This document is a research paper that examines the effects of genetically modified organisms (GMOs) on natural ecosystems. It discusses how genetic engineering of plants and animals can threaten existing species by spreading mutated traits. It also explores how introducing GMOs into environments like forests and oceans can disrupt nutrient cycles and natural balances. While GMOs may increase crop yields, the paper argues the potential harm to ecosystems is not worth the benefits. It examines case studies on transgenic fish interfering with natural populations and genetically modified trees affecting leaf litter decomposition. Overall, the document maintains that GMOs significantly impact ecosystems and pose risks that have not been fully assessed.

1. Gayathri Narayanan
Professor Noreen McAuliffe
Research Paper Final Draft
12/9/2014
The Effects of Genetically Altered Organisms on Natural Ecosystems
Abstract:
The value of natural species in the functioning of a stable environment is fairly well
known; food webs are evidence of a hierarchical system of balance between organisms.
However, by manipulating the genetic makeup of natural plants and animals, what would that
entail for the delicate environmental balance? Pushed by scientific curiosity as well as a growing
consumer demand by the increasing population, American environmental industries have been
incorporating and including GM foods and crops as a means of production. This has a
consequence on natural species, which are threatened because of the mutated traits engineered
into GMOs. Before indulging in ‘techno science,’ it is necessary to take a step back and assess
the risks posed by GMOs on natural aquatic and agricultural ecosystems. Using the theory of risk
assessment by Fern Wickson and the idea of environmental trade-off described by Sheldon
Krimsky, I will argue that the potential harm posed by GMOs is not worth their benefits. Overall
on a global scale, are GMOs worth the few extra benefits or would it just be tipping over the
delicate pyramid of cards that is our natural ecosystem?
Introduction:
The progress that humans have made in the field of synthetic biology has been gradually
increasing over the last 15 years. Specifically, American industries and biotechnology firms have
been producing new altered versions of preexisting organisms under the title of genetic
engineering, which is the practice of manipulating the genetic makeup of organisms (plants or
animals) to provide a new, ‘enhanced’ version. Usually this practice of making GMOs
(genetically modified organisms) has been carried out to isolate certain favorable traits in
particular plants or animals, while eliminating other unwanted traits. It should be understood
though that the introduction of these GMOs does have an effect on the structure and organization
of previously existing natural organisms. The question then becomes to what extent are GMOs
affecting these natural organisms in their ecosystems and what effect that has on the environment
as a whole. The areas of concern are particularly in aquatic ecosystems where fish populations
are being targeted for genetic modification and agricultural fields where crops are manipulated.
There are theories that relate to this issue, such as Fern Wickson’s theory about risk analysis and

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Jill Didur’s theory about indulging in ‘techno science’ that drives more GMOs. Vandana Shiva’s
theory about the agricultural costs resulting from genetic engineering in the seed industry is also
relevant. It is true that genetically altered organisms can provide beneficial results, such as the
production of biofuels from algae and the applications in pharmaceutical industries for
developing medicine and drugs, which involves modifying bacterial DNA. There is a point of
controversy however about the ethical implications of using GMOs in food products, which has
been increasing over the past 15 years. A counter argument arises from scientists and researchers
who believe that regulated genetic engineering suppresses the range of innovation and ideas,
preventing true development. Another counter argument is that introducing GMOs can help
expand the biodiversity in the environment. The idea that inorganic foods are entering the human
body is a source of concern for many consumers, but also ecologists because the introduction of
GMOs poses a plausible threat to naturally existing ecosystems such as forest and marine
ecosystems. Due to the ethical discrepancies, its effect on preexisting populations and the impact
on the biodiversity in those ecosystems, genetically modified crops and animals affect existing
ecosystems significantly and thus human life unfavorably as well.
Background:
Genetic modification of an organism is the mutation, insertion or deletion of a gene from
an organism’s DNA. Since 1999, there has been incredible progress in this field, especially in the
United States. While it first began out of the curiosity towards genetics, genetic engineering
slowly crept its way into consumer industries, such as food and agriculture. The idea of
genetically isolating favorable and faulty genes in an organism had a lot of potential in the field
of agriculture because crops are at high risk of being prey to insects and other plant diseases.

