• Organisms can be classified into trophic (feeding) levels depending on how they get their energy.
  • Organisms that get their energy from nonliving sources (sun, organic matter) are called autotrophs (producers) and make up the 1st trophic level.
  • Organisms that get their energy from other living things are called heterotrophs (consumers).
  • Heterotrophs that eat autotrophs make up the 2nd trophic level and are called primary consumers.
  • The third trophic levels consists of secondary consumers and eat primary consumers.
  • Ecosystems are normally limited to about 5 trophic levels.
  • All energy in an ecosystem is derived from the sun*.
  • This energy is converted to sugar (chemical energy) by plants through the process of photosynthesis.
  • A food chain shows the transfer of energy from one trophic level to another.
  • Whenever energy is transferred, some gets lost.

Energy Pyramids

  • Since energy is lost each time it is transferred, each trophic level receives less energy than the level before it.
  • Also, energy gets used at each level, so only 10% of the energy from one trophic level gets passed onto the next trophic level.
  • This can be shown using an energy pyramid.
  • The size of the boxes represent the amount of energy in each trophic level.

Ecological Niches

  • The function a species serves in its ecosystem, including what it eats, what eats it, and how it behaves.
  • No two species occupy identical niches.

Types of Consumers

  • A sequence of organisms, each feeding on the next, showing how energy is transferred from one organism to another.
  • pine cone -> red squirrel -> weasel -> goshawk
  • Energy is continuously lost from all levels of the food chain.
  • Food chains do not exist in nature.
  • Create a sample food chain using the following organisms: grass, snakes, snails, birds.
  • What happens when one link is broken in a food chain?

Trophic Level

  • The level of an organism in an ecosystem depending on its feeding position along a food chain.
  • First trophic level – producers
  • Second trophic level – primary consumers
  • Third trophic level – secondary consumers
  • Fourth trophic level – tertiary consumers

Ecological Pyramids

  • A representation of energy, numbers, or biomass (the mass of living organisms in a given area) relationships in ecosystems.
  • Energy pyramid – Energy loss and transfer between trophic levels; the size of each layer represents the amount of energy available at that trophic level.
  • Only about 10% of the energy taken in by the individuals at one trophic level is passed on to individuals at the next level.
  • 10% of it is used to build new biomass (the rest going to metabolic processes). In a pyramid of productivity each step will be 10% the size of the previous step (100, 10, 1, 0.1, 0.01)

Energy Pyramid

  • Pyramid of Energy Flow
  • 10% passed on to next level (a lot energy is lost as HEAT or to fuel prey’s bodily functions)
  • At each trophic level, the bulk of the energy received from the previous level is used in metabolism
  • This energy is released as heat energy and lost to the ecosystem
  • Eventually, all energy is released as heat

Numbers and Biomass Pyramids

  • In a forest ecosystem, the tiny plant-feeding insects in the second trophic level outnumber the trees in the first trophic level.
  • However, the biomass of all the trees is much greater than the biomass of herbivores.
  • Example Biomass Pyramid

9
Leave a Reply

avatar
8 Comment threads
1 Thread replies
0 Followers
 
Most reacted comment
Hottest comment thread
8 Comment authors
BOBdogEMMY LOVEEdewiholybyte Recent comment authors
newest oldest most voted
EMMY LOVEE
Guest
EMMY LOVEE

10% of it is used to build new biomass (the rest going to metabolic processes). In a pyramid of productivity each step will be 10% the size of the previous step (100, 10, 1, 0.1, 0.01)

Bob T.
Guest
Bob T.

This helped me

dewi
Guest
dewi

thank you for your information. it help me being a new biology teacher

swiftie shielo
Guest
swiftie shielo

I love this page even if it only displays few informations, one can still learn a lot from it… but what realy is Kcal???

swiftie shielo
Guest
swiftie shielo

what is kcal??? coz i don’t know what is it

dog
Guest
dog

I think Kcal is kilocalories

ginky
Guest
ginky

thru eating process..the higher the consumer, the lower energy it gets…..

Lila
Guest
Lila

I think you should put more of an explanation for why only 10% of the energy gets transferred.

holybyte
Guest
holybyte

kilo calories!