Ashley S.

When humans inevitably go extinct, plants and animals will not only continue to exist, they will thrive. Without our mass combustion of fossil fuels, our continuing evasion of natural ecosystems, our overall consumption of every discovery made and our astounding mounds of wastes, the Earth as an ecosystem would blossom.

Humans are most definitely not a keystone species. The removal of our species may determine the dramatic shift of an ecosystem, which is the partial definition of a keystone species, but we are most certainly not a species that plays a critical role in maintaining the structure of an ecological community. We are merely a dot on a 4.5 billion year timeline. The Earth has existed and remained resilient well before us, when dinosaurs roamed the land. After we “leave”, the land will repair its wounds and forget us, just as we forgot it.

Angela K.

To be a keystone species, a species has to have a disappropriate effect on the ecosystem. As humans, I do believe that we are noted as a keystone species. Our existence on Earth has become a large part of it as a whole, and in many different ways. We use/deplete numerous resources that the Earth provides, and therefore affect the lives of the amount numerous amount of species that we coexist with. We play an important role in maintaining our ecological community, as well as constantly changing it. We have declared this dominance over the years, and through this authority we have caused the Earth to evolve, and this evolution has been directed to benefit us. However, Paine does provide an accountable point about plants and trees. Without them, we as humans, could not exist. There would be less animal habitat and supply of oxygen. Huge quantities of animals would have no way to survive. Therefore, yes we as humans are a keystone species, but I feel as if plants and trees, or even microbiological world effect us a great deal more.

Darryl Cato-Bishop

Humans are an example of keystone species. Humans has a great impact on the world today. We have the ability to change the environment as well. With the developement of technology it help us grow and use things like farms. As the environment changes, we change the environment to fit our needs and wants. As we change the environment for our needs and wants it kills other species. I think without humans the environment would be totally different. The species we kill will be here and the technology we use would not impact the ecosystem.

Aaron T.

A keystone species can be defined as one whose impacts on its community or ecosystem are large and greater than would be expected from its relative abundance or total biomass. Based upon scientific observation, certain species have such an impact on a biological community or ecosystem that the remove of that species from it's habitat can create an instability within that ecosystem changing the dynamics of which species becomes dominate. In other words the removal of a that species would allow other species to take over a given population because they are not longer checked by the keystone species. As this theory applies to humans and agriculture, humans may be seen as keystone species. Take for example many of the planted rice fields in Asia. Year after year, the same wetlands are continuously being planted with rich and maintained to maximize the total yield of crops from those areas. This maintenance includes the removal of invasive species competing for the resources that the rice plants do. If humans for some reason decided to not try and cultivate the rice, other species would then move in and compete for the rices resourses and may eventually even replace the rice plants as a dominate species. In this sense man is a keystone species in man maintained environments.

Humans a Keystone species- Sam Jones

In the dictionary it states that a keystone species is "a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically". After watching the documentary on this subject during last weeks class, it dawned on me how something so small as a movement or change in one species could trigger a huge domino affect of events. During the video, the narrorator gave an example of the starfish on a shoreline. The environmentalist removed some starfish and different consequences proceeded from this action. More mussels would cling to the shore and eat away this organism, and if they continued to eat so much of it the other organisms would not be eaten. I am sure i am more or less wrong in my example but the point was one change can affect the whole sea.
We as humans control allot of our environment and if we were eliminated the other species would not change. Humans are not a keystone species. if all our factories were shut down, all of the technology and other man made devices were suddenly removed from this earth, organisms and other species would still prosper. Except for the common household dog. the earth and species have existed before us and our contribution has done nothing but destroy and tarnish there existence. My only debate about this would be humans and hunting. In the US sometimes deer tend to overpopulate themselves and it is lawful to kill more than necessary. But at the same time if we were not here, then more deer means more food for coyotes and other wildlife who eat them.

Humans are an even greater example of keystone species than the ones listed in the paper. We have the ability to both increase and decrease populations seemingly on a whim. Fireants have made the exodus to North America by piggy backing on humans. We have almost eradicated turkeys and woodducks, yet decided it would be nice to help these species recover. The starfish and seals of the Pacific are only able to exert influence on other species by eating. Humans have monopolized the ability to move species around the globe as we see fit (or by accident), thereby affecting the entire planet.

Matt B

David Pate

The degree to which humans are a keystone species is proportional to the level of technologial developement, but with a twist at the end. In prehistoric times, humans were not keystone species. Their effect on the environment was limited due to the diverse nature of an omnivore. Then, as the humans' ability to use technology grew, humans started to greatly effect the enviroment with things like dams, pollution, farmland, and urban developement. This would certainly qualify humans as a keystone species. But now, by using new techonology to be more efficient, humans are able to do more with less, and our total biomass is increasing, making our effect on the enviroment more proportional to our biomass. So the degree to which humans are a keystone species is decreasing because our total biomass is increasing and our effect is decreasing (or will be soon) due to conservation efforts.

