2 Objectives:I will be able to discuss how human activity is changing the Earth.I will be able to discuss the value of biodiversity.BOPA – biome worksheet
3 Human activities threaten Earth’s biodiversity Biodiversity has three main levels:Genetic diversity,Species diversity,Ecosystem diversity.Major threats to biodiversity:Habitat loss,Invasive species,Overharvesting,Global change (acid precipitation, climate change, air pollution, etc.).
4 Loss of biodiversity:Minimizes the chance of survival when faced with large environmental changes.Decreases stability of the ecosystem (in nature “everything is connected”).Poses ethical concerns.Earth is changing rapidly as a result of human action.
5 Common environmental problems: EutrophicationRefers to an excessive amount of nutrients in a body of water caused by runoff of nutrients from the land.Causes overgrowth of algae.Penetration of light is diminished which leads to decreased photosynthesis and decreased oxygen.When algae die, algal decomposers consume oxygen, further decreasing amount of oxygen available for animals.
7 = conversion of forest to non-forest. Deforestation= conversion of forest to non-forest.Especially high in tropical rainforest.Due to logging, agriculture, urbanization, mining, oil exploitation, etc.
8 Ozone DepletionOzone layer (in stratosphere) absorbs most of sun’s harmful UV radiation.Caused by chlorofluorocarbons (CFCs).Strong winds carry CFCs into the stratosphere. This can take two to five years. When CFCs break down in the stratosphere, they release chlorine. Each chlorine atom attacks ozone by joining with and breaking apart as many as 100,000 ozone molecules during the time it is in the stratosphere. Currently there is no increase in the amount of chlorine in atmosphere. Ozone is constantly being made and we hope that in about 50 years the situation will improve greatly.
9 Pollution Present in water (fresh, ocean, ground water), land, air. Caused by pollutants from industry/automobiles and by nonbiodegradable wastes which cannot be broken down by natural processes.
10 Biological Magnification Toxins become more concentrated in successive trophic levels.The toxins cannot be broken down by normal chemical means, so they magnify in concentration as they move through the food chain.
11 Acid PrecipitationDue to air pollutants (sulfur dioxide and nitrogen oxide) which increase the acidity of the rain.Damages plant tissues, leaches minerals from soil, causes death of trees, ruins stone buildings, kills zooplankton .Sulfur dioxide from coal burning factories, nitrogen oxide from car exhaust
12 Global Climate ChangeDue to the greenhouse effect = heat retention by atmospheric gases such as CO2 and methane.Global temperatures and sea levels are rising.Weather patterns are affected.Species are threatened.The Earth reflects about 30% of the incident solar flux; the remaining 70% is absorbed, warms the land, atmosphere and oceans, and powers life on this planet. The United States occupies a pivotal position in the global warming arena. With 4.6% of global population it accounts for almost 25% of global CO2 emissions, a proportion that is rising fast. The biggest single source of CO2 emissions is cars.
13 What positive effects do we have on the environment?
14 Math Connection Energy Flow in a Hardwood Forest (kJ/m2) What percent of the biomass in the forest community represented above is tied up in the shrub layer? Give your answer to the nearest whole number.Tree Layer1.3 X 104Reflected4.3 X 105Energy Lost1.4 X 106Solar Radiation2.5 X 106Absorbed1.5 X 106Energy AccumulatedAs Biomass1.9 X 104Shrub Layer?Transmitted6.4 X 105Herb Layer1.1 X 10326%