Food chains webs and trophic levels
This presentation is the property of its rightful owner.
Sponsored Links
1 / 16

Food chains/webs and trophic levels PowerPoint PPT Presentation


  • 111 Views
  • Uploaded on
  • Presentation posted in: General

Food chains/webs and trophic levels. Trophic levels. Determines the pathways of energy flow and nutrient cycling (more on this later) Different species in the ecosystem are divided into different trophic levels depending on what they eat There are 5 main levels. Trophic levels.

Download Presentation

Food chains/webs and trophic levels

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Food chains webs and trophic levels

Food chains/webs and trophic levels


Trophic levels

Trophic levels

  • Determines the pathways of energy flow and nutrient cycling (more on this later)

  • Different species in the ecosystem are divided into different trophic levels depending on what they eat

  • There are 5 main levels


Trophic levels1

Trophic levels

Level 1 – Producers

  • The bases of food chains

  • Get their energy from the sun

  • E.g. Plants

    Level 2 – Primary Consumers

  • Herbivores

  • Eat a range of plant material


Trophic level

Trophic level

Level 3 – Secondary Consumers

  • Organisms that eat Primary consumers (Herbivores)

    Level 4 – Tertiary Consumers

  • Eat Secondary consumers

    Level 5 – Quaternary Consumers

  • Eat Tertiary consumers


Food chains

Food chains

  • Sequence of organisms, each of which is a source of food for the next.

  • Always begins with a producer

  • Animals with the same number of links to other organisms are on the same trophic level


Food chains food webs

Food chains/food webs

  • In real life a particular herbivore may eat more than one type of plant or a carnivore may eat lots of different herbivores

  • Hence a more accurate way of showing trophic levels is by using a food web

  • Plants


Pyramids

Pyramids

  • Another way of representing a food chain

    • Pyramid of numbers

    • Pyramid of biomass


Pyramid of numbers

Pyramid of numbers

  • Number of each type of organism at each trophic level

  • Not always accurate as does not take the size of organism at each level into account

    • E.g. One large tree could support thousands of caterpillars.


Pyramid of numbers1

Pyramid of numbers

10 Cats

500 Birds

30,000 Caterpillars

1,000 Flax bushes


2 pyramid of biomass

2. Pyramid of Biomass

  • More accurate method

  • The weight of living matter at each level is measured

  • Most accurate to use the DRY matter weight


Pyramid of biomass

Pyramid of Biomass

500 kg Humans

1 ton trout

300 tons shrimp

1,000 tons of seaweed


Ways in which food chains and webs can be affected

Ways in which food chains and webs can be affected.

  • Removing one part of the food chain

  • Biological magnification

  • Introducing an exotic species

  • Removal of too much of an organism


Ways in which food chains and webs can be affected1

Ways in which food chains and webs can be affected.

  • Removing one part of the food chain

    • Happens through over farming, fishing and cutting down of native forest.

    • If you remove too much of the producer, then the rest of the food chain suffers


Ways in which food chains and webs can be affected2

Ways in which food chains and webs can be affected.

  • Biological magnification

    • Concentrations of poison (e.g. mercury, DDT) increase as it moves up the food chain or up the pyramid

    • Top predator gets the highest concentrations


Ways in which food chains and webs can be affected3

Ways in which food chains and webs can be affected.

  • Introducing an exotic species

    • Rabbits

    • Possums

    • Deer


Ways in which food chains and webs can be affected4

Ways in which food chains and webs can be affected.

  • Removal of too much of an organism

    • Can make an ecosystem unsustainable

    • E.g. Over fishing – not enough older fish for reproduction

    • E.g. Over farming – Nutrients are not returned to the soil therefore it becomes useless


  • Login