Greg Baskwell

I think that humans are a keystone species, and they are one of, if not the biggest keystone species on the planet. Humans have such a huge impact on the ecosystem around us that if we were removed, the ecosystem and community would experience dramatic changes. Humans have changed the natural environment in many ways in order to fit our needs while not even thinking about what is happening to the environment when we do it. As our planet's population gets bigger, humans begin to take over animal habitats because there is not enough room. As we do that, it is killing certain species who also have impacts on the environment. So without humans on the planet I think that there would be huge change in the ecosystem.

Mary M.

A keystone species is one that when removed, results in a drastic change to other species, most often seen in their population densities. Using this definition, I think that humans are most definitely a keystone species. We kill such and abundance of wildlife and destroy a large number of species through deforestation and our daily lives in general. If we were removed, populations of all other species would increase, however, I do not believe it would cause chaos. I can not think of any population that would take over, however, we can only speculate since there is no way of knowing our impact on the planet. So we are a keystone species because we would affect the balance of the planet (some species that are endangered would come back and repopulate the world). However, it is arrogant and incorrect to assume that we are the main keystone species. I think grass would come before us in the level of importance because almost every other species feeds off of it. Many species would be destroyed if their main food source (grass) was depleted.

Nick S.

To start off I feel like humans are keystone species, but I can see how we might not be. From the web sources you gave us they describe a keystone species as when they are removed or disappear from an ecosystem, it results in “dramatic” or “radically” changes to the rest of the community. If you go straight from the definition, our removal will obviously alter the varieties and populations densities of other species over a mass amount of time making us a keystone species. But if you consider our removal causing the ecosystems to go back to a “normal balance” like before, when humans weren’t here and dinosaurs were around, taking us away just causes a drastic restoration of the ecosystems not a change. This would make us not a keystone species. It is almost impossible to truly now what will happen if the human race were to suddenly vanish.

Parker Y

Human beings are indeed a keystone species. Humans have a significant impact on the many ecosystems surrounding us. A keystone species is said to be a species that has a dissproportionante affect on the environment of which it lives. This being said, it is fairly evident that humans do belong in this category. Humans effect many different ecosystem throught the world. Everthing we do as humans either beneifits or harms the world around us.

Andrew H

Humans are a keystone species. They may not have the huge numbers of some other microorganisms they do have far reaching and lasting effects on the environment. Humans have no real predators. Our ability to control our natural world and shape it to our own means with general disregard to the natural environment make us a keystone species. Our effects are also felt all over the world (logging, landfills, atmospheric pollutants, Pacific Ocean Gyre). Our only real enemy is our own success.

Elizabeth M

Humans may be considered a keystone species due to the fact that our impact on ecosystems is greater than our relative biomass. However, the concept and importance of keystone species is much more complex than this definition; furthermore the impact of humans on the environment is not uniform. First of all, many cultures throughout the world exist "outside" of their natural habitat, meaning that they are disconnected from the natural interdependent relationships between species. These cultures carelessly consume resources at an extraordinarily high rate. Humans that reside in these cultures, including our own, dominate the ecosystem rather than living within it. That is not to say that all cultures are alike. In fact, some cultures have successfully maintained an appropriate role as a keystone species, acting to take what is necessary from the ecosystem, but also to replenish and nourish it at the same rate. Humans are a keystone species, but the question is: are we a beneficial keystone species?

Stephen P.

I do believe that humans act as a keystone species. I think if humans were removed there would be a great shift in all of the ecosystems that we affect. Keystone species defined is a species that has a disproportionate affect on its environment compared to its abundance. I have no doubt that we have affected more ecosystem functions than would typically be affected and if, by chance, we were removed or reduced to a point where our affect is lessoned, there would be significant changes in the way the environment around us functions.

Matthew W.

Part of being a keystone species is having a disproportionate effect on its environment relative to its biomass. Humans continue to have a very large effect on the environment across nearly the entire planet and this effect is very disproportionate since humans have a fairly small biomass compared to the amount of surface area we inhabit. Soon, nearly 70% of the world population will be urban and most humans will have a much smaller direct effect on the environment. Even though some ecosystems will change dramatically if humans are removed, humans do not inhabit the majority of the Earth's surface, and if the oceans are included they inhabit an even much smaller percentage of the planet.
However, the most important function of a keystone species is to maintain ecological structure and species diversity within its habit. Humans have the opposite effect. Through habitat destruction with urbanization, natural resource harvesting, and agricultural clearing humans have destroyed much of the habitat that thousands of species depend on. After these habitats have been destroyed only a handful of species are able to survive. It can be estimated that nearly 40% of the Earth's surface is used for agriculture that only supports a handful of species.
Even though humans have a large effect on the environment they are not a keystone species because they do not maintain species diversity.

Sommer S.

