Transcript Introduction to Ecology

Introduction to Ecology
“Ecology is the study of the interactions between
organisms and the living and nonliving
components of the environment. Each organism on
Earth depends in some way on other living and
nonliving things in the environment. Ecology
involves collecting information about organisms
and their environments, looking for patterns, and
seeking to explain these patterns.”
Today’s Ecology Issues
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Ecological information and understanding have
always been critical for humans. For our nomadic
ancestors, survival depended on practical knowledge
about the environment. While our understanding has
become more sophisticated, our need for
understanding has become more urgent: over the past
few decades, humans have changed the environment
on a greater scale than ever before.
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Rapid increase the number of people.
The sixth mass extinction?
The thinning of the ozone layer
Climatic changes: the greenhouse effect
Levels of Organization: The
Heirarchy of Ecology
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Individual
Population: all the members of
a species that live in the same
place at the same time.
Community: all the interacting
populations in an area.
Ecosystem: all the organisms
and non-living factors found in
a particular place.
Biosphere: the broadest, most
inclusive level organizationthe thin volume of Earth and
its atmosphere that supports
life.
The Key Theme of Ecology
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INTERCONNECTEDNESS!!
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No organism is isolated
All organisms interact with other organisms in their
surroundings and with the nonliving portion of the
environment.
Survival depends on these interactions.
Each ecosystem is a network in which organisms are linked
to other organisms and to the nonliving environment.
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Another word for this quality is interdependence.
Models
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Ecosystems are complex and difficult to study.
We use models to help us deal with these
complexities.
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Graphs
Diagrams
Mathematical equations
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Models are simplified systems designed only to mimic
the behavior of the natural world and cannot account for
every influence of every variable in the environment.
Ecology of Organisms I
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Ecologists separate the living from the
nonliving.
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Biotic factors: all of the living things that affect the
organism.
Abiotic factors: the physical and chemical
characteristics of the environment.
These factors are not independent.
Ecology of Organisms II
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Organisms are able to survive within a broad range of
environmental conditions. However, individual organisms
have a range of conditions to which they are well suited.
We can graph this range in a tolerance curve: a graph of
performance versus an environmental variable.
Ecology of Organisms III
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Acclimation: An ability
to adjust tolerance to
abiotic factors.
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This is NOT the same
thing as adaptation–
acclimation occurs
within the lifetime of an
organism. Adaptation is
the genetic change in a
species that occurs over
generations.
Ecology of Organisms IV
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Control of internal conditions; how organisms
deal with changes in the environment:
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Conformers: organisms that do not regulate their
internal conditions; they change with
environmental conditions.
Regulators: organisms that use energy to control
some of their internal conditions.
Ecology of Organisms V
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Escape from unsuitable
conditions; an ability to
survive unfavorable
conditions by escaping
from them temporarily.
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Dormancy: a reduced
state of activity
Migration: moving to
another, more favorable
habitat
Ecology of Organisms VI
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Resources: the energy and materials the
species needs.
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Whether a species can survive or not in a particular
habitat depends on the suitability and availability
of resources.
Resources necessary for survival vary from species
to species.
The Niche
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A species way of life, or role the
species plays in the environment.
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Includes the range of conditions that
the species can tolerate, the methods
by which it obtains resources, the
number of offspring it has, its time of
reproduction, and all other interactions
with the environment.
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Fundamental niche: the range of
conditions that a species can
POTENTIALLY tolerate and range of
resources that it can POTENTIALLY
use.
Realized niche: the range of resources
it ACTUALLY uses.
A species niche can vary within a
single lifetime.
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Generalists: species with broad niches;
can tolerate a range of conditions and
variety of resources.
Specialists: Species that have narrow
niches.