chapter 3 Flashcards
Ecological energetics
Is the study of the ways that solar energy becomes fixed by plants and other
photosynthetic organisms and is then available to be transferred to other species.
Earth is the only place that there is….
a biological fixation of energy, principally of solar radiation by photosynthetic
organisms.
What is biomass?
Weight accumulated by an organism or an ecosystem
What is productivity
Autotrophs: rate of energy fixation
Organisms and ecosystems: rate at which biomass is accumulating
What kind of system are organisms and ecosystems in with respect
to energy?
It is an open system. Energy flows into the ecosystem, some is fixed and then eventually discarded (heat)
What is the key resource in ecosystems that supports organisms?
Solar radiation
How is the amount of solar energy fixed?
By autotrophs: Self-feeding organisms (absorb solar energy)
- some energy used for plants to grow others is stored
What is the process of photosynthesis?
Solar electromagnetic energy is absorbed b chlorophyll and used to join carbon dioxide and water to form a sugar hat stores this potential energy. Generates oxygen as a waste.
- it is the heart of energy transfer
What is the formula for photosynthesis
Sunlight + 6 Co2 +6h2o __ C6 H12 O6 + 6O2
Talk to me about Heterotrophs.
- They accumulate biomass by relying on autotrophs as a primary food source.
- consist of feeding off biomass of other organisms
- herbivory, carnivores, omnivores deterivores
What is energy?
Capacity of a body’s system to perform work
What are the 3 fundamental types of energy?
Electromagnetic kinetic and potential
What is the 1st law of thermodynamics?
Energy can be transformed but not created or destroyed
- In a system, input of energy must = output
What is the second law of thermodynamics?
Energy transformations can occur spontaneously only under conditions in which entropy of the universe is increased
- Energy transformations are not totally efficient (they also take energy)
- life requires incessant input of energy (the sun)
Why does the amount of solar energy varie with latitudes
At higher latitudes, the angle of solar radiation is smaller, causing energy to be spread over a larger area of the surface and cooler temperatures.
How do greenhouse gasses work?
- Carbon dioxide h2o and meth absorb some of the infrared radiation and reradiate in all directions
Allows earth to have thermal blanket
global warming
increase the atmospheric concentration of gasses
cause of fossil fules dforestation and agriculture
What are the side effects of global warming?
- Increased rate of decomposition
- more drought
- stronger storms
- more productivity
- Destroyed habitats
- Fish move further north
- run out of land and water
What are autotrophs
Primary producers providing biological foundation
- not all plants
What are photoautotrophs?
Need sunlight
- responsible for almost all productivity in biosphere
- Chlorophyll captures photons and is most sensitive to blue and red wavelengths but reflects green thats why plants apear green.
What are chemoautotrophs
- need heat-no sunlight
What percentage of solar energy is reflected into space? What percent is absorbed by earth? What percent is absorbed by atmosphere?
30%
45%
The atmosphere absorbs about 25 percent of the incident solar radiation
Energy transfer in food web
-entropy increases whenever there is a transfer of energy in food web
- part of energy = used for growth
- part = degraded into heat (which increases entropy)
Trophic structures
90% difference in productivity in each trophic level
- Autotroph
- Herbivore: (10% of autotrophs)
- carnivores: (10% of herbivore)
- Inherent in 2ed law of thermodynamics
