Download Producers are the energy gateway

Ecology\ Third stage
Lec. 6
Department of biology
Dr. Kawther M. Ali
Energy flow
Have you ever wondered what would happen if all the plants on Earth
disappeared (along with other photosynthesizers, like algae and bacteria)?
Well, our beautiful planet would definitely look barren and sad. We
would also lose our main source of oxygen (that important stuff we
breathe and rely on for metabolism). Carbon dioxide would no longer be
cleaned out of the air, and as it trapped heat, Earth might warm up fast.
Almost every living thing on Earth would eventually run out of food and
die.
If the plants or other producers of an ecosystem were removed, there
would be no way for energy to enter the food web, and the ecological
community would collapse. That's because energy isn't recycled: instead,
it's dissipated as heat as it moves through the ecosystem, and must be
constantly replenished.
Producers are the energy gateway
Plants, algae, and photosynthetic bacteria act as producers. Producers are
autotrophs, that make their own organic molecules from carbon
dioxide. Photoautotrophs like plants use light energy to build sugars out
of carbon dioxide. The energy is stored in the chemical bonds of the
molecules, which are used as fuel and building material by the plant.
The energy stored in organic molecules can be passed to other organisms
in the ecosystem when those organisms eat plants (or eat other organisms
that have previously eaten plants). In this way, all the consumers, or
heterotrophs of an ecosystem, including herbivores, carnivores, and
decomposers, rely on the ecosystem's producers for energy.
Because producers support all the other organisms in an ecosystem,
producer abundance, biomass (dry weight), and rate of energy capture are
Ecology\ Third stage
Lec. 6
Department of biology
Dr. Kawther M. Ali
key in understanding how energy moves through an ecosystem and what
types and numbers of other organisms it can sustain.
In almost all ecosystems, photosynthesizers are the only "gateway" for
energy to flow into food webs. If photosynthesizers were removed, the
flow of energy would be cut off, and the other organisms would run out
of food. In this way, photosynthesizers lay the foundation for every lightreceiving ecosystem.
Organisms' role in the energ flow
When it comes to the flow of energy in ecosystems there are two types of
organisms: producers and consumers. Plants are a common example of
producers in all populations. They are able to convert carbon dioxide into
oxygen and glucose, a common sugar consumed by most organisms.
They do this through a process called photosynthesis which allows the
plants to use sunlight as a source of energy. Producers convert energy
from the environment into chemical energy in the form of carbon to
carbon bonds. A classic example is the one previously mentioned where
the plants convert CO2 to O2 and glucose.
The second type of organism is the consumer. Consumers are unable to
make chemical energy the way plants do and have to use metabolic
processes to get energy from carbon to carbon bonds, which is called
respiration. Respiration breaks the carbon to carbon bonds and combines
them with oxygen to make carbon dioxide. The energy released is used to
help organisms move their muscles or as heat. Energy cannot be reused
once it has been lost.