Living EnvironmentStudent Work ECI Lesson # 3

Lesson 3. Introduction to Human ImpactName: Period ______ Date :Bridge

Define the following terms in your own words:

1. Biotic

2. Consumer

3. Autotroph

Objective:Describe human activities that have had a great deal of impact on ecosystem stabilityChoose the topic that you feel the most strongly affects stability

Essential Question:What is the topic that I will be debating? Why did I choose this topic?

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Mini LessonEver since humans started to develop even the simplest technology, they have begun working against natural selection and causing changes to the natural order of things. The more advanced our technology becomes, the more damage we manage to do to our fragile ecosystems.

Today you will decide on the topic that you will be debating for. The first thing you will do is participate in an activity to familiarize yourself with the different human impacts that have caused the most damage throughout history. Once you have completed the stations, you will then decide which one you feel has had the most dramatic impact on our ecosystems.

Work Period

There are 8 topics for them to choose from in the Human Impact debate will be run like finals competitions through seeding and elimination. The 2 final debate teams will be debating for a prize.

Select the topic you feel has had the most impact. This will become your group for the debates. Your belief needs to make this choice not your friends.

SummaryWhat is the topic that I will be debating? Why did I choose this topic?

ClosingWhat materials do you think you are going to need to help you participate in this debate?

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Industrialization is the result of societies moving from a primarily agricultural society to a society based in manufacturing. This rise in a manufacturing came on the heels of technological advances and scientific discoveries as people learned how to harness and direct electricity, use water as power sources in the form of steam engines, and found a way to refine crude oil into gasoline and natural gases for power sources. The creation of machines that could do the work in half the time it would take a person increased efficiency and output, leading to a demand to increase the workforce so families started moving closer to city centers and having more children to fill the demand. With more people there became a higher demand on natural resources which meant that we needed to manufacture more things and the cycle still continues today.

Industrialization is usually depicted through large factories with their thick black smoke pouring out of them, but it started much earlier than this. Each step towards utilizing machines to do work increased the demands on our natural resources. But these demands are coming at a high price: burning of fossil fuels has increased the greenhouse gases in the atmosphere and that leads us to global warming. Increased production of waste products has increased the amount of pollution on land, in water, and in the air, that is released into the environment, and we cannot process the wastes as quickly as they buildup. The amount of land that is being used to house factories and plants are taking away homes from organisms that used to live in the area. The concept of acid rain became a reality. Species moved from thriving to a state of endangered or even extinction. Heavy metals and nuclear wastes were dumped into water sources or buried beneath the land. Urbanization began and

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rose into an environmental impact all of its own and this has led to the major overpopulation of humans on Earth…. We are well over our carrying capacity and Earth is what is suffering for it, and we will be as well. But the technology did not come without the demand.

Industrial waste is one of the leading causes of environmental damage that we see around us. It’s not just the litter on the streets but the toxic chemicals and heavy metals that have been buried and sunk into lakes and streams. This gets into the soils and the bedrock and causes problems not necessarily immediately but in the future as we are starting to see now. Some of our waterways have become so polluted that we can’t even eat the fish in them without tracking exactly how much we have eaten so that we are not at risk of heavy metal poisoning or carcinogenic exposure. Biomagnification, the process of building up toxic materials in the food chain based on location (the higher up the food chain the more toxins you will have), is something very real and something that has caught environmentalists’ attention and therefore the warnings on eating foods in certain locations.

We can see the effects of industrialization today as people scramble to develop new technologies that use renewable energy sources and produce less greenhouse gases. So the increase in demand that lead to industrialization is now what people are relying on to decrease the damage that we have done and are doing to our planet. It is happening but at a very slow place.

Is it too late to reverse the damage we have done?

Is society able to live without all of the technology that has made their lives so easy?

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An invasive species is just what it sounds like: an organism that is introduced into an environment that does not naturally belong there and it invades the area. Invasive species are organisms that may have been brought on purpose to an area or may have accidently caught a ride to a new area on someone’s clothing, luggage, ship, or some other means that would allow something to travel thousands of miles to a new area.

Since an invasive species does not belong in an area, there are no natural predators to keep the numbers of the organisms in check. However, these invasive species still need places to live and other resources such as water, food, and mates so that they can survive as well. A once stable and healthy ecosystem can collapse in a manner of years, it can force the extinction of endemic species, and can even devastate people living in the area.

