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Chapter 57a.doc

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BIOL 346
Richard Ennis

Chapter 57: Conservation Biology 57.1 What is Conservation Biology? • Devoted to preserving the diversity of life on Earth • Draws heavily on concepts and knowledge from population genetics, evolution, ecology, biogeography, wildlife management, economics and sociology Conservation biology is a normative scientific discipline • Conservation biology is a normative discipline embraces certain values and applies scientific methods to the goal of achieving these values; motivated by the belief that preservation of biodiversity is good and that loss is bad. • Is guided by three principles: o Evolution is a process that unites all of biology. o The ecological world is dynamic. o Humans are a part of ecosystems. Conservation biology aims to prevent species extinctions • Organisms have always altered Earth’s ecosystems. • Very first organisms probably reduced the supply of energetically and structurally useful compounds (replacing them with waste products). • Early photosynthetic prokaryotes and eukaryotes generated oxygen (unsuitable for anaerobic organisms). • Plants colonized the land, accelerating the weathering of rocks thus, gaining access to rock-bound nutrients. • Weathering of phosphorus increased global productivity = rise of oxygen concentrations. • Rise of vascular plants increased oxygen concentration; lower carbon dioxide concentrations. • Human beings cause extinctions of other species o When first arrived in N. America (20 000 years ago), encountered a rich fauna of large mammals. o Most species were exterminated (overhunting) within a few thousand years. • The productivity and richness of Earth’s biota has increased during the long course of life’s evolution, but current situation is unique: all environmental changes are being caused by a single species. • That’s why now more and more people value biodiversity for many reasons: o Humans depend on other species for food, fiber, and medicine o Species are necessary for the functioning of ecosystems and its many benefits and services. o Humans derive enormous aesthetic pleasure from interacting with other organisms. o Extinctions deprive us of opportunities to study and understand ecological relationships among organisms. o Living in ways that cause the extinction of other species raises serious ethical issues 57.2 How Do Biologists Predict Changes in Biodiversity? • To preserve Earth’s biodiversity, we need to both maintain the processes that generate new species and provide conditions that will keep extinction rates at a typical level • There are four reasons why scientists cannot accurately predict the number of future extinctions: o Do not know how many species live on Earth. o Do not know where species live (i.e. animal ranges are poorly known). o Difficult to determine when a species actually becomes extinct. o Do not know what will happen in the future. • Regardless, there are some methods for estimating probabl
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