MODULE 7

• Ecosystem


  A complex of living organisms, their physical environment, and all their interrelationships in a particular unit of space

  
• Ecosystems


  • Very good examples of complex systems
  • Governed by laws of physics and chemistry
  • Each component is predisposed to be involved in many different interactions that generate emergent properties
  • Patterns at higher levels emerge from localized interactions
  • Selection processes acting at lower levels
  • Interactions between components are non-linear
  • Outcomes are determined by external conditions (i.e., the environment)

  
• Complex system

  • No formal definition
  • Special class of systems
  • Consist of elements and relations
• Complexity is a fundamental feature of our universe that is not amenable to our traditional methods of modern science
• Major Terrestrial Ecosystems or Biomes

  • Tropical Rain Forest
  • Tropical Dry Forest
  • Tropical Savanna
  • Desert
  • Mediterranean Woodland and Shrubland
  • Temperate Grassland
  • Temperate Forest
  • Boreal Forest
  • Tundra
  • Mountains: Islands in the Sky
• Tropical Rain Forest


  • High biodiversity and biomass
  • Ideal for bacteria and other microorganisms; they quickly decompose matter on the forest floor allowing nutrients to be recycled
• Tropical Rain Forest


  • Straddle the equator in three major regions - Southeast Asia, West Africa, and Central America
  • Occurs within 10˚ of latitude north or south of the equator
  • Found in SE Brazil, Eastern Madagascar, Southern India, and NE Australia

  
• Tropical Dry Forest


  • During the dry season, most trees are dormant
  • In the rainy season, trees flower and insects appear to pollinate
  • Pace of life is quick

  
• Tropical Dry Forest


  • Occupy a substantial portion of earth's surface between 10˚ to 25˚ latitude
  • Found both in north and south of Central Africa, areas south and north of the Amazon rain forest and west coast of Central America, Mexico, Asia and also in Australia
  • Climate is more seasonal than that of the tropical rain forest
  • Dry season lasting from 6 to 7 months followed by abundant rainfall lasting for 5 to 6 months
  • Indicate more variation in temperature

  
• Tropical Savanna

  • Kingdom of farsighted, the stealthy and the swift and is the birthplace of humankind
  • It was from here that humans eventually moved out into every biome on the face of the earth
  • Now, most humans live away from this first home
• Tropical Savanna


  • Occur in north and south of tropical dry forests within 10˚ to 20˚ of the equator
  • South of Sahara dessert, from west to east coasts, north-south swath across the east African highlands, south-central Brazil, Venezuela and Columbia
  • Seasonal drought combines another important physical factor, fire
  • Rains come in summer and accompanied by intense lightning
  • Generally drier than that of tropical dry forest
• Desert


  • "Life on the edge"
  • For many species, the desert is the center of their world
  • Many organisms flourish on meager rations of water, high temperature, and saline soils
• Desert


  • Occupy about 20% of the land surface of the earth
  • Two bands of desert ring the globe: about 30˚ N latitude and about 30˚ S
• Mediterranean Woodland and Shrubland

  • High biological richness
  • Chaparral in Western North America
  • Matoral in Spain
  • Garrigue in farther East of the Mediterranean Basin
  • Fynbos in South Africa
  • Mallee in Australia
• Mediterranean Woodland and Shrubland

  • Occurs in all continents except the Antarctica
  • Grow between about 30˚ to 40˚ latitude
  • Found in Central Chile, Southern Australia, and Southern Africa
  • Most extensive around the Mediterranean Sea and North America
• Temperate Grassland


  • "Sea of Grass"
  • Occur in all continents except in Antarctica
  • Veldts in Africa
  • Pampas in South America
  • Steppes in Eurasia
  • Plains in North America
  • Prairie in some countries
• Temperate Grassland


  • Located north of the Tropic of Cancer 23.5˚ North and south of the Tropic of Capricorn 23.5˚ South
  • Largest biome in the North America
  • Occurs in Argentina, Uruguay, Southern Brazil, and New Zealand
  • In Eurasia, from eastern Europe all the way to eastern China

  
• Temperate Forest

  • Home of the largest trees "sequoias" and the giant Eucalyptus trees
  • Harbor the impressive ancient trees
• Temperate Forest