I agree that humans are the biggest keystone species because if we were wiped off the earth, our loss would be damaging to the ecosystem as a whole. I believe this because we are the biggest consumers and modify our environment so much. We as humans are the primary keystone species because just like the starfish that were removed in the experiment, their removal resulted in a critical effect on the ecosystem and effected everything from the otters to the mussels. Humans are considered a keystone species because we are a major source in controlling and altering the ecosystem. In an article I read, a keystone species is usually the top of the predator food chain, so this would definitely qualify humans are a keystone species. All in all, I strongly believe that humans are the biggest keystone species out there.

Kevin S.

Humans are certainly a keystone species. We affect environments over the entire planet, whether through clearing land for construction, or hunting, farming, and the inadvertent effects of our other activities. These effects on the environment certainly outpace our total biomass, and so we satisfy the first condition of a keystone species. Were humanity to vanish, the effect on the tentative balance that has arisen around us would be similarly profound. All of the land that humanity inhabits, that currently is deliberately void of most other life, would be reclaimed by opportunistic species, drastically affecting the environmental balance. This is just a single example of how humanity satisfies the second condition of a keystone species. Whether it can be readily said that humanity is the "greatest keystone species" is less certain. It is hard to imagine a single species whose effects would be as profound, but that could well be because we think on the wrong scale. Many smaller organisms, like mosquitoes and certain bacteria are as ubiquitous as humanity, and the full effects of their absence from the world environment are not completely known. While humanity is most likely the greatest keystone species on the planet, we have to recognize the uncertainty cast by our incomplete knowledge of our planet.

Bradley B.

Humans are unquestionably the greatest keystone species. Humans impacts are disproportionately more than any other species in any ecosystem. The ability to significantly alter any landscape and thus the many connected systems is noticeable all around us. Luckily we can and are recognizing this ability and it has encouraged the study and understanding of our environment. The major factor that has increased our status as the greatest keystone species is the time frame that human impacts travel through the many interconnected ecosystems. Everything is connected and although it is convenient to imagine spatial boundaries between systems in actuality they are a figment of our imagination. Humans will continue to alter the world in which they live to best suit their needs. Hopefully humans will begin to assess their needs for a future.

Will Long

The statement that humans are a keystone species is definitely true. Humans alone have the power to reshape vast expanses of earth by will, and while we may be able to do this, humans are not the most important keystone species on this planet. For example, if humans were to induce a nuclear apocalypse, much of the micro organisms (namely bacteria) on this world would survive. In another 100,000 years, the radiation levels would go down, and the world would again be teeming with these bacteria which could later evolve again. If, in the reverse, all bacteria on the earth suddenly died, life would be totally different. Humans would all die due to the lack of E. Coli in the digestive tract, along with nearly all other multicellular animals; all of which have a mutualistic relationship with bacteria. Many plants would not be able to fix Nitrogen as efficiently without these bacteria, and the world's biosphere may not be able to recover. This was just one example. Humans are a keystone species, and even if we are not the most important, we need to make sure that we are not wasteful of the resources that are provided to us; and we need to bear in mind that our actions will always have some environmental consequences. Whether or not these consequences are positive or negative on the environment depends on the decisions we make, or refuse to make. While removing humans would surely greatly affect the world's ecosystem, stating that we are the most important keystone species is likely not an accurate statement.

Ashley Marie Berfield

Paine states that a keystone species is "one whose impacts on its community or ecosystem are large and greater than would be expected from its relative abundance or total biomass". When a keystone species population is removed then a drastic change in the community will be noteable. Paine mentions sea otters and starfish as examples of keystone species. Yes, it is true that humans are a keystone species. If humans were removed from the earth for some reason there would be some very drastic changes in the earth. However, to say that humans are the greatest keystone species is not a statement that should be proudly accepted. If humans are "the keystone" species they are because the have so much influence (much negative) on the ecosystem. Humans over populate the world, create so much trash, waste everything, destroy the ozone, barely attempt to conserve anything and etc. If humans are the keystone species we have a responsiblilty and that is to pay much more attention to conservation and the way we live. It is accurate to say that humans are the keystone species. However, that comes with great responsibility.

Joseph S.

Strictly according to Dr. Paine’s definition of a keystone species, humanity should be considered a keystone species because if we are removed, dramatic changes will result. The difficulty in understanding humanity’s keystone status is that we are always taking advantage of our surroundings in positive and/or negative ways. Since Dr. Paine’s experiment concluded that the removal of the starfish ultimately had a negative impact on the intertidal zone ecosystem, it would lead us to think that, as a keystone species, removing humans from the ecosystem would be a detriment to the planet. The Gaia Hypothesis argues that the Earth’s ecosystem is self-sustainable without us. Some believe that we are the biggest problem for our planet and eliminating our species would be a great benefit to the Earth. A more positive outlook on humanity is that by accepting that we are a keystone species, we can work to ensure the survival of other keystone species and, ultimately, maintain our planet’s biodiversity. A second interpretation of humanity as a keystone species is that our actions have an environmental effect disproportionate to our biomass. We can perform global-scale environmental alterations that can either positively or negatively affect biodiversity. If we wish to undertake the role of a keystone species, we should do so with the understanding that we will be preservers, not opportunists.

