Assessment Statements:

F.1.1

Outline the classification of living organisms into three domains.

F.1.2

Explain the reasons for the reclassification of living organisms into three domains.

F.1.3

Distinguish between the characteristics of the three domains.

F.1.4

Outline the wide diversity of habitat in the Archae, as exemplified by methanogens, thermophiles and halophiles.

5.5.1

Outline the binomial system of nomenclature.

D.5.1

Outline the value of classifying organisms.

5.5.2

List seven levels in the hierarchy of taxa—kingdom, phylum, class, order, family, genus and species—using an example from two different kingdoms for each level.

D.5.8

Construct a simple cladogram. (I gave out a table from which you were to create the cladogram, also known as a phylogenic tree). 

D.5.5

Define clade and cladistics. (check out the definition of clade and cladistics here)

D.5.10

Discuss the relationship between cladograms and the classification of living organisms (The first paragraph from this site should help.  Also, the section entitled "cladistics" from this site also gives a good description comparing the cladistics and traditional classification)

D.5.9

Analyze cladograms in terms of phylogenetic relationships.  To answer this statement, use the diagram provided and answer the following questions in your assessment statement book: 1)  What is the evolutionary relationship between species A, B and D?  2)  Why does the line for species F stop before the top of the diagram?

D.5.2

Explain the biochemical evidence provided by the universality of DNA and protein structures for the common ancestry of living organisms

§         All living organisms have DNA, which suggests that all life forms had a common ancestor with DNA.

§         To determine relationships between organisms, comparing DNA and protein structure can be helpful.

o       DNA – compare DNA for the same gene from different species and see how many nucleotides are the same.  The more similar, the closer the relationship between the species (which means they shared a common ancestor, not that one came from the other).    

o       Proteins are chains of amino acids that are coded for by the DNA.  Thus a close match in amino acid sequence of two proteins from different species indicates that the genes in those proteins evolved from a common gene present in a shared ancestor. For example, the hemoglobin of gorillas only differs by one amino acid from human hemoglobin.

D.5.3 

Explain how variations in specific molecules can indicate phylogeny.

• Genes (and the amino acid sequence they code for) are passed from generation to generation.  Thus a close match in the DNA (or amino acid) sequence from different species indicates that they evolved from a common gene present in a shared ancestor.

• If two DNA sequences for the same gene are very different from each other, it can be inferred that the two species diverged a very long time ago and that the DNA has been mutating apart for quite a while.

• Mutations are random changes in gene structure but they occur at a roughly predictable rate. In general the more differences between the DNA sequence of a common gene (or amino acid sequence of a common protein), the further in the past two species had a common ancestor. 
• For example, the hemoglobin of gorillas only differs by one amino acid from human hemoglobin whereas elephant hemoglobin differs from human hemoglobin by 26 amino acids. Therefore elephants separated as a species from a common ancestor with humans longer ago then did gorillas.
• Information like this can help to group organisms in trees of descent and suggest how long ago they had a common gene pool.
• Count how many mutations there are in that specific gene and then calculate how many years the organism has evolved. For example, if there are 10 mutations and mutations occur every 5,000 years in this gene:  10 times 5,000 = 50,000 years since the species diverged.

What You Should Be Able to Do

Class Activities:

Key Terms:

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