UNIT 3 & 4 BIOLOGY BGGS

• Hierarchy of biological levels


  • Individual (one member of one species)
  • Population (a group of individuals of the same species living in one area at one time)
  • Community (all organisms; a group of interacting populations)
  • Ecosystem (a community interacting with their physical environment)
  • Biomes (a group of ecosystems with similar characteristics /geographic features and environmental factors / climates)
  • Biosphere (the sum of all ecosystems on earth)
• Ecosystem


  A community of organisms, their physical environment and the interaction that happens between them
• Balanced, healthy ecosystem


  • Knowing the types of organisms that make up the community
  • Knowing their needs for survival
  • Knowing how they interact with both the living (biotic) and non-living (abiotic) world
• Ecology


  The study of the relationships between living things and their environment
• Habitat


  A specific location, with a particular set of biotic and abiotic conditions where an organism normally lives
• Microhabitat


  A small space in which an organism lives, e.g. underbark
• Population


  A number of organisms of the same species living in the same habitat at the same time
• Community


  All organisms of different species living in the same habitat at the same time
• Environment


  All the factors both living and non-living that affect an organism's survival
• Ecosystem


  When members of a community interact with each other and their physical surroundings
• Living community


  Populations of different species that live in a given region at a particular time
• Non-living physical environment


  Surrounding abiotic factors
• Interactions that occur between organisms and


  • Biotic factors (interactions between living things that affect survival)
  • Abiotic factors (non-livings that affect survival)
• Ecosystem


  Community + Physical Environment + Interactions between them
• Abiotic factors


  The physical conditions of habitats (temperature range, humidity, wind and air currents, water currents, pH, availability of light, water and nutrients)
• In order to survive, grow and reproduce, each organism in a particular habitat must be able to survive in the physical and chemical conditions around it
• Optimal range


  The level at which an organism can best survive for each abiotic factor in the environment
• Optimal range for a plant


  • pH range of 6.5 (slightly acidic) to 8.0 (slightly basic)
• Tolerance range


  The range of abiotic conditions an organism can tolerate, but may not function as efficiently and suffers physiological stress
• Organisms do not survive outside a tolerance range
• An organism will only be found in an area where it encounters the tolerance range for all of its abiotic requirements
• Adaptation


  Any functional, physiological or behavioural feature that enhances a species chance of survival in a particular habitat / environment (Adaptations have a genetic basis and are not acquired within an organisms lifetime)
• Acclimitisation


  A process in which an individual organism adjusts to a change in its environment. It usually develops over a short time period / within an organisms lifetime
• Abiotic factors vary along spatial gradients to produce environmental gradients
• Each species in an environment has a range of abiotic conditions most suitable for its survival and reproduction, therefore these gradients are important determinants in patterns of species distribution
• Biotic components


  Living things in an ecosystem
• Biotic factors


  • Interactions or relationships between living things
• Biotic factors

  Factors relating to living organisms
• Community change over time


  Changes in the composition of a community of organisms over time
• Relationships between organisms

  • Intraspecific relationships (same species)
• Intraspecific relationships


  • May increase surviving an attack by a predator
  • Compete for limited resources such as food, shelter, water, a mate etc...
• Interspecific relationships


  Relationships between different species
• Predation


  • Predator kills prey and eats it
• Competition


  • For limited resources
• Symbiosis


  • Two or more species living closely together for a long time
  • At least one organism benefits
• Levels of ecological studies from biggest to smallest


  • biosphere
  • biome
  • ecosystem
  • community
  • population
  • individual
• Comparing Ecosystems


  • Species diversity indices
  • Species interactions (predation, competition, symbiosis, disease)
  • Abiotic factors (climate, substrate, size/depth of area)
• Spatial scale looks at how communities change over space / distance
• Temporal scale looks at how communities change over time
• Ecosystem


  A community of living organisms interacting with each other and their physical environment