Relationships
and Biodiversity
From Michael Comet biology site
Relationships and Biodiversity,
In this lab you must attempt to
determine which species (x, y, or z) is
most closely related to a hypothetical
specie, Botana curus. Botana curus
produces a substance called “Curol “
which hypothetically cures cancer.
Although this example is fictional, in
the 1970’s, scientists discovered new
and effective substance called Taxol
used as cancer medication. This
substance is found in the bark of in
the Pacific Yew tree
Pacific yew - The tree that fights cancer
Taxol – is found in the
bark of Pacific Yew tree.
Objectives of the Lab Activity –
 You will be conducting seven tests to help you determine which
species is most closely related to Botana curus, X, Y, or Z .
 You will look at the physical , Biochemical evidence.
and structural evidences .
 Understand the need for Biodiversity. Biodiversity has important
benefits to mankind, including development of new food sources and
medicines; as well as beneficial, free, ecosystem services. Ecosystem
degradation and destruction lead to the loss of genetic biodiversity
and increases the chance that an ecosystem will become less stable
and collapse
Test 1 - Structural Characteristics of Plants
QUESTION:
Botana curus
Which leaves most closely
resemble the leaves
produced by Botana
curus?
Species Z
Record your observations
in the data table.
Species X
Species Y
Test 2 – Structural Characteristics of Seeds
QUESTION:
Botana curus seeds
Which seeds most
closely resemble the
seeds produced by
Botana curus?
Species X seeds
Record your
observations in the
data table.
Species Z seeds
Species Y seeds
Test 3 – Microscopic Internal Structures of
Stems
QUESTION:
Botana curus
Which stem
structures most
closely resemble
the stem
structures of
Botana curus?
Species X
Record your
observations in
the data table.
Species Y
Species Z
Test # 4 - Paper Chromatography to
Separate Plant Pigments
Using clean, separate pipettes for each sample,
transfer two drops of each plant extract to a
piece of chromatography paper, two cm above
the bottom. Label the top of the paper with the
proper sample names
Test 4 – Paper Chromatography to Separate
Plant Pigments
Water migrates
up paper via
capillary action
and carries plant
pigments with it.
B.curus
X
Y
Z
“Spot” your chromatography
paper and label it with a
pencil.
B.curus
X
Y
Z
Test 5 – Indicator Tests for Enzyme M
Botana curus
Botana curus
(“fizzed” a little)
Species X
Species X
(no “fizz”)
Species Y
Indicator
Enzyme M
Species Y
(“fizzed” a little)
Species Z
Species Z
(“fizzed” a little)
Put two drops of each plant
Extract in separate wells of the
well tray.
Add a small
sprinkle of
“Indicator Enzyme
M”
Record your results.
Test # 6 - Gel Electrophoresis (simulated) to
Compare DNA
Obtain colored paper strips representing portions of DNA
molecules. The sequence of bases are representative of
molecules isolated from Botana curus and Species X,Y,
and Z. An enzyme will be used to cut between C and G of
the sequences to produce different sized portions of the
DNA. These will be placed on a simulated gel plate to
compare the relatedness of B. curus to X, Y, and Z.
Test 6 – Using Simulated Gel
Electrophoresis to Compare DNA
The strips below represent the DNA strands extracted from each plant (B. curus, X, Y,
and Z). Each strand will be “cut” between a double C/double G. Therefore, lines are
drawn below where each strip should be cut. Then, count up the number of bases
and paste appropriately in the simulated Gel Electrophoresis table on the next slide.
Botana curus
ATTCCGGATCGATCGCCGGATATACTCCGGTAATATC
Species X
ATTGTACCGGGATCCGGACGTCGCGACTAATATAGCA
Species Y
ACCGGTCCGGGATCGCACCCGGTACTCCTGTAATATC
Species Z
ATTCCGGATCGATCGCCGGATATTCTCCGGTAATAT
Test # 7 - Translating the DNA Code to
Make a Protein
Using the DNA codons, create the
complementary messenger RNA,
remembering that the DNA base A
specifies the RNA base U (*T is
replaced with U in RNA). Using the
Universal Genetic Code table, translate
the mRNA base sequences into the
correct amino acid sequences of the
protein.
