Zoology101: Animal Biology Last Lecture Outline Lecture 42 1. Community ecology2. Diversity Current Lecture 1. Diversity (cont'd)2. EcosystemsDiversity (cont'd)• Common features of invasive species ◦ wide environmental tolerance ◦ large native range◦ high rate of population increase ®◦ predator resistance/absence • Invaded ecosystems: disturbance (altered by grazing, fire regime, eutrophication, etc)• Biotic homogenization via trade or intentional transport is likely to contribute to establishment of invasive species.• Invasive honey suckle eradication reduces tick-borne disease risk by altering host dynamics ◦ Exotic species may have effects that are unpredictable • Overexploitation: harvesting of plant, animal populations at higher rates than population growth rates◦ tragedy of the commons (Hardin)• Solutions?◦ Education and awareness▪ prevent invasions and reduce overexploitation ◦ Biodiversity reserves ◦ reduce overexploitation◦ restoration and remediation • Reserves:◦ goals- conservation of: ▪ large, intact, functioning ecosystems▪ areas with high biodiversity▪ species or groups of special interest ▪ Important ecosystem services Ecosystems • Ecosystem = all organisms + abiotic factors with which they interact ◦ less focus on who is there (what species)◦ More focus on what organisms do▪ energy, matter= common currency for all organisms • constant input of energy needed to stay alive ▪ Chemical cycling ▪ can view organisms in terms of • how they get their energy• how energy is transferred among other organisms • Ecosystem energy conservation◦ Photosynthesis▪ carbon dioxide + water → glucose, oxygen and heat ▪ light energy → chemical energy ◦ Respiration:▪ glucose+ oxygen → carbon dioxide + water + ATP (and heat)▪ releasing chemical energy to do work • Energy Terminology◦ Photosynthesis= autotrophy▪ self-feeding▪ plants produce glucose, then feed it to themselves ◦ Organisms that cannot make their own glucose = heterotrophs ▪ consumers -eat living things ▪ decomposers- eat detritus(non-living organic matter )◦ Biomass: weight of living organism • Most simplistic model: ◦ solar power → primary source → decomposer or consumer ◦ all energy conversions are inefficient (there is always energy lose as heat somewhere )◦ energy transfers among organism done by consuming chemical energy • Energy pyramid:◦ 10% rule • Biochemical cycling ◦ nutrient: elements essential for growth, survival, and reproduction ◦ nutrient (biochemical) cycles: ▪ movement and chemical transformations of biologically important elements between biotic and abiotic components of an ecosystem • C, N, P and water in a special case ◦ acquisition of energy by organisms drives movement (cycling) of biologically important elements • Carbon dioxide, water vapor and other greenhouse gases reflect infrared radiation back toward earth; this is the greenhouse effect ◦ increased levels of atmospheric carbon dioxide are magnifying the greenhouse effect, which could cause global warming and climatic change ◦ a warming tend would also affect the geographic distribution of precipitation▪ northern coniferous forests and tundra show the strongest effects of global warming ▪ warming could also trigger increased thawing and decomposition, releasing more carbon dioxide▪ Global warming can be slowed by reducing energy needs and converting to renewable sources of energy• stabilizing carbon dioxide emissions will require an international effort• Millennium Ecosystem Assessment ◦ Made by 1300 experts in 95 different countries ◦ science assessment: social process designed to bring the findings of science to bear on needs of decision makers ◦ findings:▪ humans have radically altered ecosystems in the last 50 years ▪ changes have brought gains but at growing costs that threaten achievement development goals▪ degradation of ecosystems could grow worse but can be reversed ▪ workable solutions will require significant changes in
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