energy in ecosystems. the flow of energy the energy in ecosystems does not flow in cycles like...
TRANSCRIPT
The Flow of Energy
•The energy in ecosystems does not flow in cycles like matter does -such as nitrogen, water, carbon - but flows in a straight line.
•If energy is not passed on it is lost (such as heat).
•This means that there must be a constant supply of energy to sustain the ecosystem.
The Flow of Energy
Herbivore Omnivore Carnivore
H2O
O2
CO2 C6H12O6
Photosynthesis in the chloroplast converts light energy into chemical energy:
6CO2 + 6H2O 6O2 + C6H12O6
90% lost
20%lost
20% of energy lost
10%lost
90% of energy is lost
Energy lost through cellular Respiration + Heat
Cellular respiration takes place in the mitochondria of all cells and is responsible for releasing the energy stored in
glucose to make ATP which breaks down to ADP
6O2 + C6H12O6 6CO2 + 6H2O + Energy
Detritus: energy lost as waste products and ‘dead’ material
Decomposers such as bacteria and fungi recycle nutrients such
as nitrogen and carbon
Photosynthesis & Respiration
•These two complex reactions appear to be the reverse of each other, but in actual fact they are not.
•The plants convert the light energy into chemical energy, which is stored in organic compounds such as glucose.
•The glucose is passed from the plants to the animals when they eat them, and then on to other animals the same way.
•The breakdown of glucose releases energy into the organism which releases energy into the ecosystem.
Respiration•All living cells need a constant supply of energy all the time to stay alive.
•They need this energy to synthesize new molecules, to grow, to reproduce, to repair and maintain themselves, to transport various materials and to undergo various generalised and specialised functions.
•Respiration itself is a series of about 50 different chemical reactions, each one using a different enzyme to catalyse it.
•The chemical energy held in the bonds of glucose release energy when they are broken.
•This energy is transferred to ATP (adenosine tri phosphate) where is can then be used by the cell.
•About 40% of the energy in glucose is converted to ATP.
Respiration
•This is an over simplified diagram of how the reactants and products in respiration balance each other out.
Respiration
glucose + oxygen carbon dioxide + water + energy
ADP + P +glucose +oxygen carbon dioxide + water + ATP
ADP + P ATP
Energy out
Energy in
Respiration•The stages of respiration can be thought of as occurring in two stages.
•The first stage occurs in the cytoplasm, produces 2 ATP’s and does not require oxygen. This is known as glycolysis or anaerobic respiration.
•The second stage occurs in the mitochondria of the cell, produces 36 ATP’s and is called aerobic respiration.
When I undergo anaerobic respiration I produce lactic acid
When I undergo anaerobic respiration I produce alcohol
Sugar Lactic acid + carbon dioxide + 2ATP
Sugar Ethanol + carbon dioxide + 2ATP
Photosynthesis & Respiration
The role of Photosynthesis in the ecosystem:•To provide oxygen for all living things in order to undergo respiration
•To provide food for herbivorous animals in the form of glucose
•To trap the sunlight energy so that it can actually enter the ecosystemThe role of Respiration in the ecosystem:•To provide carbon dioxide for plants to use during photosynthesis
•To release the energy in glucose so it can be used in the ecosystem
Food Chains•A food chain represents the flow of energy from one living thing to another
•Producer•1o Consumer
•Herbivore
•2o Consumer
•1 o Carnivore
•3o Consumer
•2o Carnivore
..or if we want to look at trophic levels…..
1st trophic level
2nd trophic level
3rd trophic level
4th trophic level
Food Webs•A food web is a set of food chains interacting
1st trophic level2nd trophic level
3rd trophic level
4th trophic level
Producer
Primary consumer
Secondary consumer
Tertiary consumer
Top order consumer
Pyramids of Energy
Producers
Primary consumers
Secondary consumersTertiary consumers
•Each step represents the amount of energy available.
•At each tropic level the amount of energy is reduced.
•Greater tropic efficiency gives a pyramid with much steeper sides compared to a food chain with poor tropic efficiency.
Pyramids of Numbers
•Pyramids of numbers are essentially population pyramids.
•They need not always take the step progression of energy pyramids. So often they don’t even appear pyramidal in shape. Here are a few examples:
Plants
Kangaroos
Parasites
Producers
Biomass Pyramids
•The total amount of mass in a community, or a given tropic level is called the biomass.
•They are time consuming to make and are nearly always pyramidal.
Producers