There are hundreds of examples of invasive species throughout the world. Cane

toads were brought into Australia by people only 70 years ago to help control the cane beetle

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population and now they are considered pests and number in the millions, threatening the species native to Australia. Zebra mussels were accidently introduced into the Great Lakes by sticking to the bottoms of boats and stowing away in ballasts and on anchors and have now caused the extinction of hundreds of indigenous species and have placed some on the endangered species list. Brown gobies were brought into the Great Lakes to take care of the zebra mussel problem and they are now an invasive species as well. Purple loosestrife, brown snakes, Asian carp, Burmese pythons, snakehead fish, red eared sliders, the number of these species are in the thousands and that is in the US alone. Think of the devastation being caused in other countries as well!

The increase in competition that any invasive species brings to an area can have

impact on humans as well. We use many organisms, especially plants, as a source of medications and other resources to support us and these organisms are being threatened. Increases in populations lead to increase in waste products, pollutants, and heat being released into an area which in turn ends up hurting our crops, livestock, water, and air supplies. Many times these invasive species are not familiar with people, so they have not learned to run away from them and they will invade peoples yards, homes, and stores. In many cases, like the cane toads, these invasive species are poisonous: poisonous enough to kill people if they come in contact with the toxins.

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As we have learned through the course of our year, the evolution of photosynthetic organisms paved the way for heterotrophic organisms to evolve. Without photosynthesis, there would be no oxygen in the air and without oxygen, there is no cellular respiration which means no energy for life. As photosynthetic organisms evolved from single celled cyanobacteria to the incredible diversity of plant life on Earth today, more heterotrophic organisms were able to evolve on their heels. However, photosynthetic organisms have grown to need heterotrophs just as much. Life started as single celled photosynthetic organisms, then came heterotrophic unicellular organisms, then we started seeing the multicellular photosynthetic since there was more CO2 and nutrients for them to evolve and grow then comes multicellular heterotrophic organisms and the cycle continues. This is interdependence. One does not exist without the other: even a fish tank that has live plants in it can be sealed from the external environment and will stay clean longer and keep the balance of CO2 and O2 steady for a stable, healthy mini-ecosystem than a fish tank with fake plants that is open to the outside atmosphere.

Direct harvesting is the removal of whole populations of organisms from a given environment. It does not matter if the organism is plant, animal, fungus, or whatever, if there is a lot of them and people remove them, it is direct harvesting. With the concept of interdependence you can see if you were to get rid of one organism, it will have a dramatic effect on those around it. Some forms of direct harvesting has been done so often that they have their own names: deforestation, overfishing, and hunting/poaching.

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Deforestation is the process of removing all of the mature trees in a given area. Where this process may have started in temperate forests, that resource is just about used up and

people had to delve into the tropical rainforests to continue their destruction and follow that need for money. Since producers are at the base of the food chain, destruction of these valuable producers has rocked the organisms that rely on the trees in a bad way. The

impact, however, is not limited to the food webs in the area or just the flow of energy: it is much more far reaching than that.

The large root systems that are in place stop soil and much needed nutrients from

eroding away. This erosion will start to fill in water ways and start a process of secondary succession that will decrease the available fresh water to organisms on Earth as well as move nutrients and minerals from the area. Trees come down in the forest all the time from disease, damage from natural disasters, or from old age: but these dead trees stay in the forest and their nutrients are recycled back into the environment. But we take the trees out once we kill them and it further weakens the area. We can see this very clearly in Africa where once dense forests were cut down, increasing the grasslands and savannah ecosystems at the time, but now those grasslands are becoming deserts as the process of desertification takes over. These tree roots also serve as homes for many of the nitrogen fixing bacteria that act as decomposers. Without these decomposers, nutrients are not recycled properly into an ecosystem and more organisms start dying out. And without useable nitrogen, how will we make the proteins that we need so desperately?

