pyramids of number

• the width of the bands is meant to represent the relative number of organisms at each trophic level
• it is presented as a bar grah
• wider bar = more organisms
• bottom bar = number of producers
• What does a wider bar in a pyramid of numbers indicate?

  More organisms are present
• What does the bottom bar in a pyramid of numbers represent?

  Number of producers
• What does it mean if a producer is relatively small in a pyramid of numbers?

  It indicates fewer producers are present
• Why are many grass plants needed to feed insects?

  Grass plants provide essential nutrients
• How many caterpillars can a single oak tree feed?

  Many caterpillars can be fed
• How many robins are needed to feed an owl?

  Lots of robins are needed
• How are the bars in a pyramid of numbers arranged?

  By trophic levels
• What is biomass in ecological terms?

  • Total mass of living materials
  • Indicates energy available in an ecosystem
• What type of consumer is a bird in this context?

  Secondary consumer
• What type of consumer is an insect in this context?

  Primary consumer
• What type of producer is grass?

  Producer
• What type of consumer is an owl in this context?

  Tertiary consumer
• What type of consumer is a robin in this context?

  Secondary consumer
• What type of consumer is a caterpillar in this context?

  Primary consumer
• What type of producer is an oak tree?

  Producer
• A single oak tree can feed many caterpillars, lots of robins are needed to feed the owl

  
• where the producer is relatively small, many grass plants are needed to feed insects

  
• pyramids of numbers is arranged by the trophic levels