Use the diagram to answer the following questions: All the solar energy is measured in Joules. Use the diagram to answer the following questions: How much solar radiation is being emitted? What happens to 67J of solar energy? What percentage of incoming solar energy is reflected by the clouds and atmosphere? How much energy is absorbed by the surface? Will all the energy absorbed at the surface be used by plants? Why/why not?

Ecological energetics - Learning outcomes You should all be able to: Describe the transfer and transformation of energy through an ecosystem Most of you should be able to: Distinguish between storages and flows in energy-flow diagrams Construct and analyse simple energy flow diagrams Some of you might be able to: Explain the transfer and transformation of energy as it flows through an ecosystem

What happens to the other 99.04%? Only around 0.06% of the solar radiation falling to the Earth is captured by plants. What happens to the other 99.04%? What happens to that small amount of energy as we move through the trophic levels? 0.9% 0.009% 0.01% 0.1% 0.09%

Remember… Energy continually flows through a system. We give out energy all the time. How? How is energy stored within organisms? Materials (matter), e.g. nutrients, oxygen, carbon dioxide or water are cycled and recycled within ecosystems. Which arrows represent energy and which represent matter? How do you know?

What happens to the energy? 1st law of thermodynamics? Energy is neither created nor destroyed but can be changed from one form to another So… how is the light energy entering the planet transformed?

What happens to the energy? 2nd law of thermodynamics? The efficiency of energy conversion to useful work is never perfect So what does that mean for the energy as it moves through the trophic levels? What does that mean about the number of trophic levels in a food chain?

Conversion of energy into food Efficiency of conversion of energy to food is low… About 2-3% in terrestrial systems and 1% in aquatic systems. Why do you think it is lower in aquatic systems?

Energy flow diagrams… How are the storages represented? How are the flows represented? Why are the arrows different sizes? Producers (autotrophs) Primary consumers (herbivores) Secondary consumers (carnivores) DOM Heat and respiration Light Food Death Death and faeces

Respiratory loss by decomposers The data in the table below relate to the transfer of energy in a small clearly defined habitat. The units in each case are in kJ.m-2.yr-1 Trophic Level Gross Production Respiratory Loss Loss to decomposers Producers 60724 36120 477 Herbivores 21762 14700 3072 First Carnivores 714 576 42 Top Carnivores 7 4 1 Respiratory loss by decomposers 3120 Construct an energy flow model to represent all these data

ENERGY FLOW MODEL 1st. Carnivores Top Carnivores Producers Herbivores 60724 21762 1st. Carnivores Top Carnivores 714 7 Producers Herbivores 3072 42 477 1 Decomposers R=3120