Ecology pt 2

In an ecosystem, populations interact among themselves AND interact with the physical environment The abiotic components of an ecosystem are the nonliving components: Atmosphere, Water, Soil The biotic components of an ecosystem are based on how living things obtain their food source: Autotrophs, Heterotrophs Autotrophs - Producers - Require only inorganic nutrients & an outside energy source to produce organic nutrients; Examples - Photoautotrophs or Chemoautotrophs Heterotrophs - Consumers - Require a source of preformed organic nutrients Herbivores - Feed on plants Carnivores - Feed on other animals Omnivores - Feed on plants and animals Decomposers - Bacteria and fungi Break down dead organic matter Energy Flow and Chemical Cycling Every ecosystem is characterized by two fundamental phenomena: Energy flow – Begins when producers absorb solar energy  Make organic nutrients via photosynthesis  Organic nutrients are used by themselves  Organic nutrients are used by others  Energy eventually dissipates into the environment as heat Chemical cycling – Begins when producers take in inorganic nutrients (phosphorus, nitrogen, oxygen, carbon dioxide, etc…) from the physical environment Energy Balances Energy flows through a food web  interconnecting paths of energy flow through trophic levels Trophic Levels - level of nourishment within a food web or chain Food chain is a diagram showing a single path of energy flow in an ecosystem. Ecological Pyramids  Depict the flow of energy with large losses between successive trophic levels Only about 10% of the energy of one trophic level is available to the next trophic level Explains why few top carnivores can be supported in a food web Ch. 46 - Climate and the Biosphere Climate - Prevailing weather conditions in a region Determined primarily by temperature and precipitation Secondary influences including latitude, tilt of the earth’s axis, and topography Solar radiation Direct at the equator; Tilt of the earth causes one pole to be closer than the other to the sun Rotation of the earth affects precipitation and winds Topography is the physical features of the land Example: coastal mountain range Windward side of the mountain; Winds rise; Release moisture Leeward side; Dry winds subside; Evaporates existing water and rarely rains Terrestrial Communities Biomes - Major terrestrial ecosystems characterized by climate and geography A particular mix of plants and animals adapted to living under certain environmental conditions Tend to repeat wherever temperature and precipitation are the same Biome Types Tundra Arctic tundra - Encircles Earth just south of ice-covered polar seas in Northern Hemisphere Covers 20% of Earth’s land surface; Permafrost layer never thaws; Trees are not found in the tundra; Growing season is too short; Roots cannot penetrate permafrost; Roots cannot become anchored in shallow boggy soil Coniferous Forests (Taiga & Temperate Rainforest) Taiga - typifies coniferous forest with cone-bearing trees - near mountaintops, and along the Pacific Coast of North America Trees well adapted to cold; Leaves and bark have thick covering; Needle-like leaves can withstand weight of heavy snowfall Temperate Rainforest (old-growth forest) of Pacific Northwest - Evergreen forest Temperate Deciduous Forests Found south of taiga in eastern North America, eastern Asia, and much of Europe Moderate climate; Relatively high rainfall; Four well-defined seasons with long growing seasons; Tallest trees form a canopy; Ground-life is plentiful Tropical Forests Found in equatorial regions; Warm weather and plentiful rainfall; Complex structure with forest floor, understory, and canopy; Most animals live in trees; Abundant insect life; Epiphytes grow in many areas; Soils are nutrient-poor; Rapid recycling of nutrients Shrublands Tend to occur along coasts that have dry summers and wet winters Shrubs are adapted to withstand arid conditions; dense shrubland in California is a chaparral Grasslands Occur where annual rainfall is greater than 25 cm, but generally insufficient to support trees Grasses are well adapted to changing environment Temperate Grasslands have cold winters and hot, dry summers Savannas have a cool dry season and a hot rainy season Deserts Descending winds lack moisture; Annual rainfall is less than 25 cm; Large temperature differential between day and night Aquatic Ecosystems Aquatic ecosystems are classified as Freshwater (inland), or Saltwater Wetlands are areas that are web for at least part of the year; Marshes, Swamps, Bogs Lakes - Bodies of water classified by nutrient status Oligotrophic - Nutrient-poor; Eutrophic - Nutrient-rich Aquatic Life Zones Plankton (a protist) - Important community in fresh water and salt water ecosystems Phytoplankton - Photosynthetic algae; Zooplankton - Animals Coastal Ecosystems Estuaries Partially enclosed bodies of water where fresh water and seawater meet and mix Organisms must be able to adapt to changing salinity Nearly two thirds of all marine fishes and shellfish require development in estuaries Called the “Nursery of the sea” Seashores - zone that lies between high and low water marks Rocky Shores; Many attached organisms; Littoral zone of rocky beach divided into subzones Sandy beach; No attachment sites available; Nearly all permanent residents dwell underground Oceans - Euphotic Zone (true light zone) Contain a greater concentration of organisms than the rest of the sea Coral Reefs - Located just below the surface in shallow, warm, tropical waters; Densely populated with life Pelagic Zone (“open sea”) Abyss - Abysmal Plain High pressure and extreme cold; Organisms are dependent on debris sinking down from above Hydrothermal vents