Ecology

• Factors affecting plant growth:

  • Human: trampling, habitat destruction, pollution, use of chemicals
  • Abiotic: Soil pH, light intensity, temp, water, mineral ions
  • Biotic: competition between and within a species, predators
• Chi-squared testing: A statistical test used to determine whether the observed frequencies of a particular event are significantly different from the expected frequencies.
• Species


  A group of organisms that can potentially interbreed and produce fertile offspring
• Population

  A group of organisms of the same species that live in a particular area at the same time
• Community

  A group of populations living and interacting in a particular area
• Ecosystem

  A community and its abiotic environment
• Abiotic factors

  Non-living factors, such as pH, salinity, wind speed, type of soil, etc.
• Biotic factors

  Living factors in an ecosystem, such as the plants and animals
• Autotrophic


  A mode of nutrition which involves the organism making organic molecules using the abiotic environment
• Heterotrophic


  A mode of nutrition in which organisms obtain organic molecules from other organisms
• Mixotrophs

  Organisms which use both autotrophic and heterotrophic modes of nutrition
• Herbivores


  Consumers who feed solely on producers
• Primary consumers

  Feed on producers
• Secondary consumers

  Feed on primary consumers
• Carnivores

  Consumers who feed solely on other consumers
• Omnivores

  Consumers who feed on both producers and consumers
• Ingestion

  Taking in of a substance (be it solid or liquid food, medication, toxic substances or indigestible materials). Can be through the mouth, or other means
• Detritivores

  Organisms that gain nutrients by feeding on dead organic material and breaking it into smaller organic molecules
• Saprotrophs

  Organisms that get their nutrients by secreting digestive enzymes into their environment to break down organic debris around them (decomposers)
• Internal digestion

  Process by which an organism digests its food inside of its body, usually with a digestive tract
• External digestion

  Process by which organisms secrete enzymes into their environment to break down organic debris around them
• Heterotrophs

  • Consumers
  • Detritivores
  • Saprotrophs
• Herbivores are consumers who feed solely on producers
• Primary consumers feed on producers
• Secondary consumers feed on primary consumers
• Tertiary consumers feed on secondary consumers
• Carnivores are consumers who feed solely on other consumers
• Omnivores are consumers who feed on both producers and consumers
• Ingestion is a term used for feeding, digestion is the breakdown of food once it has been ingested, and egestion is the waste or undigested material that leaves the body
• Ecology is the branch of biology where scientists study ecosystems and the interactions of the biotic and abiotic factors
• Symbiosis

  Living together and refers to the following outcomes of interactions between populations
• Mutualism

  A type of symbiotic relationship where both organisms benefit
• Commensalism

  A type of symbiotic relationship where one organism benefits and the other is unaffected
• Parasitism

  A type of symbiotic relationship where one organism benefits and the other is harmed