LSBIO 04.2 Food Webs and Trophic Levels

Based on an energy pyramid model with 50000 Joules of energy at the producer level how much energy would be available to the secondary consumer

Only 500 Joules would be available because the 10% rule dictates that energy decreases by a power of ten at each subsequent trophic level

Evaluate why an ecosystem can typically support a much larger population of grasshoppers than it can songbirds

Songbirds occupy a higher trophic level where significantly less energy is available to sustain a large number of individuals

Predict the impact on the cycling of matter if all decomposers were removed from a food web model

Matter would become trapped in dead organic material and would not return to the soil to be reused by producers

How would you justify the claim that energy is conserved even though only 10% is transferred to the next trophic level

The remaining 90% of energy is not destroyed but is instead used for organism growth and maintenance or released to the environment as heat

Analyze a food web to determine why apex predators are usually the most vulnerable to habitat loss

Because they sit at the highest trophic level they rely on a large and stable energy base from all levels below them to meet their high caloric needs

Using proportional reasoning if the tertiary consumer level contains 15 Kilograms of biomass approximately how much biomass was required at the producer level

Approximately 15000 Kilograms of producer biomass would be required to support that level based on the 10% rule of transfer

Contrast the way matter moves through an ecosystem with the way energy moves through that same system

Matter is recycled repeatedly between organisms and the physical environment while energy flows in one direction and is eventually dissipated as heat

How would you evaluate the efficiency of a food chain that has six trophic levels compared to one that has three

A three-level chain is more efficient for the top consumer because less energy is lost to the environment through metabolic processes before reaching them

Explain why food chains in most ecosystems are limited to four or five trophic levels

There is eventually insufficient energy left after the 90% loss at each level to support a viable population of organisms at a higher stage

If a model shows energy being lost as heat during cellular respiration how does this support the law of conservation of energy

It illustrates that the energy not stored in the organism is still present in the ecosystem in a different form rather than being lost from existence

Analyze the role of producers in a model that demonstrates both energy flow and matter cycling

Producers are the entry point for energy into the biotic system and convert inorganic matter into organic forms that can be transferred to consumers

How would you refine an energy pyramid to show the "inefficiencies" mentioned in the boundary statement

The model should include arrows exiting each level to represent energy used for maintenance or lost as heat to the environment

Based on a food web diagram explain how a single organism can occupy multiple trophic levels simultaneously

An omnivore might act as a primary consumer when eating plants and a secondary consumer when eating an herbivore

Differentiate between the transfer of matter and the transfer of energy when a lion eats a zebra

The matter from the zebra is rearranged into the lion's tissues or excreted as waste while the chemical energy is used to power the lion's life processes

What evidence in an ecosystem model would support the idea that higher trophic levels have less total biomass

A pyramid of biomass showing a significant decrease in total dry mass at each step from producers to top carnivores

Evaluate the relationship between an organism's metabolism and the "10% rule"

High metabolic costs for growth and repair mean that most energy is used by the organism itself leaving only a small fraction available for the next consumer

How does a model of a food web illustrate the interdependence of organisms for the cycling of atoms

It shows the continuous path of atoms like carbon and nitrogen as they are passed from one organism to another through consumption

Determine the amount of energy available to a quaternary consumer if the producers start with 1000000 calories

The quaternary consumer would have 100 calories available

How does the increase in heart rate during exercise (homeostasis) relate to the loss of energy in an energy pyramid

The energy used to power the increased heart rate is eventually released to the environment as heat reducing the energy available for transfer to the next level

Using a model explain why the arrows in a food chain point toward the consumer and not the food source

The arrows represent the actual direction of the flow of energy and matter as it moves from the organism being eaten into the organism doing the eating