Species diveristy and human activities Flashcards
How does species diversity change as natural ecosystems develop?
Natural ecosystems develop into complex communities with many species and individuals, resulting in a high index of diversity
How do agricultural ecosystem differ from natural ecosystems in terms of species diversity?
Agricultural ecosystems have lower species diversity because humans select a few productive species, reducing the number of species and genetic variety
Why do farmers select only certain species in agricultural ecosystems?
Farmers choose species with desirable traits to increase productivity, such as high yield or disease resistance
What effect does competition have on non - farmed species in agricultural ecosystems?
Non - farmed species often cannot compete for space and resources, which may lead to them dying out or having their populations greatly reduced
Why does the presence of a single desirable species reduce biodiversity?
This is because most of the available space and resource are sued by the farmed species, limiting what is available for other species
How do pesticides affect species diversity in agricultural ecosystems?
Pesticides reduced species diversity by killing organisms that compete with the farmed species for light, nutrients, water and food
What is the overall impact of agriculture on the index of species diversity?
It lower the index of species diversity due to the reduced species numbers and increased dominance of a few selected species
Name four factors that have contributed to increased food production?
1/ Improved genetic varieties of plants and animals
2/ Greater use of chemical fertilisers
3/ Greater use of biotechnology
4/ Changes in farm practices - larger farms
What is an ecological impact of intensive food production?
A reduction in the variety of habitats with ecosystems
How does the reduction in habitat variety affect biodiversity?
It leads to a decrease in species diversity
What is the overall environmental cost of intensive farming?
Although it increases food yield, often diminishes natural habitats and reduces biodiversity
Name the four farming practices that directly reduce species diversity by removing habitats
1/ Removal of hedgerows
2/ Grubbing out woodland
3/ Creating monocultures
4/ Draining wetlands or filling in ponds
How does overgrazing affect biodiversity?
Over grazing prevents woodland regeneration and reduces species diversity
Name three indirect farming practices that reduce species diversity
1/ Lack of crop rotation
2/ Use of pesticides and inorganic fertilisers
What is monoculture, and how does it affect biodiversity?
Monoculture is the farming of a single crop species over a large area; reduces habitat variety and species diversity
How does crop rotation improve biodiversity?
Maintains soil fertility, naturally and reduces need for chemical inputs
What is an advantage of using organic fertilisers?
They are less harmful to surrounding ecosystem compared to inorganic fertilisers
