Ecological Relationships And Energy Flow Flashcards
Define biodiversity
A measure of the number of the different species living in an area
Define population
The number of organisms of the same species living in an area
Define habitat
Where a population lives
Define environment
An organisms surroundings. It contains factors that influence the organism. These factors can be divided into abiotic and biotic.
Define community
Several populations of different species living in habitats close together
Define ecosystem
An area where a community of organisms live and are affected by a range f environmental factors
What is an abiotic factor
Non living factors e.g temperature
Define biotic factors
A living factor e.g a predator
Name abiotic factors
Wind speed
Water / soil moisture
Light
Temperature
pH levels
How does wind speed affect organisms
It affects the rate of water loss by plants and therefore affects their survival rates in exposed areas.
How does water / soil moisture affect organisms
It’s measured by finding mass difference between the wet soil and it being dried out. Affects survival and therefore distribution of plants and animals.
How does light affect organisms
Measured using a light meter. Affects the survival and therefore distribution of plants as they light to photosynthesise.
How does temperature affect organisms
Messier with thermometer. Affects rate of cell reactions like photosynthesis and diffusion.
How does pH affect organisms
Measured using soil test kits or probes. The pH of soil is very important in distribution of many plants. Some plants will only grow in relative acid soils or relative alkaline soils. But most plants prefer to grow in neutral pH.
What are the biotic factors for animals
Competition between
Food
Water
Territory
Mates
What are biotic factors between plants
Competition between
Light
Water
Minerals
Space
What is a quadrat
A square frame used to measure a sample of an area.
Why are quadrants used
To investigate the distribution of organisms in a habitat
What makes a quadrat investigation reliable
A large sample needs to be obtained. For example 20 small sections should be sampled for a large area
Define representative
It needs to be representative of the entire area being investigated. In other words sampling should take place randomly across the larger area, not just concentrated in one part.
What is the method for quadrat random sampling
- Divide the area to be sampled into a grid using tape measures placed at right angles to each other.
- Use random number generator to generate coordinates within the grid to place the quadrat.
- Place quadrat at each coordinate
- Count the numbers / estimate percentage cover of each species in each quadrat.
- Use a key to identify each species
- Record results in a table.
- Calculate the average of each species.
What is a belt transect
It’s a method that is used when there is a gradual change from one side of a habitat to another, like the change in light between the outer edges of a forest to the centre.
What is the method for the belt transcet
- Extend a measuring tape from one side of the habitat to another
- Place a quadrat at 0m on the tape
- Count the numbers / estimate percentage of each species.
- Use a key to identify each species.
- Record results in a table.
- Continue this up the tape measure until the end
- Calculate average of each species
- A bar chart can be drawn to who the data obtained.
Define energy flow
The transfer of energy between organisms in a food chain
What is a producer in a food chain
A plant which absorbs sunlight creating its own energy.
What is a food chain
A food chain describes the order in which energy passes through living organisms.
Why is the sun important for food chains
It is the initial source of energy for all food chains
Define producer
A producer makes food by photosynthesis
What is a consumer
A consumer feeds on other living things
What is a food web
A food web shows how a number of food chains are interlinked. They are more realistic because very few consumers feed on only one thing.
What do arrows represent in a food chain
Arrows show the direction of transfer of substances (e.g carbon and nitrogen) through a food chain as well as showing what eats what (consumption)
And energy flow
What is energy loss due to?
The whole organism not being eaten
Not all food being digested, some passes out of the animal in excretion or egestion
Energy is lost at each stage due to heat in respiration.
Why are shorter food chains better than longer ones?
Shorter food chains are more efficient as energy is lost at each stage
What is a pyramid of numbers
A simple diagram used to represent the number of organisms at each trophic level.
What is a pyramid of biomass
A diagram showing the mass of living tissue (biomass) at each trophic level of a food chain
What are the advantages of a pyramid of numbers
Easy to collect data
What are the disadvantages of a pyramid of numbers
Does not into account the size of the organisms
What are the advantages of a pyramid of biomass
Takes into account size of organisms making it more accurate
What is a disadvantage of a pyramid of biomass
Very difficult to collect data. It’s actually the dry mass of an organism, consequently some organisms must be killed to obtain data.
What processes are involved in nutrient cycling
Decay and decomposition
How are dead organisms broken down in the decay process
Organisms such as earthworms, wood lice, and various types of insects are involved in the decay process.
Which microorganisms are responsible for the decomposition of decayed material?
Bacteria and fungi
How do bacteria and fungi decompose the decayed material
Saprophytic fungi and bacteria secrete enzymes into the soil or dead organisms.
The enzymes break down the organic material, it is then absorbed by the bacteria or fungi.
The digestion is known as extra cellular digestion as it happens outside the cells.