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Deforestation is often referred to as the ultimate act of habitat destruction. Trees also act as homes to organisms other than the nitrogen fixing bacteria. Millions of organisms across all 6 kingdoms rely on these trees for shelter and these trees are at the center of their niche. They represent shelter, food, water, and all the other things that these organisms need for survival. By destroying these forests we push these organisms closer to extinction by forcing them to move into areas they are not adapted for, increasing their chances of their genes being eliminated from the world’s gene pool. Some of these organisms serve as the only source of medications we use for treating disease or are valuable to agriculture and research practices throughout the world. And these huge, dense, rainforests are one of the two locations on Earth that we are still discovering new species in, the other being the deep depths of the ocean where we cannot yet get. One of these new species may be the answer to curing cancer or AIDS or providing a clean, renewable energy source that will help in our battle to fix mother Earth. This decrease in biodiversity leads to a decrease in our ecosystem’s health, and where we might see the lack of products that come from trees like building materials for houses and businesses, paper products, and other things as a more immediate threat to our existence, those things can be replaced with other products while we cannot replace the biodiversity, homes, and oxygen source that they offer. And with carbon dioxide being the most threatening of the greenhouse gases, when we get rid of these giant organisms, what is left to deal with getting that CO2 out of the atmosphere?

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Over three quarters of our planet are covered by the oceans. Their biodiversity is unmatched and they contain over 80 percent of all life on earth, mostly unexplored. Millions of people

worldwide are depending on the oceans for their daily livelihoods, nutritionally and economically. More and more all this is endangered because of ignorance and a global lack

of management.

Ocean overfishing is simply the taking of wildlife from the sea at rates too high for fished species to replace themselves. The earliest overfishing occurred in the early 1800s when humans, seeking blubber for lamp oil, decimated the whale population. Some fish that we eat, including Atlantic cod and herring and California's sardines, were also harvested to the brink of extinction by the mid-1900s. Highly disruptive to the food chain, these isolated, regional depletions became global and catastrophic by the late 20th century.

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When It Started

Marine scientists know when widespread overfishing of the seas began. And they have a pretty good idea when, if left unaddressed, it will end.

In the mid-20th century, international efforts to increase the availability and affordability of protein-rich foods led to concerted government efforts to increase fishing capacity. Favorable policies, loans, and subsidies spawned a rapid rise of big industrial fishing operations, which quickly supplanted local boatmen as the world's source of seafood.

These large, profit-seeking commercial fleets were extremely aggressive, scouring the world's oceans and developing ever more sophisticated methods and technologies for finding, extracting, and processing their target species. Consumers soon grew accustomed to having access to a wide selection of fish species at affordable prices.

But by 1989, when about 90 million tons (metric tons) of catch were taken from the ocean, the industry had hit its high-water mark, and yields have declined or stagnated ever since. Fisheries for the most sought-after species, like orange roughy, Chilean sea bass, and bluefin tuna have collapsed. In 2003, a scientific report estimated that industrial fishing had reduced the number of large ocean fish to just 10 percent of their pre-industrial population.

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When It Will End

Faced with the collapse of large-fish populations, commercial fleets are going deeper in the ocean and father down the food chain for viable catches. This so-called "fishing down" is triggering a chain reaction that is upsetting the ancient and delicate balance of the sea's biologic system.

A study of catch data published in 2006 in the journal Science grimly predicted that if fishing rates continue apace, all the world's fisheries will have collapsed by the year 2048.

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What's Next?

Over the past 55 years, as fisheries have returned lower and lower yields, humans have begun to understand that the oceans we'd assumed were unendingly vast and rich are in fact highly vulnerable and sensitive. Add overfishing to pollution, climate change, habitat destruction, and acidification, and a picture of a system in crisis emerges.

Many scientists say most fish populations could be restored with aggressive fisheries management, better enforcement of laws governing catches, and increased use of aquaculture. And in many regions, there is reason for hope. But illegal fishing and unsustainable harvesting still plagues the industry. And a public grown accustomed to abundant seafood and largely apathetic about the plight of the oceans complicates efforts to repair the damage we've done.

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There has also been a large impact to the coral reefs which can boast biodiversity equal to or above that of tropical rainforests; at least they used to be able to. When such large

populations of fish are taken from their environment, everything is altered. Without the fish there, they cannot breed as quickly or as successfully. This causes an increase in

competition between the predator species. Sometimes that means the predator species die out or they will need to find new sources of food and now there is competition between

organisms that never competed before: they evolved to decrease competition by eating different things and that is being taken away from them. The once thriving coral reefs are

becoming depleted and can no longer sustain the life that used to be there, in part to increased pollutants but in part to the disruption in the energy pyramid.

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There is one main difference between hunting and poaching: hunting is legal, poaching is not. But both of these past times has had a significant impact on our ecosystems’ stability.

