Accelerated Bio Ecology Part II Chapter 20: Community Ecology Chapter 22: Humans in the Environment Species Interactions of Communities Communities contain interacting populations of many species. 3 major types of interactions between species: 1)PREDATION: predator eats all or part of an individual the prey Predators survival depends on ability to capture food Adaptations of predators: venom, flesh-cutting teeth, sticky webs, speed Preys survival depends on ability to avoid capture Adaptations of prey: camouflage, chemical defenses (plants & animals), mimicry (resembles another species), thorns, spines COMPETITION limited resources force competition among living things in same niche. among same species = intraspecific competition between different species = interspecific competition all competition almost always produces a winner and a loser (dies out) ex: two species of paramecium kept in same cultureone species out competed the other. the competitive exclusion principle: no two species can occupy the same niche at the same time. dividing resources can be a truce in the competition for resources ex: one spruce tree can provide for three different niches of warbler birds feeding on high, middle, and low branches ** by dividing resources, competition helps determine the number and types of species in a community AND the niche each species occupies Predation, Herbivory and Keystone Species predator-prey: predators affect the amount of prey and where prey can live and feed herbivore-plant: herbivores affect both the size and distribution of plants and determine where those plants can grow keystone species: a change in one species can have drastic effects on many other species in the community ex: Pacific NW: sea urchins eat giant kelp stalks. Sea otters eat sea urchins. Otters are a keystone species- they keep the sea urchin population in check Over hunting of the otters allowed urchin population to explode giant kelp forests destroyed by urchin activity with no kelp, many animals were without a habitat otters are now protected species, urchin population is under control and kelp forests have rebounded Symbiotic Relationships symbiosis = together living. any relationship where 2 species live in close association with each other. 3 main types of symbiotic relationships: A) mutualism (win-win): Both benefit. ex: sea anemone and clown fish. Clown fish gets a protected home and the anemone gets a defender when attacked B) parasitism (win-lose): One benefits at the harm of the other (host) ex: tapeworm inside a human. Tapeworm absorbs digested food of host, the hosts cells starved for nutrition. C) commensalism (win-no harm/help): One benefits while the other is neither harmed nor helped ex: barnacles on a whale. Barnacles benefit by motion of whale and the movement of food particles over them. No benefit or harm comes to the whale. Ecological Succession: Primary and Secondary Succession: a progressive, predictable ecological change in a community over time In 1833, volcanic island of Krakatau completely destroyed by an eruption left completely barren. 2 years later, grasses are present 14 years later, 49 plant species and lizards, birds, insects, and bats by 1929, a forest with 300 plant species were present. today the island is a mature rainforest HOW?: Primary Succession: begins with no remnants of the previous community pioneer species are first to colonize barren land ex: lichen (fungus and algae) turn rock into soil, turn N 2 gas into useful nitrogen forms, and add organic material to the soil certain grasses are also pioneer species Secondary succession: occurs after a major event disturbs a community (fire, flood, earthquake, hurricane) SOIL survives the disturbance plants re-colonize the area faster than in primary succession can also follow human activities like forest clearing and farming once plants are established, herbivores can move in and make use of the food supply. Then, carnivores can move in if ecosystem is healthy, it may be restored to its natural state prior to disturbance (the climax community) sometimes the human impact is so traumatic, a full recovery through succession is not possible Ecological Succession: Primary and Secondary Chapter 22: Human Environmental Impact Humans: Rely on Earths life-support systems Affect our environment when we: Obtain food Eliminate waste products Build places to live Humans affect regional and global environments through agriculture, development, and industry in ways that have an impact on the quality of Earths natural resources, including soil, water, and the atmosphere. The Effect of Human Activity Agriculture - Supplies a dependable food source that can be stored for later use Positives Enabled human settlements that ultimately led to modern civilization Negatives Impacts natural resources as >7 billion people!!! need Food Fresh water Fertile soil Fossil fuels (fertilizer & farm equipment) Development - Trend to move to suburbs & cities Positives High standard of living Negatives Produce lots of waste that affect air, water, & soil resources Uses up farmland Divides natural habitats into fragments The Effect of Human Activity Industrial Growth Industry & scientific know- how Positives Modern conveniences of life Comfortable homes, clothes, electronic devices Negatives Require energy and consume power Need to burn fossil fuels (coal, oil, & natural gas) Wastes discarded into air, water, & soil Sustainable Development Renewable and Nonrenewable Resources Renewable can be renewed or replaced by a healthy ecosystem Ex: trees, wind, sunlight, etc. Nonrenewable natural processes cannot replenish them in a reasonable amount of time Fossil fuels (formed from buried organic material over millions of years) Minerals and metals Sustainable Development Sustainable Resource Use Sustainable