APES: Chapter 1: The Living World (Ecosystem)

• Ecosystem


  A community of living (biotic) organisms interacting with the non-living (abiotic) components of their environment as a system through various nutrients and energy cycles
• Organism


  A living thing that can function on its own
• Species


  Organisms that resemble each other; are similar in genetic makeup, chemistry, and behavior; and are able to interbreed and produce fertile offspring
• Interspecific


  Means between different species
• Population


  Organisms of the same species that interact with each other and occupy a specific area
• Community


  Population of different species
• Ecological Niche

  A particular area within a habitat occupied by an organism, as well as the function of that organism within its ecological community
• Physical environment


  It influences how organisms affect and is affected by resources and competitors
• Niche


  It reflects the specific adaptations that a species has acquired through evolution
• Characteristics of a niche


  • Habitat
  • Interactions with living and nonliving factors
  • Place/role in the food web
  • Types and amounts of resources available
• Symbiosis


  A term used to describe any type of close and long-term biological interaction between two different biological organisms of the same or different species
• Amensalism

  The interaction between two species whereby one species suffers and the other species is not affected
• Amensalism example


  • The black walnut tree releases a chemical that kills neighboring plants
• Commensalism


  The interaction between two species whereby one organism benefits and the other species is not affected
• Forms of commensalism


  • Using another organism for transportation
  • Using another organism for housing
  • Using something that another organism created
• Competition


  It can be either intraspecific and interspecific. It is the driving force of evolution whether it is for food, mating partners, or territory
• Intraspecific competition


  Competition between members of the same species
• Interspecific competition


  Competition between members of different species
• Competition is prominent in predator–prey relationships, with the predator seeking food and the prey seeking survival
• Mutualism


  The interaction between two species whereby both species benefit
• Parasitism

  The interaction between two species whereby one species is benefited, and the other species is harmed
• Predation


  Predators hunt and kill their prey
• Opportunistic predators


  Kill and eat almost anything
• Specialist predators


  Only prey upon certain organisms
• Saprottrophism


  Saprotrophs obtain their nutrients from dead or decaying plants or animals through the absorption of soluble organic compounds
• Law of Tolerance


  It states that the existence, abundance, and distribution of species depend on the tolerance level of each species to both physical and chemical factors
• Some factors can control an organism's abundance or distribution if they exceed its tolerance limits
• Limiting Factor

  Any abiotic factor that limits or prevents the growth of a population
• Limiting factors in terrestrial ecosystems


  • The level of soil nutrients
  • The available amount of water and light
  • The temperature
• Limiting factors in aquatic ecosystems


  • The pH of the water
  • The amount of dissolved oxygen
  • Light
  • The degree of salinity
• Predator-prey cycles

  Based on a feeding relationship between two species: if the prey species rapidly multiply, the number of predators increases until the predators eventually eat so many of the prey that the prey population dwindles again
• Morphological partitioning


  It occurs when two species share the same resource but have evolved slightly different structures to utilize the same resource
• Spatial partitioning


  It occurs when competing species use the same resource by occupying different areas or habitats within the range of occurrence of the resource
• Temporal partitioning

  It occurs when two species eliminate direct competition by utilizing the same resource at different times
• Biomes

  Major regional or global biotic communities characterized by dominant forms of plant life and the prevailing climates
• Temperature and precipitation are the most important determinants of biomes

  • The geographical distribution of the various terrestrial biomes is controlled primarily by the average air temperature and the amount of rainfall the biome receives.
• Deserts


  Defined in terms of the amount of rainfall they receive, not temperature. They cover about 20% of Earth's surface and occur where rainfall is less than 20 inches (50 cm) per year
• Deserts


  • Cover about 20% of Earth's surface
  • Occur where rainfall is less than 20 inches (50 cm) per year
  • Daily extremes in temperature result from exceptionally low humidity as water vapor tends to block solar radiation
  • Most deserts are located between 15° and 35° north and south latitudes
• Arctic tundra


  A cold desert due to the low amount of rainfall it receives yearly
• Succulents


  • Have fleshy leaves or stems that store water
  • Have deep roots to tap groundwater
  • Have open stomata at night
  • Have shallow roots to collect and store water after short rainfalls
  • Have small surface areas exposed to sunlight
  • Have vertical orientation to minimize exposure to the sun
  • Have waxy leaves to minimize transpiration