2.2 & 2.8 ECOSYSTEMS and BIOMES

1. 2.2 & 2.8 ECOSYSTEMS and BIOMES

2. 2.2 - Introducing Ecosystems Ecology: the study of the relationships among organisms and their environment The study of ecology is undertaken at various spatial scales, ranging from: • individual organisms • populations • communities • ecoscapes (landscapes & seascapes) • biomes and ecozones • the biosphere

3. The universe has a hierarchical organization • Within this context, the realm of ecology includes the study of: • individual organisms • their populations • communities • ecoscapes • large-regional ecozones • global biomes • ultimately, the biosphere

5. Describing Ecosystems The term “ecosystem” is vaguely defined: any defined area or volume in which organisms and their environment are interacting • ecologists must delineate ecosystems for the purpose of studying them • ecosystems range enormously in size, from: • tiny contained systems, such as those within a pitcher plant or an aquarium • to a particular lake or stand of forest • to an ecoscape containing a mosaic of communities • and ultimately, the entire biosphere • the term “ecosystem” may also be used in general reference to a major habitat , such as “forest” or “prairie” or “bog” or “cultivated land”

6. Sustainability of Ecosystems • Ecosystems tend to maintain a relatively constant set of characteristics over a long period of time  Human activities that alter the biotic and/or abiotic features of an ecosystem can render it unsustainable • Sustainability in ecosystems can be maintained by conservation or by management  Artificial, human-created ecosystems must be maintained with significant energy input to maintain their sustainability • Humans are not separate from the ecosystems which they inhabit, and are affected by their biotic and abiotic features as much as any other species • The economies of northern and southern Ontario are based on the biotic and abiotic conditions that enable forestry and mining, and agricultural and manufacturing respectively • People’s health are affected by the biotic and abiotic conditions in the ecosystems they inhabit (e.g. SAD, asthma)

7. Biomes A biome is a geographically extensive ecosystem, occurring throughout the world wherever environmental conditions are suitable for its development • biomes are characterized by their dominant life forms, but not by their constituent species • terrestrial biomes are usually identified on the basis of their mature or older-growth vegetation • marine biomes are generally distinguished by their dominant animals • ecologists working in different countries classify biomes in similar ways

9. Major Biomes Earth's biomes are characterized by their dominant natural communities of indigenous plants, animals, & microorganisms • there are also anthropogenic ecosystems, whose dominant influence is human activities • in fact, all biomes have now been influenced to some degree by humans (nothing is “pristine”) • for instance, all organisms contain traces of organochlorines in their bodies, e.g., DDT & PCBs — these manufactured chemicals have been widely dispersed into the environment Ecologists have used a number of classifications to divide the biosphere into major biomes • the classification of global biomes described here is modified from a scheme proposed by the American ecologist, E.P. Odum

11. Terrestrial Biomes • Tundra • Alpine and Arctic Tundra • Boreal Coniferous Forest or taiga • Montane forest • Temperate Deciduous Forest • Temperate Rain-forest • Temperate Grassland • Chaparral • Desert • Tropical Grassland and Savannah • Tropical Forest • Semi-evergreen Tropical Forest • Evergreen Tropical Rain-forest

12. Tallgrass prairie Temperate hardwood forest Arctic tundra Lowland tropical rainforest

13. 2.8 - Major Terrestrial Ecosystems • Temperate Deciduous Forest • Abiotic Factors • longer growing season than some forests • higher temperatures than some forests • fertile soil • precipitation up to 100 cm/y • Biotic Factors • deciduous trees • many shrubs, ferns • many insects • black bears • woodpeckers • weasels • deer • tree and ground squirrels • shrews, mice • wolves

15. Boreal Coniferous Forest

18. Biomes are Not Homogeneous Biomes are characterized by their dominant, most extensive kinds of communities • in the boreal forest, this is stands of coniferous trees • prairies are dominated by perennial grasses and forbs • however, biomes also contain other kinds of ecosystems within their dominant matrix — they are a dynamic mosaicof “patches”

19. Anthropogenic Ecosystems • Urban-Industrial Techno-ecosystems • residential and industrial habitats of urban or built-up areas • Rural Techno-ecosystems • transportation & transmission corridors, reservoirs, power plants & smelters • Agroecosystems • cultivated fields, pastures, plantations, aquaculture sites

20. A horticultural park Urban ecosystems A clear-cut of old-growth forest Cultivated agriculture