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UNIT V:The Organism and Its Environment Are Humans fully Integrated into the Biosphere? (Obj. 1,4) The Scope of Ecology 1. Ecology: “oikos”-home, house; “-logy”-study of (1866) 2. Study of how living things interact with each other and with the physical environment 3. Modern ecology not just descriptive, also predictive 4. One goal of ecology is to develop models that explain and predict the abundance of populations. (Obj. 1,4) Levels of Ecological Organization 1. 2. 3. 4. 1 (Obj. 2,3) Abiotic components of Ecosystems 1. WATER 2. SUNLIGHT 3. OXYGEN 4. TEMPERATURE 5. SOIL Biotic Components of Ecosystems (Obj. 2) •All the living parts of an ecosystem •Prairie dogs, hawks, snakes, grasses, seeds, berries, worms, bacteria, fungi •??? Name one in your environment ??? •??? How do abiotic and biotic differ ??? (Obj. 5) Biotic Components of Ecosystems 1. Autotrophs (producers) • Make their own food • Manufacture organic nutrients for all organisms • Green plants and algae carry on photosynthesis • Some bacteria are chemoautotrophs 2. Heterotrophs (consumers) • Cannot make their own food (need outside source of nutrients) • Herbivores--eat plants and/or algae (name some ???) • Carnivores--eat other animals (name some ???) • Omnivores--eat plants and animals (YOU ???) 2 (Obj. 5) Biotic Components of Ecosystems 3. Decomposers • Break down wastes and dead organisms and return raw materials to the environment • Bacteria and fungi (molds, mushrooms) • Obtain energy for own needs and return simple molecules back to environment to be used by other organisms (producers) • Detritus: partially decomposed matter (Obj. 5,6) Energy Flow and Nutrient Cycling Food chain Food web Trophic level (Obj. 7) Energy Balances in Ecosystems ***NET ENERGY LOSS*** Solar energy 100% Plants 55% Herbivores 10% Carnivores 3 (Obj.5-6) Grazing and Detrital Food Webs (Obj.6) Energy Flow • Trophic Levels – A trophic level is composed of all the organisms that feed at a particular link in a food chain. – Example of a food chain leaves caterpillars tree birds hawks (Obj. 6,7)) Ecological Pyramid BIOMASS # organisms X weight 4 (OBJ. 1,2,3 P.2) PHOTOSYNTHESIS SOLAR ENERGY + 6 CO2 + 6H2O C 6 H 120 6 + 6O2 CELLULAR RESPIRATION C6H120 6 + 6O2 6CO2 + 6H2 O + ENERGY (ATP) Photosynthesis & Cellular Respiration (Obj. 8,9, p.2) POPULATION • All the members of one species in a particular area • Population Density= # of individuals unit area • Population Distribution: uniform, clumped, random • Changes in Population Size – Growth Rate = Per capita rate of increase – Example: A population has 1000 members Birth rate = 30 / year Death rate = 10 /year The growth rate per year will be: 30 - 10 / 1000 = 0.02 = 2.0% per year 5 (Obj. 8,9, p.2) Patterns of Population Growth • Exponential growth 1. “J” shape 2. Lag phase 3. Exponential phase • Carrying Capacity 1. “S” shape 2. Exponential growth 3. Deceleration 4. Biotic effects 5. Stable equilibrium Fig. 33.3 (p.2, Obj. 9) Survivorship Curves I: death later II: death unrelated to age III: death early (p. 3, Obj. 1,2) Human Population Growth • World population approx. 6 billion • Approximately 225,000 people are added to the world’s population every day. • Approximately 82 million people are added to the world’s population every year. • Current doubling time is 56 years • US population growth currently 0.6% • US population around 285 million in 2001 (4.75% of world population) 6 (p.3) World Population Growth MDCs= North America, Japan, Europe, Australia LDCs= Latin America, Africa, Asia Environmental Impact World Population: MDCs= 22%; LDCs= 78% Hazardous Waste: MDCs= 90%; LDCs= 10% Fossil fuels: MDCs= 60 %; LDCs= 40% Metals: MDCs= 80%; LDCs= 20% Paper: MDCs= 75%; LDCs= 25% (p. 3, Obj.3) Fig. 36.1 (p. 3, Obj. 4) Reduction in Human Mortality •Medical advances •Standard of living •Technological advances 7 (p. 3, “Finally” Obj. 1) What is Pollution? •Pollution: a change to the environment that has a negative effect on living things •Pollutants: a substance or condition that contaminates air, water or soil; can be artificial (pesticides, detergents,CFC’s, fertilizers, acid rain), or naturally occurring (oil, CO2, goose poop); heat and uncontained radioactivity also; typically a waste product. Air Pollution Acid deposition: burning of fossil fuels releases sulfur dioxides and nitrogen dioxides into air; combine with water vapor to create sulfuric acid and nitric acids (OW!!); dissolve in rain or snow= acid rain Ozone Depletion: Ozone layer is layer of upper atmosphere (thin to begin with)--protects Earth from UV radiation; Late 1970’s= hole in layer (CFCs); agreement in 1990; believe ozone layer will recover if ban stays in place. Ozone Pollution: O3=photochemical smog; gases from cars, trucks, etc. react with sunlight to form ozone; toxic Greenhouse Effect: water vapor, CO2, other gases allow sunlight to enter the earth, but prevent heat from escaping; trapping of heat near the Earth’s surface; Global Warming: increased CO2 in atmosphere; 1800s-280ppm; 2000s--350ppm; Why you need to ask questions 8 Water Pollution •Agriculture-fertilizer runoff; animal waste; pesticides •Salt--changes species survivability •Sewage--O2 depletion in lakes, disease-causing bacteria •Heavy metals--lead, mercury, arsenic, tin, etc. •Industrial wastes--heavy metals, pesticides, organic solvents •Acid rain and Heat •Biological Magnification: as a pollutant enters the food chain, it gets more concentrated as it moves up the food chain (industrial waste not decomposed--stays in organism; DDT, PCBs--lead to health problems) Mud water plant fish bird human? Extinction What is it? The disappearance of all members of a species from Earth (natural process-earthquakes, volcanos) Human Activities that cause Extinction •Habitat Destruction: forests, wetlands •Poaching: illegal killing of animals (pets, pelts, teeth, claws) •Pollution: air, water, soil; health problems •Exotic species: outcompete native species; no natural enemies •Overfishing/hunting: don’t allow recovery time Protecting Species: captive breeding, laws and treaties, habitat preservation Non-Native Species Nene goose Japanese honeysuckle Mongoose European Starling Wild boar Garlic mustard 9