Grade 11A
Name:______________________________ Class: _________________
Active reading 11A – Evolution by natural selection
Topic 3: Recreating dinosaurs
In the film Jurassic park and its sequel The lost world, dinosaurs were recreated
from fragments of their DNA. This came from the stomachs of ancient bloodsucking insects, which had been mummified inside amber.
Recently, American scientists claimed they had managed to
extract insect DNA from amber that was up to 120 million
years old. It was thought that DNA could not last more than
100,000 years. Scientists from the Natural History Museum in
London spent over 2 years searching for fossil DNA from
museum specimens. They could not find any DNA in their
insect specimens but did find DNA from modern fungi and
themselves! This contamination of DNA samples explained A fly encased in amber
the American’s findings. Molecular techniques are routinely used in the
identification and classification of organisms.
Systematics (or taxonomy as it is sometimes referred to) is the study of
classifying or grouping organisms, both living and fossil. It is concerned with:
 Discovering and describing biological diversity,
 Investigating evolutionary relationships between organisms,
 Classifying so as to reflect these relationships.
Many biologists mistakenly think that all organisms have been classified and
species identified. The estimated number of species in the world is between 3 and
30 million. Only 2 million have so far been identified.
The use of museum collections to identify and classify species is on the increase.
An example is the status of the red wolf, which is extinct in the wild. Comparing
mitochondrial cytochrome b genes from museum skins with the gene sequence of
the grey wolf and the coyote enabled its status to be re-assessed. This suggests
that the red wolf was genetically very similar to the coyote and may not have
been a separate species.
Grade 11A
Name:______________________________ Class: _________________
Red Wolf
Coyote
Correct identification and classification has important applications.
 Agriculture – the control of the cassava mealy bug in Africa failed initially
because of incorrect identification of the pest.
 Medicine – the anti-viral casteanospermine is a potential new drug found in
an Australian plant. A closely related Amazonian genus was identified and
found to have greater quantities and less toxic forms of the drug.
 Industry – because fermentation products vary according to the strain of
microbe involved, correct identification is essential for reliable production.
 Forensic science – sequencing the stages of corpse decomposition relies on
the succession of decomposer communities. This is essential to reconstruct
the events surrounding the cause of death.
 Environmental assessment – bio-indicators are used
in pollution assessment. These include the use of
diatoms to measure surface water acidification, the
use of lichens for air pollution and freshwater
invertebrates for river pollution.
The mayfly Ecdyonurus is
an indicator of clean water
Jurassic Park and resurrection of dinosaurs remain science fiction.
Key words
Grade 11A
Amber
Systematics
Name:______________________________ Class: _________________
Fossil DNA
Taxonomy
Fungi
Classification
Contamination
A. Write one or more sentences to answer the following questions
1. From the first paragraph where ancient DNA can be found?
_____________________________________________________________
_____________________________________________________________
2. Why did scientist use specimens from museums?
_____________________________________________________________
_____________________________________________________________
3. What are molecular techniques used for?
_____________________________________________________________
_____________________________________________________________
4. Define Systematics?
_____________________________________________________________
_____________________________________________________________
5. Calculate how many species that are not identifies out of the 30 million
species?
_____________________________________________________________
_____________________________________________________________
6. What did scientists found when they studied the fossilized specimens of the
red wolf?
_____________________________________________________________
_____________________________________________________________
B. Fill in the graphic organizer regarding the contribution of Taxonomy in
many different fields:
Grade 11A
Name:______________________________ Class: _________________
Agriculture
Industry
----------------------------------------------------------------
----------------------------------------------------------------
Explain the
contributions of
taxonomy in the
field of …
Medicine
Forensic science
----------------------------------------------------------------
----------------------------------------------------------------
C. Circle the letter of the phrase that best answers the question.
1. American scientists claime extracted insect DNA from amber can live up to..
a. 100,000 years
b. 30 million years
c. 120 years
d. 120 million years
2. One of the following sentences is NOT true about classification ...
a. Describing biological diversity
b. Investigating relationships between organisms
c. study the different ecosystems
d. Identifying species
3. The number of species that have been identified so far...
a. 3000 species
Grade 11A
Name:______________________________ Class: _________________
b. 2 million
c. 30 million
d. 2000 species
4. The Amazonian genus was preferred because it has ...
a. greater quantities and more toxic forms of anti-viral casteanospermine
b. less quantities and less toxic forms of anti-viral casteanospermine
c. greater quantities and less toxic forms of anti-viral casteanospermine
d. less quantities and more toxic forms of anti-viral casteanospermine
5. One of the following is used as an indicator of pollution.
a. Lichens
b. virus
c. fingi
d. Algae
D. Do you think that someday dinosaurs may come back to life?
Discuss with your partner