Unit 4 Biology Slapton ley research

  • Sampling 
  • Succession
  • Investigating populations
  • Methods
  • Abiotic/ biotic factors
  • Freshwater ecology
  • Farming 
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  • Created by: Joanna
  • Created on: 11-10-11 19:23


Abundance- the # of individuals of one species in a particular area

Frequency - the # of samples a species is recorded

% Cover - for plants only - how much of the area you're investigating is covered by a species

Distribution - where a particular species is within the area you're investigating

Random Sampling / Systematic / Stratified

Prevents bias 

Precision - how many decimal places you've got and how well defined a value is

Accuracy - how close to the true value

Reliability - a test that produces the same result on repeated trials 

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Succession vegetation

1. Tree fall - leaves seed bank

2. Pioneers - macarangas - adapted to receive maximum sunlight

3. Competition for light

4. Hardwood trees - tall and long lasting so out complete outer trees

5. Stable - for around 200 years

Climatic climax community = oak woodland

Succession Shingle ridge 

1. Wave action - creates a GAP

2. Pioneers - sea spurge (xerophytes - adapted to reduce water loss! hairy leaves, small surface area so less water loss, thick water inside stems )

3. #2 Facilitates legumes / rosette - flat on floor - good against wind and trampling on! The root nodules has bacteria (useful for nitrogen fixing bacteria into nitrates 

4. Grassland - outcompetes other plants that shades out for light

5. Woody shrubs - plagio climax  / sub climax community

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Abiotic and Biotic factors

Abiotic factors:

  • Light intensity
  • Humidity
  • Wind speed
  • Temperature
  • Rainfall
  • Edaphic factors (soil depth, soil pH, soil moisture - organic matter amount of nutrients)

Biotic factors:

  • Competition
  • Predation
  • Number of organisms 
  • Food supply
  • Disease
  • Parasitism 
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Different methods used to investigate different organisms

  • Pitfall traps - steep sided containers sunk in a hole - partially open - insect falls on the container + can't escape - protected from rain / predators .. some small predators can enter - eat other insects - affect the result
  • Pooters - jars have rubber bungs - 2 tubes stuck on bung - inhale through short tube - time consuming but get large sample .. some maybe missed if not large enough 
  • Quadrats - investigate plant populations - square frame divided into a grid - placed on ground at different points (species frequency  # of individuals + % cover - quick but subjective)  different size of quadrats
  • Transects - use lines calle dtransects - find out the distribution of plants (line transects - tape measure along a transect - touch the tape measure recorded, belt transects - quadrats placed next to eac other along transect + interrupted transects - measurements at intervals)
  • Beating trays - used to investigate insects found in vegetation - beating tray / sheet held under a plant / tree .. plant / tree is shaken - insects falls onto beating tray - take large samples - good estimate of the abundance but maybe not random 
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Methods (part 2)

Independent Variable 

  • Centre vs Edge
  • Valley bottom vs top
  • south / north facing

How data will be collected

  • For ground flora = % cover quick but subjective
  • think about the size of quadrat
  • gridded quadrat? 
  • will it destroy the habitat ?
  • For leaf litter - grab sample 
  • sample size? 
  • will you keep altitude the same? 
  • consistent measurements?

Conserving local habitats on slapton ley

  • Conservation - protecting certain species by conserving their habitat
  • Coppicing - special way of cutting trees at an angle so they can grow shoots e.g hazel trees  to produce food for dormice
  • Butterfly Glade - in this area, shrubs (e.g. brambles and flowering plants)  have been growing which creates a canopy - all plants absorb light 
  • Management - management has cut down trees so that other plants can grow
  • Ex situ conservation - conserving off the site- sending seeds to millenium seed banks
  • In situ conservation - conserving on the site 
  • Sanctuaries are habitats that are private from the public but used for other animals e.g. otters.
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Method (part three)

  • Description of methods Description, explanation, anomaly and limitations    
  • 1. Invertebrates Tally / Grab sample and count- place on tay To find out the species richness and species diversity Grab sample
  • Had to wash the tray after collecting invertebrates
  • Returned back to their habitats 
  • Repeats - keep fairly standardised    
  • 2. Ground flora Percentage cover
  • Used an open quadrat than grid Quick and easy
  • Find out species diversity Subjective
  • different %'s from other people so take an average    
  • 3. Light / temp
  • (abiotic factors) Using light meter in lux
  • Thermometer Measure light intensity, soil temperature. 3 readings and took an average
  • People can block the actual light that the plants are getting and temperature varies during the day  
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Freshwater ecology