Taylor Massey

Dr. Paine describes a keystone species as one who has a greater impact on their ecosystem than would be expected from a species of that size. These species are generally noticed when they are taken out of an ecosystem. This causes drastic changes within the ecosystem. Based on these definitions I believe that humans are the greatest keystone species on Earth. When separated into individuals, humans are only a very small portion of the ecosystem that we are a part of, yet one individual can have a huge impact on that ecosystem. Each person produces several tons of trash each year and destroys countless plants and animals. If we were to remove humans from the ecosystem, drastic changes would be observed. Many of the animals and plants that we eat would flourish. Many of the domesticated animals would become extinct while others would adapt back towards their more wild relatives. The impact would not just be on plants and animals however. The amount of pollutants that we put in the air and water would also be greatly reduced. In addition to the positive aspects of removing humans from the ecosystem, there would be many negative effects as well. A new species would take over the top of the food chain and many species that have become dependent on humans would die out. Over population would almost certainly occur in many animal populations as well.

Brock S.

Yes, by Dr. Paine’s definition of a keystone specie humans should be considered within that group. Humans develop lands all around animal habitats. Humans also hunt and fish for harvest not to mention killing them with their vehicles. This would definitely reduce populations. So, I would say that humans have a critical role in the environment/ecosystems.

If you look at other definitions of a keystone species it can be viewed by predators, the view seems to be that if you’re a predator you must have a large impact on other organisms thus controlling the communities.

Brian H.

I think that the abilities of humans, both destructive and creative, prove that we are indeed a keystone species. Humans have always changed the environment to suit themselves in ways that make life easier, more productive, profitable, and sometimes just more fun. As Dr. Paines experiment illustrated, humans can recognize a "problem" and "do" something about it, in this case, removing starfish from a tidal pool where mussels live and watching for any changes.

A consequence of our exploding population and need for resources, we have to mine, farm, manufacture, and build. These processes are rarely beneficial to other species and we must work diligently to minimize the impact we have on them and also to improve what we have left for them whenever possible. We sure are a meddlesome species.

Daniel K

A Keystone Species is a species that has a disproportionate effect on its environment relative to its abundance. This species have a great impact on other species in an ecosystem determining their types and amounts. We humans are one of this “Keystone Species.” We are the ones that most impact the ecosystem as a whole. It is explained on the article that removing the starfish from its environment had a great impact on the mussel’s population growth. This is an example of when a species is removed from its own environment. But what happens when we add a new species to an existing environment?
Humans basically “destroy” (with roads, buildings, etc.) whatever ecosystem we encounter on our way. We are just focused on ourselves and in maximizing profits. Also we are not aware of the effects we cause on other ecosystems, like wastewater running into rivers or lakes. In conclusion, we are kind of the biggest keystone species, because we can change any ecosystem in a negative way (very few times in a positive way).

Dillon S

Based on the various sources dealing with keystone species I believe that humans are not a keystone species. I think that humans are different than other types of animals. We have advanced and learned new technologies over time. A lot of these advancements is not in the best interest of the environment as a whole. Things such as buildings, paper, furniture, etc. require a lot of wood to make. To produce all these various items humans destroy many forest including rain forests which include a huge variety of life. Without thinking of consequences we have run many animals out of their natural habitat and in turn caused many extinctions on this planet. Humans alone have destroyed much of the Ozone layer with technologies such as the vehicles, and coal burning power plants. Not to mention that the planet has been around millions of years without humans and the natural circle of life has been in check. In my opinion, as the world works presently, humans are the opposite of keystone species and we need to change the way we live or we will keep losing different types of species that might make us regret are disregard for the environment.

Christine J.

A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass. Given this definition, as predators and modifiers of the ecosystem, humans can be considered a keystone species. The extinction of the human species would have a significant impact on the environment, although this impact would most likely be more positive than negative over time. Humans have such a destructive impact when compared to our total mass on this earth. If humans ceased to exist, deforestation would decrease, pollution in fresh waterways would begin to clear up and the population size of endangered species may increase. The extinction of us would also most likely result in the extinction of many pathogens that rely on humans as a host, furthering the point that humans are a keystone species.

Bhavin. T

As much as I like to acknowledge our existence on this planet as being parasitic of sort, I believe that we are not a keystone species. Namely, our biomass is extremely small to even compete as a contender for the award for a keystone species. Plants and other organisms of great value are looked down upon for their role in the environment. Without these organisms, we would not have food to eat, textiles, fuel, and the list goes on and on. So would that make a specific sort of plant a keystone species? Also, we tend to the forget the microbial world when we taken into account the influence of life in the ecosystem. Without, certain types of bacteria (cyanobacteria and alpha-proteobacteria) we would not mitochondria and plants and algae would not have chloroplasts. So does that make bacteria a keystone species? Going back to the original question, I feel that humans are not keystone species. Granted that we have a upper hand in the ecosystem. However we do not control life. For me, that defines a keystone species.

