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Ecosystems and Communities Chapter 4 4-1 The Role of Climate • What is climate? – Weather is temperature, precipitation, other environmental factors – It usually refers to a specific area – Climate is the weather of a given area over a period of time • Ex. – Artic Climate versus Tropical Climate Greenhouse Effect • This is a natural situation!! • Carbon dioxide, methane, water vapor and other gases trap heat energy and maintain the Earth’s temperature range The Effect of Latitude on Climate • How does the position of the sun in the sky effect climate? (see the next slide for the answer) The Earth has three main climate zones: Polar Temperate Tropical Different latitudes have different angles of heating, affecting climate Heat Transport in the Biosphere • Unequal heating and cooling drives winds and ocean currents. What Shapes an Ecosystem? • Key Concept: Biotic and abiotic factors determine the survival and growth of an organism and the productivity of the ecosystem in which the organism lives. • Biotic Factors – All living things in an ecosystem • Abiotic Factors – – – – – – – Temperature, Precipitation Humidity Wind Nutrient availability Soil type Sunlight The Niche • An organisms occupation in its environment is it’s niche. • This includes the following factors – Type of food – How it obtains food – Which other species use the organism as food – Physical conditions. WARNING WARNING No two species can share the same niche in the same habitat. Resource Sharing Community Interactions • Community interaction, such as competition, predation and various forms of symbiosis can powerfully affect an ecosystem • Competition – Happen when two organisms try to use the same resource in the same place at the same time – A Resource is: water, nutrients, light, food, or space. • Competitive Exclusion Principle – No two species can occupy the same niche in the same habitat at the same time!!! Predation • An interaction in which one organism captures and feeds on another. Symbiosis: Living together closely • Mutualism: both species benefit • +/+ Commensalism • One member benefits and the other is neither helped nor harmed • +/0 Parasitism • One organism lives on or inside another organism and harms it. • +/- Ecological Succession • Ecosystems are constantly changing in response to natural and human disturbances. • As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community The series of predictable changes that occur in a community over time. • Primary Succession – Succession that occurs on surfaces where no soil exists. Primary Succession • Occurs on the surfaces formed as volcanic activity builds new islands or covers the land with lava or volcanic ash. • Also occurs on bare rock exposed when glaciers melt. • The first species to populate an area: pioneer species Secondary Succession A disturbance of some kind that changes an existing community without removing the soil. Caused by farming, wildfires The series of predictable changes ends with a mature, stable community called a climax community Secondary Succession Climax Community Temperate Rain Forest Biomes • There are at least 10 different biomes. • Each of these biomes is defined by a unique set of abiotic factors and has a characteristic ecological community The Effect of Coastal Mountains Biomes #1 - What is this Biome? #2 - What Biome is this? #3 - Name That Biome!! #4 - What Biome is this? Last but not least… #5 Water, water everywhere… • Aquatic ecosystems are determined primarily by the depth, temperature, flow, and chemistry of the overlying water. Freshwater Ecosystems • • • • Flowing water: rivers and streams Standing water: lakes and ponds Wetlands: marshes and swamps Estuaries: where rivers meet the sea. – Contain a mixture of fresh and salt water – Serve as spawning and nursery grounds for many fish and shellfish species. Estuary River Delta – Lena, Russia Marine Ecosystems • Divided into two zones based on the amount of light penetration. – Photic Zone: well-lit upper layer down to about 200 meters. Photosynthesis possible. – Aphotic Zone: permanently dark. Only producers in this zone are chemoautotrophs. Marine Ecosystems (cont.) • Scientists also divide the ocean into zones based on the depth and distance from shore. – Intertidal: subject to tides – Coastal ocean: from the low tide mark to the edge of the continental shelf. Contain coral reefs in tropical areas. Marine Ecosystems (cont.) • Open Ocean: from the continental shelf and extends outward – Largest marine zone – Organisms in the deep open ocean have adapted to great pressure, freezing temperatures and no light Benthic Zone: the ocean floor. Continental Shelf Ocean Zones