development Provides for human needs & wants Preserves the ecosystems that produce natural resources What does it look like? Does not cause harm to the soil, water, and climate Consumes as little energy and material as possible Flexible to survive environmental stress/disasters Takes into account human economic systems as well as ecosystem goods and services SURVIVE AND IMPROVE Using Resources Wisely: Soil Why is it needed? When healthy, supports agriculture and forestry Topsoil absorbs/retains moisture but allows water to drain How are we affecting it? Allowing soil erosion nutrients are washed away with rain Desertification over-plowing, overgrazing, allowing land to be barren between plantings Deforestation loss of forests Forests help to hold soil in place, absorb CO 2, absorb freshwater Using Resources Wisely: Soil How can we protect it? Leaving stems and roots in place between plantings Crop-rotation Contour Plowing and Terracing creating steps to prevent water and soil from flowing downward Dont clear-cut forests Add wind-breaks Freshwater Resources Why is it needed? Drinking water Industry Transportation Energy Waste Disposal How are we affecting it? Overuse Pollution Factories, oil spills Industrial/Agricultural Chemicals Biomagnification pollutants (like DDT, PCBs, heavy metals) magnify as they move through the food chain from primary producers to primary consumers, etc. Residential Sewage Freshwater Resources How can we protect it? Protection of natural resources involved in water cycle Plants can filter out pollutants Watershed conservation protecting all inter-connected bodies of water Pollution control Sewage treatment Decrease pesticide use Use biological controls instead of poisonous sprays Water conservation Drip irrigation Warm-Up What does this diagram represent? The Atmosphere Why is it needed? Oxygen Absorption of UV radiation Regulation of global temperature How are human affecting it? Pollution (Industry, Burning Fossil Fuels) Smog - Ground Level Ozone Causes respiratory diseases Acid Rain nitrogen and sulfur oxides mixing with precipitation Damages plants, releases toxic elements from soil Greenhouse Gases burning of fossil fuels releases CO 2, CH 4, and H 2 O Releases carbon dioxide into the air, contributes to global warming and climate change Particulates microscopic particles of ash and dust released by industry Cause respiratory problems when inhaled The Atmosphere How can we protect it? Emission standards Clean-air regulations Cleaner fuels What is biodiversity? Contracted form of biological diversity Biodiversity: variety of life forms living within an ecosystem Which picture represents a greater amount of biodiversity? High species diversityLow species diversity Which picture represents a greater amount of biodiversity? Low genetic diversityHigher genetic diversity Biodiversity When a habitat is very diverse with a variety of different species, it is much healthier and more stable Biodiversity Ecosystem Diversity - variety of habitats, communities, and ecological processes in that biosphere 1.8 million species already identified! 30 million more estimated yet to be discovered!! Species Diversity - number of different organisms in a particular area Genetic Diversity sum total of all different forms of genetic information carried by a particular species Biodiversity Benefits of Biodiversity Sources of medicines Genetic diversity used to increase pest resistance Keystone species (if removed) can change entire ecosystem Biodiversity Threats to Biodiversity Altering habitats Hunting Invasive Species Pollution Climate Change Conserving Biodiversity Protect Individual Species Preserve Habitats and Ecosystems Consider Local Interests Ecological Footprint How big is your footprint? What is a footprint? Footprint a mark left on the Earth, varying in size from person to person Ecological Footprint your impact on the Earth, varying in size from person to person How is a eco-footprint measured? Diet Transportation Waste Housing Energy sources Appliances Footprint by Country Published in 2008 by the Global Footprint Network Source: Ecological Footprint of Nations, 2004 CountryEco-Footprint (acres per person) U.S.23.6 Canada21.6 France14.2 UK11.7 El Salvador4.3 Ethiopia1.7 Ozone Layer Why is it needed? Ozone Layer molecules of O 3 At ground level = pollutant Upper atmosphere = protection against harmful UV radiation which can cause cancer, eye damage and decreased immunity How are we affecting it? Primary problem is CFCs (Chloroflurocarbons) Found in refrigerants, aerosol cans and plastic foams How can we protect it? CFCs were banned in the late 1980s (Montreal Protocol); however, residual CFCs can remain in the atmosphere for more than 30 years! OzonegIdr8http://www.youtube.com/watch?v=qUfVMo gIdr8-x3ghttp://www.youtube.com/watch?v=t27fdgK -x3g Fisheries What is the problem? Despite increased efforts and new technology, seafood catch numbers continue to decline How are we affecting it? Overfishing: Fish thought to be a renewable resource Death rates (commercial fishing) surpassed the birth rates of the fish Fisheries How can we protect it? Regulations put in place to limit fish catches Certain areas closed to fishing until populations recovered (Sustainable Fisheries Act) Aquaculture farming of aquatic animals Climate Change Whats the Problem? Global warming increase in average temperature of our planet (0.74C between 1906 and 2005) with 11 of the 12 warmest years occurring between Melting sea ice Rising seal levels What are we doing to destroy it? Enhanced Greenhouse Effect not allowing solar heat to move back into outer space Burning fossil fuels Automobile exhaust Industrial pollution Climate Change How can we protect it? Alternative energy sources (water, wind, solar) Decrease our ecological footprint