K. Usry

Whether humans are the "greatest" keystone species, to me, depends on how we think of our role in the universe.

On the one hand, if we include ourselves in the natural environment and consider our influence a part of it, then in many respects human beings are a keystone species. Thanks to technology (i.e. automobiles) and infrastructure (i.e. cities and urban sprawl) our impact on ecosystems is enormous and much greater than would be expected from our "relative abundance or total biomass." Paine's theory makes no claim about keystone species having a net positive influence on the environment, and if human beings completely disappeared from the earth there would certainly be "dramatic changes to the rest of the community."

On the other hand, if we consider ourselves removed from the natural environment I think it is harder to make the claim that we are a keystone species. If human beings completely disappeared, there would be dramatic changes but the earth would eventually return to the state it was before we ever existed. In fact, Alan Weisman has written a book on the subject (The World Without Us) which outlines what would happen if human beings suddenly disappeared. Eventually all traces of human beings and society would disintegrate over time. I'm not an expert, but from what I can tell, the balance of most ecosystems doesn't depend on our existence. In this respect, we are not the greatest keystone species.

Steven Elliott -- Human's as a Keystone Species?

At the beginning of their existence, humans were just another species. As they evolved, they began to dominate other animals with tools and brainpower. Now, the world bends to the whims of mankind. This indicates that if humans are removed dramatic changes result in the varieties and population densities of all the other species in the community, which by definition makes humans a keystone species. Humans have forced their way into becoming one of the most important group of organisms in the world. Before man dominated the world, humans would not be classified as a keystone species but through time have forced their way to becoming one. Thousands of years ago, predator animals and Native Americans regulated the population of deer in the south. Now, without hunters, deer would become overpopulated, causing a disease and a reduction in the population, and then the cycle would repeat itself. This is a direct result of the over-hunting of predator animals such as wolves. Another example would be any invasive species. Without active human participation, the species would not be wreaking havoc on its new environment; however, without humans to combat this new threat, the species would take over. Therefore, if humans became extinct, there would be globally catastrophic consequences as the balance of many species rests in their hands, proving that they are, in fact, a keystone species. Early humans, however, were not as important to the state of other species and had little impact on the environment and other species and therefore were not a keystone species.

Steven Elliott

Tyler C

It is obvious that humans are a keystone species, but being the greatest keystone species seems to be up to debate. In my personal opinion, we are the greatest keystone species because we have more conscious control over every ecosystem than any other species. If it is our desire, we could completely eliminate any and all rainforests in the world with teams of logging crews, not to mention weapons of mass destruction. Also, if it were our desire, we can choose to save and protect many species from going extinct throughout the world, through the use of such programs as zoos. Several different populations of different animals have been saved from extinction from activities such as overhunting by growing populations of the animal in captive environments and releasing them into their natural habitat. I believe the best reason that humans are the most influential keystone species is that we are so aware of our surroundings and the impact we have on them. We are trying to reduce global climate change by reducing harmful emissions from our factories and transportation systems. Without consciously changing our ways, we would continue to damage the global ecosystem, potentially making it unlivable for much of the life on Earth.

Tyler A.

I agree wholeheartedly that Humans are the greatest keystone species. Our impact on the global ecosystem is as far reaching as it is varied. Our rampant use of pesticides, herbicides, anti-virals, and antibiotics has profoundly effected insect, plant, and microbial biomass around the world; leading to stronger, more robust insects and microbes. By building, harvesting, and traveling we have altered ecosystems all around the planet; flooding areas with dams, clear-cutting forests and plowing under prairie land, and transporting exotic species. While all species impact the world ecosystem in varying degrees, humans claim an impact far exceeding our relative bio mass. No other species alters their habitat on the same scale as humans. If we were removed from this world as Dr. Paine removed the starfish, the ecosystem would be vastly different; all of the species we suppress with poisons would return to significant numbers. Flora and fauna would quickly reclaim our former habitats. Simply put, our impact on the globe is undeniable; compare the image of a world without humans to a world without deer, without the dogwood tree, without geese. The fact is clear; humans are the greatest keystone species.

Evan B

To be considered a “keystone species” a species must be significantly crucial to the equilibrium of an ecosystem. As a result, these species have a dramatic effect on other species when they are “taken out of the equation.” It is hard to define how crucial a species must be in order to be considered a “keystone species” and as the article from University of Washington suggest, the boundaries of what constitutes such a species is growing wider and wider. Despite this, I believe that humans deserve to be designated the most pivotal or “greatest” of all keystone species because we seem to be capable of having the most direct effect and the most potent effect on the greatest number of species. Furthermore, we have an awareness of our magnitude and have the ability to limit or control the ways in which we effect the ecosystem. If humans were to be removed from the ecosystem the overall change in the ecosystem would be profound, even if our absence proved more favorable for many species.

Mills R.

