Ecosystem Ecology I
Question One:
What are the 4 components that energy flow links?
1. Primary producers (autotrophs); Organisms that can synthesize their own food.
2. Consumers; Organisms that eat other living organisms.
3. Decomposers (bacteria, archaea, fungi); Organisms that feed on dead organisms or their waste products.
4. Abiotic environment; The soil, climate, atmosphere, and the particulate matter and solutes in water.
Question Three
Where do the following organisms get their energy?
Photoautotroph
Photoheterotroph
Chemoautotroph
Chemoheterotroph
Sunlight and Chemical compounds
Question Ten
Provide the complete equation for cellular respiration.
6O2 + glucose --> 6CO2 + 6 H2O + ATP
Question Two
What is the purpose of a food web? What does it tell us?
Food webs connect the trophic levels in an ecosystem and describe the movement of energy among trophic levels.
Question Eight
Explain GPP in your own words and how to calculate it. Can we measure it directly? How do NPP and respiration contribute to GPP?
GPP is the total amount of chemical energy produced by autotrophs in a particular ecosystem. GPP = NPP + respiration. GPP is measured indirectly (by directly measuring NPP and respiration).
Question Eleven
What kind of organisms do cellular respiration and which domain(s) do they belong to?
All cells belonging to all domains of life do cellular respiration. It is important to note that even photosynthetic organisms do cellular respiration.
Question Four
Provide the complete "equation" for photosynthesis.
Sunlight + 6H2O + 6CO2 --> glucose (C6H12O6) + 6O2
Question Nine
Explain NPP in your own words and how to calculate it. Can we measure it directly?
NPP is the chemical energy that remains after cellular respiration by autotrophs. NPP can be directly measured by measuring the primary producer biomass, which is an appropriate way to measure chemical energy since the chemical energy of the autotrophs is a result of the chemical bonds in the biomass of the autotrophs.
Question Three
What are examples of:
Photoautotroph
Photoheterotroph
Chemoautotroph
Chemoheterotroph
Photoautotroph - plants
Photoheterotroph - green non-sulfur bacteria
Chemoautotroph - Hydrogen bacteria
Chemoheterotroph - Animals
What kind of organisms do photosynthesis and which domain(s) do they belong to?
Only photoautotrophs do photosynthesis. We know of photosynthetic eukaryotes and bacteria, but we do not know of any photosynthetic archaea.
Question Twelve
What would happen to CO2 and oxygen concentrations if you isolated plants in clear chambers without herbivores...
1. during a sunny day
2. during the night
1. During a sunny day, the plants will be doing both cellular respiration and photosynthesis. Plants are a net carbon sink, which means that they consume more CO2 in photosynthesis than they produce in cellular respiration (and they produce more O2 in photosynthesis than they consume in cellular respiration). As a result, we would expect CO2 concentrations to decrease and O2 concentrations to increase.
2. During a dark night, due to the lack of sunlight, the plants will only be doing cellular respiration and will not be doing photosynthesis. We would expect CO2 concentrations to increase and O2 concentrations to decrease.
Question Thirteen
What is a limiting nutrient? What limits NPP? Do these factors limit NPP everywhere, or is NPP limited by different things in different places?
A limiting nutrient of a biological reaction is one whose relative scarcity limits the overall rate of reaction from increasing. In other words, a limiting nutrient is one where if more of the nutrient is added, the biological reaction will increase in rate. Globally in terrestrial environments, NPP is limited by temperature and precipitation. Locally in terrestrial environments, NPP is limited by nutrients, especially nitrogen. In aquatic environments such as open oceans, light and nutrients limit NPP. In freshwater environments, phosphorous is limiting. In open oceans, nitrogen and iron are limiting.
Question Six
In terms of carbon and energy acquisition, what kind of organisms are we?
Humans (and animals) are chemoheterotrophs.
Question Seven
Do macroscopic photoautotrophs or microscopic photoautotrophs account for a disproportionately high level of Earth's photosynthesis when compared to their biomass? Describe where this type of photoautotroph is predominantly found on Earth.
Microscopic photoautotrophs account for less than 1% of the planet's photosynthetic biomass but more than 45% of the planet's photosynthesis. These organisms are abundant in the surface waters of open oceans and make open oceans the biome that accounts for the largest amount of NPP on Earth.
Question Three
Where do the following organisms get their carbon?
Photoautotroph
Photoheterotroph
Chemoautotroph
Chemoheterotroph
Heterotrophs - get carbon from organic compounds
Autotrophs - get carbon from inorganic sources