The term poaching is reserved for hunters that kill endangered animals. They are not

hunting for food, but for their furs or other body parts that are worth a lot of money. Elephant and rhino horns are made of ivory which is worth quite a bit of money. Collectors would be interested in purchasing pelts from many of the larger, endangered cats like tigers and mountain lions. Some poachers just like the thrill of the hunt on these large, dangerous animals and will kill them to mount their heads on their walls. No matter which way you look at it, these are dangerous and damaging activities.

Hunting has much the same ecological impact, but can have both positive and

negative consequences. Many hunters are content with following the Department of Environmental Conservation, going out only during certain times of the year with certain weapons and tagging their catches, reporting them to the DEC. These are the people that

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will take and have the meat processed (or they process it themselves), use it for food, and then compost the remains that they do not use so the nutrients are returned to the environment. In some cases, hunting is encouraged in cases of animals that are overpopulating certain residential areas (just think about the number of white tailed deer in Durand Eastman Park where the Sheriff’s department has to go out and kill so many each year to avoid people’s houses being overrun). When people moved into these once forested areas, predator species were displaced and forced to move to new locations, leaving no natural predators in the area and this leads to overpopulation.

Hunting may mean well, but in some cases, society has taken it too far. On Grande

Isle, an island in Lake Michigan between Canada and the US, people became very concerned about the moose and elk populations dropping too low because they felt there were too many predators. The government sanctioned that hunters were to go out and kill all of the top level predators in the area which included wolves, coyotes, foxes, and bear. Once the ecosystem was devoid of the predators, the prey species increased drastically in number and the researchers in charge of the project noticed that the island became near barren of plant life and they were witnessing several carcasses of the prey species and a decline in number. It became apparent that even though they were concerned with the predators and did not want to see the prey species being eaten, that the predators had an important role in maintaining stability. Eventually, they reintroduced the predator species back into the failing ecosystem and it is just now, over 20 years later, starting to recover. And Grand Isle is not the only place that people have done this.

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There are several guidelines in place now to regulate hunting. They have created hunting seasons, weapons guidelines, limits to how much and what you can hunt, and impose very heavy fines and sometimes jail time to those that do not follow those guidelines. When it comes to poachers, the consequences are even more harsh, usually involving fines in the hundreds of thousands of dollars and often jail time as well. Unfortunately, wherever there is profit to be made, people will still keep doing it, whether its poaching, overfishing, or cutting down forests, regardless of the impact it has on our planet.

If you take a look at an energy pyramid, it represents the amount of energy available at each level of the pyramid. The largest biomass is at the bottom and represents the producer organisms. This large bottom layer is supporting all of the organisms above it. Just like the base level, or foundation, of a building any damage that is done to the base, the rest of the building is in a threat to collapse. If you remove the next layer up that is mostly herbivores, the collapse will happen in the levels above it and leave the bottommost layer to go unchecked. This will repeat through the levels of the pyramid. Since the top level really should represent the decomposers, if we lose those, the minerals and materials needed for that bottom level to flourish, and even without something eating them, they will still die out because of the increase in competition and lack of those materials the decomposers make useable for them.

Each of the three methods of direct harvesting poses an immediate threat on our ecosystems for this very reason. No one level stands without the other ones and humans are here chipping away at each level every way they turn. At some point, people will need to realize that they stand at the uppermost point in those relationships and they are doing nothing more than chipping away and destroying their own futures.

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People automatically think of farming when we say the word agriculture, but there is a lot more to it than that. Agriculture is anything that has to do with raising organisms to provide people with nutrients. But in this case, we are not dealing with small farms that house a handful of animals and a vegetable garden in the summer. We are talking major, profit making farms that take up hundreds of thousands of acres at a time, slaughter houses, and specific breeding programs. There are different things that these large agricultural industries do that are threatening our environment and our world’s stability, some very obvious and others not so much. Farming has been along for as long as people went from being nomadic tribes to settling down in river valleys. They would plant enough crops to feed their small villages and store what they could to get through the winter if they had a winter. Domesticated animals such as cows and chickens came once the villages became larger and more permanent. Once they were settled in and noticed that some plants grew better and larger crops or some animals made more milk or laid more eggs, selective breeding began. But it wasn’t like it is today: they would breed certain animals and plants together but not using the technology and interference they do today.

As villages grew and grew, agriculture became a great industry for some people while other people choose to perform other tasks. And as cities began to emerge, farmers became that much more important because there were less people farming and more working in factories and manufacturing. Today, anyone still in the agriculture business has all sorts of technology backing them up and that is where some of these issues come up.