3. Gayathri Narayanan
Professor Noreen McAuliffe
Research Paper Final Draft
12/9/2014
Genetically modified crops have started to become incorporated into the agricultural industry,
conflicting with traditional farming techniques. Since 2010, certain crops have become the target
of genetic modification, such as corn, soybeans and cotton. The introduction of Ht and Bt crops,
i.e herbicide resistant and insecticide resistant crops, have revolutionized the farming industry.
This however poses a problem because resistance against pesticides was also found to spread in
weeds and surrounding crops. According to a report by the US Department of Agriculture,
“Because no new major herbicide chemistry has been made commercially available in the last 20
years... plant scientists believe that slowing the rate of…the spread of glyphosate-resistant (GR)
weeds are among the most important problems facing U.S. crop producers” (32) indicating that
while pesticide resistant plants can be considered beneficial, it does have side effects. The spread
of the mutated genes, in this case the “glyphosphate-resistant (GR)” gene from weeds to
surrounding plants is one of the most pressing issues regarding the effects of transgenic crops on
the environment. Another source of ecological conflict between GMOs and natural species is in
marine ecosystems. The creation of GM salmon was mainly to increase the amount of salmon
available to consumers. However, the presence of a transgenic growth hormone gene has posed a
problem and “increasing the frequency of the transgene [means] the viability of the natural
population is reduced” (Hedrick 841) affecting natural salmon populations. The viability of a
population is key for its survival, as it means the species in the population can maintain and
recover from harm. Reducing the viability of a population would endanger the safety of those
natural species, resulting in a larger scale effect on that ecosystem. The introduction of GMOs
into natural ecosystems where traditional organisms live can mean many things regarding the
balance within that ecosystem, in terms of food webs and natural order. The presence of GMOs
can even lead to completely new interactions between species, such as “putative symbiotic

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interactions” (Klitgord) which is type of interaction between microbial species. Creating new
interactions can be just as jeopardizing as destroying old ones. Either way, the introduction of
GM species into ecosystems should be carefully evaluated.
Consequences on Natural Aquatic Ecosystems:
The increasing rate of consumer demand in industries results in a necessary increase in
supply, especially agricultural industries. One particular example of how synthetic biology yields
to the booming rates of demand is transgenic fish. Transgenic fish such as genetically modified
salmon, were created solely to supply more for the price that consumers were paying. They were
made to “include accelerated growth, size enhancement, disease resistance and…tolerance for
low temperatures,” (Krimsky 245) all qualities that would enhance the marketability of fish and
make it a better food source. The goal with engineering transgenic fish, which by definition have
altered DNA, is to have a superior species that can have all of the above-mentioned qualities.
However, ultimately these fish do end up mixing in with naturally existing fish populations that
reside in aquatic ecosystems such as oceans and freshwater sources. This poses a problem to the
natural, non-genetically modified fish because transgenic fish have “greater vulnerability to
predation, alternate foraging behavior, increased ability to compete for food and swimming
deficits” (Krimsky 245) all of which are deficits that can threaten the existence of natural fish
populations. For example, by introducing transgenic fish back into the ocean, they are able to
reproduce and mate with natural fish, which means that there is a possibility for the “swimming
deficits” to be inherited in future generations of fish, ultimately leading to the extinction or
endangerment of that particular fish species due to the introduction of a new faulty trait.
Additionally, in terms of competition for survival, transgenic fish are built with their enhanced

