5 Energy transfers- Energy & Ecosystems Flashcards
What does an ecosystem in a particular area include?
-All living components (biotic factors like organisms & their interactions)
-All non-living components (abiotic factors like temperature and rainfall)
What are primary producers?
Organisms that make their own glucose, e.g. plants & algae make glucose via photosynthesis
All ecosystems include and depend on primary producers, even deep-sea ecosystems with no light depend on primary producers, for chemosynthesis to make glucose
How to plants gain food?
Ecosystems with sunlight and water—> process of photosynthesis enables plants to synthesise organic compounds like glucose from carbon dioxide
-In terrestrial (land) ecosystems, plants use carbon dioxide from the atmosphere
-In aquatic (water) ecosystems, plants use carbon dioxide dissolved in water
Process of photosynthesis transforms light energy into chemical energy held in biological molecules
How is energy from photosynthesis transferred between organisms?
Chemical energy in the biological molecules can be used by other organisms within the community (consumers, e.g. organisms in higher trophic levels)
- Primary consumers (herbivores, omnivores) feed on producers
- Secondary consumers (carnivores, omnivores) feed on primary consumers
- Tertiary consumers (carnivores, omnivores) feed on secondary consumers
What are photosynthetic products used for?
Photosynthesis transfers light energy—> chemical energy in bio molecules
This process allows plants to make organic compounds (e.g. glucose) from CO2, in ecosystems where sunlight and water are available. Most of the sugars made are used by plants as respiratory substrates (molecule that can be used in respiration, to release energy for growth)
Remaining sugars are used to make other bio molecules, like;
- Starch, short term energy storage molecule
- Cellulose, structural component of cell walls
-Lipids, longer term energy storage molecule
-Proteins
What is the biomass of a plant?
The different groups of bio molecules formed from sugar synthesis in photosynthesis make up biomass of a plant. This is the mass of living material, or the chemical energy stored within the plant
What is biomass and how can it be measured?
Mass of living organisms or tissue/chemical energy stored within organism
Measured in terms of: dry mass of organism/tissue in given area, mass of carbon that organism/tissue has (generally taken to be 50% of dry mass of sample)
What is dry mass and how can it be used?
Mass of organism/tissue after all water has been removed
Dry mass of sample can be used to calculate biomass of a total population of organisms/particular area
(E.g. is dry mass of 1 daffodil is 0.1kg, then 200 would be 20kg)
How can biomass change?
E.g. biomass of deciduous trees decreases over autumn and winter, so biomass is sometimes given with units of time too- showing the average biomass of organism within given area over that time period.
What is calorimetry and why is it used?
Can be used to estimate chemical energy stored in dry biomass
Involves burning the sample of dry biomass in calorimeter;
Burning sample heats a known volume of water;
Change in temp of water provides estimate of chemical energy the sample has
