Introduction to EcologyIntroduction to Ecology““Ecology is the study of the interactions between Ecology is the study of the interactions between

organisms and the living and nonliving organisms and the living and nonliving components of the environment. Each organism on components of the environment. Each organism on

Earth depends in some way on other living and Earth depends in some way on other living and nonliving things in the environment. Ecology nonliving things in the environment. Ecology

involves collecting information about organisms involves collecting information about organisms and their environments, looking for patterns, and and their environments, looking for patterns, and

seeking to explain these patterns.”seeking to explain these patterns.”

Today’s Ecology IssuesToday’s Ecology Issues Ecological information and understanding have Ecological information and understanding have

always been critical for humans. For our nomadic always been critical for humans. For our nomadic ancestors, survival depended on practical knowledge ancestors, survival depended on practical knowledge about the environment. While our understanding has about the environment. While our understanding has become more sophisticated, our need for become more sophisticated, our need for understanding has become more urgent: over the past understanding has become more urgent: over the past few decades, humans have changed the environment few decades, humans have changed the environment on a greater scale than ever before.on a greater scale than ever before. Rapid increase the number of people.Rapid increase the number of people. The sixth mass extinction? The sixth mass extinction? The thinning of the ozone layerThe thinning of the ozone layer Climatic changes: the greenhouse effectClimatic changes: the greenhouse effect

Levels of Organization: The Levels of Organization: The Heirarchy of EcologyHeirarchy of Ecology

IndividualIndividual Population: all the members of Population: all the members of

a species that live in the same a species that live in the same place at the same time.place at the same time.

Community: all the interacting Community: all the interacting populations in an area.populations in an area.

Ecosystem: all the organisms Ecosystem: all the organisms and non-living factors found in and non-living factors found in a particular place.a particular place.

Biosphere: the broadest, most Biosphere: the broadest, most inclusive level organization- inclusive level organization- the thin volume of Earth and the thin volume of Earth and its atmosphere that supports its atmosphere that supports life.life.

The Key Theme of EcologyThe Key Theme of Ecology

INTERCONNECTEDNESS!!INTERCONNECTEDNESS!! No organism is isolatedNo organism is isolated All organisms interact with other organisms in their All organisms interact with other organisms in their

surroundings and with the nonliving portion of the surroundings and with the nonliving portion of the environment.environment.

Survival depends on these interactions.Survival depends on these interactions. Each ecosystem is a network in which organisms are linked Each ecosystem is a network in which organisms are linked

to other organisms and to the nonliving environment.to other organisms and to the nonliving environment. Another word for this quality is interdependence. Another word for this quality is interdependence.

ModelsModels

Ecosystems are complex and difficult to study. Ecosystems are complex and difficult to study. We use models to help us deal with these We use models to help us deal with these complexities.complexities. GraphsGraphs DiagramsDiagrams Mathematical equationsMathematical equations

Models are simplified systems designed only to mimic Models are simplified systems designed only to mimic the behavior of the natural world and cannot account for the behavior of the natural world and cannot account for every influence of every variable in the environment.every influence of every variable in the environment.

Ecology of Organisms IEcology of Organisms I

Ecologists separate the living from the Ecologists separate the living from the nonliving.nonliving. Biotic factors: all of the living things that affect the Biotic factors: all of the living things that affect the

organism.organism. Abiotic factors: the physical and chemical Abiotic factors: the physical and chemical

characteristics of the environment.characteristics of the environment. These factors are not independent.These factors are not independent.

Ecology of Organisms IIEcology of Organisms II

Organisms are able to survive within a broad range of Organisms are able to survive within a broad range of environmental conditions. However, individual organisms environmental conditions. However, individual organisms have a range of conditions to which they are well suited.have a range of conditions to which they are well suited.

We can graph this range in a tolerance curve: a graph of We can graph this range in a tolerance curve: a graph of performance versus an environmental variable.performance versus an environmental variable.

Ecology of Organisms IIIEcology of Organisms III

Acclimation: An ability Acclimation: An ability to adjust tolerance to to adjust tolerance to abiotic factors.abiotic factors. This is NOT the same This is NOT the same

thing as adaptation– thing as adaptation– acclimation occurs acclimation occurs within the lifetime of an within the lifetime of an organism. Adaptation is organism. Adaptation is the genetic change in a the genetic change in a species that occurs over species that occurs over generations. generations.

Ecology of Organisms IVEcology of Organisms IV

Control of internal conditions; how organisms Control of internal conditions; how organisms deal with changes in the environment:deal with changes in the environment: Conformers: organisms that do not regulate their Conformers: organisms that do not regulate their

internal conditions; they change with internal conditions; they change with environmental conditions.environmental conditions.

Regulators: organisms that use energy to control Regulators: organisms that use energy to control some of their internal conditions.some of their internal conditions.

Ecology of Organisms VEcology of Organisms V

Escape from unsuitable Escape from unsuitable conditions; an ability to conditions; an ability to survive unfavorable survive unfavorable conditions by escaping conditions by escaping from them temporarily.from them temporarily. Dormancy: a reduced Dormancy: a reduced

state of activitystate of activity Migration: moving to Migration: moving to

another, more favorable another, more favorable habitathabitat

Ecology of Organisms VIEcology of Organisms VI

Resources: the energy and materials the Resources: the energy and materials the species needs.species needs. Whether a species can survive or not in a particular Whether a species can survive or not in a particular

habitat depends on the suitability and availability habitat depends on the suitability and availability of resources.of resources.

Resources necessary for survival vary from species Resources necessary for survival vary from species to species.to species.

The NicheThe Niche A species way of life, or role the A species way of life, or role the

species plays in the environment. species plays in the environment. Includes the range of conditions that Includes the range of conditions that

the species can tolerate, the methods the species can tolerate, the methods by which it obtains resources, the by which it obtains resources, the number of offspring it has, its time of number of offspring it has, its time of reproduction, and all other interactions reproduction, and all other interactions with the environment.with the environment.

Fundamental niche: the range of Fundamental niche: the range of conditions that a species can conditions that a species can POTENTIALLY tolerate and range of POTENTIALLY tolerate and range of resources that it can POTENTIALLY resources that it can POTENTIALLY use.use.

Realized niche: the range of resources Realized niche: the range of resources it ACTUALLY uses.it ACTUALLY uses.

A species niche can vary within a A species niche can vary within a single lifetime.single lifetime.

Generalists: species with broad niches; Generalists: species with broad niches; can tolerate a range of conditions and can tolerate a range of conditions and variety of resources.variety of resources.

Specialists: Species that have narrow Specialists: Species that have narrow niches.niches.