Science Unit 5

• The carrying capacity can be affected by factors such as food availability, water supply, climate, predators, disease, and competition. The largest population an area can support with its resources (i.e. food, water, land) is called its carrying capacity.  A population usually stays near its carrying capacity because of the limiting factors of a habitat. 
• • Energy Pyramid: represents the energy available at each trophic level; levels ALWAYS get smaller as you go up the pyramid (Remember the Rule of 10!)
• • Numbers Pyramid: represents the number of organisms at each trophic level; since energy decreases as you go up the pyramid, fewer organisms can be supported
• • Biomass Pyramid: represents the total mass of living organic matter at each trophic level
• • Density-dependent limiting factors have a bigger impact on more dense populations. 
  • These are factors that can be triggered by an increase in population size, and thus crowding.
  • Competition for resources
  • Disease and parasites
  • Predation
• • Density-independent limiting factors regulate population growth regardless of its size or density.
  • Nearly all species in an ecosystem are affected equally by density independent limiting factors.
  • Natural disasters (tornados, floods, wildfires, hurricanes)
  • Temperature
  • Climate change
  • Human activities
  • Pollution
  • Habitat destruction
• Food and Water

  When organisms like animals do not get the food and water they require to survive, some of these animals will die and this will limit the population’s growth.
• Living Space

  When organisms do not have enough space to carry out essential things like getting the nutrients they need or nesting, this will prevent them from doing these essential things that would help grow their population by keeping their survival or generating more offspring.
• Weather and Random Events

  Weather and unsuspected events can cause abrupt changes to the organisms life styles like randomly restricting organisms from their food source and also leads to death. With organisms being unprepared of this and dying, this will cause a lot of death and therefore limit the population.
• Habitat: the actual area in the ecosystem where an organism lives, including all of its abiotic and biotic resources.
• • Niche: all of the things an organism needs and does within its habitat.
• Within an environment, there are limited resources to be used and so organisms compete for resources (space, food, and mates) and this leads to interactions and relationships between organisms.
• • A predator/prey graph shows the cycling of the populations in response to each other over time.
  • Lack of predators can lead to overpopulation

  
• Keystone species: a species that holds the the ecosystem together; it is critical for the survival of the other species in the ecosystem.
• Mutualism: Both organisms involved benefit. 
• Commensalism: One species benefits while the other is unaffected (neither benefited or harmed).
• Parasitism: One organism (parasite) benefits from the relationship, while the other organism (the host) is harmed.
• Competition: a relationship that exists between two or more organisms that are fighting for the same limited resource.
• Interspecific Competition = where competition is occurring between different species.
• Intraspecific Competition = where competition is occurring within the same species.
• Limiting factors are anything that constrains a population's size and slows or stops it from growing (Population)
• Ecosystem


  A community or group of living organisms that live in and interact with each other in a specific environment.
• Autotroph


  An organism that makes/produces their own energy.
• Hetrotroph 


  An organism that gets their energy from living or dead organisms.
• Chemotroph


  An organism that makes its own energy/food through chemosynthesis.
• Food Chain


  Traces a single flow of energy that shows trophic levels and levels of nourishment.
• Food Web


  Traces multiple flows of energy/food chains at once and how they interconnect.
• Trophic Level


  The position an organism occupies in a food web.
• Biomass


  The total mass of living organic matter.
• Consumer


  A organism that can't produce its own food and must eat other organisms for food and energy.
• Producer


  An organism that makes its own food/energy, at the bottom of the trophic pyramid.
• Carrying Capacity


  The theoretical maximum population a given environment can support.
• Predation


  When one animals kills another for food.
• Endangered Species


  A species of animal or plant that is seriously at risk of extinction.
• Threatened Species


  A species which is vulnerable to extinction in the near future.
• Biodiversity


  Variety of different organisms and species in an area.
• How does the water cycle impact an ecosystem?

  {answer} one answer is that when too much evaporation happens in a area, this can dry out water bodies like lakes that animals need to survive, with no water, these animals will die and reduce population density.
• How does the carbon cycle impact an ecosystem?

  {answer} One answer is that excess carbon in the ocean makes the water more acidic, putting marine life in danger, this can kill prey which will have an impact on the food chain and have a domino effect on the food web. ex. no fish -> bears die -> overpopulation of fish -> competition for resources reduce fish population.
• How do humans impact the ecosystem?

  Multiple different ways:

  • Deforestation -> ruins habitats and living space that animals need to carry out survival functions.
  • Climate change leads to ocean acidification -> kills marine life which impacts food chains and has domino effect on food web
• How to calculate biomass loss percentage?

  Divide the (difference between biomass of higher and lower level) by the (total biomass) and times that by 100.