2Pyramids Of Number & Biomass Thursday, April 13, 2017Pyramids Of Number & BiomassTo understand pyramids of number and biomass
3Big Mac Where does the energy in a Big Mac come from? There is no energy in a big Mac – that is why they are bad for youIt comes from the sugar in the burger sauceIt comes from the cows that make the burgerIt comes from the green parts because they are healthierIt comes from the sun
4Big MacAll the energy within our food originates from the sun – transferred through food chains...It comes from the sun
5Food Chains & WebsA food chain shows what eats what in a particular habitat - the arrow points in the direction of the energy flow, e.g.Here the grass (producer) is eaten by the vole (primary consumer) which is eaten by the barn owl (secondary consumer)Energy is passed along the food chain, so the number of organisms decreases from one trophic level to the next (as energy is lost)
6PopulationThe population of each organism in a food chain can be shown in a sort of bar chart called a pyramid of numbersThe more organisms there are, the wider the bar. The producer in the food chain always goes at the bottom of the pyramid of numbersE.g. clover snail thrush hawk
7Pyramid Of NumberPyramids of number show how many organisms there are in a habitatA pyramid of number for the food chain below might look like this: -If there were 200 grass plants; 25 voles; and 1 barn owl
8Pyramid Of NumberPyramids of number show how many organisms there are in a habitatHowever they may not always look like classical pyramids: -Here there are much more caterpillars than there are oak trees which is why the pyramid is oddly shaped.
9Pyramid Of Biomass Biomass means the amount of biological material The pyramid shows the amount of biological material at each levelThis means the oak tree has the most biological material whilst the sparrow hawk has the least
12grass grasshopper frog grass snake Questions1. Draw out, and explain why this pyramid looks a funny shape: -Look at the food chain below: -grass grasshopper frog grass snake100’2. Draw a pyramid of numbers for the food chain3. Write down the names of: the top predator; the producer; the consumers; the primary consumer; the tertiary consumer; the herbivores; the carnivoresFleasRabbitsLettuce plants
13Questions 1. Pyramid of number: many fleas can feed of just one rabbit 2.3. Top predator – grass snakes;Producer - grass;Consumers – grasshoppers, frogs, grass snakes;Primary consumer - grasshoppers;Tertiary consumer – grass snakes;Herbivores - grasshoppers;Carnivores – frogs, grass snakesFleasRabbitsLettuce plantsGrass snakeFrogGrasshoppersGrass
14Fox & SunExplain as fully as you can why a fox is reliant on the Sun...
15Sun → Grass → Rabbit → Fox Fox & SunProducers (e.g. grass) grow via photosynthesis, getting their energy from the SunThis energy is used to allow the producer to grow (increase in biomass), eventually being passed on to consumers (e.g. a rabbit) when they eat itWhen a fox eats the consumer energy is again passed on, so completing the energy chain from Sun to producer to consumer to secondary consumer (fox)Sun → Grass → Rabbit → Fox