World Biomes

Today we learned about the 5 basic biomes of the world.   There are many types of biomes but in this class we will concentrate on the basic five: Tundra, Forest, Grasslands, Deserts, and Aquatics.   A biome is a definition for a particular type of community and is classified based on its environment, organisms, and vegetation.

For your review I want you to research a particular biome.  Please comment below on which biome you will be researching.   There are 35 students in the class so no more than 7 students to research a particular biome.  If there are more than 7 people to a biome the last person to sign up for that biome will receive a 0 for this assignment. Sign up early and PAY ATTENTION!!

While you are reviewing and researching I want you to concentrate on these particular aspects:

Where is you biome located in the world?

What are the average temperatures of the seasons? Are there different seasons? 

Give three examples of the type of vegetation.  

Give three examples of the types of animals. 

Is there any ecological harm being caused by humans? Give details.

Are there any defining features about this biome that are particularly special? 

Are there other more specific biomes within this particular biome? Explain.

Tomorrow you will be meeting with the 6 other members of your group and create a special presentation for the class on the biome you researched.  Your group can do a skit, poem, song, poster, PowerPoint, etc.  You may not get up in front of the class and read from your paper without any other supplemental material.  Whatever is not finished in class tomorrow you are required to finish on your own time.  We will present two days from now.  Feel free to figure out the other members of you group and begin working on your presentations tonight. 

I have included some websites below to aid in your research.  These are not exclusive and feel free to use any other sources besides Wikipedia:

http://www.ucmp.berkeley.edu/glossary/gloss5/biome/

http://www.blueplanetbiomes.org/world_biomes.htm 

Descent with Modification by Natural Selection

Today we discussed how species evolve over time. Of the things we discussed in class we have now realized that species in the past were dramatically different than species from today.  We discussed the several theories behind the idea of how species have changed over time but we concentrated closely on Alfred Wallace and Charles Darwin’s contributions.  Wallace and Darwin are considered co-founders of the theory of descent with modification by natural selection.   While Charles Darwin was ravaging the seas and exploring the Galapagos Islands, Alfred Wallace was exploring wildlife in South America and Asia.  During these studies Wallace and Darwin corresponded with each other through the sharing of specimens and Wallace turned to Darwin for help in publishing his works in evolutionary processes.   Shockingly, Alfred Wallace’s ideas were a duplicate of Charles Darwin’s.  Although they were working on opposite sides of the world and had some correspondence with each other, their ideas were almost identical.  The concept is descent with modification by natural selection and it consists of 4 main components.

1.      Variation: within a population, the individuals possesses a multitude of different traits in physical appearances and behavior ( hair color, skin color, height).

2.      Inheritance: parents pass their traits to their offspring.  Some traits are more desirable than others based on other factors such as environment and resources.

3.      Over-reproduction: more offspring are produced than can survive. 

4.      Competition: offspring compete for resources and only the fittest survive and are able to reproduce passing on those desired traits to their offspring.  Individuals that posess less desirable traits typically do not survive and pass on their traits to their offspring.

These four aspects are intertwined to explain how species have changed or evolved over time.  Individuals within a species must survive long enough to compete for resources, reproduce, and pass on those desired traits to their offspring.  Those who do not survive will typically not reproduce and their traits become extinct.  For your review I want you to concentrate on the 4 aspects of Descent with modification by means of Natural selection: Variation, Inheritance, Over-reproduction, and Competition.  Make a mind map to help in your memory retention of the four aspects.  A mind map is a picture, diagram, organized drawing that helps you link the ideas and concepts to easy to remember pictures.  You can organize these pictures however you want but you may not use any words to demonstrate a concept.  Bring your mind maps with you to class and we will be discussing and comparing these concepts with each other.  Below I have given you some basic outlines without the pictures so you can get a visual of what a mind map would look like.  Again the only words you may use for this mind map is a title that states: Descent with Modification by means of Natural Selection.

Punnett Square Review

Today in class we learned about Gregor Mendel and his manipulation of genetic traits using pea plants.  These traits are called alleles and occur in sets of two; receiving one from mom and one from dad.  A plant is homozygous when it receives the same alleles for a particular trait from each parent.  This is also called a purebred. A heterozygous plant receives a different allele from each parent for a single particular trait.  Alleles are considered dominant or recessive based upon the physical appearance of the plant (phenotype) as well as what their genes dictate (genotype).

  

 A dominant allele will always show up in the phenotype regardless if the plant is homozygous or heterozygous.  The dominant allele is represented by using an uppercase letter ( i.e T= tall, Y= yellow, R=round). The recessive allele will only alter the plant’s appearance if the plant receives the recessive trait from both parents.  For recessive alleles a lowercase letter of the dominant feature is used (i.e t=short, y=green, r=wrinkled).  We can assume these traits are dominant and recessive based Gregor Mendel’s study of selective cross breeding.  By breeding his pea plants for particular traits Gregor Mendel was able to discover that traits of offspring are not purely a mix or an intermediate of the parental traits. 

In order to predict the offspring of a particular mating cross, us scientists like to use what is called a Punnett Square and it looks like this:

This example is a cross of two heterozygous yellow pea plants.  These alleles are representing the color of the pea plant pods; green or yellow.  We know that the allele for yellow pea pods is dominant over the allele for green pea pods, therefore, YY and Yy genotypes indicate a yellow phenotype and yy indicates a green phenotype.

For your review answer questions 1 and 2 above in addition to these practice Punnett Square crosses.

1.Does genotype determine phenotype? Why?

2. Sometimes the traits show up in the phenotype of offspring that did not occur in the phenotype of either parent! How can this happen?

3. Heterozygous yellow x Homozygous green

4. Homozygous yellow x Homozygous green

5. Heterozygous yellow x Homozygous yellow