PECOSY

• Symbiosis


  a close ecological relationship between the individuals of two or more species
• Four main symbiotic relationship

  Mutualism

  Commensalism

  Parasitism

  Cooperation
• Mutualism


  is a association between organisms of two different species in which each member benefits
• Commensalism


  is a symbiotic relationship between two organisms of different species in which one derives some benefit while the other is unaffected
• Parasitism


  Is a form of symbiosis in which one species benefits at the expense of another species; similar to predation, but acts more slowly than predators and may not always kill the host
• Cooperation


  is the act of working or acting together. Ex. Ants and bees colonies work together
• Competition


  occurs when two or more individuals seek to utilize the same recourcesw
• Predation


  describe an interaction where a predator species kills and eats other organism, known as prey
• Predation


  sometimes, predators themselves become prey
• Ecological succesion


  is the process by which the mix of species and habitat in an area changes over time
• Two major types of ecological succesion

  Primary succesion

  Secondary succesion
• Primary succesion


  happens when a new patch of land is created or exposed for the first time
• Primary succesion


  this can happen, for example, when lava cools and creates new rock, or when a glacier retreats and exposes rocks without any soil
• Primary succesion


  organism must start from scratch.

  Bare rock ~ Lichens/moss~ Grasses ~ Shrubs ~ Trees
• Primary Succesion: Pioneer species

  Lichens/moss~ Grasses ~ Shrubs ~ Trees
• Secondary succesion


  happens when a climax community or intermediate community is impacted by a disturbance.
• Secondary succesion


  this restart the cycle of succesion, but not back to the beginning-- soil and nutrients are still present
• Secodary succesion: Climax Community


  the "endpoint" of succesion within the context of a particular climate and geography.
• Climax Community: Examples


  Tundra

  Grassland

  Dessert

  Deciduous

  Coniferous

  Tropical rain forest
• Endangered species


  are organisms that are near extinction
• Secondary succesion


  invasive species harm native species
• Greenhouse gases


  absorb energy, slowing or preventing the loss of heat to the atmosphere
• Acid rain


  is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air
• Biomagnification


  the condition where the chemical concentration in an organism exceeds the concentration of its food when the major exposure route occurs from the organism's diet
• Umbrella species


  selected for making conservation-related decisions, typically because protecting these species indirectly protects the many other species that make up the ecological community of its habitat (the umbrella effect)
• Limiting factor

  is an abiotic or biotic factor that restricts the number of individuals in a population
• Limiting Factor


  a resource or environmental condition that limits the growth, distribution, or abundance of an organism or population within an ecosystem
• Two types of limiting factors

  Density dependent factors

  Density Independent factors
• Density dependent factors


  those whose effect on the population is determined by the total size of the population
• Density denpendent factor


  operate only when the population is large or dense.
• Density dependent factors: examples

  predation

  disease

  resource availability
• Density independent factors


  those that limit the size of a population (the number of indiciduals). They affect all population regardless of the population size.
• Density independent factors: examples

  earthquakes

  stunami

  volcanic eruption

  drought

  flood
• Limiting factors include:


  competitors

  dieases and parasites

  weather

  fires

  available habitat

  predators
• Competitors


  results when organisms struggle to survive in a habitat with limited recources
• Disease and parasites


  can be dependent on population size and habitat.
• Weather


  storms

  drought

  flooding

  heat/cold
• Fires


  lead to succesion which is a predictable change in the community over time.
• Available habitat


  human activities play a large role.

  development, damming rivers, clear cutting forests, hunting.

  parts of the habitat can also be limiting: amount of food, available nesting sites
• Predators


  Predator/prey relationship can be a delicate balance between the two population.