FRQ 7 and 8 answers - Troy High School

Directions:
• Underline all portions you are receiving credit for and write points awarded. Total
your points for each question.
• Add anything that you are missing look for key words/vocab terms you may have
left out. Include extra examples in your correction – if it asked for 2 add one.
FRQ #7 Invasive Species – 8 points
(A) Specify 2 characteristics of an introduced species that cause it to be a considerable pest.
2 points – 1 for each characteristic
An introduced species will interfere with human activities – not all introduced species are pests.
2 characteristics of an introduced species as pests would be one that poisons pets, competes
with native species for nutrients, is hard to control the population or growth, creates excess
waste or noise, and spreads disease.
(B) Describe 2 physical or behavioral adaptions that allow introduced species to gain competitive
advantage over populations of native species.
3 points – 1 point for naming + 1 point for DESCRIBING each (2)
Characteristics or adaptations that allow introduced species to gain competitive advantage over
native species are
lack of predators – having no predators allows organism to reach its biotic potential
fast reproductive rate – fast reproductive rate means the population can grow quickly
resistant to pesticides – unable to get rid of the invasive organism
generalist– easily adapts to new food sources and living conditions allows the organism to
survive and reproduce easily in a new environment.
(C) Discuss a strategy to combat the cane toad population.
1 point
Giving government subsidies/rewards for killing any toad seen. Utilizing them as a food source.
Introducing a predator to eat it (risky business).
(D) Name one other introduced species and its location in the world that has become a pest.
2 points – 1 for organism, 1 for location
Killer Bees – North America
Zebra Mussels – Great Lakes
Termites – Western US
FRQ #8 Pesticide Use 11 points
(a) Discuss one of the toxic effects of DDT on organisms.
2 points -1 point each
Some studies have linked DDT to these affects:
− Neurotoxin- affecting the nervous system (in fish)
− Endocrine disruptor or HAA (Hoinionally Active Agent)- disruption of functioning of
hormonal system (reduced semen quality, miscarriage, reduced birth weight, pre-term
birth)
− Teratogen- causing birth/developmental defects (especially gender-related)
(b) (i) Explain how DDT moves through an environment.

2 points - 1 point persistence explained + 1 point
Bioaccumulation or Biomagnification explained
Persistence
− DDT is a POP (Persistent Organic Pollution) and therefore it does not easily
biodegrade because it is fat soluble and stored in the fatty tissues of animals
Bioaccumulation or Biomagnification EXPLAINED
− Because of this it remains in an environment and can be bioaccumulated in increasing
concentrations in the fatty tissue of organisms . overtime.
− It is passed from predator to prey up the food chain. Because of the loss of energy at
each trophic level more biomass must be consumed at each level and therefore the
concentration of the DDT increases as you move up the food chain.
(ii) Who is most affected, why?
2 points - 1 point name + 1 point discussion why
Possible answers- must be named and include a discussion of why
• Top level consumers — because of biomagnification up the food chain
• Animals in aquatic environments- because the food chains are often much
more extensive and the bioaccumulation is greater
• Infants who are transferred the DDT through the mother's milk and are at greater
risk due to size and reduced ability to detoxify system
• Mothers – at risk of transferring it to their unborn fetus
• Birds of prey- top level consumers who's endocrine system is affect so that their
eggs do not sufficiently harden and offspring are lost
(c) How could DDT be used to alleviate malaria?
1 point
DDT is a potent pesticide, and spraying it could kill the anopheles mosquitoes, the
vector of malaria.
(d) Argue your risk assessment of human health between the risks of DDT exposure and
malaria exposure.
Argue one side – 2 points
MORE RISK WITH DDT
MORE RISK WITHOUT DDT
- So many of the side effects from DDT - More people die a year from malaria
exposure are not well documented and exposure than the accumulated possible
can occur over long periods of time.
side effects from DDT
- If there are non-toxic options shouldn't
the precautionary principal be used.
- Should not trade one human health
adverse affect for another- verses
looking for healthy and sustainable
alternative.

(e) What are some other methods that could be used to control malaria that do not involve
the use of chemical pesticides? 2 points max – 1 point each
Other means of reducing malaria:
− Bed nets
− Screening for windows and doors on houses
− Draining swamp areas
− Increase circulation in tropical lakes (solar pumps, etc)
− Create proper drainage in towns to reduce standing water
− Education of people to clean up areas of containers which could hold standing water and
create breeding areas