Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
KEY TERMS Ecological pyramid Energy pyramid Numbers pyramid Biomass pyramid Trophic level TROPHIC LEVELS We have already learned about trophic levels on food chains Organisms in the food chain rise from the producers all the way up to the top carnivore PYRAMIDS Ecological pyramids are used by ecologists to illustrate certain characteristics of food chains and food webs. They show certain relationships that exist between the different trophic levels TYPES OF PYRAMIDS • There are three types of ecological pyramids: • • • Energy Numbers and Biomass ENERGY PYRAMIDS • All organisms require energy to live • They contain energy within themselves • Energy is measured in calories or Joules ENERGY PYRAMIDS Energy pyramids are shaped in a conventional way. That is, in an ecosystem, low trophic levels (i.e. producers), have the most energy and high levels have the least In fact, as energy flows from one level to the next, only about 10% of the energy remains. That’s because the rest of the energy is used by the organism for it’s life processes BIOMASS PYRAMIDS Biomass pyramids show the relative mass of living organisms at each trophic level Just like energy pyramids, the lower trophic levels in an ecosystem have the most biomass and the upper levels have the least NUMBERS PYRAMIDS Number pyramids can be a little different than the other two; but don’t have to be It depends on the ecosystem Sometimes they appear the same as energy and numbers; highest numbers at the lowest level NUMBERS PYRAMIDS But not always. For example, in some forests, huge trees make up the lowest trophic level and, while there aren’t that many of them compared to the next level (insects, birds…), they have the most mass and energy . So number pyramids can look inverted NUMBER PYRAMIDS They can look conventional Or they can be somewhere in between TIME TO DO SOME WORK!!! Page 47 1-6, 8