Ch 42: Ecology Flashcards
Ecosystems
the sum of all organisms living within its boundaries (biotic community) and all the abiotic factors with which they interact.
Ecosystem ecology requires two processes
- Energy Flow
2. Chemical Cycling
primary producers
plants
Autotrophs
an organism that is able to form nutritional organic substances from simple inorganic substances such as carbon dioxide.
Heterotrophs
an organism deriving its nutritional requirements from complex organic substances.
Primary Consumers
herbivores, feeding on plants
Secondary Consumers
organisms that eat primary consumers for energy
Tertiary Consumers
an animal that obtains its nutrition by eating primary consumers and secondary consumers
Decomposers
an organism, especially a soil bacterium, fungus, or invertebrate, that decomposes organic material.
The amount of light energy converted to chemical energy by autotrophs is an ecosystem’s primary production
1%
The spending limit for the energy budget of the entire of the ecosystem=
all the photosynthetic production
Gross Primary Production (GPP)
total primary production in an ecosystem
Net Primary Production (NPP)
GPP – the energy used by the primary produces for their “autotrophic respiration” (Ra)
NPP
GPP – Ra
In aquatic systems, primary production is affected by two factors
Light availability
Nutrient availability (nitrogen and phosphorus)
A eutrophic lake
nutrient-rich and supports a vast array of algae. ( man-made runoff)
In terrestrial ecosystems, primary production is affected by(3)
Temperature
Moisture (most important annual precipitation)
Evapotranspiration – combines both factors
Only % of the available energy at each trophic level is passed on to the one above it.
10
At each level, energy is lost too
Heat, For movement, reproduction, and or other life processes
because of this loss food chains are short
If only 10% is passed on from primary producer to primary consumers then only 1% of net primary production (10% of 10%) is available to the secondary consumer
Ecological pyramids
diagrams that give insight into food chains, biomass, energy, and pyramid numbers
Restoration Ecology
The process of returning a degraded ecosystem to a more natural state
Bioremediation
use organisms to detoxify polluted ecosystems, This has been used to restore areas degraded by mining or polluted by oil or radioactive elements
Bioaugmentation
Introduction of desirable species such as nitrogen fixers to add essential nutrients.
Biogeochemical Cycles(4 cycles)
- water
- carbon
- nitrogen
- phosphorus
Water cycle
- Water is essential to all organisms
- Liquid water is the primary physical phase in which water is used
- The oceans contain 97% of the biosphere’s water; 2% is in glaciers and polar ice caps, and 1% is in lakes, rivers, and groundwater
- Water moves by the processes of evaporation, transpiration, condensation, precipitation, and movement through surface and groundwater
The Carbon Cycle
- Carbon-based organic molecules are essential to all organisms
- Photosynthetic organisms convert CO2 to organic molecules that are used by heterotrophs
- Carbon reservoirs include fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, the atmosphere, and sedimentary rocks
- CO2 is taken up and released through photosynthesis and respiration; additionally, volcanoes and the burning of fossil fuels contribute CO2 to the atmosphere
The Nitrogen Cycle
- Nitrogen is a component of amino acids, proteins, and nucleic acids
- The main reservoir of nitrogen in the atmosphere (N2), though this nitrogen must be converted to NH4+ or NO3– for uptake by plants, via nitrogen fixation by bacteria
- Organic nitrogen is decomposed to NH4+ by ammonification, and NH4+ is decomposed to NO3– by nitrification (by bacteria)
Denitrification: converts NO3–back to N2 (by bacteria)
- Nitrogen Fixation is the process by which bacteria take atmospheric N2 which is biological unavailable to most organisms and change it into a biologically available form that can be used.
- A plant called Legumes and the bacterium (Rhizobium) have a mutualistic relationship
- This is the major pathway for N to enter an ecosystem
The Phosphorus Cycle
- Phosphorus is a major constituent of nucleic acids, phospholipids, and ATP
- Phosphate (PO43–) is the most important inorganic form of phosphorus
- The largest reservoirs are sedimentary rocks of marine origin, the oceans, and organisms
- Phosphate binds with soil particles, and movement is often localized
Sere
Sequence of Growth
Greenhouse effect
Causes Climate changes due to CO2
Ozone Depletion
Be causing cancer due to pollution
Acid Rain
decreases pH
pollution
causes toxins to spread
intro of diseases
in the name