What is humus
It is the organic content of the soil formed from decomposing plant and animal material.
What factors speed up decomposition
Warm temperature
Adequate moisture
A large surface area in the decomposing organism
Presence of oxygen
What causes the rate of decomposition to decrease
Anaerobic conditions (little to no oxygen e.g water logged soil).
How does photosynthesis contribute to the carbon cycle
Plants absorb carbon dioxide from the atmosphere and form it into sugar, starch and other organic compounds. This is the only process in the cycle that decreases the level of carbon dioxide in the atmosphere
Define feeding in terms of carbon cycle
Moves carbon in the form of biological molecules along the food chain.
Define respiration in terms of carbon cycle
When living organisms respire they release carbon dioxide into the atmosphere
Define fossilisation in terms of carbon cycle
If conditions are not favourable for the process of decomposition, dead organisms decay slowly or not at all. These organisms build up and, if compressed over millions of years, can form fossil fuels
Define combustion (carbon cycle)
The burning of fossil fuels releases stored carbon dioxide into the atmosphere
Define excretion in terms of carbon cycle
When waste is removed from the body (urine). This excreted material can be broken down using the process of decomposition.
Define egestion in terms of carbon cycle
The removal of faeces from an animal that will contain carbon. This egested material can be broken down during the process of decomposition.
Define decomposition in terms of carbon cycle
When complex, carbon compounds in dead organisms, urine and faeces are broken down into simpler carbon compounds by bacteria or fungi.
Why is there more carbon dioxide in Earths atmosphere
Increased combustion of fossil fuels
Increased deforestation has removed the amount of CO2 being removed from the atnospehere via photosynthesis
What are problems associated with rising temperatures on earth
Climate change- more weather extremes such as droughts and severe storms
Polar ice caps melt
Sea levels rise and increase flooding
More land to become desert
Loss of habitats
Define nitrification
The process that describes the conversion of ammonium compounds to nitrate
Define nitrogen fixation
The process that describes the conversion of nitrogen gas to nitrate
Define denitrification
The process that describes the conversion of nitrate to nitrogen gas
How does nitrogen fixing occur
Nitrogen gas in converted into nitrates by nitrogen fixing bacteria
Nitrogen fixing bacteria need oxygen.
Where are nitrogen fixing bacteria found
Free in soil
Or in root nodules found on the roots of plants such as peas, beans and clover.
Within these root nodules the bacteria gain carbohydrates from the plant and the plant gains a source of nitrates in return.
How are the processes of nitrification and nitrogen fixing quickened?
A presence of oxygen and higher temperatures
How and where does nitrification happen?
It is carried out by nitrifying bacteria and in soil. Ammonia is converted into nitrates
Where does denitrifying bacteria thrive?
They thrive in water logged soil as they are anaerobic and don’t need oxygen.
How is denitrification done?
Denitrifying bacteria convert nitrates into nitrogen gas. This process is disadvantageous for the soil and plants
How are nitrates and other minerals taken into a plant
Via root hair cells
How are root hair cells specially adapted to uptake minerals
They have a long extension which provides a large surface area for absorption.
Define active uptake
The movement of particles form and area of low concentration to an area of high concentration using energy from respiration against the concentration gradient.
What do plants use nitrates for
Plants use nitrates to make amino acids and proteins
What other minerals are absorbed and what for
Calcium for cell walls
Magnesium for chlorophyll
Why do farmers add fertilisers
When crops are harvested and animals aer slaughtered the nutrients they took from the soil are lost. To replace these lost nutrients growers add either natural fertilisers or artificial fertilisers to their crops.
Give some examples of natural fertilisers
Manure, slurry and compost
Define eutrophication
A type of water pollutant that is triggered by too many minerals/nutrients entering the water.
Why does eutrophication occur
Fertiliser runoff into waterways
Minerals in sewage entering water ways
How is fertiliser more likely to leach into water ways?
Too much is used on the land
It is sprayed during rainfall or onto wet sloping ground
What is the full process of eutrophication
- Sewage or fertiliser runoff increase nutrient concentration of water
- Extra nutrients cause increase growth of algae (algal bloom)
- Algal bloom covers waters surface killing any plants below the surface as light and oxygen cannot reach them
- Algae also die as nutrients run out
- Aerobic bacteria decompose dead plants
- Bacteria use up oxygen for respiration
- Fish and other organisms die from lack of oxygen
What is a sustainable woodland and how is it done
A sustainable woodland allows for timber to be harvested in a controlled way.
It’s done by:
Only a small number of large trees are harvested at one time
Saplings are planted to replace the trees harvested. This is called reforestation
Harvesting of the same area does not happen again after the medium trees have grown to become large (25-30 years)
Which international treaties have been signed to reduce global carbon dioxide levels?
Kyoto 1997 and Paris 2015
