The flow of energy in Ecosystems Flashcards
Energy is…
Never recycled
How is energy used in the ecosystem?
-Radiant energy from the sun reaches Earth makes a one way pass through the our planet’s ecosystems before being converted to heat & radiated back into space
Why is Energy different from Matter?
- Energy exists in many different forms
- Organisms cannot convert heat to any other forms of energy (cannot cycle energy back into its original form
What are the 2 principles to understand why the Earth must function as an open system?
- Organisms can use only certain forms of energy (neither plants, animals, or other organisms can use heat as a source of energy
- Whenever organisms use chemical-bond or light energy, some of it is converted into heat
What are Trophic Levels?
-The organization of the limited number of feeding levels
What are the different levels in Trophic Levels?
- Primary Producers (all autotrophs in systems)
- Consumers/ Detritivore/ Decomposers (Heterotrophs/ feed on remains of other organisms)
- Herbivores (all heterotrophs that feed directly on primary producers)
- Primary Carnivores (heterotrophs that feed on herbivores)
- Secondary Carnivores (those that feed on primary carnivores)
- Aside note: omnivores
What do the Trophic Levels consist of?
-Consist of whole populations of organisms
What is the Productivity of a Trophic level?
-Is the rate at which the organisms in the trophic level collectively synthesize new organic matter (new tissue substance)
What is the Primary Productivity of a Trophic level?
-Is the productivity of the Primary producers= synthesizing new organic matter via photosynthesis & breaking down organic matter to release energy via aerobic cellular respiration= chemical bond energy= makes ATP
What is Respiration of a Trophic level?
-Is the rate at which they break down organic compounds
What is Gross Primary Productivity? of a Trophic level (GPP)?
-The raw rate at which the primary producers synthesize new organic matter
What is Net Primary Productivity (NPP) of a Trophic level?
- is the GPP minus the respiration of the primary producers
- the NPP represents the organic matter available to herbavores to use as food
What is Secondary Productivity?
- The productivity of a heterotroph trophic level
- EX= the rate that new organic matter is made by means of individual growth & reproduction in all herbivores in an ecosystem
Over the course of the year, what is the percentage of solar energy captured by primary producers?
-about 1%
What percentage of the solar energy impinging on an ecosystem turns to heat?
99%
What is the consequence of chemical-bond energy being passed down from one heterotrophic level to the next?
-A great amount of energy is diverted= the amount of chemical energy available to primary carnivores is far less than that available to herbivores & the amount available to secondary carnivores is far less than that available to primary carnivores
What is the rule of thumb for the amount of chemical-energy available to a trophic level over time?
-about 10% if that available to the PRECEDING trophic level over the SAME period of time
Which type of biomes are the most productive?
- Wetlands & tropical rainforests
- They have 2000g/m2/year of dry weight of new organic matter produced
The rate at which chemical-bond energy is made available to organisms in different trophic levels…
-DECREASES EXPONENTIALLY as energy makes way from primary producers to herbivores & then to various levels of carnivores
What does the exponential decline of chemical-bond energy in a trophic chain limit?
-The lengths of trophic chains & the numbers of top carnivores that an ecosystem can support
Why are there very little numbers of top-level predators?
-They have relatively large individual body sizes & high individual energy needs
Where do the longest trophic chains occur?
-In the ocean
How is more energy available in human populations?
-More energy is available if plants/ other primary producers are eaten= more energy is available if herbivores vs carnivores were consumed
In an Ecological pyramid, why is each box narrower than the one under it?
-Because of the rules of energy flow (proportional to the productivity of the trophic level it represents)
What can Pyramid diagrams represent?
- Standing crop biomass (the biomass of all individuals alive at the same time
- Numbers of individuals
- Productivity
- BUT THEY ARE NOT ALWAYS UPRIGHT
In the Pyramid of Biomass, what is the width of the boxes proprotional to?
-They’re proportional to standing crop biomass
What is a Limiting Nutrient?
- An element in the shortest supply in the ecosystem
- Often nitrogen or phosphorous
What are the 3 types of groups in the Carbon Energy cycle? (FIND OUT THE 3RD ONE)
-Autotrophs
-Heterotrophs
-
What are Autotrophs?
- AKA producers= self-feeding
- They get C from CO2 & make reduced compounds
Who is included in the Autotroph group?
- Photoautotrophs
- Chemolithoautotrophs
What are Photoautotrophs?
-They use energy from sunlight to reduce CO2= making C compounds (sugar first then it becomes complex carbs & fats)
What are Chemolithoautotrophs?
- They’re more important where the sun don’t shine & early history of life
- They take energy from oxidizing inorganic compounds to make reduced C compounds
What do all Autotrophs have in common?
-They transfer energy & carbon (reduced C compound to other organisms when they’re eaten
What are Heterotrophs?
- AKA Consumers= other feeders
- They get reduced C (thus energy) from their diet to provide energy & release it as CO2 when they oxidize it
Who is included in the Heterotroph group?
- Primary consumers
- Secondary consumers
- Tertiary consumers
- Detritivores
What are Primary consumers?
- Herbivores
- They eat producers
What are Secondary consumers?
- Carnivores
- They eat the primary producers
What are Tertiary consumers?
- Top carnivores
- They eat secondary consumers
What is a Detritivore?
- Special kind of heterotroph
- They get reduced C from dead organisms & release their C as simpler, more oxidized compounds for CO2
What 2 parts make up an Ecosystem ?
- Biotic= living part= consumers, producers, decomposers
- Abiotic= non-living part
What does the process of the food chain promote?
-Entropy
How do ecosystems relate to the 2nd law of thermodynamics?
-They are LESS efficient in transferring energy as required by the second law of thermodynamics
How is the energy flow of an ecosystem?
- It results in the generation of waste heat (entropy)
- It’s associated w/ the flow of carbon atoms
