Topic 4

• Ecology


  The science of the relationships between organisms and their environments.
• Organism


  an individual living thing that uses energy, reproduces, responds, grows, and develops

  
• Species


  a group of similar organisms that can breed and produce fertile offspring

  
• Population


  group of individuals of the same species that live in the same area

  
• Community


  all living, or biotic, things in an area

  
• Ecosystem


  all biotic (living) and abiotic (nonliving) things in an area

  
• Autotroph


  - also known as a producer

  - an organism capable of making its own food from inorganic substances using light or chemical energy.

  - eg. Green plants, algae, and certain bacteria

  
• Heterotroph


  An organism that obtains organic food molecules by eating other organisms or substances derived from them.

  
• Carbon cycle


  the continuous process by which carbon is exchanged between organisms and the environment

  
• Energy flow


  - sunlight is the source of energy for most ecosystems

  
• Trophic level


  step in a food chain or food web

  
• Food chain


  shows the transfer of energy between organisms.

  
  

  producer --> primary consumer --> secondary consumer --> tertiary consumer

  
  

  eg. passion flower --> heliconius butterfly --> tegu lizard --> jaguar

  
  

  the energy in the carbon compounds (food) is released through respiration. much of this energy is lost as heat.

  
• Food web


  network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

  
• Pyramid of energy


  - diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web

  - should be stepped

  - the length of the bar represents the amount of energy transferred to the trophic level (resulting in an increase in biomass)

  - the unit = KJ m^-2 yr^-1

  - around 10% of energy at any trophic level is passed on to the next trophic level

  - the number of trophic levels is limited, as there is ever decreasing quantities of energy available for transfer and the energy is passed along the food chain.

  - reasons for loss of energy between the trophic levels include:

  * energy is lost as heat due to respiration

  * not all of the individuals at each trophic level is consumed

  * not all parts of the organism can be digested.
• 10% Rule


  Only 10% of the energy in one trophic level gets passed onto the next trophic level

  
• Biological magnification


  increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain or food web

  
• Producer


  organism that can capture energy from sunlight or chemicals and use it to produce food from inorganic compounds; also called an autotroph

  
• Consumer


  organism that relies on other organisms for its energy and food supply; also called a heterotroph

  
• Primary Consumer


  Consumer that feeds directly on producers;

  The animal that directly eats the producer;

  this category includes organisms that consume producers (plants and algae).

  
• Secondary Consumer


  An organism that eats primary consumers;

  A member of the trophic level of an ecosystem consisting of carnivores that eat herbivores;

  eats primary consumers

  
• Tertiary Consumer


  An organism that eats secondary consumers;

  The third trophic level of consumer in a food chain; A carnivore that eats other carnivores.

  
• Detritivore


  organism that feeds on plant and animal remains and other dead matter (ex. vultures, earthworms, crabs, etc.)

  
• Saprotroph


  an organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion (e.g. mushrooms, bacteria);

  Obtains nutrients from decaying organic matter

  
• Precautionary Principle


  The principle that states that when an activity raises threats of harm to human health or to the environment safety should prevail in control measures should be initiated even if cause-and-effect relationships are fully established

  
• Detritus


  nonliving organic matter; typically includes decaying dead organisms as well as fecal matter

  
• Habitat


  the area where an organism lives, including the biotic and abiotic factors that affect it

  
• Limiting factor


  factor that causes the growth of a population to decrease or not grow any larger (ex. food, water, shelter, predation, disease, etc.- abiotic or biotic factors)

  
• External factor


  any living or nonliving factor that impacts the survival of an organism, population, or community (can be a limiting factor or a non-limiting factor)

  
• Abiotic


  non-living
• Biotic


  living
• Greenhouse effect


  is a natural phenomenon which maintains temperatures required for life to live on Earth.

  
  

  short wave (visible light) radiation from sunlight passes through the Earth's atmosphere and strikes the surface of the planet.

  
  

  much of the light is reflected, but some is absorbed and transferred to heat. the earth radiated the hear as infrared (long wavelength) into the atmosphere.

  
  

  the greenhouse effect traps some of the heat keeping the atmosphere warm

  
  

  most important greenhouse gases = CO2 & H2O (methane and nitrogen also contribute to greenhouse effect)

  
  

  if the concentration of green house gases increase, more heat will be trapped. there is evidence that this is happening due to human activities (eg. combustion of fossil fuels)

  
• Potential problems associated with climate change

  1) ice habitats are melting (destruction of habitats)

  2) flooding (destruction of habitats)

  3) desertification

  4) more extreme weather events

  5) species extinction

  6) movement of species further north=

  7) destruction of food webs
• Microorganism


  an organism that is microscopic, or too small to be seen by the unaided human eye; examples include bacteria, archaea, most protists, and some fungi (viruses, although microscopic, are not considered microorganisms because they are non-living)

  
• Chemoautotrophs


  Obtaining energy from inorganic substances;

  organisms that obtain energy from chemicals to make their own food;

  Autotrophic bacteria that derive energy from inorganic sulfur compounds; often live in deep-ocean vents, bacteria

  
• Quadrat Sampling


  Using a known small area at random to count organisms within that area. The number of organisms within that area can give an approximate estimate of the population of that particular species in a larger area.

  
• Transect


  use string across a place where you collect data, collect the data of whatever passes the string

  
• Fundamental Niche


  all of the places a species can live if no competition;

  
  

  The entire range of resource opportunities an organism is potentially able to occupy within an ecosystem

  
• Natality


  Birth rate;

  
  

  increases population size as offspring are added to the population
• Immigration


  Migration to a new location;

  Movement of individuals into a population
• Emigration


  Movement of individuals out of an area.