

Success Criteria:

• You can identify the different biomes in Canada and describe their biotic and abiotic features.
• You can identify and describe the major types of aquatic ecosystems.

Handouts:

• Terrestrial Ecosystems
• Aquatic Ecosystems

We started by briefly covering the major biomes in Canada:

Boreal Forests

Grasslands

Mountain Forests

Temperate Deciduous Forests

Tundra

You should know roughly where these biomes are located on a map.  We then split up into groups and I gave you the task of trying to figure out how you can survive if you were alone in one of these biomes far away from a city.  What could you hunt or forage to eat?  What dangers might you have to be aware of?  What type of abiotic factors would affect your survival?

Next we discussed different types of aquatic ecosystems.  They can be divided in two major categories: freshwater and marine.

Freshwater ecosystems includes rivers and lakes

They can be oligotrophic (low in nutrients) or eutrophic (rich in nutrients).  This can have major impacts in the types of life that can be found there.

An oligotrophic lake.

A eutrophic river.

Marine ecosystems cover most of the planet.  Much of the ocean is nutrient poor and supports little life.

But shallow waters near shores can support a huge diversity of living things.

Coral reefs appear in shallow waters that are at just the right temperature.

Estuaries are where fresh water from rivers mixes with salt water from the oceans.

Mangroves are found in tropical regions with trees that grow out over the water.

The intertidal zone alternates being above and below water as the tides change.

Finally, in the deep ocean, there is natural light, but some creatures still manage to survive there.  Here is a video of some strange and fascinating creatures.

Homework:

• Read Chapters 2.8 and 2.9
• Do the homework that we skipped due to the unit test.
• P. 31 #2, 5
• P. 35 # 1-5

Nov. 26 – Biogeochemical Cycles, Biotic and Abiotic Influences

Learning Goals:

• Understand the how water, carbon dioxide, and nitrogen are cycled through the environment.
• Understand the biotic and abiotic factors that affect a species survival.

Success Criteria:

• You can describe the water cycle, the carbon cycle and the nitrogen cycle.
• You can identify biotic and abiotic influences that affect a specie's success.

Handouts:

• Cycling of Matter in Ecosystems
• Biotic and Abiotic Influences

We covered today's topics quickly and then took some time to study for the test tomorrow.  Here's what you'll need to bring tomorrow:

1. Pencil
2. Eraser
3. Calculator
4. Ruler

That's it! Good luck!

Nov. 25 – Energy Flow, Food Webs and Ecological Pyramids

Learning Goals:

• Understand how energy from the sun flows through all life on Earth.
• Understand how to organize organisms into trophic levels and ecological pyramids.

Success Criteria:

• You can identify if an organism is a producer or consumer.
• You can describe the way organisms acquire energy necessary to survive.
• You can organize organisms into trophic levels.

We began by looking at energy from the sun.

In the most direct way, sunlight can be used to produce heat and light fires.  It can also accidentally melt cars!

Parts of his car melted when sunlight reflected off the curved building and focused on his car.

Nature has found ways to take energy from the sun and convert it into chemical energy which is necessary for life.

Plants can turn sunlight into chemical energy in the form of sugars.

Plants are considered producers because they create their own food from sunlight, water and carbon dioxide.

Humans and other organisms take in the oxygen and chemical food energy (sugars, glucose, carbohydrates, etc.) to produce energy, water and carbon dioxide.

Organisms that don't photosynthesize are considered consumers.  You can further divide the consumers into different trophic levels, depending on what they consume.

Food webs are diagrams used to show how energy flows throughout an ecosystem.  They can become quite complex.

Ecological pyramids are yet another way to show the relationships among different organisms.  Each level of the pyramids refers to a different trophic level.

An energy pyramid shows the amount of energy available at each level.

A number pyramid shows how many organisms are in each level.  These pyramids might be inverted in shape.

Refer to the handouts and your textbook, Chapters 2.4 and 2.5 for further details on all these topics.

Handouts:

• Energy Flow in Ecosystems 
• Food Webs and Ecological Pyramids

Homework:

• Continue studying for your test on Wednesday!

Here is a video showing a food web in action in unexpected and dramatic ways.  It involves lions, crocodiles and water buffalos.  Spoiler alert: it all works out well for the baby water buffalo in the end, but this case is very rare.

Nov. 22 – Introduction to Ecology

New Unit!

Ecology

Learning Goals: Understand the concept of the biosphere and ecosystems.

Success Criteria: 

• You can describe the biosphere and its components.  
• You can distinguish between biotic and abiotic factors of an ecosystem.

Handout:

• Life on planet Earth
• Introduction to Ecosystems

This is it, our planet! In this unit, we study the parts of it where life exists and look at how all the parts of it work together to keep us and all the organisms on it alive.

