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 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. 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. 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 layer The thinning of the ozone layer Climatic changes: the greenhouse effect Climatic changes: the greenhouse effect

Levels of Organization: The Heirarchy of Ecology Individual Individual Population: all the members of a species that live in the same place at the same time. 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. Community: all the interacting populations in an area. Ecosystem: all the organisms and non-living factors found in a particular place. Ecosystem: all the organisms and non-living factors found in a particular place. Ecosystem: all the organisms and non-living factors found in a particular place. Ecosystem: all the organisms and non-living factors found in a particular place. Biosphere: the broadest, most inclusive level organization- the thin volume of Earth and its atmosphere that supports life. Biosphere: the broadest, most inclusive level organization- the thin volume of Earth and its atmosphere that supports life.

The Key Theme of Ecology INTERCONNECTEDNESS!! INTERCONNECTEDNESS!! No organism is isolated No organism is isolated All organisms interact with other organisms in their surroundings and with the nonliving portion of the environment. All organisms interact with other organisms in their surroundings and with the nonliving portion of the environment. Survival depends on these interactions. Survival depends on these interactions. Each ecosystem is a network in which organisms are linked to other organisms and to the nonliving environment. Each ecosystem is a network in which organisms are linked to other organisms and to the nonliving environment. Another word for this quality is interdependence. Another word for this quality is interdependence.

Models Ecosystems are complex and difficult to study. We use models to help us deal with these complexities. Ecosystems are complex and difficult to study. We use models to help us deal with these complexities. Graphs Graphs Diagrams Diagrams Mathematical equations Mathematical equations 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. 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 Ecologists separate the living from the nonliving. Ecologists separate the living from the nonliving. Biotic factors: all of the living things that affect the organism. Biotic factors: all of the living things that affect the organism. Biotic factors: all of the living things that affect the organism. Biotic factors: all of the living things that affect the organism. Abiotic factors: the physical and chemical characteristics of the environment. Abiotic factors: the physical and chemical characteristics of the environment. Abiotic factors: the physical and chemical characteristics of the environment. Abiotic factors: the physical and chemical characteristics of the environment. These factors are not independent. These factors are not independent.

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

Ecology of Organisms III Acclimation: An ability to adjust tolerance to abiotic factors. Acclimation: An ability to adjust tolerance to abiotic factors. 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 Control of internal conditions; how organisms deal with changes in the environment: Control of internal conditions; how organisms deal with changes in the environment: Conformers: organisms that do not regulate their internal conditions; they change with environmental conditions. 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. Regulators: organisms that use energy to control some of their internal conditions.

Ecology of Organisms V Escape from unsuitable conditions; an ability to survive unfavorable conditions by escaping from them temporarily. Escape from unsuitable conditions; an ability to survive unfavorable conditions by escaping from them temporarily. Dormancy: a reduced state of activity Migration: moving to another, more favorable habitat Migration: moving to another, more favorable habitat

Ecology of Organisms VI Resources: the energy and materials the species needs. Resources: the energy and materials the species needs. Whether a species can survive or not in a particular habitat depends on the suitability and availability of resources. 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. Resources necessary for survival vary from species to species.

The Niche A species way of life, or role the species plays in the environment. A species way of life, or role the species plays in the environment. 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. 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. Fundamental niche: the range of conditions that a species can POTENTIALLY tolerate and range of resources that it can POTENTIALLY use. 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. Realized niche: the range of resources it ACTUALLY uses. A species niche can vary within a single lifetime. A species niche can vary within a single lifetime. Generalists: species with broad niches; can tolerate a range of conditions and variety of resources. Generalists: species with broad niches; can tolerate a range of conditions and variety of resources. Specialists: Species that have narrow niches. Specialists: Species that have narrow niches.