Lecture 01 - 12 Jan.doc

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Western University
Environmental Science
Environmental Science 1021F/G
Christie Stewart

Environmental Issues, EnviroSci 1021 Lecture 1 Part One: Ecosystems & Humans Reading: Freedman Chapter 1 (3 fields of study from here ) Environmental science vs ecology Environmental science is an interdisciplinary field that investigates questions related to the human population, resources, and damage caused by pollution and disturbance • Sustainability is a key subject area – of both the human economy and the natural world Ecology is the study of the relationships of organisms and their environment • The focus is on factors affecting the organization of the natural world; sustainability and other ‘environmental’ issues are not core themes of ecology Hierarchical framework of the universe • includes consideration of life on Earth • organized at various scales, ranging from extremely small to incredibly large • life occupies intermediate levels of the hierarchy • the realm of ecology encompasses: o Individual organisms o Populations 1 o Communities o Landscapes (and seascapes) o The biosphere Species and Ecosystems Species: an aggregation of individuals and populations that can potentially interbreed and produce fertile offspring Ecosystem: one or more communities of organisms interacting with their environment as a defined unit. Important principles of the ecosystem approach Ecological interpretations of the natural world consider the diverse, web-like interconnections among the many components of ecosystems in a holistic manner This ecosystem approach does not view an ecosystem as a random grouping of populations, species, communities, and environments — rather, it confirms them as intrinsically connected and interdependent, although in varying degrees Species’ abilities to cope with environmental constraints All species are constrained by limitations that environmental factors place on their productivity and reproduction Humans have been enormously more effective than other species in finding ways to overcome those constraints Our sociocultural evolution has been characterized by a cumulative series of discoveries of better ways of exploiting our environment to foster our population growth and lifestyle How environmental stressors and disturbances can affect species and ecosystems • Environmental stressors (including pollution and disturbance) are constraints on the development and productivity of individual organisms, populations, communities, and larger ecosystems • Stressors may be anthropogenic or natural • If the intensity of stressors is high, ecological development may be limited to low-productivity desert or tundra • But if stressors are moderate, tropical rainforest or coral reefs may be able to develop 2 Three direct ways in which humans influence their environment 1. by harvesting economically valuable biomass for use as food, materials, or medicine, such as trees and hunted animals 2. by causing toxicity through pollution by chemicals or excessive heat 3. by converting natural ecosystems into agricultural, industrial, or urban land- uses Cultural Evolution of Humans • Tools • Domestication of animals and plants • Fire • Medicine • Communication Technology o innovations increased ability to exploit resources BUT rarely developed with compensating cultural ethic Four broad classes of environmental values Utilitarian (or instrumental) values are based on the usefulness of something to human welfare Ecological values are related to the utility of something to both humans and other species, as well as natural ecosystems Aesthetic values are based on an appreciation of beauty, including that of the natural world Intrinsic value insists that all entities have inherent worth and a right to exist, regardless of the needs of people Five important worldviews • The anthropocentric worldview considers humans as the centre of moral consideration – everything else is of lesser importance • The frontier worldview asserts that people have the right to exploit natural resources • The biocentric worldview considers all species to have inherent value • The ecocentric worldview additionally assigns importance to the components, functions, and organization of ecosystems 3 • The sustainability worldview insists that the use of natural resources should be governed by appropriate ecological, aesthetic, and inherent values, and should take a long-term view (can be anthro/ecocentric) Three categories of environmental crises Population – the abundance of people and their mutualistic species Resources – the use and abuse of non-renewable and renewable natural resources Environmental damage – the effects of pollution, disturbance, and other stressors on human welfare and on other speci
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