Week of May 23 

The Galapagos Islands

What's the Big Idea?

Diversity of species occurs through gradual processes over many generations.

I can...

 - explain why genetic variation is a survival advantage

 - explain how an why variations in appearance and behavior of an organism can be different    than their ancestors

Vocabulary:  evolution, variation, natural selection, mutation, adaptation, extinction, diversity, ancestors

Question 1.  Organisms that evolve over time on islands are typically very unique to their environments.  What are some explanations why? (Think back to the mammoth activity from last week)



The Giant Tortoises of the Galapagos Islands

The Galapagos Islands were named for their giant tortoises.  Currently their are about 14 different species of tortoises on the Galapagos Islands.  Even though these tortoises are able to survive for about 1 year without food and water, in the past 200 years their population numbers have decreased from close to 200,000 to about 20,000 due to mostly human involvement.  

Consider the following:

Question 2:  Study the various tortoise shells of the main species of giant tortoise found on the different islands of the Galapagos. 

What are some similarities and differences between these shells?  What can you infer about why and how these giant tortoises evolved into different species on these islands?  Use the link below to help out.

Background Information Tortoises and Iguanas

Consider the following: 

There are 3 different species of iguanas on the Galapagos Islands.

Land Iguana

Land Iguana

Marine Iguana

Question 3.  Why do you think these different iguana species found in the same small, isolated location, evolved the way they did?

Consider the following:

Darwin collected birds from the Galapagos Islands and he discovered that the birds, in the finch species, were different from island to island and from mainland South America.  

Darwin's Finches

Question 4.  What do you notice about the finches?  Why would the same basic species of bird have have such different physical features that changed depending on what island they were from and if they were from the mainland?

What About Natural Selection?

• Evolution - process where populations of living things change over time
• Natural Selection - process where organisms that inherit advantageous traits tend to reproduce more successfully than other organisms do-(4 parts of natural selection include: overproduction, genetic variation, selection, and adaptation)

How does this work?

1.  Most species will make more offspring than the environment can support - overproduction

2.  Sexual reproduction and DNA mutation result in  - genetic diversity or variation in traits within a species

3.  Advantageous traits are  - selected to be more common in future generations of living things

4.  These inherited traits that help organisms to survive result in - adaptations that grow over time helping the population of living things become successful in their environment

Consider the following:

Elephant Evolution

Question 5.  Study the progression of basic elephant evolution above.  Think about what you have learned about mammoths this year, what factors were most likely involved that would have influenced how elephants have changed over time? (Check out p. 362-363 for a little help)

Consider the following:

Genetic Diversity of Dogs

The genetic diversity of dogs is one of the most complicated and varied of all the animal species.  The dog is the most physically diverse land animal on the planet.  

Question 6.  Dog diversity has been influenced by both artificial selection and natural selection.   Explain how each of these processes have resulted in so many species of our four-legged friends. 

Consider the following:

If the environment changes, a species with more genetic variation is more likely to survive.  

Due to a warming climate, moose populations are declining. Moose do not handle warmer temperatures very well.  When it's warm, moose seek shelter instead of finding food, and warmer temperatures bring out more ticks which moose do not have advantageous traits to help deal with them.  Go to the information on this link Moose Populations and Climate Change and study the moose and Minnesota Moose population charts below.

Question 7.  Since it is predicted that our climate will continue to warm up, besides human intervention, what will have to happen to our moose populations if they are not going to become extinct? (Use the concepts of natural selection to help you answer this question)

Links:

Galapagos Wildlife

The Galapagos Islands Interactive NOVA


The Galapagos Islands World Heritage SIte

Week of April 20th and Beyond!

