Envi Sci 2

• energy


  it is transferred between organisms in food webs from producers to consumers and also used by organisms to carry out complex tasks
• energy starts from the sun.
• plants produce metabolic energy via photosynthesis.
• energy pyramid is also called trophic pyramid or ecological pyramid.
• energy pyramid


  it is the basic structure of interaction in all biological communities characterized by the manner in which food energy is passed from one trophic level to the next along the food chain.
• autotrophs


  they are the primary producers in an ecosystem.
• autotrophs obtain energy and nutrients by harnessing sunlight through photosynthesis (photoautotrophs), or more rarely, obtain chemical energy through oxidation (chemoautotrophs) to make organic substances from inorganic ones.
• autotrophs


  they do not consume other organisms
• heterotrophs


  they are an organism that eats other plants or animals for energy and nutrients.
• heterotrophs occupy the second and third levels in a food chain, a sequence of organisms that provide energy and nutrients to other organisms.
• food chain


  it is a linear sequence of organisms where nutrients and energy is transferred from one organism to the other. this occurs when one organism consumes another organism.
• food chain


  it explains which organism eats another organism in the environment.
• four major parts of food chain

  • the sun
  • producers
  • consumers
  • decomposers
• the sun is the initial source of energy, which provides energy for everything on the planet.
• the producers in a food chain include all autotrophs such as phytoplankton, cyanobacteria, algae, and green plants.
• the producers make up the first level of a food chain.
• the producers are known as autotrophs as they make their own food, utilizing the energy from the sun.
• producers are any plant or other organisms that produce their own nutrients through photosynthesis.
• consumers are all organisms that are dependent on plants or other organisms for food. this is the largest part of a food web as it contains almost all living organisms.
• consumers include herbivores which are animals that eat plants, carnivores which are animals that eat other animals, parasites that live on other organisms by harming them, and scavengers which are animals that eat dead animals' carcasses.
• decomposers are organisms that get energy from dead or waste organic material. this is the last stage in a food chain.
• decomposers are an integral part of a food chain, as they convert organic waste materials into inorganic materials, which enriches the soil or land with nutrients.
• food web


  formed by several interconnected food chains.
• a food web is similar to a food chain but the food web is comparatively larger than a food chain.
• the food web is able to show the proper representation of energy flow, as it displays the interactions between different organisms.
• types of food chain

  • detritus food chain
  • grazing food chain
• the detritus food chain begins with dead organic material. the food energy passes into decomposers and detritivores, which are further eaten by smaller organisms like carnivores.
• the grazing food chain starts with green plants, passes through herbivores and then to carnivores. in this type of food chain, energy in the lowest trophic level is acquired from photosynthesis.
• food webs are defined by their biomass. biomass is the energy in living organisms. autotrophs, the producers in a food web, convert the sun's energy into biomass. biomass decreases with each tropic level. there is always more biomass in lower trophic levels than in higher ones.
• bioaccumulation


  it is the process of accumulating toxic chemicals such as pollutants, pesticides, and other toxins directly into the human body either through air, water, food intake, or directly through the skin.
• causes of bioaccumulation

  • persistent organic pollutants (POPs)
  • heavy metals
  • hydrophobic substances
  • food chain magnification
• effects of bioaccumulation

  • ecological disruption
  • human health risks
  • wildlife impacts
  • threats to endangered species
  • environmental persistence
• biomagnification


  it is the process of a buildup of certain chemical substances or toxins at the higher trophic levels of a food chain.
• biomagnification can be defined as the rise or increase in the contaminated substances caused by the intoxicating environment.
• causes of biomagnification

  • agriculture
  • organic contaminants
  • industrial activities
  • mining activities in the ocean
• effects of biomagnification

  • impact on human health
  • effects on reproduction and development of marine creatures
  • destruction of coral reefs
  • disruption of food chain
• energy balance is the state at which the number of calories eaten equals the number of calories used. it is affected by physical activity, body size, amount of body fat and muscle, and genetics.
• energy balance is the relationship between "energy in" (food calories taken into the body through food and drink) and "energy out" (calories being used in the body for our daily energy requirements).
• according to the laws of thermodynamics, energy is never really created and it's never really destroyed. rather, energy is transferred between entities.
• our body weight is influenced by our energy intake and our energy output. this relationship is defined by the energy balance equation:

  energy balance = energy intake - energy expenditure