B6.1 Bidoicersity Flashcards
What is abundance, distribution and thus sampling
Abundance is the amount of organisms in an area anf the distribution is where the irgabism is found. To investigate this would take too long to properly do it so a sample is taken- measurements from a s area which can be representative of a larger area
How to estimate population size with capture recapture method?
What assumptions must be made when carrying it out
Capture organism, mark them ALL and release them inti the area
2) come back and recapture organisms in tbe orginal sample area. Use formula ti work out edtimate for jumber of populatiin
Mumber 1st sample * number 2nd sample/
Number of marked recaptured dons
When marking, mark in harmless pen/ nail pilish so that they dont get more likely to die or it messes up
3) that none gave birth or died or marking affected chance of survival
If they did die you still have to count them in tour samples
How to actually capture the organisms?
Part1
2/5
Pooters: ground insects
- jars with rubber bungs and two tubes, suck on them and the rubber mesh stops them from going to you. So you can collect insects
Pitfall trap: more ground insedts
- glass in a hole and crawling invertabrates will fall in. Make sure to put lid on so rain doesnt drown them to death.
Part 2 how to capture (nit ground ones)
3/5
Tree beating
- stretch a white cloth under a tree kr bush, shake or beat the tree with a stick where invertebrates will fall intk it and you can analyse
Sweep net-
Sweep through air or long grads to collect
Kick sampling (rivers and pond) - where tou get a net and kick the riverbed, dislodiging debris and creatures in this and catch these in the net
How to use identification keys to then identify unknown organisms that you’ve captured
Keys are series of wuetsions that lead you to the answer
1) series if yes no answers that follow and end up telling you what it is
2)could be numbered so dichromous, where the correct answer to a question tells you what question to go to next, where again yku eventuakky get it
To sample plants?
Work out population?
Use a quadrat, and count number of plants, ignoring two sides because of overlap.
Repeat 10 times or so
Make sire that the sampling is random, by using random number generator to determine c ordinates, otherwise bias comes into play
Then work out average and then do area x average (if it 1m)
How to measure distribution of organisms and hiw they vary with abiotic
Use a transcect and place quadrats along it in regular inteevals, counting the same number of species.
To ensure it is reliable do a parallel transect which should offer similar results
Now you can see how different plants are as you go along
How to measure distribution of planstd from bank to bank across river?
What does overlap show
How do abiotic factors interact anf biotic with distribution give examples
Place 30m transect
Mark regular intervals and place quadrats
Count number of species each quadrat and run parallel to make reliable
Map distribution for them
2) overlap means there will be competiton between those species
3) for example some could be more adapted to land so grow higher on bank, or water so lower, or like daises dont grow under trees due to light, or even competition meaning they have ti be distributed differently
How to measure abootic
Temperature = thermometer
Light intensity = light sensor electric device
Soil pH= pH monitord or universal indicator and water
Mositure= soil moisture meter
What to do if its grass
Measure lercentage wise and then plot on kite doagrams which shows this
What is biodiveru and why is it important
Why have himans effected it thr most
Biodiversity is the variety of organisms in a habitat
Because of population increase, humans tske more and more resources from the environment , and also a higher standard ofnliving means more resources too and foof as well
We taking more than they can replace and leaving behind waste- this negative impact causing destruction of biodiversity
How is biodiversity lost?
1) Deforestation: loss of habitats, reduce tree speices, predator species affected die to loss of prey, c02 decreeed
2) agriculture:
3) hunting and fishing
4) pollution
How agricukture led to loss
Hedgerows
Bioaccumulation
Herb
Mono
Land is cleared to keep up with demand for food.
- However removing things like hedgerow for machinery wildlife corridors mean habitas for aniamls like hedgehogs gone.
- pesticides being used , meaning pest species for foodchain gone, causing lroblems and pesticides can build up in the food chain unexpectedly BIOACCUMULATION
- Herbicides= kill plants so less food for animals bad
- MONOCULTURE: farmers grow one crop, limiting biodiversity as whole habitats are cleared for just one crop
Hunting and fishing loss?
Overfishing has lead to fish populations decreasing a lot as not enough time is given for them to regrow
Hunting targets specific species meaning food for other species are directly reloved, this may allow for some plant soecoes to massively grow and cause competition that wouldnt have been there for other species,
Summary
- huntin also leads to extinction
- hunting causes knock on effects in food chains
- less fish
Pollution?
General
Fertilisers
Tree, sukfur?
Mire pollution= less species
Feetilisers being used lead to eutrophication.
When fertilisers run off into lakes etc they give food for algae, and go crazy and form algal bloom, blocking out sunlight for aquatic plants . This means they cant do photosynthesis and produce oxygen for water. This means fish etc who need disolved oxygen die
2) less trees due to agriculture etc, more co2 in air and global warming= bad for biodiversity. Aswell we burn them which release more co2 and potentially schwefel dioxie which acid rain and kill and prevent plants from growing
Finally general nuclear waste etc is bad