Agriculture TodayFirst, farmland takes up millions of acres or useable land all over the world. When

farmers plant their crops, they usually place one crop in a field each year. With any luck, the farmers actually rotate the crops from year to year since each one needs different minerals and nutrients from the soil so rotation keeps from destroying the land. One field should be left empty each year during the rotation so that it has time to regain its fertility. However, by planting just one crop in the field, there is a major decrease in the amount of biodiversity in the area. The less biodiverse an area, the less healthy it is.

In addition to planting the crops, farmers often spray pesticides on the fields to keep insects from destroying their profits. Prior to the 1950’s DDT was the top used pesticide and it wasn’t until years after its banning that people actually saw how much damage DDT can really do. It poisoned the wildlife in the area, acts as a carcinogen for people, gets caught in the runoff from rainwater and is spread throughout the watershed. Some of the DDT got

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caught in sediment in lakes and rivers and with erosion, it is still being released into the environment every day. Where pesticides today may not be as harmful as DDT is, they still threaten to either cause extinction of organisms, still get pushed into the surrounding environments. This can have detrimental effects on the wildlife, threatening their young and many of the reproductive cycles are interrupted. These chemicals get into the food webs in the area through the plant life on and off the farm, and a build up will be seen in the animals in the food chain through biomagnification.

Crops also mean fertilizers. Fertilizers as a general rule are very high in phosphate and nitrogen compounds which we need in small doses but not in the amount that is used on fields. It too gets soaked into the soil and added to the surrounding watershed through ground water and runoff. These fertilizers act on the plant life in waterways just like it does to the corps: you will see a large algal bloom which will start to choke off the heterotrophic organisms in the waterway. Once the heterotrophic organisms die off, a waterway will go through a eutrophication process and succession will most likely begin. And definitely don’t forget the use of farm equipment to get this all done….. that adds its own contribution to global warming and greenhouse gases.

And that was just dealing with the plants! How the agricultural industry is handling the

animals and meat production makes the vegetable farmers look like environmental activists. Did you ever wonder why you can get a cheeseburger so cheap now days? Farmers have been meddling more and more with nature on this front. It used to be just selective breeding practices, much like you saw in the supercow video. Where that was kind of disgusting, they do things far worse than that. Farmers will buy large warehouses that are hundreds of thousands of square feet large to house their meat producers. They will pump the animals full of steroids and growth hormones. Females they will treat with massive amounts of fertility drugs and they will force breeding cycles much more closely together than they should. For example, cows have one to two calves once a year on a normal cycle during their reproductive ages. Scientists have developed ways to force a cow to have 2 birth cycles in a year with no time to heal and repair and prepare her body for the next cycle. These calves will be taken away at birth, given growth hormones and steroids that will cause them to grow to full size which normally takes a few years in one year. The growth is so fast that their bones never properly develop and they are not capable of standing on their own and they are kept in very dark conditions because the meat is more tender if they don’t see sunlight. Once the cow is grown enough to have a decent amount of meat, they will slaughter them and send them out for processing. So where it would normally take 4-6 years for a cow to mature enough and build up enough bulk to be eaten, they can now force it in a year.

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For farmers that are a little more traditional and humane with their animals, there are

other environmental problems that arise as well. An increase in the number of domesticated animals used for meat, dairy, and egg production has also increased these problems drastically. While fields are plowed for plants to grow and be a food source, more land is needed for herds of these animals to be raised. The increase in the animals means an increase in the release of carbon dioxide and methane gas, both greenhouse gases produced from animal wastes, well above the rate at which nature can process them. These farm animals are well over their carrying capacity and nature just can’t keep up with them. And again, we see a loss of biodiversity to these areas since they have been cleared to make way for the one or two species that are being raised in these large numbers.

And the increase in knowledge of genetics and DNA manipulation has brought the

agricultural industry into the new century. Using recombant DNA techniques, they are starting to genetically modify plants to produce their own pesticides and will kill the bugs and animals that are eating them without having to spray. They are genetically modifying the genes to produce other crops that are more pleasing to the consumers who buy them at the store. They have developed techniques where they no longer have to mate pairs of animals or plants to hope for offspring they desire: they look at the genes of the potential mates and can guarantee those offspring. But all of this circumvents natural selection: they are taking the process out of nature, getting rid of the natural process of evolution, and narrowing the gene pool to decrease biodiversity.

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Name: Period ______ Date :

Name: Period ______ Date :

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