5. Gayathri Narayanan
Professor Noreen McAuliffe
Research Paper Final Draft
12/9/2014
ability to “compete for food” which proves a disadvantage for normal fish who cannot compete
with transgenic fish because of this, and thus slowly the natural fish population cannot feed itself
and it may go extinct.
In addition to transgenic fish, another genetic modified threat to aquatic ecosystems
comes from GM trees. Silviculture, or the regulation of the quality of forests and trees, has also
incorporated biotechnology and started to cultivate GM trees. This is mainly to introduce variety
into forests and improve biodiversity. One of the main characteristics of trees that are targeted to
be genetically modified is lignin, a compound primarily found in tree wood and bark. A study
assessing the effects of GM tree leaf litter (the leaf debris that fell from these GM trees) found
that “After 84 days in streams, CAD-litter had lost 6.1% less mass than the non-GM litter”
(Axelsson et. Al 1049) comparing the GM tree (CAD) and the non-genetically modified tree’s
leaf litter. What this means in terms of aquatic ecosystems is that the rate of decomposition of
leaf litter from GM trees was less (specifically 6.1% less with respect to the CAD tree) than that
of natural trees. This is significant because decomposition of natural wastes is an integral part of
balancing an ecosystem, and if waste such as leaf litter is not properly decomposed of, then it
could affect the natural order in that ecological community. Genetic modification in trees can
affect the quality of leafs and thus the decomposition of leaf litter thereby having the potential to
affect ecosystem processes. Not only does this mean that aquatic ecosystems such as streams and
rivers can be affected, but other animals and organisms that depend on those sources of water can
also be affected. The decomposition of litter is “an important process in all ecosystems and
changes to decomposition rates may in addition to potential effects on primary consumers also
affect the cycling of nutrients and carbon.” (Axelsson et. Al 1057) which threatens surrounding
ecosystems as well because carbon and nutrients are used by organisms throughout the global

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environment. Changing the carbon and nutrient cycles could cause a nutrient deficit in aquatic
ecosystems, which could impact other species dependent on these ecosystems.
This threat of aquatic life existence correlates with Fern Wickson’s theory about risk
analysis. Wickson believes that risk assessment should be conducted prior to devising
management strategies, and in order to minimize the environmental harm of any technological
advance, in this case genetic manipulation and modification of organisms, it is vital to “employ
the tool of risk assessment to identify potential hazards, assess the probability of their occurrence
and calculate the magnitude of their impact” (Wickson 1) which is exactly what should be done
prior to releasing GM organisms, such as transgenic fish or GM trees into the natural
environment.
Effects of GM Plants on Natural Ecosystems:
GM Plants have been cultivated since genetic engineering was known to have potential
benefits agriculturally, however they have had undesirable effects on surrounding crops as well.
GM plants, as mentioned previously, were made primarily for their pesticide and insecticide
resistance traits as well as additional nutritional value. Agricultural biotechnology, which is
involved with engineering superior crops with traits such as insecticide resistance, disease
resistance or enhanced water retention, is slowly creeping its way into the food production
industries. However, apart from the effect on consumers, the effect on surrounding natural crops
is also worth discussing. The most targeted crops for genetic modification are corn, soybeans and
cotton, which are grown and cultivated in close proximity to natural corn, soybeans and cotton
plants as well. As a report conducted by the US Department of Agriculture notes regarding the
cultivation of GM crops, “An important issue...is the coexistence of crop production”

7. Gayathri Narayanan
Professor Noreen McAuliffe
Research Paper Final Draft
12/9/2014
(Fernando-Cornejo et.al 41) or the existence of both traditional and genetically engineered crops
in the same area. The “coexistence of crop production” plays an important role in deciding the
extent of how GM crops affect natural crops. There is a possibility that the enhanced traits being
engineered into the GM crops hinder the GM crops from peacefully coexisting with their
traditional counterparts. As mentioned before, some of the modified traits could result in
increased competition for nutrients that would let the GM crops grow healthier than the natural
ones, affecting their coexistence and ultimately the balance within that agricultural ecosystem.
Along with the issue of obstructed coexistence between GM and traditional crops, there is
also the threat of what GM crops could do to the surrounding environment itself. When growing
crops, transgenic crops are planted in areas near natural crops. This leads to the possibility of
undesirable effects on the habitat of the natural crops. Once GM crops have been cultivated, the
habitat of natural crops is threatened because “transgenic crops might invade natural habitats if
their germination, root growth, resistance to abiotic stresses, or dispersal has been enhanced”
(Krimsky 244) due to the spread of those traits into the surrounding areas. The traits that are
genetically enhanced in transgenic crops, such as “germination, root growth” and “resistance to
abiotic stresses” are potential hazards for the environment where natural crops are growing as
these traits mean that GM crops will develop an advantage in obtaining nutrients from the soil,
due to their enhanced root growth, as well as survive through adverse conditions (such as
droughts, extreme heat) because of their resistance to those types of stresses. In the long term
perspective, this means that transgenic crops have a higher chance of surviving and thereby
spreading into the areas where natural crops (which are more prone to dying) were once growing.
The genes that are engineering into these transgenic plants pose a threat to the habitat but also to
the natural plants themselves. One of the main areas of concern with the mutated genes in GM

