Energy Transfer and Nurtient Cycles- Topic 5B Flashcards
How can you work out the mass of carbon present in a sample of dry mass?
Generally taken to be 50% of the dry mass
What is a producer?
an organism that makes it’s own food e.g. plants through photosynthesis
What is a consumer?
An organism that gains it’s energy by consuming other organisms rather than by using the energy from sunlight directly
What is a saprobiont?
(decomposers) are a group of organisms that break down complex materials in dead organisms into simple ones
What is a food chain
Something that describes a feeding relationship in which the producers are eaten by primary consumers which are eaten by secondary etc
What is each stage in the food chain known as?
A trophic level
What is Biomass?
The total mass of living material in a specific area at a given time. (and the chemical energy store for an organism)
What is Biomass measured in?
g m-2 (grams per square metre)
How can you measure the energy contained in dry biomass?
using a calorimeter
As energy passes from one ….. ……. to the next, energy is ……
As energy passes from one trophic level to the next, energy is lost.
How is energy lost between trophic levels? Give 2 examples
Respiration and Excretion
What is GPP?
Chemical energy stored in plant biomass
Farmers can overcome limiting factors by…
Maximising plant exposure to light
Using warmer temps in greenhouses
irrigation to maximise water supply
Mycorrhizae
fungi that form symbiotic relationships with the roots of plants. Mycorrhizae help plants absorb inorganic ions and water from the soil.
What is NPP
net primary production, energy available to plant
how do you calculate NPP?
NPP= GPP- respiratory loss
How do you calculate the net production of consumers?
N = I - (F + R)
Net production = chemical energy in food - (energy lost in faeces and urine - energy lost through respiration)
Suggest how you could estimate the chemical energy store in a dry biomass?
Obtain a dry sample e.g in a low temp oven. Then burn in calorimeter
The change in temperature of the water is used to calculate the chemical energy of the dry biomass
Why may a hare not have the same net productivity as the grass it eats?
Because not all energy is taken in as some energy is used in RESPIRATION, as well as FAECES/URINE, some parts of the grass aren’t eaten.
What do food webs and food chains show?
The transfer of energy through an ecosystem.
What’s the difference between a food web and a food chain?
Food chains show simple lines and each stage is a trophic level WHEREAS food webs show lots of food chains and show overlapping
What do decomposers do?
Decomposers break down dead or undigested material
What do farming practices aim to increase?
The efficiency of energy transfer
Name 2 main ways farmers increase the energy available for human consumption
Reduce the energy lost to other organisms
Reduce the energy lost through respiration
How does simplifying a food web help farmers?
By reducing energy loss to other organisms
How can farmers increase the net production of their livestock?
By controlling the conditions that they live in so more energy is used for growth and less lost through respirations e.g. decrease movement increase heat (so less energy wasted generating body heat)
Why are saprobionts important?
They recycle important chemical element in remains and in the process break down organic molecules into inorganic ions.
What does the Nitrogen cycle show?
How nitrogen is recycled in ecosystems
Name the 4 different processes involving bacteria in the Nitrogen cycle
Nitrogen fixation, ammonification, nitrification, denitrification
What happens during nitrogen fixation?
Nitrogen gas in the atmosphere is turning into nitrogen containing compounds. Bacteria turn nitrogen into ammonia.
What happens during ammonification?
Nitrogen compounds from dead organisms are turned into ammonia by saprobionts, which goes on the form ammonium ions. Animal waste also contains nitrogen compounds which are turned to ammonia by saprobionts
What happens during nitrification?
Ammonium ions in the soil are changed into nitrogen compounds that can then be used by plants (NITRATES)
First ammonium ions - nitrites, then nitrites- nitrates
What happens during denitrification?
Nitrates in the soil are converted into Nitrogen gas by denitrifying bacteria using nitrates to carry out respiration under anaerobic conditions.
What other way can nitrogen enter an ecosystem?
Lightning, artificial fertilisers or industrial scale in Haber process
Explain 2 ways that farmers can increase the net production of their animals.
Keep them in enclosures/pens to minimise respiratory losses through movement.
Keep them warm so less energy wasted in generating body heat.
Plants and animals need phosphorus to …
make phospholipids, DNA, and ATP
Phosphorus can be found in…. and dissolved in ….. in the form of….
Phosphorus can be found in rocks and dissolved oceans in the form of phosphate ions
Phosphate ions in…. are released into the soil by ……
Phosphate ions in rocks are released into the soil by weathering.
What increases the rate at which phosphorus can be assimilated?
Mycorrhizae
How are phosphate ions transferred through the food chain?
Animals eating plants which are in turn eaten by other animals
Phosphate ions are taken into plants through the ….
roots
How are phosphate ions lost from animals
in waste products
Saprobionts are involved in breaking down organic compounds releasing ….. ….. into the soil
Phosphate ions into the soil.
What is guano
waste produced by seabirds containing high proportion of phosphate ions. often used as natural fertiliser
Weathering of rocks releases phosphate ions into …, … and …. which is taken up by ……… and passed along the food chain to birds
Weathering of rocks releases phosphate ions into seas, lakes and rivers which is taken up by aquatic producers (ie algae) and passed along food chain to birds
What process do plants use to produce biomass?
Photosynthesis.
Consumers can’t convert all energy available from the previous trophic level into new biomass. How is this energy primarily lost?
Respiration
Excretion
What is a pyramid of biomass?
A pyramid draw with bar lengths proportional to the mass of plants/animals
What is a pyramid of energy?
A pyramid drawn with bar lengths proportional to the energy stored in organisms, with units as energy per unit area per unit time.
Describe how saprobionts obtain their nutrients (2)
by secreting enzymes to digest food externally
then absorbing the nutrients they need
How Mycorrhizae increases rate of uptake
increases the surface area of root system.
The use of natural and artificial fertilisers?
to replace the nitrates and phosphates lost by harvesting plants and removing livestock.
what environmental issues are arising from the use of fertilisers ?
leaching and eutrophication
