4.1 Study Guide Flashcards
Define Biomass and explain why it is interchangeable with Energy.
Biomass is, as the name suggests, biotic mass. It is matter that makes up organisms. It is interchangeable with energy because biomass is converted to energy within organisms and vice versa, so the two have a direct relationship where having one generally means having the other.
Define both Productivity and Efficiency and explain how they differ and also how they are related.
Productivity is an organism’s rate of energy/biomass production over time, while efficiency refers to how much energy an organism receives from consuming another organism relative to the original amount of energy produced by producers. They differ because they represent somewhat different sections of energy production and transfer, but they are related because higher production rates generally translate to higher efficiency.
State the inputs and outputs of photosynthesis and cellular respiration respectively.
Photosynthesis requires the input of water, carbon dioxide, and light (sunlight) and creates the output of oxygen and glucose (sugars). Cellular respiration requires the input of glucose and oxygen and creates the output of water, carbon dioxide, and energy (ATP).
What types of organisms perform photosynthesis? What types perform cellular respiration?
Photosynthesis is performed mainly by plants (and by essentially all of them) but is also performed by a select few animals and bacteria. Cellular respiration, on the other hand, is performed by almost all living organisms.
Explain the differences between what is represented in pyramids of energy, pyramids of numbers, and pyramids of biomass.
Pyramids of energy show and compare the total amounts of energy present within each trophic level of a food web, showing how much energy passes through each level. Pyramids of numbers show and compare the productivity rates of each trophic level of a food web, showing how each level supports those above it. Pyramids of biomass show and compare the total amounts of biomass making up the organisms within each trophic level of a food web, showing how many individuals of a species or type of organism (producer, various consumers) are supported in each level.
A plant produces 8 Watts of energy through photosynthesis. The plant is eaten by a primary consumer, which is later eaten by a secondary consumer, which is later eaten by a tertiary consumer. What percentage of the original 8 Watts of energy does the tertiary consumer’s body utilize to produce biomass and how much energy is utilized?
According to the rule of 10, 10% of the energy produced by the plant is truly absorbed by the primary consumer, then 10% of that is absorbed by the secondary consumer, and then 10% of that is absorbed by the tertiary consumer. 10% of 10% of 10% is 0.1% or 1/1000, and 0.1% or 1/1000 of 8 Watts is 0.008 Watts. Thus, 0.008 Watts of energy is absorbed by the tertiary consumer.
Explain why consuming biomass from an organism in a lower trophic level is more energy-efficient than consuming biomass from one of a higher trophic level. State the name of the rule that makes this true.
According to the Rule of 10, approximately 10% of the energy consumed by an organism is actually absorbed to use for producing biomass. Thus, the higher you go up a trophic pyramid, the less energy is absorbed in each level. Because of this, consuming organisms from a lower trophic level would supply an organism with more energy than consuming a higher-level organism. This would mean that fewer organisms would need to be consumed to sustain that organism and, therefore, that that strategy is more energy-efficient.
Moss patches in a boreal forest grow in different levels of sunlight. While both patches cover the same area of ground, Patch A receives approximately 35% sunlight, while Patch B receives only approximately 10%. Predict how the two patches’ productivities will compare and explain your prediction.
Because the moss patches have the same area, their biomass is approximately the same. However, with more sunlight per day to utilize for energy and biomass production, Patch A will be able to produce more energy per day than Patch B. This will allow Patch A’s biomass and production rate to increase much faster than Patch B’s will be able to with only 10% daily sunlight. Moreover, Patch A will have higher initial productivity which, with its continuously higher sunlight amount, will also allow its long-term productivity to skyrocket above Patch B’s.
Two populations of the same species of grass grow in different areas. Both populations have essentially limitless space to grow, but Population A grows in an open meadow, while Population B grows in a sparse but tree-filled forest. Predict which population will end up with higher biomass and explain your prediction.
Because Population A grows in a completely open area and Population B grows in a partially covered area, it can be inferred that Population A will receive more daily sunlight than Population B. This will allow Population A to absorb more energy over time and, thus, utilize more energy for growing and producing biomass. This higher growth rate will make it so that, after a while, Population A’s standing biomass amount will be much higher than Population B’s.
