Ecosystem Ecology Community interacts with abiotic factors Abiotic Factors that the community interacts with • Energy it is needed by organisms to do the processes to keep alive Forms: light, chemical, heat Type of energy used by living things: • Chemical elements carbon, nitrogen, phosphorous, oxygen Organisms are made of these elements Type of molecules that organisms are made of: Remember the law of matter and energy! 1 Two processes that transform energy and matter Photosynthesis Energy transformation Matter transformation Autotrophic organisms (producers) are the ONLY ones that can do photosynthesis in plants Heterotrophic organisms (consumers) can not do photosynthesis Cellular Respiration Energy transformation Matter transformation in plants and animals This occurs in autotrophs AND in the heterotrophs that eat them These processes allow for the movement of energy and chemicals in an ecosystem Movement of energy and chemicals in an ecosystem 2 Movement of energy and chemicals Movement of energy and chemicals in an ecosystem is different Energy flows - not recyclable - energy as heat can’t be used again - Ecosystem always needs an external input of energy Chemicals cycle - recyclable - e.g. carbon dioxide can be used again - Ecosystem does not need external input of chemicals if cycling is complete Their movement is linked because both depend on transfer of food. We can represent their movement Via a food chain: Simplified linear diagram of who eats whom In an ecosystem, food chains interconnect forming Food Web Complex network of who eats whom We can group organisms by the level at which they feed 3 Trophic structure: The different feeding relationships in an ecosystem Detritivores and decomposers eat nonliving organic matter; they recycle chemicals. Animals that eat herbivores are secondary consumers, at the third trophic level. Animals that eat plants are primary consumers, or herbivores, and are at the second trophic level. Plants and other photosynthetic organisms are producers. What trophic level are you if you eat an apple? What trophic level are you if you eat a steak? Amount of energy and Trophic structure What happens to the energy at each trophic level? Which energy is available to the next trophic level? Energy available to all the consumers and decomposers in an ecosystem comes from the energy in the producers What would a diagram showing the available energy at each trophic level would look like? Square or a pyramid 4 Energy pyramid shows the available energy to the next trophic level The higher the trophic level a species is at, the less available energy that it has from the original energy stored as photosynthesis Implication: Animals at higher trophic levels require more vegetation to provide for their food than animals at lower trophic levels We can apply this information to the human diet! Meat eaters vs. Plant eaters 3,000 lbs of corn and soybeans is capable of supporting ONE person if converted to beef, however, the same amount of soybeans and corn utilized directly without converting to beef will support 22 people! If the world population ate like in the US, ONLY less than ½ of the population could be fed. If the world population ate strict vegetarian diets we could feed 1 billion MORE than present 5 BIOMASS PYRAMID shows that amount of mass is reduced in higher trophic levels We can use a biomass pyramid to understand why organisms at higher trophic levels have higher concentration of toxic chemicals than lower ones 6 What happens to these toxics in the food chain? As biomass is consumed through food chain The amount of biomass is reduced But The amount of toxic does not (due to persistence) RESULT: The concentration of the toxic increases Having a greater impact on top predators Biological Magnification or Biomagnification: accumulation of toxics in tissues of consumers in food chains 7 Carbon makes up the skeleton of all organic molecules Presence of Carbon Dioxide allows for life on earth The amount of CO2 in the atmosphere determines the temperature, by the GREEN HOUSE EFFECT Some of the sun energy is absorbed by Earth some of this absorbed energy is reflected back some of this reflected energy is reemitted back by Carbon Dioxide and other GH gases Without these gases the Earth would be 59oF cooler!!! What will be the effect of changing the amount of carbon dioxide in the atmosphere? 8 Human impact on the carbon cycle • We have increased the amount CO2 in the atmosphere by burning fossil fuels • We have decreased the removal of atmospheric CO2 by deforestation CONSEQUENCE OF TWO more CO2 than normal enhanced greenhouse effect increased global temperature change in climate The IPCC reports summarize evidence of recent changes in global climate • Since 1990, the world’s climate scientists have been gathering to produce the single most comprehensive and authoritative research summary on climate change: 9 Why we need to talk about the scientific consensus on climate change Is climate the same as weather? Weather is for a given day and place Climate are long term patterns 10 Should climate be stable? Climate changes naturally and always has Concerns: change is happening more quickly few decades instead of thousands of years What is causing this current warming? The relationship between CO2 and temperature is one of cause and effect 11 Is the current change natural or human driven ? Extremely Likely human responsibility emissions of GH gases from human activities have caused “most of the observed increase in globally averaged temperatures since the mid-20th century.” Adaptation and Mitigation 12 What are the observed changes? If we reduce our emissions, An estimated $0.14 billion dollars can be saved from sea level rise by 2050 What are the observed changes? Scientists say peak snowpack could be as much as 30 percent reduced by 2040. Though the result will be less snow, California is expected to see more intense storms punctuated by longer periods of drought. "Then it rains for a very long period of time and we can’t capture it and store it." 13 What are the observed changes? If we reduce our emissions, An estimated 1,700 fewer deaths And savings of $21 billion , can be saved from extreme weather by 2050 14 Higher ozone concentrations due to rising temperatures could lead to an average of 3,700 more seniors and 1,400 more infants hospitalized for respiratory related problems in 2020. In 2050, that could rise to 24,000 more seniors and 5,700 more infants hospitalized . If we reduce our emissions, An estimated $160-300 million can be saved from reducing wildfires by 2050 An estimated 13, 000 fewer deaths from poor air quality and savings of $160 billion 15 What are the observed changes? Ocean warming accounts for more than 90% of the energy accumulated between 1971 and 2010 If we reduce our emissions, An estimated 53% of coral in Hawaii, 4% in Florida can be saved by 2050 Losses valued at $1.4 billion What are the observed changes? Ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification If we reduce our emissions, An estimated avoided loss of 11% of oyster supply, 12% scallop supply can be saved by 2050 Consumer benefits Of $85 million 16 What are the observed changes? Species and Climate Change: More than just the Polar Bear A large fraction of species face increased extinction risk due to climate change during and beyond the 21st century. Geographic ranges of many species have shifted toward the poles and up in elevation Most plant species cannot naturally shift their geographical ranges sufficiently fast to keep up with climate change. Temperature extremes will cause health problems; tropical diseases will move north into the U.S. 17 We have warmed under 1 oC Where do we go from here? We are committed to ½ oC If we continue business as usual: 1-5 oC Danger zone is 2 oC! At the end of the last ice age, when the Northeast United States was covered by more than 3,000 feet of ice, The average temperatures were only 5 oC cooler than today. What can be done? Texas example 18 What can you do? INFLUENCE U.S. ACTION 5 THINGS YOU CAN DO 19 .