Topic 2: Ecosystems Flashcards
Ecology
The study of interactions of organisms with their physical environment and with each other
Abiotic
Non- living: temp, light, rainfall, soil chem, soil moisture, wind
Biotic
Living
Ecosystem
The organisms and abiotic factors interacting with each other in a given location
Biome
A major ecological community characterised by a distinctive type of vegetation influenced by rainfall and temperature almost exclusively
Food Chain
Producers- trap solar energy through the process of photosynthesis and provide the energy for the rest of the chain
direction of arrows up to indicate energy flow
top carnivours are dependent on the sucess of many levels
Trophic Level
Organisms at a particular trophic level are the same number of energy transfers away from the original source of energy that enters the ecosystem
refers to a level on an ecological pyramid
Producers
Providing energy and material to the rest of the organisms in the web/ ecosystem.
create new biomass through photosynthesis
can also act as a home to some consumers
energy source to decomposers
serve to hold nutrients in the soil and help resist soil erosion
Consumers
Feeding on producersand providing food as prey to heigher level consumers
compete with eachother for food causes –> competition predetor prey relashinships mutualism or parasitism
Decomposers
Reduce large organic compounds into simple inorganic compounds
break down dead matter and return various nutrients to the soils
scavengers- each whole dead organisms (decomposers, large animals)
detritovours -feed on large pieces of organic matter in the soil (small insects and invertebrates)
Saprotrophs- feed on dead or decaying matter, digest large organic molecules into simple inorganic molecules for plants (fungi and decomposers)
Solar Energy
Critical to life on earth.
1) drives photosynthesis –> no usable energy for living organisms –> energy used for movement active transport, biosynthesis, growth, reproduction
2) warms up earth–> providing temperature suitable for living organisms
3) drives cycling of water and transfers of heat by wind and water –> cycle provides basis for development of ecosystems –> winds serve to circulate water and inorganic nutrients
Photosynthesis
Visible light absorbed by the chlorophyll, green light reflected –> transformed into chemical energy in the form of glucose –> glucose food of producers, energy storage, building material, building proteins and fats –. chlorophyl needed to conduct transformation
inputs- solar energy carbon dioxide and water
outputs - glucose and oxygen
6CO2 + 6H2O –> C6H12O6 +6O2
Respiration
6O2 + C6H12O6 –> 6CO2 + 6H2O
inputs- glucose and oxygen
outputs - carbon dioxide heat and water
mitochondria –> energy released through process form ATP –> used for movement, synthesis of large molecules, active transport and reporduction
when respiration does not occur with oxygen outputs are carbon dioxide and:
methane, ethyl alcohol, hydrogen sulfide, nitrogen gas
Primary Productivity
Rate of energy capture in autotrophs
Gross Primary Productivity
Plants
The total gain in energy or biomass per unit area per unit time fixed though photosynthesis (example unit g/cm^3/hour)
too hard to measure, can only be calculated by using
NPP= GPP -Respiration
Net Primary Productivity
the rate at which energy is stored as biomass. represents food that is available to consumers in an ecosystem.
(example unit g/cm^3/hour)
New mass
NPP= GPP- Resp
Secondary Production
energy capture by heterotrophs
Gross Secondary Production
Total gain of energy or biomass by consumers per unit area, per unit time through absorption
GSP= Food Eaten - Feces
mass/ area / time
energy / area / time
Net Secondary Production
new mass
food eaten - feces - respiration
Gain by consumers of energy or biomass per unit area, per unit time remaining after respiratory losses.
g/cm^3/hour
Biomass/ Energy/ Productivity Pyramid
Producers–> primary consumers -> ….
Energy decreases from level to level because of second law of thermodynamics –> respiratory losses
Productivity/ energy pyramid is ALWAYS shape of a pyramid
Approx 10% of energy available to next level
Biomass is an instantaneous measure
productivity is gathered over time
Number Pyramid
producers –> primary consumers –> …
Can have 1 tree, but many insects, this tree would provide lots of energy for the insects because it is so large…
Vegetarian
if we ate plants, more food available for people, more people could be supported
but risk protein deficciencies, lack of particular amino aicids
Biomagnification
The increase in concentration of toxic molecules from one trophic level to another.
molecules cannot be transformed by the body
Increase –> passed on, less organisms same # of toxins
heighest levels suffer first
DDT/ pestacide, kills birds in US
reduced the egg shell thickness, when falcons sat on them they would break, reproduction decreased
Limit in Length of Food Chains
The cumulative decline in energy, there isn’t enough energy to support another trophic level- animals would spend more energy looking for food than gained by the food.
The efficiency of energy transfer between trophic levels.
If efficiency is high, more energy available to the next trophic level.
Total photosynthetic productivity , GPP, the base of the pyramid, can support more trophic levels.
Top Carnivours are Rare
This is due to the fact that they are fully dependent on the success of the lower levels
in addition there is less energy available to them
catastrophe of any kind could wipe out their population
genetic diversity is less
rare, more valuble, more poachers
Efficiency
Output/ input
Output= NPP
Input = GPP
Compare & Contrast Aquatic and Terrestrial Food Chains
1) Solar energy- water absorbs energy therefore not as much reaches the plants, lower efficiency
2) Transfer of energy- more efficient in aquatic food systems because less indigestible material
3) Movement- abundancy of water supports aquatic organisms, don’t spend as much energy, spend less energy, is lost as heat, more available to next trophic level
4) Warm blooded- cold blooded animals do not loose as much heat through respiration (aquatic) more energy available to next trophic level
5) Single celled base- more reproduction, more GPP, can support more levels (aquatic)
6) Humans- aquatic feed heigher in food chain
Measure Biomass
Cutting grass, random places in the ecosystem, over long period of time, dry mass, calculate year long average
instantaneous measure
Units Flows Stocks
Flows- rates- energy/area/time
stock- energy/ area
