factors affecting biodiversity Flashcards
(31 cards)
climate change
significant, long lasting changes in weather patterns
monoculture
a crop consisting of one strain of one species
why is it essential to maintain biodiversity
to preserve a balanced ecosystem for all organisms.
why does the removal of one species have a profound effect on others
species are interconnected
why is human population growing at a dramatic rate
improvements in medicine, hygeiene, housing and ifrastructure enabled people to live for longer
what are humans doing to create enough space for housing, industry and farming to support the increasing population
humans are disrupting the ecology of many areas. they often harm other species directly or indirectly leading to extinction
which factors affect biodiversity
deforestation
agriculture
climate change
how does deforestation affect biodiversity
permanent removal of large areas of forest to provide wood for building and fuel (logging) and to create space for roads, buildings and agriculture
how does agriculture affect biodiversity
an increasing amount of land has to be formed in order to feed the growing population. resulted in large amounts of land being created and in many cases planted with a single crop (monoculture)
how does climate change affect biodiversity
release of carbon dioxide and other pollutants into the atmosphere from burning fossil fuels is increasing global temperatures
what does pollution result from
industry and agriculture such as the chemical pollution of waterways
what causes deforestation
- can occur naturally due to forest fires caused by lightning or extreme heat and dry weather
- mostly caused by humans
- some areas of forest indirectly destroyed by humans through acid rain (result of pollution)
what are the effects of deforestation
- animals are forced to migrate to other areas to ensure their survival it could increase biodiversity of surrounding areas
- reduces number of animal species as their habitats is destroyed including their food source and home. it also reduces number of other animal species present by reducing or removing their food sources
- if only a specific tree is felled, species diversity is reduced
- directly reduces number of trees present in an area
what is happening in some forests
they are being replaced to help restore biodiversity but only a few commercially viable tree species are planted so biodiversity is still reduced
what do farmers do that reduces biodiversity
farmers only grow few different species of crop plants or rear only a few species of animals. farmers select species based on characteristics that give a high yield. this selection of only a few species greatly reduces biodiversity of that area
what have farmers done for economic viability
when farmers have selected their desired species, farmers use techniques to increase the number of these species to maximise food production. this leads to reduced biodiversity.
which agricultural methods reduce biodiversity
- deforestation
- removal of hedgerows
- pesticides
- herbicides
- monoculture
- eutrophication
how does agricultural deforestation affect biodiversity
to increase area of land available for growing crops or rearing animals destroys habitats
how does removal of hedgerows reduce biodiversity
result of mechanisation. farmers use machinery to help plant, fertilise and harvest crops. it frees up extra land for crop growing. this reduces number of plant species and destroys habitats for blackbirds, hedgehogs.
ways that pesticides and herbicides affect biodiversity
pesticides = used to kill pests that would eat crops or live on animals. reduces species diversity (destroys pests and food source of other organisms)
herbicides = kill weeds (plants growing in an area where its not wanted) weeds are destroyed as they compete with the cultivated plants for light, minerals and water. destroying weeds reduces plant diversity and indirectly animal diversity
how does monoculture affect biodiversity
many farms produce one crop using many acres of land to grow one species. greatly reduces biodiversity. only one plant and few animal species will be supported by one type of plant. growth of vast oil palm plantations causes rainforests deforestation leading to loss of habitat
what is eutrophication
- Fertilisers used in farming are washed away by the rain and they fall into ponds, lakes or rivers.
- This fertiliser leads to algae growing at the surface of the water which blocks any sunlight so other plant species cannot photosynthesise.
- These plant species die and microorganisms feed on them using oxygen produced from photosynthesis to respire in order to decay the dead matter.
- However, if there is no photosynthesis due to lack of sunlight, there is less oxygen produced which means that respiration in microorganisms cannot occur so they also die aswell.
- This depletion in oxygen is also harmful for other aqautic organisms that require oxygen to respire and also for gas exchange
what is climate change
a significant long term change in an area’s climate. e.g temperature and rainfall
what does global warming refer to
a rise in the Earth’s mean surface temperature. climate does not fluctuate but carbon dioxide levels have increasing trapping more thermal energy in the atmosphere so scientists believe human activities have contributed to global warming