Here's another picture of the Earth taken from far far away.

See the pale blue dot in the middle of the light brown line?  That's Earth!

The above photo was taken by this space probe called Voyager 1.

Here's what astronomer Carl Sagan had to say about it:

From this distant vantage point, the Earth might not seem of any particular interest. But for us, it's different. Consider again that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.

In the next unit we will look at what's around the Earth and in the rest of the universe, but for this unit, we look at our home and where we live.

You should understand what all these "spheres" are and what they are made up of.

Atmosphere

The layer of gas that surrounds the Earth.

Here's a video of "Fearless Felix" Baumgartner, who jumped to earth from 39 km up.  Not very far on the ground, but straight up, it reaches the edge of the stratosphere.

Lithosphere

All the rocks and minerals that make up the solid part of where we life.  It includes mountains and the bottom of the ocean floor.

Hydrosphere

All the water around the Earth in solid, liquid and gas form.

Ecosystems

All of the living organisms that share a region and interact with each other and their non-living environment.

It is composed of both living and non-living e.g. insects and bears are living things, and weather and terrain are non-living.

Here are some examples of different ecosystems.

You should be able to identify the biotic (living) and abiotic (non-living) aspects of different ecosystems.  Refer to page 34 in your textbook for some examples.

Homework: Continue to study for the unit test!

Nov. 21 – Review Period

Today we reviewed the electricity unit by playing Jeopardy!

Here's the PowerPoint file for you to play at home: Electricity Review Jeopardy

On your actually test, most of the questions will be around the 600 point questions difficulty.  There will be some in the 800 point level and maybe one or two in the 1000 point level.

Homework:  Study for the test.

• Try the "Self Test" at the end of each chapter.
• Do the following chapter review questions:
• Chapter 11, P 498 #2-8, 10, 15-20
• Chapter 12, P 542 #1-3, 5-12
• Chapter 13, P 580 #1-9, 11-19, 23-26

Nov. 20 – Review

Today and Tomorrow is dedicated to review and studying!

I went over some of the solutions to the more complicated circuit questions.  Please let me know if you have more questions about them.  I then discussed the Unit Test that is coming up on Nov. 27th!

Handouts:

• Test Review Topics
• Formula Sheet

The formula sheet linked above is the exact same as the one you will get on the test.  Study with it and get use to it so that you'll be familiar with it when the test comes around.  Here are the types of questions you can expect for each category:

Knowledge & Understanding: Multiple choice and fill in the blank.

Application: Word problems, GRASS, and short answer.

Thinking & Inquiry: Graphing, solving circuits

Communication: Explaining things using words and diagrams.

Homework: 

• Try the "Self Quiz" at the end of each chapter.
• Try the review questions at the end of each chapter.

Nov. 19 – Equivalent Resistance

We began by going over some of the answers from yesterday's homework:

• Ohm's Law Worksheet 2

You should  now have the answers to question #1 and #2 on the back.  I left #3 and #4 for you to continue working on your own.

Equivalent Resistance

Learning Goals: Understand how to calculate equivalent resistance.

Success Criteria: You can successfully calculate the equivalent resistance for series and parallel circuits.

We began by looking at this picture:

Why is the parallel circuit brighter?  By the end of the lesson, you should understand why.

Handout: Equivalent Resistance

We looked at two circuits with resistors.  What is the equivalent resistance?  Asking for the "equivalent resistance" is the same thing as asking for the "total resistance".

Series

In series the total resistance is the SUM of each resistor.

So in this case we have,

The equivalent resistance is 6 Ω.

Parallel

In parallel the total resistance is the RECIPROCAL SUM of the each resistor.

So in this case we have,

Notice the step where we had to flip over both sides of the equation.  We must do this because the answer needs to have R total and Ohms on top.

Notice that we used the same three resistors.  The total resistance in series is 6 Ω, but the total in parallel is only 0.5 Ω, much less than any of the resistors on their own!  Why is this the case?  Look at this image:

Imagine the wires are roads and electrons are cars.  Adding a resistor is like adding a toll booth.  It slows down the cars passing through.  If there are three toll booths in a row, every electron has to go through all three tolls, slowing everyone down.  If there are three toll booths in parallel, cars can choose which one to go through and traffic flows a lot smoother.

In the same way, resistors in parallel have less equivalent resistance allowing more current.  That's why light bulb in parallel shine brighter!

Homework: Complete the rest of the handout.  Notice there are some circuits that are a combination of series and parallel!

Solutions to the first 4 questions:

1. RT = 13 Ω
2. RT = 4.6 Ω
3. RT = 4.65 Ω
4. RT = 4.3 Ω

Nov. 18 – Potential Difference and Current in Series and Parallel

Learning Goals: Understand what happens to potential difference and current in series and parallel circuits.

