Ecosystems and succession Flashcards
why the biomass of phytoplankton less than zoo plankton
phytoplankton reproduce at a rate which is greater than their consumption
advantages of using an organic fertilizer
greater range of nutrients
nutrients released slowly
improves soil quality adds humus adds microbes and improved the soil structure
improves water holding capacity of soil reducing leaching
improves soil aeration
already available
advantages of using inorganic fertilizer
known nutrient content fast acting nutrients distributed evenly no pests contained better to handle store and transport concentrated in nutrients applied using light machinery avoids soil compaction
how deforestation leads to a decrease in diversity of organisms
removal forest removes habitats ecological niches shelter
reducing the number of species that can exist in that area
how deforestation changes levels of CO2
increases
reduced amount of CO2 used in photosynthesis
increase CO2 produced in combustion and decomposition
decreases
less respiration
by plants animals decomposers
units for energy transferred bet trophic levels
KJm-2 year-1
difference in the amount of solar energy reaching the primary producer and the energy in the biomass of primary producers
light reflected light misses a chlorophyl wrong wavelength respiration inefficiency of photosynthesis
explain the affect of sodium nitrate on the growth of the plant
the nitrate places the nutrients already removed
nitrate needed for protein AA production
more fertiliser more growth more yield
why a large volume of insecticide was found in ladybirds
greenflies take in insecticide from plant
ladybirds eat many greenflies
bioaccumulation
insecticide cannot be excreted remains in body stored as fat not broken down
factors which make effective pesticides
SPECIFIC- only toxic to organisms its directed harmless humans nat predators earthworms pollinating bees
BIODEGRADE - once applied breakdown harmless substances in soil and chemically stable - long shelf life
COST EFFECTIVE -dev costs high new pesticides only useful short time - genetic resistance
NOT ACCUMULATE -not build up specific parts organism or passes along food chain (BIOACCUMULATION)
integrated control
choosing variety suit local area and pest resistant as poss
suitable habitats close crops for nat predators
reg monitoring crops- signs of pests early action can be taken
remove pests mechanically if exceed the level
using biological agents if necc and available
why are integrated pest control systems good
effective
min impact on enviroment
equation for net productivity
net = gross - respiratory losses
what is net productivity
chemical energy stored in the plant from sunlight
what is gross productivity
the rate at which plants assimilate chemical energy from photosynthesis
monoculture
large area of land where only 1 type of crop is grown
how does factory farming increase energy conversion rate
movement restricted- less E used muscle contraction
environment kept warm- reduce heat loss
controlled feeding -opt food max growth no wastage
excluded predators- no loss other organisms in food web
other means of improving E conversion rate
selective breeding-more eff converting food into body mass
hormones to increase growth rate
why the biomass of primary consumers is less than the biomass of producers
loss of energy and heat -
respiration and movement
loss of mass -excretion
less energy left to sustain a higher level
more inedible parts
biomass
total mass of living material in a specific area at the same time -usually measured as dry mass - amount of water in an organism very variable
Farming practices which reduce species diversity
(direct) Removal of hedgerows and woodland monocultures-grass cereal crops filling in ponds and draining wetlands over grazing of land - sheep--> preventing regeneration of woodland
(indirect)
pesticides inorganic fertilisers- reduce diversity, polluting water courses
escape of farm waste into water courses
absence of crop rotation- poor soil structure
species diversity
the number of different species and the number of individuals of each species within one community
conservation
methods of painting a ecosystem and the living organisms which occupy them. Best use of resources while preserving natural landscape and wildlife.
conservation techniques
Maintaining existing hedgerows ( height and shape)
planting hedges not hedges
maintaining existing ponds
leaving wet corners of fields
planting native trees on land with a low species diversity
use biological control
organic fertilisers
crop rotation using a nitrogen fixing crop not fertilisers to improve soil fertility
natural meadows
leaving cutting of field edges until after flowering and seeds dispersed