I have to disagree with Dr. Paine about humans being a keystone species. Yes humans do alter habitat and species richness, which can then affect other species abundances, but I feel that humans should not be called the greatest keystone species of all. As with beavers, humans make a suitable habitat for several other species where they decide to make their home and in the process eliminating habitat for others. Several key differences about beavers and humans make me want to say humans are something beyond a keystone species. Beavers only inhabit 2 continents in the world where as humans live on six with visitation to the 7th. Beavers only alter habitat not an entire ecosystem or global weathers. Beavers have never caused the extinction of another species and have never had another species dependent on them to keep the species from going extinct. I feel that humans because of their massive amount of influence on all species of the world have become a super species.

Derek P.

There seem to be many opinions on the definition of keystone species and what entails a species falling under this classification. They seem to all agree that a species' overall influence on an ecosystem is one of the characteristics that makes a species keystone or not. I believe that humans are keystone, the effect we have on the environment and the consequences of our vacancy would be profound. We have domesticated hundreds of animals that would perish with out us, while at the same time other species would move up the food chain and propagate their numbers. However I think it is a egocentric for us to label ourselves the "greatest keystone species" of all. While it is true our impact to the world is far reaching there are other species that may be just as important or more important to the world's ecosystem as we are. For example it is estimated that 80% of the world's oxygen is produced by single celled marine algae, without it we would not exist, nor would many other oxygen requiring species. If algae disappeared, so would most of the known ecosystem. So while human's footprint is large and getting larger, I would have to disagree that we are the greatest keystone species, at least for now.

Proof that humans are keystone species?

Bradley M-Keystone species

According to wikipedia A keystone species is a species that has a disproportionate effect on its environment relative to its biomass. Such species affect many other organisms in an ecosystem and help to determine the types and numbers of various others species in a community. With that being said I do not believe that humans are a Keystone species. If humans were wiped off the earth I believe that plants and animals would keep the environment at equilibrium. Animals and plants have evolved throughout the years to become accustomed to the changing environment and I beleive if humans were not here they would continue to evolve to living without us. I do agree that humans do have an effect on the environment we have also had a negative effect on the environment and we would actually be doing the environment a favor if we were no there. The ecosystem would go back to functioning like it did thousands of years ago without our existence.

Duncan B.

Based on the descriptions of a keystone species concept,a keystone species being one whose impacts on its community or ecosystem are large and greater than would be expected from its relative abundance or total biomass noticed when they are removed or they disappear from an ecosystem, resulting in dramatic changes to the rest of the community, I would have to agree that Humans are the greatest keystone species of all. The impacts that we humans have on our community and surrounding ecosystem is larger and more apparent then any other species. I do not see humans drastically being removed from the earth, but if it were to happen there would be dramatic changes to the community and ecosystem. The affects we have on our ecosystem includes all aspects of the ecosystem. Our removal would definitely affect the abundance of other species that are suppressed by our existence. Humans control and alteration of ecosystems is so great that if they were removed the natural ecosystem would be able to take back over. I would have to agree with Dr. Paine's statement the humans are the greatest keystone species.

Thomas T.

The definition of a keystone species, as is stated by Wikipedia, is a species that affects its environment in a disproportionally large manner relative to its biomass. In nature, keystone species tend to have a stabilizing and/or diversifying effect on their environment, though this is not the cause when considering humans. Humans have a relatively low biomass in comparison to primary producers and other organisms found lower on the food chain. In spite of this lower biomass, humans span the earth and affect nearly every place they (we) go, changing the environment with centers of civilization and by harvesting resources. By spanning the globe, humans transcend individual ecosystems and affect the earth's biosphere as a whole. Humans meet both of the requirements to be a keystone species: they have an effect on their environment and their biomass is relatively low for the degree of that effect. It could be argued that humans are, in fact, the greatest keystone species, meaning that they have the greatest effect per unit biomass.

Natalie P

In order to classify whether or not a species is keystone or not, often times one looks into the ratio of biomass to environmental impact. In other words, if a species has a relatively large amount of biomass present on earth and its effect on surrounding environments is also large, it can be seen that this is what can be logically expected. A large amount of biomass would be expected to require a large amount of input, and thus generate a large amount of output (any outward effect on the environment). However, an interesting situation is when there is a relatively small amount of biomass that generates a significant effect on its surrounding environment. This would define a keystone species. Humans are indeed keystone species because our relatively low amount of biomass has been responsible for colossal effects globally. For instance, we learned in class that the total mass of insects on the earth far exceeds that of human species, but the total population of insects could not have solely been responsible for what humans have accomplished. Humans appeared on earth relatively not that long ago, with respect to the age of our planet. However, our presence has been attributed to huge changes in our planet's chemical composition. We might be the best example of a keystone species there is.