Gregor Mendel - Father of Genetics

• The first major experiments investigating heredity were done by Gregor Mendel in the 1800's

 Mendel was an Austrian monk who lived in Austria

Mendelian Genetics:

Examples of Some of His Results:

1.  Pea Plant Color

2.  Pea Plant Flower Color

Mendel's Laws of Heredity:

1.  Law of Segregation - during the formation of sex cells or gametes, two copies of each allele separate so offspring receive one allele from each parent

2.  Law of Independent Assortment - traits are transmitted to offspring independent of each other

What Mendel Did Not Know:

Incomplete Dominance - notice how the white and red/brown parent pig colors blended to make the pink pig

Codominance - This Apaloosa Horse is an example of  Codominance. Black and white alleles were neither dominant or recessive so both colors are seen in the horse

Human Genetics

The image above is a visual representation of typical human chromosomes.  Notice the various sizes and shapes!  There is an estimated 25,000 genes on these chromosomes that control all of the various human traits.  

The diagram below illustrates the relationship between genes and DNA.  Genes are segments of DNA found in chromosomes that give the instructions for producing specific traits. 

What about alleles?

Gene vs Allele

A gene is a part of the DNA. Alleles on the other hand refer to different versions of the same gene. 

• Genes are the different parts of the DNA that decide the genetic traits a person is going to have. Alleles are the different sequences on the DNA-they determine a single characteristic in an individual.

Typical Chromosome Pair; each segment is a gene; genes are made of DNA.  Each letter represents an allele, or different form of the gene.

Consider the following:

• Linked Genes = when 1 gene influences more than 1 trait

        Example:

White tigers are usually born with blue, night vision eyes due to linked genes.  Why do you think white tigers would need to see much better than non-white tigers at night?

• Acquired Traits -  when the environment influences an organism's phenotype (how it looks)

Examples:

1.  Developing large muscles due to weight training

2.  Learning to read and write

3.  Fur color changes with the seasons (arctic fox)

4.  Lamark's Giraffes - see below

Some theories about acquired traits attempt to explain that the animals physically adapt in order to survive in their changing environments.   For example, giraffes developed a longer neck due their main food source found in taller trees.

Links:

Mouse Genetics Gizmo

Bill Nye: Mendel

Mendel's Experiments Interactive

Punnett Square Interactive

Kinetic and Potential Energy!

Where is potential energy the lowest/highest and where is kinetic energy the lowest/highest?

Big idea!

There are different types of potential energy.

I can ...

• investigate to determine how height and mass of an object affect gravitational potential energy.

    · experiment with an object to change its elastic potential            energy.

   ·  experiment with the different types of potential energy               (gravitational potential, elastic potential, chemical                      potential, electrical potential and magnetic potential) to            explore the relationship of energy transfer and springs,              magnets or static electricity.

     ·  describe the different types of potential energy.

      ·  recognize that rearranging atoms into new positions to              form new substances (chemical reaction) is evidence that           the chemical potential energy has most likely changed.

Vocabulary:

chemical potential energy  
elastic potential energy
gravitational potential energy
magnetic potential energy
potential energy
chemical reaction
electrical potential energy

Energy is the ability to do work!  There are 2 types of energy: kinetic and potential.  Kinetic energy is the energy of motion and potential energy is the energy that is stored and ready to do work.  


Study the chart above - can you relate each type of potential and kinetic energy to its source?

Question 1:  Now match each of the following images to its type of potential energy.  

Example 1 - Sponge Bob and Patrick are falling off the cliff


Example 2



Example 3

Example 4


Example 5


Example 5


Example 6


Example 7


Example 8


Question 2 - Where in these wrecking ball examples would be the potential energy the highest and the kinetic energy the highest?

     A

             B

Links:

K and E Energy Painter and Can Interactive

Bill Nye Kinetic and Potential Energy

Road Runner  - Identify all of the different types of potential energy that you see in this cartoon!

Kinetic and Potential Energy Interactive

Angry Birds

Week of March 23

Magnetism!

Big Idea: Forces between objects act when the objects are in direct contact or when not touching.

I can...

• Build and electromagnet to investigate magnetic properties and fields
• Explain how generators and motors produce their own magnetic field when an electric current flows through it

Vocabulary:  magnet, magnetic force, magnetic pole, magnetic field, electromagnetism, solenoid, electromagnet, electric motor, electric, generator, electromagnetic induction

Magnetic Force - feel the push and pull!

What makes some materials magnetic and some not magnetic?