Test 7 – Molecular Evidence for
Relationships
Botana curus
CAC
GTG
GAC
TGA
GGA
CTC
CTC
mRNA
GUG
CAC
CUG
ACU
CCU
GAG
GAG
Amino acid
Val
His
Leu
Thr
Pro
Glu
Glu
Species X
CAC
GTG
GAC
AGA
GGA
CAC
CTC
mRNA
GUG
CAC
CUG
UCU
CCU
GUG
GAG
Amino acid
Val
His
Leu
Ser
Pro
Val
Glu
Species Y
CAC
GTG
GAC
AGA
GGA
CAC
CTC
mRNA
GUG
CAC
CUG
UCU
CCU
GUG
GAG
Amino acid
Val
His
Leu
Ser
Pro
Val
Glu
Species Z
CAC
GTA
GAC
TGA
GGA
CTT
CTC
mRNA
GUG
CAC
CUG
ACU
CCU
GAA
GAG
Val
His
Leu
Thr
Pro
Glu
Glu
Amino acid
So, what is the closest and most probable alternative
source for Curol???
Test
Most similar to Botana curus?
Test 1 – Structural Characteristics of Plants
Species Z as it has the same kind of parallel
veination in the leaves.
Test 2 - Structural Characteristics of Seeds
Species Z seeds are flat and striped, much the
same as Botana curus seeds are.
Test 3 – Microscopic Internal Structure of Stems
Species Z vascular bundles closely resemble
those of Botana curus.
Test 4 – Paper Chromatography of Pigments
Species Z and Botana curus share a similar
pattern of pigmentation in paper chromatography.
Test 5 – Indicator Tests for Enzyme M
While many “fizzed”, once again Species Z and
Botana curus reacted the same.
Test 6 – Simulated Gel Electrophoresis
Identical banding pattern in both Botana curus
and Species Z.
Test 7 – Amino Acid Comparison
Species Z and Botana curus have the most
similarities.
Biodiversity
Biodiversity is the variety of life on Earth.
Threats to biodiversity
habitat loss, introduced species, overexploitation, and pollution
Fact : Many of the areas richest in biodiversity
are in some of the poorest parts of the world.
If impoverished locals use their natural
resources for income, these ecosystems could
disappear
What can be done ?
1. Educating individuals in developing countries about the
need to preserve biodiversity .
2. Protecting the environment
3. Energy conservation
4. Preserve our resources
Define the term biodiversity.
List three activities by humans which could endanger plant species.
Why is preserving Botana curus so important?
List 2 reasons for not saving Botana curus from extinction.
The loss of biodiversity is a huge ecological problem.
a.) list two human actions which may result in the loss of biodiversity
b.) list two ways the loss of biodiversity can negatively effect humans
c.) list one positive action humans could take to reduce the loss of
biodiversity
Analysis
1.This lab has 7 tests used to determine the relatedness of 4 plant samples. Remember that scientists use
a variety of evidence to determine evolutionary relationships, including cell types, structural morphology,
DNA, behavior, embryology, and fossils. The more criteria that are shared between organisms, the more
likely they are closely related.
2.Relatedness can be shown using a “branching tree diagram”, or cladogram. Organisms that are closely
related are next to each other on the same branch. More distant relations are further apart on the branch.
3.Botana curus shares the most characteristics with Sample Z, making this sample the most closely
related. These characteristics included the presence of Enzyme M, the same pigments blue, yellow, and
pink, scattered bundles, no difference in the amino acid sequences, and the same DNA banding pattern.
4.The evidence that should receive the most emphasis when determining the relatedness would be the
genetic sequence, as many things can look similar structurally (convergent evolution), but would be
unlikely to share the same DNA sequence if they are not truly closely related.
5.The loss of even a single species (extinction) can have major implications for mankind and natural
ecosystems.
6.Scientists use gel electrophoresis to separate DNA fragments. Negatively charged DNA molecules
migrate through the gel like material towards the positively charged pole. The smaller molecules migrate
more rapidly through the gel than the larger ones do.