Ecosystems: What Are They and How Do They Work?

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Ecosystems What Are They and How Do They Work?

• Chapter 3

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Ecosystems Biomes

• Because different geographic areas of the Earth
  differ in abiotic and biotic factors, we can
  place them in broad categories.
• The most major division
• Biomes - terrestrial
• Based on climate
• Aquatic life zones fresh and salt
• Based on degrees of salinity

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Revisit the Worlds Major Biomes
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The Worlds Major Biomes
Biome Annual Rainfall Soil Type Major Vegetation World Location
Deciduous Forest (temperate and tropical) 75-250 cm, rich soil with high organic content Hardwood trees N. America, Europe, Australia, Eastern Asia
Tropical Rainforest 200-400 cm, poor quality soil Tall trees with few lower limbs, vines, epiphytes, plants adapted to low light intensity S. America, West Africa, Southeast Asia
Grasslands 10-60 cm, rich soil Sod-forming grasses N. American plains and prairies Russian steppes S. African velds Argentinean pampas
Coniferous forest (Taiga, Boreal Forest) 20-60 cm mostly in summer, soil is acidic due to vegetation Coniferous Trees Northern N. America, northern Eurasia
Tundra Less than 25 cm, soil is permafrost Herbaceous plants The northern latitudes of N. America, Europe and Russia
Chaparral (scrub forest) 50-75 cm mostly in winter, soil is shallow and infertile Small trees with large hard leaves, spiny shrubs Western N. America, Mediterranean region
Deserts (hot and cold) Less than 25 cm, soil has a coarse texture (sandy) Cactus, other low-water adapted plants 30 degrees north and south of equator
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The Worlds Biomes

• Causes of major biomes
• Temperature and precipitation (climate)
• Caused by wind patterns

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Ecosystems Biomes

• ECOREGIONS (ECOZONES) are smaller regions within
  ecosystems that share similar physical features
• Northeastern Coastal Zone where we live

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Ecosystems Biomes

• ECOREGIONS (ECOZONES) are smaller regions within
  ecosystems that share similar physical features
• Major Biome Deciduous Forest
• Ecozone Northeastern Coastal Zone where we
  live
• Recently glaciated
• Irregular topography, hilly
• Soil rocky nutrient poor
• Mixed hardwood gt70 of region
• Salt marshes

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Ecosystems Biomes

• Although the list of biomes seems very distinct,
  biomes blend
• ECOTONE the area where two biomes meet and
  transition
• Marsh and mangrove
• Salt marsh and hardwood forest

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What Are the Major Components of an Ecosystem?

• Some organisms produce the nutrients they need,
  others get the nutrients they need by consuming
  other organisms, and some recycle nutrients back
  to producers by decomposing the wastes and
  remains of organisms.

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Living and Nonliving Components

• Abiotic
• Water
• Air
• Nutrients
• Solar energy
• Biotic
• Plants
• Animals
• Microbes

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Biomes and Organisms
Oxygen (O2)
Precipitation
Carbon dioxide (CO2)

• The biotic and abiotic factors of a biome
  determine the types and numbers of organisms that
  are capable of living in it.

Producer
Secondary consumer (fox)
Primary consumer (rabbit)
Producers
Water
Decomposers
Soluble mineral nutrients
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Animation Species Diversity By Latitude
Animations/species_by_latitude.html
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Animation Diet of a Red Fox
Animations/red_fox.html
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Laws of Minimum and Tolerance

• Law of Minimum
• Organisms will continue to live, consuming
  available materials until the supply of these
  materials is exhausted.
• Law of Tolerance
• Basis for natural selection
• Describes the degree to which living organisms
  are capable of tolerating changes in their
  environment.
• Even individuals differ in their range

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Range of Tolerance, Limiting Factors
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Limiting Factors

• Limit number or organisms in a population even
  if all other factors are optimal
• Common terrestrial factors
• Precipitation
• Soil nutrients
• Temperature
• Common aquatic factors
• Dissolved oxygen
• Salinity

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Biotic Factors, Trophic (feeding) Levels

• TWO MAJOR DIVISIONS
• Producers autotrophs
• Photosynthesis
• Consumers heterotrophs
• Primary (herbivores)
• Secondary (carnivores that eat herbivores)
• Third-level (eat carnivores)
• Omnivores (eat plants and animals)
• Decomposers (primarily bacteria fungus)
• Detritivores (feed on wastes carcasses)

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Biotic Factors, Trophic (feeding) Levels
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Detritus Feeders and Decomposers
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Animation Categories of Food Webs
Animations/food_webs_v2.html
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Animation Rainforest Food Web
Animations/rainforest_anim.html
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Biotic Factors, Trophic (feeding) Levels

• SUMMARY
• Some organisms produce the food they need
• Others consume other organisms for nutrients
• Still others recycle wastes and nutrients for
  producers to use them again

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Production of Energy

• Solar energy converted to Chemical energy stored
  in food
• Photosynthesis

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Consumption of Energy

• Chemical energy stored in food fuels life
  processes
• Aerobic respiration
• Anaerobic respiration (fermentation)
• C6H12O6 ? 2C3H6O3 2 ATP
• Can result in the production of lactic acid,
  methane, ethyl alcohol, acetic acid, and hydrogen
  sulfide

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Energy Flow and Nutrient Recycling

• Ecosystems sustained through
• One-way energy flow from the sun
• Nutrient recycling
• Energy flow arises from
• Structure and function of ecosystems
• Law of conservation of matter
• Laws of thermodynamics

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Structural Components of an Ecosystem
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Animation Roles of Organisms in an Ecosystem
Animations/ecosystem_roles.html