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Humans in the Biosphere Biodiversity The variety of life in an area that is determined by the number of different species in that area Benefits Increases stability of the ecosystem (more for food chains!) Contributes to the health of the biosphere 3 types of Biodiversity Genetic Diversity Species Diversity Ecosystem Diversity Genetic Diversity The variety of genes or inheritable characteristics that are present in a population Example: If a trait allows an insect to survive a certain type of pesticide, it would be beneficial for that insect to pass on that trait that is found in its DNA (survival of the fittest!) Species Diversity The number of different species and the relative abundance of each species in a biological community As you move from the polar regions to the equator, species diversity increases Rainforests have the greatest amount of species diversity Ecosystem Diversity The variety of ecosystems that are present in the biosphere Remember the different ecosystems? Different abiotic factors in each ecosystem support different types of living things The Tundra is home to moose and wolves while the Rainforest is home to exotic birds and spider monkeys! So why is biodiversity important for us? Economics We’re able to cross different plants to get a new better hybrid plant Teosinte plant = genes that are resistant to viruses Corn = yummy food for us Corn + Teosinte = Yummy food without viruses = more food! So why is biodiversity important for us? Medicine We use various plants for medicinal purposes! Quinine plants for malaria Madagascar Periwinkle to treat Ovarian Cancer and leukemias Has increased survival rates from 20% to more than 95%!!! We’re still searching for more uses of plants and animals that benefit humans So why is biodiversity important for us? How do other organisms supply humans? Plants = Oxygen Tiny Plankton = food for small fish = food for us! Healthy Ecosystems can help to provide us with clean drinking water We just have to keep them clean! Threats to Biodiversity Review! Extinction – a species is COMPLETELY gone! Endangered – a species is almost extinct! Threatened – a species is almost endangered! These things are not always humans fault, however they have been recently! Mass Extinctions An event in which a large percentage of all living species become extinct in a relatively short period of time. The last mass extinction occurred about 65 million years ago – remember the dinosaurs? Causes of Extinction Aside from natural disasters, actions by humans such as: Habitat destruction Poaching Pollution and Introducing an exotic species can cause extinction. Estimated # of Extinctions Since 1600 Group Main land Island Ocean Total Approximate # of species % of Group Extinct Mammals 30 51 4 85 4000 2.1 Birds 21 92 0 113 9000 1.3 Reptiles 1 20 0 21 6300 0.3 Amphibians 2 0 0 2 4200 0.05 Fish 22 1 0 23 19,100 0.1 Invertebrates 49 48 1 98 1,000,000+ 0.01 Flowering Plants 245 139 0 384 250,000 0.2 How do humans impact the Earth? Habitat Disruption Deforestation – removal of trees and destruction of forests Why is this bad? Less trees = less species diversity, habitat loss, disruption of carbon cycle Desertification – over-farming and overgrazing turn productive farm land into a desert Erosion Wearing away of surface soil by wind and water Caused by humans removing too many trees which serve as a buffer for erosion Pollution Greenhouse Effect A natural phenomenon where gases reflect heat back toward the Earth, keeping it warm Caused by an accumulation of greenhouse gases (such as CO2) CO2 is released by burning fossil fuels and breathing! Effects of Greenhouse Gases Greenhouse gases create a heat blanket in the atmosphere increasing the Earth’s temperature Most people believe this is causing Global Warming! Can be helped by planting more trees which convert CO2 to O2 during photosynthesis Acid Rain Nitric Oxides and Sulfur Dioxides accumulate in the atmosphere and contribute to precipitation being acidic Causes damage to plants and also manmade structures The Ozone Layer Protects us from harmful UV Rays Which cause sunburns (ouch!), eye damage, and even cancer (yikes!) Made of Ozone Molecules (O3) Destroyed by CFC’s (chloroflourocarbons) Released from aerosol spray cans (banned in the 1980s) Have caused a major hole in the ozone layer Resource Use Renewable Resources - natural resources that can be replaced in a relatively short amount of time (sun, wind, rain …) Nonrenewable Resources - those that either take a very long time to replace or cannot be replaced at all (coal and oil) Global Warming An increase in Earth’s average temperature The Earth is getting warmer, however it fluctuates between warm and cool periods Do your part to keep the Earth clean and to decrease your carbon footprint! How do you decrease your carbon footprint? Use renewable sources of energy Take quicker showers (water conservations) Plant trees and shrubs Turn off the lights when you’re not in the room Can you think of any others?