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crops is that the “genes transplanted to the crops for herbicide tolerance might transfer to other
plants, thereby spreading...in a way that is ecologically undesirable.” (Krimsky 244) leading to a
greater chance of threat for traditional crops.
The addition or modification of preexisting genes in crops can lead to undesirable
consequences for surrounding plant species. This becomes a greater issue when discussing crops
that are cultivated in close proximity to weeds. Certain “...crops that already have weedy
characteristics...might be expected to improve crop competitiveness in agricultural or natural
habitats.” (Dale et.al 569) after having mutated genes, which can affect surrounding non-GM
crops due to the increased competitiveness for nutrients and water engineered into them,
allowing them to access those nutrients more efficiently. This can lead to natural plants being
bereft of necessary nutrients, resulting in them becoming malnourished and slowly dying off.
This would affect the animals and other organisms, such as microorganisms, that rely on those
natural plants and crops as food sources. In addition, most agricultural practices involve moving
crops from one location to another area. This is problematic with regards to GM crops because
changing habitats of a GM plant can “potentially result in the evolution of a weed from a
cultivated plant or...a feral plant” (Dale et.al 569) which poses a threat to the existing ecosystem
balance within that area. Feral plants, or wild plants, can have adverse effects on surrounding
dependent organisms, destroying the intricate ecosystem balance. The balance in a particular
ecosystem, for example terrestrial ecosystems, is like a pyramid of cards. If one card is removed,
then the whole structure collapses, and if one organism in a food web is altered, it can potentially
destroy the whole ecosystem.
Another aspect to consider when debating whether GM crops affect agricultural
ecosystems significantly is the concept of environmental trade-off. This is the idea of giving up

9. Gayathri Narayanan
Professor Noreen McAuliffe
Research Paper Final Draft
12/9/2014
certain aspects of an ecosystem or environment in general, to obtain benefits such as more
productive crop yields and more efficient crop production. One of the adverse effects that are
“traded off” in return for the possible benefits of GM crops are the non-target effects of these
modified crops, which are “ undesirable effects of a novel gene...on “friendly” organisms in the
environment” (Dale et.al 569) ‘friendly’ referring to the natural, non GM plants and crops near
the vicinity of where the GM crops are being cultivated. This trade-off between non-target effects
for the disease resistance and pesticide resistance in GM crops is not as straightforward as
making simple decisions about what kind of plants people want to grow. In order to avoid or
curtail these non-target effects caused by GM crops, researchers and geneticists would have to
identify “a resistance gene and [target[ its product to appropriate plant tissues so that it acts only
against the pest, without adverse effects on friendly organisms” (Dale et.al 569) which is
extremely challenging. Having to restrict a particular target gene for each kind of crop, such as
corn, soybeans, etc is a tedious process and may not be a practical solution for avoiding these
non-target effects. Although it is true that the herbicide and insecticide resistant crops have their
benefits for farming and have their own economic value, it is a question of whether the ends
justify the means, that is, whether this trade-off between the possibility of affecting hundreds and
thousands of surrounding organisms, including plants directly and other organisms indirectly, is
worth the countable number of benefits from a few GM crops.
Impact on Natural Biodiversity in Ecosystems:
This risk of cross contamination within natural and GM crops is further applied to the
potential danger GM crops pose to plant diversity. Plant diversity plays a significant role in the
entire biodiversity of an ecosystem. The variety in plant species allows multiple kinds of animal

