Chapter 3- Ecosystem classification and relationships

• Ecology


  Study of interactions of organisms with their physical environments and with other organisms
• Ecosystem


  Ecological system which includes the organisms in an area (biotic factors), their physical environment (abiotic factors) and the interactions of these factors
• Ecosystems can vary greatly in their biotic and abiotic factors, scientists use these diverse characteristics for classification
• Biosphere


  Sum of all ecosystems across the world
• Biomes


  Biospheres classified into major life zones, are regions of the world with similar climate, animals and plants
• Biomes can be further classified into ecosystems, smaller units where communities that are almost distinct interact
• Terrestrial biomes


  • Tropical rainforests
  • Deserts
  • Grasslands
  • Tundras
• Aquatic biomes


  • Lakes
  • Oceans
  • Rocky shores
• Ecosystem


  A community and its environment, and the interactions between them
• Community


  Sum of all living organisms in a habitat
• Abiotic factors


  Physical and chemical factors such as temperature, light intensity, texture and pH of soil, concentration of significant gases in water or air, nutrient availability and availability of water
• Biotic factors


  Presence or absence of other living organisms that affect an organism, such as other members of their own species, competitors, collaborators, predators, disease-causing organisms, parasites and availability of mates
• Ecosystems are relatively self-contained and are able to support themselves by cycling or exchanging materials e.g. fallen leaves decompose and return their nutrients into the soil
• Habitat


  An area or environment within an ecosystem where an individual of a species lives, feeds and reproduces
• Population


  A group of individual belonging to the same species, living in the same habitat at the same time
• Earth's ecosystem is interconnected and many are under threat
• Damage or change to one ecosystem can affect connected ecosystems as they are interdependent
• Ecosystems classified so that scientists who monitor change in ecosystems can accurately share information
• Ecologists


  Study the relationships between living things and their surroundings
• Ecologists use both qualitative and quantitative data to classify ecosystems and environments based on their abiotic and biotic components
• Substrate


  Supporting surface on which an organism such as a plant grows, may simply provide structural support, or may provide water and nutrients, may be inorganic such as rock or soil, may be organic such as wood
• Soil type properties


  • Location
  • Depth
  • Texture
  • Colour
  • Porosity
  • pH
  • Water-carrying capacity
  • Nutrient status
• Distribution of ecosystems depends on abiotic factors such as soil type and climate
• Vegetation classification


  • Percentage of ground shaded or covered by the tallest layer of vegetation
  • The form (tree, shrub or grass) of tallest layer
• Hard to notice where one ecosystem ends and another begins if you travel from one ecosystem to next
• In neighbouring ecosystem, physical conditions such as soil type and temperature gradually change or merge and ecosystem overlaps
• Some animals (birds) will be part of multiple communities because they move from one area to another
• Ecosystems are described as open, in fact, it is rare that ecosystems are truly 'closed'
• Climate


  Atmospheric weather of an area, measured and averaged over long period of time
• Main elements of climate


  • Temperature
  • Water
  • Light
  • Wind
• Water and temperature both significantly affect geographic range of organisms living in an environment e.g. climate of deserts and rainforests differ
• Marine environments


  Have salt concentration of 3%
• Freshwater environments


  Have salt concentration of 1%
• Estuaries


  Have fluctuating salt concentration, during high tide, salt concentration increases to almost equal to that of the ocean, low tide, it decreases, as you move up estuary, the salt concentration almost equal that of fresh water
• Community


  A group of populations of different species living in close enough proximity, in an ecosystem, to interact
• Relationships between living things affect biodiversity of a region, some being harmful to it and others, beneficial
• Every living thing and environment is affected by presence or absence of other living and non-living things
• Symbiosis


  Relationship between individuals of two or more species that benefits at least one of the species
• Types of symbiosis


  • Parasitism: one species, the parasite, benefits at the expense if the other, the host
  • Mutualism: both species in relationship benefit and neither is harmed
  • Commensalism: one species benefits and the other neither benefits nor is harmed
• Parasitism


  Interactive relationship between two species: parasite and host, parasite is an organism that lives on or in another organism which is the host, parasite derives its nutrients from host, which is harmed during process but not always killed