Animals in an ecosystem compete for food, mates and their territory. Organisms which have more of these resources tend to grow more healthily and are more likely to have offspring. Competition can be interspecific or intraspecific depending on whether organisms from different species or the same species are competing for resources.
A stable community is one in which the size of the populations of all species remain relatively constant over time. In the example above the amount of grass, and the numbers of rabbits and foxes all remain relatively constant. The different populations are living in a healthy balance with their environment.
Communities These are important key terms: An ecosystem is the interaction between a community of living organisms and their environment. A community is two or more populations of organisms.
An ecosystem is two or more populations of organisms usually many more in their environment. A population is all the organisms of the same or closely-related species in an area. Levels of organisation within an ecosystem Organisms within an ecosystem are organised into levels.
Producer Producers are plants and algae, which photosynthesise. Primary consumer Primary consumers are herbivores, which eat producers. Secondary consumer Secondary consumers are carnivores, which eat primary consumers.
Tertiary consumer Tertiary consumers are also carnivores. They eat secondary consumers. A woodland ecosystem showing the habitats of different species. He is the author of Land of Bears and Honey: Development and the Biota. He lives in New Mexico.
Foreword Acknowledgments Prologue 1. Out of the Forest 3.
Science and Faith 4. Pleasing to the Eye 6. Where the Short Grass Grows 7. An Ecological Primer 9.
Bison Plains and Prairie Dogs Taming of the West Production Science Comes to the Range The Last Pariah