What is ecology? Ecology basic concepts. Energy flow in ecosystems. We use the energy that plants capture from the sun

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1 What is ecology? The study of how organisms adapt to The environment Other organisms Ecology basic concepts Energy flow Trophic (feeding) relationships Global climate change Energy flow in ecosystems We use the energy that plants capture from the sun Photosynthesis (plants, algae) Cellular respiration (all organisms) Producers: The beginning of the food chain Plants The leaf is the primary site of photosynthesis Solar-powered chemical factories Produce food for themselves and other organisms Capture solar energy and use it to build carbohydrates from CO2 and water Basic Photosynthesis Photosynthesis feeds nearly all life on earth Plants take light energy and CO2 and convert them into sugars Generate oxygen Without plants we would have no food to eat or oxygen to breath Animals exhale CO2 that plants need for photosynthesis

2 Food Chains Energy passes from 1 trophic level to another Step 1: Producers Producers Plants and algae capture solar energy and produce food Primary consumers Herbivores Secondary consumers Decomposers Carnivores & omnivores break down dead organisms, return nutrients to the soil The food chain continues Last step in the food chain Fungi decomposing a dead log Consumers Herbivores Carnivores Omnivores eat plants & animals Decomposers get energy from the dead material left by all trophic levels. They break down organic substances, making them available to other organisms Trophic structure of a community Increase nutrients in the soil Where do humans fit in the food chain?

3 Checkpoint You are eating a pizza. At which trophic level(s) are you feeding? Flour (in the crust) and tomato sauce Primary consumer Cheese and meat Secondary consumer Energy loss in ecosystems In a food chain, only about 10% of the energy at one trophic level is available to the next An idealized energy pyramid What limits the length of food chains? Most of the energy captured by plants is lost Only about 10% of the calories an herbivore eats are stored as body mass available to the next link in the food chain. Inefficient conversion of energy Producing animals for food is less efficient than directly eating the grains Only 10% is of the energy in the grain eaten by cattle is converted to meat Where does the energy go? Food energy available to humans Eating plants instead of animals reduces our impact on the environment

4 Global warming Global Climate Change The Greenhouse effect Global warming What is global warming? How is it affecting living organisms? What can we do about it? What is the evidence for global warming? The whole earth is warming compared to The largest temperature increases are in dark red Why is the earth warming up? Atmospheric concentration of CO 2 Greenhouse gases in atmosphere Solar energy passes through Radiant heat is trapped Greenhouse gases (CO 2, methane, water vapor) trap heat in the atmosphere. Burning fossil fuels releases huge amounts of CO 2 into the atmosphere Global warming is associated with increased CO 2 in the atmosphere The Greenhouse Effect Global warming 101 Natl Geo 3:04 The industrial revolution

5 How CO2 enters and leaves the atmosphere The Carbon cycle Who are the bad guys? The US accounts for 18% of all greenhouse emissions ranking it second in the world China emits 19% of the global total What is the major source of CO2 released by human activities? Burning carbon-containing fossil fuels Likely effects of global warming Increasing drought Decreasing crop productivity Melting of ice in glaciers and the polar ice caps, causing sea level to rise If sea level rises by 15 feet, large areas of Florida will disappear How is global warming altering the oceans? If sea level rises 15 feet Flooding Water quality coastal sewage release 13 of 20 largest cities in world are at sea level, as are hospitals and watertreatment plants Many cities around the world have sewer systems that overflow into water supplies during heavy rainstorms Increase in water-borne diseases Excess CO2 has made the oceans more acidic

6 The effects of ocean acidification How urgent is climate change? No emission cuts A doomsday scenario for coral reefs? Science 318:1230, 2007 Ecological footprint of people in different countries Ecological footprint A way to understand our consumption of energy and resources The ecological footprint = amount of land required to provide the raw materials an individual consumes Acres food, fuel, water, housing and waste disposal The ecological footprint of a person in the US is 10X greater than someone in India Families in India and the US display their possessions Resource consumption We in the industrialized countries, with 20% of world population, use 86% of the world s resources The other 80% of the world s population must share the remaining 14% of the resources

7 We need to reduce our resource consumption If all humans lived at our standard of living, 6 planet earths would be needed. How can we do it? Phase-out coal Increase energy efficiency Use renewable energy Needed: Stronger emission standards and a carbon tax Solar, wind, geothermal Improve the electrical grid More R&D R E DUC E CO2 EM I SSI O N S Renewable Energy Sources Top candidates Solar power Wind power Nuclear power Next generation of nuclear reactors (reduced waste) Carbon capture and sequestration YOU can make a difference What can we do about global warming? Conserve energy: Walk, bike, use public transit, or carpool Make sure your tires are fully inflated and your car tuned up Lower your water heater and home thermostats Safety issues Waste disposal The Greatest Threat There is no doubt in my mind that climate change is the greatest threat facing the biosphere today. Only run your dishwasher with full loads Reduce your shower length and temperature Turn off lights when leaving a room Use recycled paper Reuse or recycle as much as you can Global Warning DiCaprio 4:44 pujlkstqo&nr=1