Chapter 20: Human Influences on Ecosystems Flashcards
How has modern technology improved food production?
Insecticides - destroy insects that eat crops
Selective Breeding - improved traits in crops and livestock
Herbicides - kills plants that compete with the crop
Pesticide - destroys agricultural pests or competitors
Chemical fertilisers - adds minerals to increase crop yield
Agricultural machinery - used to clear land, prepare soil, plant, maintain and harvest crops
What are the advantages of monoculture farming?
- Maximises the efficient use of soil and local climate conditions.
- In most cases, farmers select crops that will thrive best in the local environment.
- Plants that can resist or thrive in specific weather conditions become the focal point of the agricultural monoculture system.
- Productivity and efficiency is higher despite increased efforts.
- Allows farmers to specialise in a particular crop as they usually deal with the same issues and problems that may arise in the process of growing.
- This increases profits and reduces costs.
What are the disadvantages of monoculture farming?
1.Pest infestations are greater.
- No genetic diversity which may make them prone to blight/pests
- Upsets the natural balance of soils are there are two many of the same plant species in one field are robbing the soil of its nutrients, resulting in decreasing varieties of bacteria that are needed to maintain the fertility of the soil.
- Negative effect on important participants of the the natural reproductive cycle like bees due to increased use of pesticides.
What is intensive livestock production?
A type of intensive agriculture. An approach to animal husbandry designed to maximise production while minimising costs.
To do this, they keep livestock at high stocking densities at a large scale using machinery and biotechnology and global trade.
What are the productis of intensive livestock production?
meat
milk
eggs
for human consumption
List the advantages of intensive livestock production.
- Higher yields
- Can create multiple food products from one location
- Each food item is potentially in-season throughout the year
- Factory farming reduces the amount of time it takes to bring a product to the market
- Factory farming can occur almost anywhere
Lis the disadvantages of intensive livestock production.
- Welfare issues for the livestock
- Diseases can spread easily among them
- They focus on result instead of the processes meaning that it is not unusual for them to crossbreed different species to generate more efficient growth behaviours.
- Greenhouse gas emissions are significant
- Can create additional health issues that require management dure to the reduction of the amt of sunlight absorbed, reflecting heat back onto the animals. (impact of greenhouse gases increased)
List the reasons for habitat destruction.
Removal of habitats
Extraction of natural resources
Marine pollution
How does the removal of habitats cause habitat destruction?
- Creation of farmland removes hedgerows, hay meadows and stubble fields that are important habitats for plants and animals. As a result, populations of butterflies, flowers and birds have declined
- Intensive agriculture destroys many habitats as hedges are grubbed out to make fields larger, monocultures of grasses replace diverse populations found in hay meadows and planting of wheat denies animal’s access to stubble fields.
- Development of towns and cities requires a large amount of land which also destroys natural habitats
- Crowding of growing populations into town leads to problems of waste disposal. The sewage and domestic waste from a town of several thousand people can cause disease and pollution in the absence of effective means of disposal, damaging surrounding habitats.
What issues do the extraction of fossil fuels cause?
Dumping of extracted rock in spoil heaps
Seepage into water systems and soil
What issues does the extraction of raw materials cause?
Overturns landscape, causes erosion
How does marine pollution destroy habitats?
- Contamination with human debris including untreated sewage, agricultural fertilisers and pesticides
- Oil spills still cause problems but are gradually reducing
- Plastic products which are non-biodegradable persist in the environment
- Other plastic products form micro-particles as they break down and these are mistaken by marine organisms for food these stay in the stomach causing sickness or prevent the gills from working efficiently
- Fertilisers and sewage which enter the marine environment create ‘dead zones’ where there is insufficient oxygen to sustain life.
Tell me the impact of deforestation.
How does untreated sewage affect human health?
Contains waterborne pathogens that can cause serious human illnesses
How does untreated sewage affect marine life?
It destroys aquatic ecosystems.
This can threaten human livelihoods, when the associated biological oxygen demand and nutrient loading deplete oxygen in the water to levels too low to sustain life.
How does the greenhouse effect work?
What factors enhance the greenhouse effect?
What problems does global warming cause?
