Environmental Science 1021F/G Lecture Notes - Null Hypothesis, Resource Consumption, Inductive Reasoning

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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:
oIndividual organisms
oPopulations
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oCommunities
oLandscapes (and seascapes)
oThe 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
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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
oinnovations 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
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