B18 Biodiversity and Ecosytems Flashcards
What is biodiversity ?
The variety of all the different species of organisms on Earth .
-Biodiveristy can als refer to an individual ecosytem (biodversity in the amazon rainforest )
One reason biodiveristy is important for ecosytsems .
-Species depend on eachother for food and shelter .
Another reason biodveristy is important for ecosytems .
-Species also help to maintain the enivornemnt . For example , decomposers break down the remains df dead organsisms .
What does a high level of biodiversity mean ?
-There are a lot of different species , and this makes an eocystem more stable .
-As lots of different species means that the ecosytem is less dependant on one species .
-Therefore if the population of a species falls , it is less liekey to effect the whole ecosytem .
How are humans having a negative effect on biodiveristy ?
Example , deforestation .
-Tropicl forests contain a very rich biodiversity . However , large areas of these ofretss are being destroyed to provide land .
IN EXAM YOU CAN BE AKSED FOR THIS .
EXAM QUESTION ,,, Why are humans doing deforestation ?
-The land is used for rice fields or for grazing cattle .
-The land is used to grow crops which are then used to make biofuels .
-Over the last hundred years , the opulation of humans has increased massively as wella s the averge standard of living .
Because of this , humans are using more of the Earth’s resources than ever before .
-They are also producing more waste that is leading to pollutoin .
An example of water pollution
Humans porduce a large amouont of sweage , this contains urine and faeces .
-In the UK , sewage is treated before being released .
-However , in some cases , untreated sewafe is accidetally released into rivers or streams ..
How else can rivers and streams be polluted ?
By fertilsiers onf arms .
-both fertilisrs and untreated sewafe causes dissolved oxygen levells to fall and this can kill aquatic chemicals .
How else can rivers and streams be polluted .
-Toxic chemicals are released into rivers form factroies , and these can kill animals in the rivers .
WASTE FROM HUMAN ACTIVITY IS REDUCING BIODIVERISTY IN AQUATIC ECOSYTEMS .
Air pollution
-Waste from human activiies is also polluting the air .
-e.g burning coal in power stations can release acidic gases and these can cause acid rain .
-burnign lso releases smooke
AIR POLLUTION IKE THIS CAN KILL PLANTS AND ANIMALS AND THIS REDUCES BIODIVERSITY .
Land pollution
-Millions of tons of waste are dumped into landfills .
-Landfills destroy habitats for plants and animals .
Land pollution - Toixc Chemicals
-Toxic chemicals can also leach out of the landfills and pollute the soil .
-Toxic chemicals are simply dumped onto the land , all these are killing living organisms .
a note to take from pollutiion .
-From all these activities ,w aste from huamns is reducing biodveristy .
-Therefore , we need to carefully ahndle our waste material and dispose it without harming the environment .
temperautre like over the last hundred years
-avergae temeprature has been increasing
causes of temperature change ?
-Naatural changesi n the climate .
-However current increase is caused by human activity .
Human activity effecting cilmate ?
-For many decades now humans have release huge amounts of crbondioxide into the atmopshere . Mainly due to burning fossil fuels .
–Mehthane also release - which is porduced b y bacteria , i releasedin pddy rice field .
-cows passing wind .
Significance of Methane and arbondioxide
-Both cabrondioxide and methane are greenhouse gases so they trap heat in the atopshere leading to global warming .
What is peer review ?
-Thousands of scientifc papers have been published on global warming .
-These have been chekce dby other scientists before published this is PEER REVIEW .
-this hellps to detct flse claims , makes reasrch pblished in scientific journals valid .
example of something that is NOT peer re view
-Repororts in popular media , newspapers ar not subject to peer review .
-Some reports are just ismplifed , inaccurate or biased .
One consequence of temperatures on Earth increasing .
1.Loss of habitats
-Reduction in ice levels in the artic and this has cuased the populations of artic organisms like polar bears to decrease due to habitat reduction .
Another consequence of temperatures on Earth rising .
-Animals like birds and insects may gradually extend their range northward towards cooler conditions .
(MOSQUITO , can’t surive in the UK , but with global warming , they could spread to the UK and diseases like Malaria coul dbe brought with them .)
Final consequence o temperatures on Earth rising
-Migration patterns of animals may change .
-Effect palnts , like flowering seaons , some plant grown in palces htey could not before , ro some may not be able to be grown in a certain place again .
What is eutrophication ?
-The addition ofnutrients to water stryems that break down the natural chemical balance .
Stage one of eutrophication ?
-Farmers apply fertilisers containing nitrates and phosophates to their field .
Stage two of eutrophication ?
-Heavy rain washes the fertilisers off int rivers and lakes .
Stage three of eutrophication ?
-Nitrates abd phosphates encourga ealge to grown on the water’s surface .
Stage four of eutrophication ?
-Algae blocks sunlight reaching plnts below the surface .
Stage five of eutrophication ?
-Plants stop photosynthesising and releasing oxygen .
Stage six of eutrophication ?
-Decomposers break down dead plants and animals using up even more oxygen .
Stage seven of eutrophication ?
-Fish die due to lack of oxygen .