Chaptwr 23 Ecosystems Flashcards
What is ecology?
Ecology is name given to the study if the relationships between organisms and their environments
An ecosystem
Sizes of them?
Is made up of all the living organisms that interact with one another in a defined area , (biotic), and also all th non living conditions/ factors there (so abiotic)
All the living organisms as well as the biotic factors, and non living conditonsin an area
Ecosystems can vary in size, from it being a tiny bacterial colony to the entire biosphere of earth
Factors affecting ecosystems (what are they all)
Abiotic = the non living physical factors like
- light,
- temperature,
- water availability ,
- oxygen availability ,
- Edaphic soil factors
And biotic living factors
- competition (food water space mates terroriory’
- predator prey relationships
-
Abiotic factor light effect?
What does high light do to a plant, and low light , and what have plants adapted for
Most plants affected by light intensity because light is directly needed for photosynthesis, so the greater the light the greater the succes of plant
- however plants can cope with different intensities using adaptations
- low light areas have larger leaves
- may have photosynthetic pigmented thst require less light
- only operate when at an optimum
Temoertwure
What is good in high temps
What can changes in temp do
Big effect because it effects the enzymes controlling metabolic reactions and thus hoe effienct twn organism csn be
- plants develop better in warmer temps as well as ectothermic animals
- also changes in temp can initiate hibernation migration dormancy etc
Water availability
Lack of water for most things = stress
- plants hav adapted to survive for them, cacti
- as need for photo and hydrostatic skeleton
Oxygen availability
Obvs need oxygen to respire and survive
Better to have fast flowing cold water because more concentration of oxygen, if become too war, can suffocate aquatic animals snd plants
Waterlogged soil, spaces between soil filled with oxygen so less available for lkantd, thatswhy specialised arenchyma tissue in hydrophytes come in clutch
Edaphic = soil factors
Soil exists in different particle sizes, based on them the organism will have to adapt differently
For example
Clay is essilky waterlogged and forms clumps
Loam (different sized) retains water but does not before waterlogged
Sandy coarse particles allows free draining , so water not retained and soil eroded
Food chains and trophies levels?
What are they
Food chains show the transfer of energy in an ecosystem , with different trophies levels
All start from producer which gets energy from sun and converts using photos , then primary consumer eats that secondary and tertiary,
Why do food chains not sustain more than max quaternary consumer
Because there is nit ENOUGH BIOMASS and stored energy keft to support life processes for any more organisms
Why are decomposed useful?
They break down dead organisms and release nutrientd BACK INTO ecosystem and clear waste
What two ways can food chains be represented in a more groahical like form
- pyramid of numbers
- pyramid of biomass
What is biomass and how to calculate
What DO PYRAMID OF BIOMASS REPRESENT SND WHAT DOES IT JOT TAKE INTO SCCOUNT
Is the mass of DRY living material present in a particular place , where energy is stored
Here you need to multiply the biomass (could be an average) of one by all the organisms present in thst level
Then you can put this into a pyramid of biomass
2) they represent biomass present of thst trophies level at a SPECIFIC MOMENT IN TIME , and nit take into account any seasonal changes
Why is pyramid of biomass preferred over number
Pyramid of numbers nit necaseikt a pyramid because one organism can have huge mass
As a result pyramid of bikmass is normally a pyramid
But there is an exception for onyplnaktom one because less mass but mroe number
How to messure biomass directly and why
Like before had to be dry content because water varies between organisms
Therefore dry mass done by
- killing organisms
- placed in a kiln at 80° until all evaporated
As a result only few samples taken to minise this, but then won’t be representative, so a problem
Why is biomass ALWAYS LESS IN THE NEXT TROPHIC LEVEL ALMOST ALWAYS ?
1) why is not all biomass even taken up (plants then animals)
2) what happens to biomass that is taken up
- for plants because it csntuse all the light (wrong wavelength ) + it’s reflected + so,e doesn’t hit the leaves
- also bones and stalks etc not eaten
- some parts are indigestible and come out in egestion and excretion
Then what is available biomass converted to energy but not all converted to increasing biomass
- some is used for respiration for energy in MOVEMENT , and KEEPIMG WARM , respiratory loss,
- and whatever energy actually left becomes biomass
As a result only about 10% of biomass is actually converted into more biomass
What are unite of energy available
Why per year?
Assuming energy = biomass
KJ/ M2/ year
Measure dpernyesr to take into account photosynthetic changing patterns in the year
What is the effienct synthetics biomass is transferred from one level to the other called
Ecological effienct , and shown by pyrsmid of energy
Again why is not all energy from sun converted to biomass
What is energy actually fully taken in called, and what is energy used for biomass called
- some reflected, not all csn be absorbed, some don’t hit the leaves
- photosynthesis can be limited by other factors so energy wasted
- some of energy used for other photosynthetic reactions + respiration for processes
Energy fully taken in = gross production
But this energy used repsirsiton , remaining into biomass
So energy for biomass = net production
So equation for net production = GROSS PRODUCTION - RESPIRATIORY LOSS A
Again terms for energy available to organism, and energy used as biomass and equation
Gross production available
Net production biomass
Net production = gross - respiratory
What is formula for ecological effeicney (effienct for biomass transfer) then
Energy / biomass available after the transfer/ energy available before x100
How have human activities affected biomass transfer for their needs
How do make sure trsnsfer of biomass is max
By farming , we set optimum conditions for things we want to grow so their biomass is at maximum (most food, shelter protection abiotic condiins ti grow )
And then we limit the transfer to max 3 levels, either cosumer, primary and secondary which is us for meat or just producer and then primary which is us
This way we ensure less biomass is lost and as much energy is transferred and thus Availble for us
Does effeicny if energy transfers increase higher trophic levels , why?
Yes, osknt start low because sun gives out so much energy so effienct ginsn be low
Then lrinsry ginsn be a bit higher but lower than secondary because plants have more indigestible contents (cellulose) than animals which is probably just boned , so they increase
But stilk deepeneds
Why can you use biomass as an indication
Because energy is stored as this so you can