Amanda Unger- Humans A Keystone Species

If humans were removed over an interval of time, they would prove to be a keystone species, comparable to starfish in a tidal zone. Humans are the starfish, controlling all aspects of the ecosystem. Dramatic results would show in the man-made landscape that has been created over the years of human inhabitants. The removal of humans would impact the ecosystem positively. Plants, trees, animals, and water could all move as they did before humans; they could take over. Wildlife would flourish, the air would be cleaner and all man made traces would dissolve away over time. For thousands of years earth turned without humans making any sort of "footprint". Humans, earth's keystone species, evolved over time making dramatic changes to the earth as a whole. If humans were taken away, out of earth's picture, change would occur. The earth could bounce back to what it once was, or it could completely change, sparking a new keystone species to arise. Humans play a large role in the earth ecosystem, intruding, evolving, and creating new(sometimes good and sometimes bad) diversity.

Jeremy B

Humans are certainly the most important keystone species of all. As Paine defines the keystone species as a certain species that "has a critical effect on the entire ecosystem." This is undoubtedly true because we humans impact the ecosystem far greater then any other species in the entire world. We are able to control the environment around us and change it as we see fit. Without us, the world would be a simple ball of water and land, without any interference to harm or help it. In addition, we are the highest being on the food chain and without us countless numbers of different species would be able to thrive, or get destroyed without our presence. The world would be a much quieter, healthy, and primitive place if not for humans.

Vasilios D

Humans can directly relate to the Starfish who run the tides. Without humans everything will change and thus we are most definitely keystone species. Following Paine's definition, the keystone species is one whose impacts on its community are larger and greater than its relative total biomass. Needless to say that since we have the accessibility of technology, we are that much greater than that of the common keystone species. The planet would be nothing but green and blue if it were not for us and all of our equipment. Even though our population is rising at exponential rates, our technologies are double if not tripling(especially in China) what humans can do on their own; and for that sole reason is why humans are indeed keystone species.

Greg D

One component of the keystone species hypothesis essentially says that any species whose impact on the environment is larger than its population would suggest it is a keystone species. In this regard, I feel that there is very little argument as to whether humans qualify as a keyston species or not. Our impact on the environment around us is much furhter reaching than any other organism on the planet. The amount of space and resources we use are very disproportionate to our population. The second component of the keystone species hypothesis focuses more on the degree to the effect of the removal of the species would have on the overall environment. In this regard there is much more room for debate. Initially huamns would not have been a keystone species in this regard because if we were removed from the planet at the earliest outset of human civilization the overall balance of ecosystems would have been small because we were able to adapt to many environments and no certain ecosystems relied on us for balance. Today however, we have disrupted the balance of many ecosystems for our benefit through technology, the elimination of certain species, and the introduction of others into environments in which they have no natural predators. Because of this, many species and ecosystems rely on humans to keep them in balance. If we were removed some populations would rise dramatically, while others would become extinct. Certain ecosystems would eventually fail. Due to this, modern humans must be considered a keystone species.

James M.

       The keystone species hypothesis implies that there is normally an almost balanced proportion of a species' effect on an ecosystem vs. its presence. Any species that produces a larger effect than its relative population is considered a keystone species. In this sense, humans, without question, are a keystone species since the changes we have caused are much greater and more apparent than those of any other single species. But what the keystone species experiment highlighted was mainly the freeing of a niche. When the starfish were removed, a niche was opened in which another organism was able to thrive. If that niche weren't initially filled by the starfish, their removal wouldn't have caused any substantial change. This means that the niche is more important than the species which currently occupies it. Humans' ability to externally adapt to a wide variety of environments makes our species' niche requirement largely irrelevant. Our ability to affect ecosystems stems less from our filling of a niche but more from our actions to change or destroy the niche itself. Unlike the starfish, a sudden absence of humans would not reopen a former niche. From this perspective, humans are not a keystone species but rather a larger force with a far greater ability to effect change in ecosystems than other species.

Matt Avery - Humans as a Keystone Species

According to Paine, a keystone species is one whose impacts on its ecosystem are greater than would be expected from its relative abundance. Based on this definition, I would have to agree with the narrator in that humans are a keystone species, perhaps even the greatest keystone species of all time. In this sense, “greatest” would by no means indicate that humans have had a positive impact on the environment. More so, I would use the term “greatest” to mean that humans have had the largest effect on the environment. During our existence, humans have had a tremendous impact on the natural environment – we have driven several species to extinction, destroyed much of the tropical rainforests, and have done serious damage to our atmosphere and environmental climate. We have been one of the greatest keystone species of all time. Recently, however, it seems like humans are attempting to become less of a keystone species – That is, we are trying to reduce our impact on the environment, and correct several of the “environmental wrongs” we have committed. It will be interesting to see how we can lessen our identity as one of the greatest harmful keystone species in the history of the Earth over the next century.

