| Plants photosynthesis to produce biomass | - Some sugars from photo. are used in respiration, to release energy for growth
- Its also used to make other biological molecules, like cellulose
- These mols. make up plants biomass, the mass of living material
- Biomass = chemical energy stored in the plant
- Energy is transferred through the living organisms of an ecosystem |
| The three groups organisms can be divided in on how they obtain their energy and nutrients | - Producers
- Consumers
- Saprobionts (decomposers) |
| Producers | - Photosynthetic organisms that manufacture organic substances using light energy, water, CO2, and mineral ions |
| Consumers | - Organisms that obtain their energy by consuming other organisms rather than using the energy of sunlight directly |
| Primary consumers | - Those that directly eat producers (green plants)
- First on the chain of consumers |
| Secondary and tertiary consumers | - SC = those that eat primary consumers
- TC = those that eat secondary consumers
- SC + TC are usually predators but they may also be scavengers or parasites |
| Saprobionts (decomposers) | - Bacteria that produce extracellular enzymes and breakdown dead organisms |
| Food chain | - Simple lines of energy transfer, each stage is a 'trophic level' |
| Food webs | - Show lots of food chains in an ecosystem + how they overlap
- In reality, most animals do not rely on a single food source
- However food webs are v complex |
| Biomass meaning | - Total mass of carbon that an organism contains or the dry mass of its tissue per unit area
- Dry mass is the mass of the organism with the water removed |
| Measuring biomass | - Can be measure as dry mass or using a calorimeter |
| Measuring dry mass | - Sample of the organism is dried
- Weighed at regular intervals
- Once the mass becomes constant you know that all the water has been removed
- The result from the sample can be scaled up to give the dry mass (biomass) of the total population of the area being investigated
- The mass of carbon present is generally taken to be 50 % of the dry mass |
| Measuring biomass using a calorimeter | - Can estimate amount of chemical energy stored in biomass by burning the biomass in a calorimeter
- The amount of heat given off tells you how much energy is in it
- Energy measure in Joules (J)
- A sample of dry biomass is burnt + energy released is used to heat a known vol. of water
- The change in temp. of the water is used to calculate the chemical energy of the dry biomass |
| Why is dry mass required? | - Measure of organic material of an organism
- Water content varies, so can compare |
| 1 example that is not a pyramid shape? | - Aquatic ecosystems
- Bottom tropic level is smaller than one above because bottom one reproduces at a faster rate or equal to the rate at which they are eaten |
| Where is 99% of light energy get wasted? | - Respiration
- Heat energy
- Reflection
- Misses chlorophyll
- Evaporation |
