Lab 9 Goals and Objectives:

1
Lab 9 Goals and Objectives Discuss formal
report assignment Get acquainted with the
library Make new streak for isolation plate of
each unknown Finish getting Gram reaction results
for each unknown Discuss observations of the 12
possible organisms Discuss how to rule some
out Start working on a dichotomous key of logic
for solving all 12 unknowns
2
1
2
3
4
Bacillus subtilis
Escherichia coli
Enterobacter cloacae
Klebsiella pneumoniae
5
6
7
8
Proteus vulgaris
Pseudomonas aeruginosa
Salmonella typhimurium
Shigella flexnari
9
10
11
12
Staphylococcus epidermidis
Streptococcus faecalis
Streptococcus pyogenes
Staphylococcus aureus
3
The Dichotomous Key -a visible map of logic
flow -divides a group of possible things into
smaller and smaller groupings until it leads to
the identification of just one -tracing the
pathway backwards shows all the characteristics
that collectively are unique to only that
one -assesses only one characteristic per
branch -lines all the answers up across the
bottom of the key
4
Example explain with the least number of
characteristics how to tell the difference
between an old lady and her three pets sort a
human, a cat, a dog and a bird. Construct a
Dichotomous key to ascertain the identity of
each from this small group
Animals in the house
External covering feathers
External covering hair
No tail
Tail
Meow
Woof
Bird
Human
Cat
Dog
5
12 Possible Unknowns
6
1
2
3
4
Bacillus subtilis
Escherichia coli
Enterobacter cloacae
Klebsiella pneumoniae
5
6
7
8
Proteus vulgaris
Pseudomonas aeruginosa
Salmonella typhimurium
Shigella flexnari
9
10
11
12
Staphylococcus epidermidis
Streptococcus faecalis
Streptococcus pyogenes
Staphylococcus aureus
7
12 Possible Unknowns
Gram Positive
Gram Negative
8
12 Possible Unknowns
Gram Positive
Gram Negative
9
12 Possible Unknowns
Gram Positive
Gram Negative
Gelatinase
Gelatinase -
Gelatinase
Gelatinase -
Pseudomonas aeruginosa
Bacillus subtilis
10
1
2
3
4
Bacillus subtilis
Escherichia coli
Enterobacter cloacae
Klebsiella pneumoniae
5
6
7
8
Proteus vulgaris
Pseudomonas aeruginosa
Salmonella typhimurium
Shigella flexnari
9
10
11
12
Staphylococcus epidermidis
Streptococcus faecalis
Streptococcus pyogenes
Staphylococcus aureus