Freshwater shrimps 

  • More than 6 jointed legs
  • More than 8 jointed legs
  • A fast swimmer and flattened body - able to escape from predators and let it move through the water easily
  • They are detritivores - eat detritus and have lots of legs for movement
  • Often paired up

Blackfly larva

  • It has a sucker to aid it from attaching to surfaces e.g. rocks
  • It has filter feeders which has the ability to make silk - track / crawl back to where it has come from
  • Body has segments which aid it to loop around / movement

Stonefly Nymph

  • Has 2 tails - aid to swim and help diffusion of gases / tiny holes on taiks
  • Long tails more than half the body
  • Little claws to help them grip
  • Streamlined body- aid it to swim 
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Methods of investigation DEAL = Description, Explain, Anomalies and limitations!!!!

Stratified sampling 

  • Overall strategy in the riffles and pool
  • D = use gridded quadrat
  • E = percentage cover - estimated value and not exact value and quick
  • A = counting number of algae and detritus 
  • L = subjective
  • Invertebrate sampling
  • Grab sample
  • place on a tray
  • disturbance on habitat
  • combining grouped data
  • shuffle and kick for 20 seconds
  • use a net to transfer invertebrates
  • had to rinse the tray with water


  • Temperature changes during the day
  • hold the probe on the water
  • cannot use an electric thermometer
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Investigating populations

Mark release recapture techniques - investigate mobile species

  • capture sample - appropiate technique + count
  • mark in a harmless way
  • release back in habitat
  • 2nd sample - same populatio
  • count how many marked
  • total pop size = number caught (1) x number caught (2) / number marked in 2nd
  • marked sample - enough time to mix back with pop 
  • marking hasn't affected chance of survival +mark still visible
  • changes in pop size due to death,birth+ migration = small 

Risk assessments

  • trips falls + slips - suitable footwear / wellies aware of cliffs / steep ground
  • bad weather - weather forecast - clothing 
  • stings + bites - insect repellent / allergy/ medications 

Ethical issues

  • Fieldwork affects environment - people walking / trodding - soil erosion - ensure to have smallest impact / avoid habitat disturbances
  • Fieldwork affects organisms - capturing may cause stress - great care + handled well + as little as poss = released asap
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Statistical tests

  •  Spearmank rank correlation - look for a relationship between 2 sets of numerical data  ... IS THERE A SIGNIFICANT CORRELATION ETC minimum of 10 paired data / compare critical value in # of pairs of data 
  • Standard error and 95 % confidence intervals -  SIGNIFICANT DIFFERENCE - 5/10 more than one set of data .. IS THERE AN OVERLAP / DIFFERENCE? PROBABILITY AND CHANCE!
  • Chi squared - SIGNIFICANT ASSOCIATION (preference) expected value should be >5 - compare to critical value - number of categories 

1) state which stats test to use

2) explain why it's chosen

3)state null hypothesis OPPOSITE OF HYPOTHESIS!

4) calulate stat test

5) interpret -- > than crit value or < crit value - null hyp accepted/rejected

6) explain in terms of PROBABILITY AND CHANCEEE!!!!

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Soil management and fertility

  • Soil erosion
  • Pollution Use of pesticides and herbicides Different layers of crops
  • Crows eat some insects Planting vetch as ‘green manure’    

Crop management

  • Pests / diseases Antibiotics and pesticides 
  • predation Chemicals used are bad for health 
  • Inorganic = damaging Pest + Disease = planting different crops
  • Use lime to balance PH    

Pest management

  • Margins around edge of the field 
  • Habitat for natural predators
  • Plant variety of crops
  • Mixed cropping = confuse potential pests Use of pesticides to kill pests 
  • Can be poisonous to other vegetation and affect crop rains = cause eutrophication Crops can be damaged or eaten by pests 
  • Affecting rain -
  • cause eutrophication
  • Cause organophospho poisoning Have to sell crop for less and have less profits    

Production and profits

  • Supermarkets set price – can be low and changes
  • Supermarkets undercutting farmers Intensive farming – produce higher yield Chemicals used can run into the lake = eutrophication Use other predators of any pests e.g. aphids and ladybirds  
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