Week 3 Part 2 Flashcards
What is secondary production
Heterotrophs get their energy by consuming organic compounds that were produced by other organisms which is secondary production
What is the equation of Net secondary production
Igenstion- respiration-egestion
What is lower net secondary or primary production
Secondary because so much is lost
What are trophic interactions
What they eat and what eats them determines the influence of an organism on the movement of energy and nutrients through an ecossytem so it describes the feeding positions of groups of organisms in ecosystem
What are the different levels of trophic interacations
Autotrophs - herbivores - primary carinvores - secondary carinvores
What are detritus and detrtivores apart of
Detritus is the first trophic level detritivores are part of the second level
What is allochthonous
External energy inputs for example the stuff that grows on the outside of rivers dies and goes into the water
What is autochthonous
Energy produced by autotrophs this becomes more important as water flows downstream (energy that comes from itself)
What bodies of water reley on what
Moves downstream wider rivers and slower current autochthonous because more important
What do trophic pyramids portray
Realtive amounts of energy or biomasses at each trophic level
What do terrestrial ecosystems pyramids look like
Heavier on the base for both energy and biomass
What do aquatic ecosystems trophic pyramids look like
Energy is the same most exist at the lowest trophic level but inverted biomass there are not alot of primary producers
Where are inverted biomass pyramids most common
When productivity is lowest such as nutrient- poor regions of the open ocean because there is very few nutries avialble anything that does usally get eaten
What are the three hypotheses of why don’t terrestrial herbivores consume more of the available biomass
- Herbivores are constrained by predators and never reach carrying capacity (experiments support this hypothesis in some ecosystem)
- Autotrophs have defences against herbivory such as secondary compounds
- Phytoplankton are more nutritious and easier to digest for herbivores than terrestrial plants (there is a lot of terrestrial herbivores where not every part is nutrious
What plants have stronger defences
plants from resource-poor environments
What is trophic efficiency and how much gets transfered
Amount of energy at one trophic level divided by the amount of energy at the trophic level immediately below it about 10% gets transfered
What is consumption efficiency
Proportion of available energy that is consumed ( how good is the trophic level of consuming)
What is assimilation efficiency
Proportion of ingested food that is assimilated lost during respiration and injestion
What is production effciency
Proportion of assimilated food that goes into biomass
Where is consumption higher
In aquatic ecosystems that in terrestrial ecosystems also tend to be higher for carnivores than for heribvorese because they arent intrested in eating woody parts of the plants there more food for carnivores
Why is foodquality of plants and fetritus low
Complex compounds such as cellulose and lignin that are not easily digested 2. Low concentrations of nutrients such as nitrogen and phosphorus
What is production of efficiency related to
Thermal physiology and the size of the consumer endotherms allocate more energy to heat production and have less for growth and reproduction and have less for growth and reproduction than ecotherms
What effects heat loss
Body size as body size increase the surface area to volume ration decreases
What has the lowest production efficiency
Birds because they are so active
What determines the # of trophic levels in an ecosystem
- The amount of energy entering via primary production: More production should allow more trophic levels the larger the base the more levels
- Frequency of disturbances Higher trophic levels depend on lower levels, and take time to re-establish after disturbance for higher to even exist if disturbance is frequent higher levels may never establish
- Ecosystem size larger ecosystems support larger populations, have more habitat heterogenity and higher species diversity
What did a study in the Bahamas show
Found that island size was correlated with number of trophic levels. Disturbance frequency didnt really impact it hto
What are food webs
Conceptual models of the trophic interactions of the organisms in an ecosystem
What is a problem with food webs
Many organisms change their feeding over their lifetime
Why did Inuit women have higher PCB concentration in their breast milk higher than women in southern quebec
The higher up the trophic level they feed the highest levels of POP. Concentrations of these animals at higher trophic levels become higher eating prey withhigher concentrations this is biomagnificaition
What are PCB
Industrial chemical compounds they remain in the envionroment for a long time have no direct exposure to PCBS
How do PCB get to the Artic
Produced at low latitudes are in gaseous form and enter the atmospher circulation patterns carry them to the artic where they condens to liquid and fall to earth
What is the relation to POP and diet
Communities that eat mammals tend to have the highest levels of POP eating
What is bioaccumulation
Chemicals are not metabolized or excreted and become progressively more concetrated in tissues over an organisms lifetime
