Biomass

Competition – Who will finish first? Herbivore Consumer Carnivore Producer Omnivore Mass Weight

The sun's radiant energy is the energy source for all life on earth The sun's radiant energy is the energy source for all life on earth. Green plants trap the sunlight and use chlorophyll to make food. We call green plants producers

This food is in the form of starch, which is a carbohydrate This food is in the form of starch, which is a carbohydrate. The green plants can also convert this into fats and proteins. They use this to provide enough building materials for their own bodies.

By adding more to their bodies they are adding more mass to themselves By adding more to their bodies they are adding more mass to themselves. Because it’s alive we say that it’s adding more Biomass to itself.

Definition: the total mass of living matter in a given unit area The total amount of living material in a given habitat, population, or sample Specific measures of biomass are expressed in dry weight (after removal of all water from the sample) It’s measured in kilograms (kg)

Food Chains Examples of food chains include: Grass Rose bush Squirrel Food chains commonly have four links but seldom more than six. In food chains the arrows go from food to feeder. In other words the arrows mean ‘eaten by’ Examples of food chains include: Top carnivore Carnivore Herbivore Producer Animals eat the green plants in other words they eat the biomass! They use the energy locked up in the chemicals such as starch, protein and fat to enable their own bodies to respire and make new cells and so their own biomass increases. These are called consumers. A food chain can be used to show how this energy is passed from one organism to another. Grass Rose bush Squirrel Beetles Racoon Shrew Cougar Wolf

Complete - Aquarium ecosystem

Animals respire, keep warm, excrete and move = MRS NERG Animals respire, keep warm, excrete and move = MRS NERG. All the time, energy is being used up by each organism in the food chain link!

In a food chain there is energy lost between each link  In a food chain there is energy lost between each link. This means that the number of organisms at each level gets less.

Complete – Energy Transfer

Pyramids of Numbers Energy is passed along food chains The number of organisms decreases as you go from one trophic level to the next. This is because most of the energy is lost as you go from one level to the next in a food chain. The number of organisms in each level can be represented using a pyramid of numbers.
It is obvious that food chains can only sustain a few top carnivores because there is so much energy lost between each level.

Pyramids of Numbers Just staying alive uses up most of the food energy that’s ‘acquired’ by a consumer. Its needed for moving, growing and keeping warm. Not all of the material from each level is eaten. The food energy only passes along the food chain when its eaten by a consumer from the next level up.

Pyramids of Numbers Pyramids of numbers can look weird. This is because an oak tree is very large compared to the caterpillar. There is only 1 oak tree but 1000’s of leaves for the caterpillars to feed on.

Pyramids of Biomass Pyramid of numbers looks weird because it doesn’t take into account the mass of the oak tree. If the pyramid represented the total mass of the organisms at each level it would look more like a pyramid. It would then be a pyramid of biomass. Some organisms are far bigger and heavier than others, so a pyramid of numbers is not the most accurate way of representing the movement of energy through a food chain. The most accurate method would be to calculate the amount of energy at each level. This would require killing all the organisms to determine their energy content. Instead of this, the amount of biological matter, or biomass, is calculated. This is measured in Kg. Robins (10 kg) Caterpillars (20 kg) Oak Tree (10,000kg)

Complete: Produce a pyramid of numbers and then a pyramid of biomass using this data. Use graph paper, colour pencils and a ruler. What do you notice about the pyramids? 10 cabbages 250 caterpillars 5 thrushes 1 sparrow hawk

Energy Flow So: in a food chain, usually only 1% to 10% of the biomass (energy) in one feeding level is passed on to the next feeding level Assuming only 10% of the biomass is passed on at each stage of the following food chain, calculate the biomass at each successive feeding level Top carnivore 6.6 Carnivores 66 Herbivores 660 Producers 6,600 Figures show dry mass in grammes per square metre Thus at each stage of a food chain, less material and less energy are contained in the biomass of the organisms. This means that the efficiency of food production can be improved by reducing the number of stages in the food chains involved, so that less biomass is lost

Food chains involved in feeding humans: Cereals human Grass sheep human Algae mayfly larvae pond skater (insect) trout human Which of the above food chains is most efficient at getting biomass to humans? ‘Cereals to humans’ is most efficient, because it has least stages (one) to lose biomass ‘Algae to humans’ is least efficient, because it has most stages (four) to lose biomass

To sum up: the amounts of the material and energy contained in the biomass of organisms is reduced at each successive stage in a food chain because: Some materials and energy are lost in the organism’s waste materials (excretion) or via undigested or indigestible (defaecation); The heat losses are especially large in mammals and birds whose bodies must be kept at a a constant temperature which is usually higher than that of their surroundings

Energy Flow So the efficiency of food production in food animals, (for example, chickens, turkeys, sheep, pigs, cattle), can be improved by: Restricting energy loss from food animals by limiting their movement; By controlling the temperature of their surroundings so that they do not lose biomass trying to keep warm