•  Iron, nickel, and cobalt are the top 3 materials that have magnetic properties
• Materials are magnetic due to spinning electric charges 
• Magnetic force can act at a distance - just like gravity and electrostatic force
• Magnet have poles - a north pole and a south pole
• Unlike poles attract - like poles repel

Magnetic Field - the area surrounding a magnet

Magnetic charge flows from north to south; the magnetic force is strongest at the poles

The Earth is a Magnet!

The Earth's Magnetic Field

What does our magnetic field have to do with auroras?

What is going on inside magnetic materials?

• Whether a material is magnetic or not depends on the type of atom the material is made of
• As an electron moves around an atom, it makes an magnetic field - in substances like iron - a north and south pole are created
• In a substance like copper, the magnetic fields cancel each other out and therefore it is not magnetic
• In substances like iron, nickel, and cobalt, the north and south poles form areas called domains
• If the domains can line up, then the material can be become magnetic or be temporarily magnetized

Types of Magnets

 1.  Ferromagnets - these are materials that can be turned into magnets

2.  Temporary Magnets

• Some materials can be magnetized for a short period of time - the domains line and it becomes a magnet

3.  Electromagnets

• Electromagnets use an electric current to create a strong magnetic field that can be turned off and on
• Electromagnets are used to pick up heavy materials like scrap in a junkyard

• Electromagnetism results when an electric current and magnetic field interact
• When a magnetic field creates an electric current in a wire it is called electromagnetic induction
• Electromagnets are used in motors

• Electric generators use induction to change mechanical energy to electrical energy

How an electric generator works

Links:

Magnet Game

Bill Nye Magnetism

The Auroras

Magnetism and Electromagnets

Maglev Trains

Junkyard Magnet

Magnet and Compass Interactive

Generator Interactive

Magnets and Electromagnets Interactive

Week of March 16

Welcome to a new topic!  It is a very charged one!  

Electric Charge and Static Electricity!  

Big Idea - Forces between objects act when the objects are in direct contact or when not touching

I can...

• Recognize that the electrical force increases as electrical charges increase
• Recognize that the electrical force decreases when the distance between the charges increases
• Given a simple interaction between 2 objects not touching, identify objects, interaction, and direction of force on objects

Vocabulary:  electric charge, static electricity, electrical 

conductor, electrical insulator, semiconductor, electrical field 

and force, induction, current

---------------------------------------------------------------------------------------

What is electrical charge?

• Electrical charge is a property of matter!

• Electric charge involves electromagnetic interactions between particles of matter 
• Matter can be overall negatively, positively, or neutrally charged by the loss or gain of negative electrons
• Charged objects exert a force on each other even if they are not touching - this is called electric force
• How strongly the electric force pushes or pulls depends on the amount of charge and the distance between the objects
• Charging objects involves moving negative electrons from one object to another - but they are not lost - just moved
• Electric charge is always conserved - this means that the total amount of charges always remains the same - they just trade places 

• Objects with the same charge (like charges) - repel each each other
• Objects with different charges (unlike charges) - attract each other
• The closer the charged objects are, the stronger the electric force

How Do Objects Become Charged?

• Objects become charged when they gain or lose electrons
• This can happen 3 ways:  friction, contact, induction (charges are rearranged int he object without touching it)

What is Static Electricity?

You guessed it! The best example of static electricity is lightning!

Static Electricity is the build up of charges - lightning works likes this :

• During storms or windy conditions, negative charges (electrons) build up in the bottom of clouds due to friction mostly
• When enough negative charges build up, they induce or induction occurs and electric discharge happens in the form of lightning 

Conductor and Insulators

• Some materials are better conductors of electricity than others
• Most metals like copper are very good conductors - meaning they allow the charges to move freely 
• Other materials like plastics, rubber, and wood are not good conductors - but they are used to insulate metals that conduct electricity - this stops a lot of shocks and electrical fires!
• Semiconductors are a special type of conductor used in computer chips - their main material is silicon
• Semiconductors conduct electricity better than insulators but not as well as a material like copper - but they are perfect for usage in electronics 

Links:

Bill Nye Van de Graaff

Nat Geo Lightning