Energy in Ecosystems
Against the clock! Using the cards at your table produce as many different food chains as you can in 3mins!
Energy in Ecosystems Title Page... P.S. Make a note of one of your food chains on the next page.
Now try a food web...
Match the words to organisms in your food web.. Predator Primary Consumer Producer Omnivore Herbivore Secondary Consumer Carnivore Prey
Now try.... The Questions on page 17 of Torrance.
Why be a vegetarian? and Why your mum told you to eat your greens?!!
Watch this clip... Can you see a food chain? http://www.bbc.co.uk/programmes/p017kcc4 Can you see a food chain?
Energy Loss In a food chain energy is passed on from one organism to another. 1000 units of energy 100 10 1 At each stage in a food chain only about 10% of the energy is passed on.
Energy Loss 90% of the energy is lost as Heat Movement Undigested Material
So, why be a vegetarian?
Pyramid of Numbers Green Plants Slug Frog Fox What happens to a) The size of and b) The no. of organisms as you go along the food chain?
Pyramid of Numbers A pyramid of numbers can be used to show the number of organisms at each stage of a food chain. Small numbers of large organisms 1 fox 30 Rabbits 100,000 blades of grass Large numbers of small organisms
GREEN FLY Sometimes a pyramid of numbers is not accurate. e.g. Ladybird BlackBird Rose Bush BLACKBIRD LADYBIRD GREEN FLY ROSE BUSH A more accurate way to explain this food chain would be to weigh all the organisms at each level. The result is a PYRAMID OF BIOMASS.
Pyramid of Biomass Small biomass This shows the total mass of living organisms at each stage of the food chain. 1g/m2 fox 30 g/m2 Rabbits 100,000g/m2 blades of grass Large biomass
Pyramid of Energy Less energy This shows the total energy at each stage of the food chain. 1 kJ fox 30 kJ Rabbits 100,000 kJ blades of grass Lots of energy
Quiz time!
Food Webs
What will happen if the barnacles are removed?
What will happen if the barnacles are removed? There will be fewer Blenny There will be more zooplankton
What will happen if the dog whelks are removed? Why?
What will happen if the dog whelks are removed? There will be fewer Crabs As they will have less food
What will happen if the dog whelks are removed? There will be more limpets and mussels As they will not be eaten by dog whelks
What will happen if the dog whelks are removed? There will be fewer Periwinkles As the crabs will have to eat more of them
Choose another organism, and explain the consequences of it was removed
Monster Crab Invasion!
What do organisms compete for in their environments? Animals Plants WFS WLN
Plants compete for water, light and soil nutrients
Animals compete for water, food and shelter
Types of Competition Interspecific competition – occurs between individuals of different species. Intraspecific competition – competition between members of the same species.
Competition Investigation What factors might affect how well seeds germinate?