  • Found between 30°and 55° latitude
  • In Asia, it covered much of Japan, eastern China, Korea, and eastern Siberia
  • North American, from the Atlantic sea coast to the Great Plains and reappear on the West Coast as temperate coniferous forests that extend from northern California through southeastern Alaska
  • In western Europe, it extend from southern Scandinavia to northwestern Iberia and from the British Isles through eastern Europe
  • In the Southern Hemisphere, found in southern Chile, New Zealand, and southern Australia
• Coniferous Forest


  • Made up mainly of cone-bearing or coniferous trees, such as spruces, hemlocks, pines and firs
  • The leaves of these trees are either small and needle-like or scale-like and most stay green all year around (evergreen)
• Deciduous Forest


  • Deciduous means "falling off at maturity" or "tending to fall off"
  • Typically used in order to refer to trees or shrubs that lose their leaves seasonally (most commonly during autumn) and to the shedding of other plant structures such as petals after flowering or fruit when ripe
• Boreal Forest


  • "Taiga"
  • World of wood and water that covers over 11% of the earth's land area
  • Extends right around the globe in a repeating pattern: forest-water, forest-water
  • Largest terrestrial biome in North America
• Boreal Forest


  • Boreal comes from the Greek word for North
  • Extend from Scandinavia, through European Russia, across Siberia, to central Alaska, and across all of central Canada in a band between 50°and 65°N latitude
  • Bounded in the south either by temperate forests or temperate grasslands and in the north by tundra
  • Fingers of boreal forest follow the Rocky Mountains south along the spine of North America, and patches of boreal forest reappear on the mountain slopes of south-central Europe and Asia
• Tundra

  • Tundras are among Earth's coldest, harshest biomes
  • Treeless regions found in the Arctic and on the tops of mountains, where the climate is cold and windy and rainfall is scant
  • Snow-covered for much of the year, until summer brings a burst of wildflowers
• Tundra


  • Rings the top of the globe, covering most of the lands north of the Arctic Circle
  • Extend from Scandinavia, through European Russia, across Siberia, to central Alaska, and across all of central Canada in a band between 50°and 65°N L.
  • It reaches far south of the Arctic Circle in the Hudson Bay region of Canada
  • Also found in patches on the coast of Greenland and in northern Iceland
• Mountains: Islands in the Sky


  • Do not represent a specific biome
  • Because of the environmental changes that occur with altitude several biomes may be found on a single mountainside
  • This environmental and biological diversity is something common to mountains
  • They often introduce unique environmental conditions and organisms to regions around the globe
  • Mountains capture the imagination as places of geological, biological, and climatic diversity and as places with a view

  
• Mountains


  • Are built by geological processes, such as volcanism and movements of the earth's crust that elevate and fold the earth's surface
  • These processes operate with greater intensity in some places than others, and so mountains are concentrated in belts where these geological forces have been at work
• Major Aquatic Biomes or Ecosystems

  • Oceans
  • Lakes
  • Rivers
  • Estuaries
  • Wetlands
• Rivers

  • Form from water moving from a higher altitude to a lower altitude due to gravity
  • When rain falls on the land, it either seeps into the ground or becomes runoff, which flows downhill into rivers and lakes, on its journey towards the seas
• Mountains


  • They often introduce unique environmental conditions and organisms to regions around the globe
  • They capture the imagination as places of geological, biological, and climatic diversity and as places with a view

  
• Mountains

  Built by geological processes, such as volcanism and movements of the earth's crust that elevate and fold the earth's surface
• These geological processes operate with greater intensity in some places than others, and so mountains are concentrated in belts where these geological forces have been at work
• Major Aquatic Biomes or Ecosystems

  • Oceans
  • Lakes
  • Rivers
  • Estuaries
  • Wetlands
• Rivers


  • Forms from water moving from a higher altitude to a lower altitude due to gravity
  • When rain falls on the land, it either seeps into the ground or becomes runoff, which flows downhill into rivers and lakes, on its journey towards the seas
• Lakes


  A depression in the ground that gets filled with water

  Body of water surrounded by land
• Lake Origins

  • Glacial
  • Tectonic
  • Volcanic
  • Fluvial
• Lake Trophic Status

  • Oligotrophic
  • Mesotrophic
  • Eutrophic
• Importance of Lakes

  • Water use for agriculture and industry
  • Water use for drinking
  • Food source (fish, crustaceans, plants, etc.)
  • Recreation (tourism)
  • Habitat (animals, plants, microorganisms)
• Finland is known as the "Land of a Thousand Lakes" (187,000 lakes), while Minnesota is known as the "Land of 10,000 Lakes" (11,842 lakes)
• The Caspian Sea is the largest lake in the world (386,400 km2)