Unit 3 Lesson 5: Ten Percent Rule Flashcards
Why is energy needed for organisms
Energy is needed for organisms to undergo life processes. Some examples of life processes include growth, repair, development, maintenance of cells and tissues, and reproduction.
Energy enters most ecosystems from the
sun
producer
an organism, also known as an autotroph, that makes its own food. A plant is an autotroph.
primary consumer
an organism, also known as an herbivore, that feeds on producers such as plants
How does energey flow
Energy flows from lower levels upward when organisms in a higher level consume organisms in lower levels.
photosynthesis
the process during which green plants and some other organisms use carbon dioxide and water to convert light energy into chemical energy
secondary consumers
an organism that feeds on primary consumers (herbivores)
tertiary (third) consumers
top-level consumers that are carnivores and feed on secondary consumers
What happens to the biomass of organsims in trophic levels as we go up
Since there is less energy available at each level, this means the number of organisms, or biomass, also decreases in higher trophic levels.
biomass
the amount of organisms in a given area or volume
trophic level
the level in which organisms are found within the food chain
In addition to energy pyramids, there is also an ecological pyramid called the
pyramid of biomass
pyramid of biomass
the amount of biomass in each trophic level
What would a pyramid of biomass look like in a land-based ecosystem
In land-based ecosystems, this usually aligns in shape to its energy pyramid.
What would pyramid of biomass look like in a marine ecosystme
. In some ecosystems, such as marine ecosystems, the pyramid of biomass may be inverted.
In some ecosystems, such as marine ecosystems, the pyramid of biomass may be inverted. Why is that?
Many marine ecosystems rely on phytoplankton as their producer, or base of the food web. Phytoplankton (as seen in the image below) are very tiny and reproduce and die rapidly. Since they reproduce quickly, they can still supply energy for the rest of the ecosystem while having a small biomass. The biomass of fish is larger since they typically have a larger mass and tend to live for several years.
Although the ten percent rule is widely accepted, it is important to understand the actual efficiency of energy transfer to determine the health of the ecosystem. Farmers and scientists use energy transfer calculations to determine the percentage of energy that is being transferred from one trophic level to the next in an ecosystem. The following calculation is used:
Energy level transfered to next level/Total energy input ×100
What is the approximate percentage of energy that is transferred from one organism to the next when consumed?
About 10 percent of the energy is available for the next organism when an organism is consumed.
How many kilograms of hawk would an ecosystem support that contained 1000 kilograms of producers?
There would be enough energy to support just one kilogram of hawk in an ecosystem with 1000 kilograms worth of producers.
If energy decreases as you move up the energy pyramid, why would the biomass decrease as well?
If energy decreases, there is not enough energy to sustain more organisms. This means there are fewer organisms in higher trophic levels.
Describe an energy pyramid and why it is used to model the energy in an ecosystem.
An energy pyramid is a model that shows the flow and amount of energy in an ecosystem. There is less energy available as you move up trophic levels and the pyramid becomes smaller as you progress; this may reveal the relationship between energy and trophic levels.
invasive species
any kind of living organism that is not native to the ecosystem and causes harm
Invasive species can include
Invasive species can include plants, animals, parasites, and even seeds or eggs of organisms.
What can invasive species harm
They can harm the health of the ecosystem, humans, and even the economy.
. Invasive species grow and reproduce quickly without natural predators to keep them in check. What can this harm
This can harm the energy flow of an ecosystem. Predators may lose their source of energy and could become endangered or extinct.
If invasive species reduce or wipe out the population of producers, wha towuld happen
If invasive species reduce or wipe out the population of producers, there may not be enough energy available for the rest of the organisms in the ecosystem. For example, an area that contained 3000 kilograms of producers contains enough energy to keep 3 kilograms of top or tertiary consumers alive. If the number of producers declines, then the tertiary consumers would have to compete for resources, and some would die.
Human activities can unintentionally spread invasive species.
People can pick up organisms in the goods that they carry, and a ship can pick up organisms on its hull. Plants and pets can escape into the wild.
Direct threats to the ecosystem from invasive species include
Direct threats to the ecosystem from invasive species include outcompeting native species for food and resources, causing or carrying diseases, and preventing a native species from reproducing.
Zebra mussels are invasive species that threaten many bodies of water. Elaboratre
Zebra mussels filter out algae that is used by other organisms as energy. They also attach themselves to other mussels, and those mussels are not able to move or eat. Zebra mussels clog nuclear power plants’ water intake, and millions of dollars have been spent to have them removed. Zebra mussels reproduce quickly and outcompete native species for food and space.
How can invasive species alter the availability of energy to native organisms in an ecosystem?
Invasive species can wipe out the producers in an ecosystem. This would limit the amount of energy that is left for the other organisms in the food web.
If an ecosystem typically contains 5000 kilograms of producers, and the introduction of an invasive species reduces this to 2000 kilograms, what could happen to consumers in the highest trophic level?
The ecosystem originally has enough energy for five kilograms of the top-level consumers or those in the highest trophic levels. Having fewer producers means the ecosystem only has enough energy for two kilograms of the top-level consumers.