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species as well as other organisms such as bacteria or fungi to thrive off of them. Breeding GM
crops, specifically “...herbicide-tolerant crops may cause a shift in weed populations and thus
reduce weed species diversity and ecosystem complexity in the GM field and on neighboring
farms” (Dale et.al 571) which would ultimately affect the diversity of crops in those neighboring
farms and fields. Introducing herbicide-tolerant crops is an issue mainly because of the “shift in
weed populations” that it causes, as mentioned. Although weeds are usually thought of as
undesirable where farming, the diversity in weed species is essential for the productivity of an
agricultural ecosystem, as certain animal species may be dependent on weeds as a food source,
or source of shelter. Any GM organism that causes a “shift” in weed populations in an ecosystem
is a threat to the ecosystem balance because it can result in a shift in biodiversity. Biodiversity
plays a key role in regulating the stability of an ecosystem because it boosts ecosystem
productivity. Each organism in an ecosystem has an integral role in maintaining an ecosystem,
and reducing this needed diversity or “ecosystem complexity” can ruin this delicate order of
balance within an ecosystem. Introducing GM animals also has a similar effect on the natural
biodiversity of an ecosystem, such as in aquatic ecosystems. For example, as mentioned earlier,
transgenic salmon are a main source of concern regarding natural salmon populations in aquatic
ecosystems. Introducing GM salmon into a freshwater source would result in a disruption of the
natural ecological order existing among the traditional salmon populations. As a result of the
“non-target” effects of gene modification (again, mentioned in the Effects of GM Plants on
Natural Ecosystems) the genetic makeup of the ecosystem is altered, which reflects in a change
in biodiversity among the organisms. Although this has the potential benefit of increasing the
overall biodiversity in the area, it would be wise to assess the risks as well.

11. Gayathri Narayanan
Professor Noreen McAuliffe
Research Paper Final Draft
12/9/2014
Conclusion:
Overall, although the benefits obtained from GM organisms seem exciting and may move
the realm of science forward, it is essential to weight the risks of GM organisms against the
benefits and see if this trade off is indeed worth it. The increasing scientific curiosity since 1999
in the field of bioengineering has propelled the discovery of a multitude of new species, such as
genetically modified mice, or genetically modified bacteria. These creations laid the foundation
for further research and experimentation in the field of synthetic biology, which led way to the
production of GMOs. The introduction of GMOs into the consumer world was thought to be
beneficial because of the altered genetic makeup in these organisms that gave them superior
traits, such as herbicide resistance in the case of GM crops or increased speed in the case of GM
salmon. Although these organisms are revolutionary and have the potential to change
Works Cited:
Axelsson, E. P., et al. "Can Leaf Litter from Genetically Modified Trees Affect Aquatic
Ecosystems?" Ecosystems 13.7 (2010): 1049-59. ProQuest. Web. 28 Oct. 2014.
Dale, Philip J., Belinda Clarke, and Eliana MG Fontes. "Potential for the environmental impact
of transgenic crops." Nature biotechnology 20.6 (2002): 567-574.

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Fernandez-Cornejo, Jorge, et al. "Genetically Engineered Crops in the United States." US
Department of Agriculture Economic Research Service (2014).
Klitgord, Niels, and Daniel Segrè. "Environments that induce synthetic microbial ecosystems."
PLoS computational biology 6.11 (2010): e1001002.
Krimsky, Sheldon. "Environmental Impacts of the Release of Genetically Modified
Organisms." Encyclopedia of Pest Management. CRC, 2002. 243-246.
Hedrick, Philip W. "Invasion of transgenes from salmon or other genetically modified organisms
into natural populations." Canadian Journal of Fisheries and Aquatic Sciences 58.5
(2001): 841-844.
Shiva, Vandana, et al. "Seeds of suicide: the ecological and human costs of globalisation of
agriculture." Seeds of suicide: the ecological and human costs of globalisation of
agriculture (2000).
Wickson, Fern. "From risk to uncertainty in the regulation of GMOs: social theory and
Australian practice." New Genetics and Society 26.3 (2007): 325-339.
Salafsky, Nick, et al. "A standard lexicon for biodiversity conservation: unified classifications of
12threats and actions." Conservation Biology 22.4 (2008): 897-911.