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