Unit 3 Lesson 6: Life Processes Flashcards
The rate that plants and other photosynthetic organisms produce organic compounds, like glucose, is known as
primary productivity
What is primary productivity
This is the rate of energy captured and stored by plants and some algae that is then available to the next trophic level
Primary productivity takes into account the amounts of
rimary productivity takes into account the amounts of organic compounds used in cellular processes that are not transferred to the next trophic level and any outside factors that might be storing or releasing organic compounds.
Gross primary productivity (GPP)
Gross primary productivity (GPP) is the overall amount of energy captured by plants and other photosynthetic organisms.
What does GPP measure
GPP measures all the production of organic compounds in an ecosystem during photosynthesis.
What is net producitivty
The net primary productivity is the organic materials that remain after organisms have used energy for other cellular processes such as respiration.
How to find NPP
To find the net primary productivity (NPP), subtract all the amount of energy that was used in cellular respiration and released as heat from the gross primary productivity.
Exmaple of finding NPP
An example of this is if the GPP for a patch of forest is 10 kg Carbon/m2/year
and the amount of carbon dioxide leaving is 7 kg Carbon/m2/year
, then the NPP would be 3 kg Carbon/m2/year
.
There are several reasons the energy transfer is inefficient between organisms.
Not all of the organisms at the lower trophic levels will be consumed when they die off. Dead organisms and waste are broken down by decomposers and are recycled through the ecosystem. Organisms are not always fully consumed, and they may contain some molecules that cannot be digested. These molecules are lost in the organism’s waste or by-products.
Explain how net primary productivity is determined.
To find net primary productivity, subtract organic compounds absorbed during respiration from the gross primary productivity (the amounts of organic compounds released during photosynthesis).
Explain why the gross primary productivity and net primary productivity will not be the same.
Some of the gross primary productivity is converted into chemical energy during photosynthesis that plants use for other cellular processes such as respiration. Net primary productivity will be the total amount of organic material that remains.
What are some of the reasons that energy transfer is inefficient between ecosystems?
Not all organisms will be eaten, and those that are, not all parts will be consumed. There will be some molecules that cannot be digested and will be part of waste products. Decomposers also feed on organic material that is stored in dead or dying organisms.
If the gross primary productivity for a patch of forest is 21 kg Carbon/m2/year
and the amount of carbon dioxide used during respiration is 5 kg Carbon/m2/year
, what is the net primary productivity?
The NPP is 16 kg Carbon/m2/year
. The GPP minus the amount of carbon used during respiration equals the NPP
Explain the ten percent rule in ecosystems.
The energy available for the next trophic level is 10 percent. The remaining 90 percent the organisms use for life processes.
What are some examples of life processes that organisms undergo?
Organisms will use some energy for cellular respiration. This energy is used to breathe, hunt for food, hide from prey, and reproduce as some examples.
Why is the energy transfer between trophic levels inefficient?
The energy transfer is inefficient due to some lower level organisms do not get eaten by the organisms in higher trophic levels. Some molecules that are eaten cannot be digested and are lost in the feces of the organism. The number will not always be a perfect 10 percent, but will be close.
Explain where energy goes that is used in metabolic processes.
Energy is given off as heat into the environment when an organism undergoes metabolic processes.
One of the consequences of human activity on food webs in ecological systems is
biomagnification
Toxins that are introduced at the producer level will be passed up the trophic levels as they are consumed, what does this mean
This means that organisms at higher trophic levels have a higher rate of biomagnification.
biomagnification
the increase of toxic substances that have accumulated in organisms and that increases at each trophic level
If the prey has a higher biomagnification factor what does this mean
If the prey has a higher biomagnification factor, the pesticides are accumulating through the food chain.
What will happen to toxins introduced at the producer level
Toxins that are introduced at the producer level will be passed up the trophic levels as they are consumed
An example of biomagnification that has impacted an ecosystem was the use of DDT, whats DDT
, a pesticide once widely used for insect control and then banned in 1972
What imapct did DDT have on Wildlife
The use of this pesticide was believed to be linked to the thinning of eggshells in many bird species. This decreased the population of many species, including the bald eagle.
DDT is a pesticide that was once widely used for insect control and then banned in 1972. The use of this pesticide was believed to be linked to the thinning of eggshells in many bird species. How did this effect organisms in the higher trophic levels
. Organisms in the higher trophic levels such as bald eagles and peregrine falcon, had higher levels of DDT due to eating contaminated fish.
A potential side effect of biomagnification is the decrease in population of secondary and tertiary consumers. Elaborate
The higher the trophic level, the higher the concentration of toxin, which could decrease the population affecting the flow of matter and energy within the ecosystem.
Tuna are large predators that eat smaller fish and invertebrates such as squid. They can be at the top of the food chain in some ecosystems. Experts recommend only eating tuna a few times a month. The recommendations for children and pregnant women are to eat even less due to possible mercury contamination. How does this reflect biomagnification in the food chain?
Since Tuna are larger fish and are at the top of some food chains, the mercury accumulates from the producers to the smaller fish until it reaches the tuna. This means tuna are ingesting more mercury and storing more in their tissues.
A scientist compares the biomagnification factor (BMF) of two organisms in a forest ecosystem. The scientist checks the BMF of a primary consumer and compares this factor to that of a predator. The scientist notices that the factors are about the same. What does this indicate about the biomagnification of this forest ecosystem?
The fact that the BMF of the two organisms are almost the same indicates that there are no pollutants or contaminants that are being passed through the food chain.