Success Criteria: You can solve circuits to find the missing potential difference or current.

Cells

Have a look at these diagrams:

What's the difference?  When cells are in series, you add up the potential difference.  When they're in parallel the potential difference is the same as if they were one cell.  Here's another way to think about it...

Cells in series add up, like a bunch of acrobats on top of each other.
Together, the add up and lift the electrons up very high.  V = V1 + V2 + V3 + V4 + V5.

Cells in parallel do not add up, like a bunch of acrobats standing next to each other.
Together, they all lift the electrons the same height.  V = V1 = V2 = V3 = V4 = V5.

They advantage of putting cells in parallel is that they each have to do less work.  Cells in parallel will last longer!

Loads

We then looked at loads in series and parallel.

Handouts: 

• Voltage and Current in Series and Parallel
• Voltage and Current in Series and Parallel - solutions
• Ohm's Law Worksheet 2

Please have a look at the solutions, particularly the table that describes the different situations.

You must know when to add current and when to add the potential difference (voltage).

The equations provided in the worksheet will also be provided on your equation sheet on the test.


Homework

Complete Ohm's Law Worksheet 2.

Announcement

The UNIT TEST has been moved to Nov. 27th to accommodate people who are going on the music trip.

Nov. 14 – Ohm's Law Lab

Today we gathered the data for the Ohm's Law Lab.

• Ohm's Law Lab

At this point you should all have the data necessary to graph and calculate the resistance of each resistor.  Remember, I want both sets of data plotted on the same graph.  You should have TWO lines of best fit and TWO slopes calculated.

I also provided another worksheet for you to practice Ohm's Law type problems.

• Ohm's Law Worksheet
• Ohm's Law Worksheet Solutions

Homework: 

• Complete the Ohm's Law Lab including the questions on the back.

Have a great long weekend!

Nov. 14 – Calculating Resistance

Here's a fun video that shows how you can create circuits and resistors using pencil and paper!

Videos:

• Paper circuit
  http://www.youtube.com/watch?v=BwKQ9Idq9FM
  
• Listening to variable resistance
  http://www.youtube.com/watch?v=LsvqEN3XVX4

Next we talked about how resistance is calculated.

Ohm's Law

Learning Goals: Understand Ohm's Law.

Success Criteria: You can solve problems involving Ohm's Law.

The total resistance in a circuit will affect the current.

• If the resistance increases, the current decreases.
• This is called Ohm's Law.

In equations, this is written as,

Here are a couple of examples:

Example

If a light bulb has 3.0 V of potential difference across it and a current of 4.0 A going through it.  What is its resistance?

G: ∆V = 3.0 V, I = 4.0 A

R: What is the resistance, R?

A: R = V / I

S: R = 3.0V / 4.0 A

        = 0.75 Ω

S: The light bulb has a resistance of 0.75 Ω.

Example

An average human body has a resistance of 1875 Ω from one hand to the other if the skin is dry.  If this person touches a 100 V power supply, how much current goes through him?

G: R = 1875 Ω, ∆V = 100 V

R: I = ?

A: I = V / R

S: I = 100 V / 1875 Ω

      = 0.053 A

S: A current of 53 mA will go through him.  He will be immobilized!

Next we did a review of graphing and calculating slope.  Tomorrow, you will be doing a lab where you measure the current and potential difference across different resistors.

Handouts: 

• Graphing Ohm's Law Practice
• Ohm's Law Lab

Homework:

• Complete the graphing practice.
• Read the Ohm's Law Lab for tomorrow.

Nov. 12 – Resistance

Congratulations on completing the quiz!  Now for the final, and perhaps the most difficult section of this unit...

Chapter 13.7: Resistance

Learning Goals: Understand the factors that affect resistance.

Success Criteria: You can describe factors that affect resistance and how the affect resistance.

Definition: Resistance is the ability of a material to oppose the flow of electrons.  Measured in units of Ohms, Ω

Do conductors or insulators have higher resistance?  Answer: insulators!

Here are some analogies for resistors.

Resistors behave like a small pipe.  They restrict the flow of electrons.

A regular slide has low resistance.

A slide made of sandpaper has very high resistance!

Factors that affect resistance

•  material (conductors have low resistance)
•  cross sectional area (thick wires have low resistance)
•  length (shorter wires have low resistance)
•  temperature (colder things have lower resistance)

Superconductors have zero resistance.  They do amazing things like levitate above magnets.  Watch this:

Video: http://www.youtube.com/watch?v=xuEY2bm-W50

Resistors in Circuits

Resistors can be added to circuits to increase the resistance.

The symbol for resistors when you draw circuit diagrams.

Here's what they look like in real life.

Increasing resistance decreases the current.

Homework questions: P. 566 # 3, 4, 5, 6