Chapter 20: Human Influence Flashcards
Describe how humans have increased food production
(a) agricultural machinery to use larger areas of land and improve efficiency
(b) chemical fertilisers to improve yields
(c) insecticides to improve quality and yield
(d) herbicides to reduce competition with weeds
(e) selective breeding to improve production by crop plants and livestock
Describe the advantages and disadvantages of large-scale monocultures of crop plants
Advantages: It makes farming much more efficient, keeps down costs. Machines and procedures can be used totally systematically on a large scale.
Disadvantages: It totally removes all of the diversity of the natural land and eliminates the habitat of almost all of the other plants and animals that lived there before the monoculture.
Describe the advantages and disadvantages of intensive livestock production
Adv
High Output
more efficient in resource usage
Cost-Effectiveness
Disadv
Habitat Destruction
Reduced Genetic Diversity
Greenhouse Gas Emissions
Describe biodiversity
the number of different species that live in an area
Describe the reasons for habitat destruction
(a) increased area for housing, crop plant production and livestock production
(b) extraction of natural resources
(c) freshwater and marine pollution
How humans can have a negative impact on habitats
altering food webs and food chains
undesirable effects of deforestation
reducing biodiversity, extinction, loss of soil, flooding and increase of carbon dioxide in the atmosphere
State the effects of untreated sewage on water pollution
Sewage contains nitrates. Nitrates are used by algae to make proteins for growth. Excess nitrates can cause algal blooms and eutrophication.
State the effects of fertiliser use on water pollution.
Fertilisers contain nitrates.
Excess fertilisers are washed into bodies of water by the rain.
Nitrates are used by algae to make proteins for growth, which leads to algal blooms and eutrophication.
Explain the process of eutrophication of water
• increased availability of nitrate and other ions
• increased growth of producers
• increased decomposition after death of
producers
• increased aerobic respiration by decomposers
• reduction in dissolved oxygen
• death of organisms requiring dissolved oxygen in water
Describe the effects of non-biodegradable plastics, in both aquatic and terrestrial ecosystems
Pollute soli and water
Describe the sources and effects of pollution of the air by methane and carbon dioxide, limited to: the enhanced greenhouse effect and climate change
When excess carbon dioxide and methane are released in the air it can cause climate change and worsens the greenhouse effect. These substances speed up the rate of climate change because they absorb infrared radiation.
Describe a sustainable resource
one which is produced as rapidly as it is removed from the environment so that it does not run out
Explain how forests can be conserved using:
education, protected areas, quotas and replanting
Explain how fish stocks can be conserved using:
education, closed seasons, protected areas, controlled net types and mesh size, quotas and monitoring
Explain why organisms become endangered or extinct, including:
climate change, habitat destruction, hunting, overharvesting, pollution and competition from introduced species
Describe how endangered species can be conserved
(a) monitoring and protecting species and habitats
(b) education
(c) captive breeding programmes (breeding of endangered animals in enclosures (such as zoos) to increase population numbers and preserve biodiversity.)
(d) seed banks (seeds of endangered plant species are carefully stored so that new plants may be grown in the future.)
Describe the reasons for conservation programmes
(a) maintaining or increasing biodiversity
(b) reducing extinction
(c) protecting vulnerable ecosystems
(d) maintaining ecosystem functions, limited to nutrient cycling and resource provision, including food, drugs, fuel and genes
Describe the use of artificial insemination (AI) and in vitro fertilisation (IVF) in captive breeding programmes
AI-artificially introducing sperm into a female’s reproductive tract to fertilise her eggs. Adv male infertile or the don’t for bonds
IVF- allowing fertilisation of an egg with sperm outside the body in a controlled lab setting.
Explain the risks to a species if its population size decreases, reducing genetic variation
a population cannot adapt/ susceptible to changing environmental variables and, as a result, may face an increased risk of extinction.