Amber A - Keystone Species

According to Wikipedia, "A keystone species is a species that has a disproportionate effect on its environment relative to its abundance. Such species affect many other organisms in an ecosystem and help to determine the types and numbers of various other species in a community." In relevance to this definition, I believe that humans are a keystone species. If humans were to go extinct, it would affect other organisms in the ecosystem. Humans are the top predator on the food chain, This means that the animals that humans would eat would become more abundant. There are already vast numbers of animals that humans raise for food, but it humans became extinct, these animals would not be eaten and they would continue to multiply. Humans also regulate some ecosystems by cutting down forests, destroying natural wetlands, and tapering with water resources for various reasons. If humans were to go extinct, they would no longer be able to maintain the re-growth of forests and certain habitats. These habitats would grow back to as they were before humans interfered with them and the animals that live in these habitats would also grow in population. Humans are a keystone species because they affect the ecosystem in many ways. If humans were to go extinct, these ecosystems would change and the population of animals in these ecosystems would grow.

Amy Doster

I think this question depends heavily on what definition of keystone species you use, and how you use it. One definition I found uses it as such: “a species that has a disproportionate effect on its environment relative to its biomass”. In this case, it seems like humans would be an obvious keystone species, as we affect things in a much broader scale than maybe should be possible for a species of our biomass. Humans have far-reaching effects, in nearly every area of the earth, and now even on other planets and our moon. Since this definition doesn’t imply a positive or negative connotation on the term “keystone”, it is then permissible to assume that humans are. However, when other definitions are used, many of which imply a positive impact of the species in question, most people then agree that humans are not. With a definition such as “plays a role analogous to the role of a keystone in an arch; the arch still collapses without it”, it seems like humans would then not be keystone. Humans have far-reaching effects, but many of them impact the other species and the environment in very negative ways. Overall, I think it is more correct to generalize that humans are not keystone, in that although we may affect the world around us in many ways, it tends to be in negative ways, and this is not the connotation often associated with the term “keystone species”.

Definitions from Wikipedia - Keystone Species article

Rickey Dowdy- Keystone Species

Keystone Species are species whose extinction would affect the ecological community in a negative way. Humans are not keystone species because if all humans die we will not really affect the world as much as we will be affected if certain other species die. We depend on other species more than they depend on us. Instead of species being extinct and not being able to survive, their populations would get bigger because of them not being hunted and their habitats not being destroyed. In our society today humans' existence harms species because of our lack of caring. By this i mean us humans being careless about where we throw our trash or how we neglect to take care of our environment. For example, when we cut down woods to build new shopping centers and housing developments we're sending these species off to live in places that their not accustomed to. Also we drive these big heavy machinery trucks with these huge mufflers that pollute deadly toxins. Therefore humans' absence would have a positive effect on species because their lives would be better and more productive.

ARE HUMANS A KEYSTONE SPECIES????

Sylvester Crawford

2/14/10
IDS
Are humans a keystone species?
According to Paine a keystone species is a species that plays a large role
in the community and ecosystem if removed from the planet the effect would
be big; if humans were to be removed from earth I feel the conditions in
the enviorment would improve. With humans roaming the earth the enviorment
suffers because of pollution and the killing of animal habitats. Everyday
many rainforest are cut down leaving animals to abandon their habitats
therefore they have nowhere to live and many animals lose there lives in
the process. Without the humans on the earth animals would live a better
lifestyle. Without humans on the earth there would never had been a issue
involving the ozone layer beacause pollution would not be a issue.
Therefore this makes humans a keystone species because with humans on the
earth it hurts the enviornment rather than helping the enviornment. The
effect of the humans being eliminated from the earth would play a big role
in the ecosystem.

Jarvis Byrd- Keystone Species

Are humans a keystone species? No. Humans are not important keystone species on the earth because before humans even exist animals were living well on their own. When the humans came on the earth more animals began to die because of the living styles of humans they have to survive off killing animals and eating them. Animals are big parts of natural environment, also domesticated animals depends on humans because without humans no one is going to feed the aminals. Humans litter in the oceans and lakes that's cause the animals to get infection with bacteria. Bacteria infection causes the animals to get sick and die out so therefore not having humans might just be better for keeping animals alive. The animals and the rainforest are dying out everyday from humans cutting down trees and taking away tfrom their living habitats, causing them to be unable to get away from their predators. Therefore, humans are not a keystone species and the natural environment might just be better without humans.

Priya G- Humans are not Keystone Species

According to the video in class and the links provided, keystone species are pivotal in the balance of an ecosystem. A keystone is a species whose very presence contributes to a diversity of life and whose extinction would consequently lead to the extinction of other forms of life. Using this information I have come to the conclusion that humans are not a keystone species. Before humans populated planet Earth, life on Earth functioned and carried on for millions of years. It is when human population increased that problems arose on this planet. Now we have issues such as the global warming, an increase in the number of species that are considered extinct , an increase in diseases caused by human ignorance that are killing our own kind and more problems solely caused by people. I believe that if the human population understood better how this planet operates and learn what actions better our environment; we could all live longer and healthier lives without ruining the lives of natural species. Humans have put themselves at the top of the food chain while wiping out those that fall below them. Frank Lloyd Wright once said, Study nature, love nature, stay close to nature. It will never fail you”. The human population is currently serving as a major disservice to nature and I think it is in our best interest to treat this planet with the respect and understanding it deserves; this way we can hang around a little longer.