6.6.5 Human Impact on the Environment Flashcards
(6 cards)
What has been the human impact on the environment?
There has been rapid human population growth on Earth since the 18th century
Humans need food, space for infrastructure and farming, clean water and resources
The increasing need for resources means that humans are having a disproportionate effect on other species
Effects of human activities that are influencing animal and plant populations include:
climate change
introduction of non-native species
hunting by humans
degradation and loss of habitats
How does burning fossil fuels affect plant and animal populations?
The large-scale burning of fossil fuels by humans in recent years has led to a large increase in the levels of carbon dioxide in the atmosphere
The increased carbon dioxide concentration in the atmosphere has resulted in higher average global temperatures, the effects of which include:
changes in weather patterns
melting polar ice caps
rising sea levels, causing flooding and salination of soil in coastal areas
rising ocean temperatures and acidity
These effects have changed the habitats of some species, putting their survival at risk
E.g. polar bears are struggling to survive as more of their habitat melts away earlier each year; the earlier melting of the ice caps means they have to swim further to reach seal populations that they prey upon for food
How does the introduction of species impact plant and animal species?
The introduction of non-native species can occur due to, e.g.:
travel, e.g. marine species in the ballast water of ships
keeping animals as pets, e.g. cats introduced to Australia
growing attractive plants in gardens, e.g. Rhododendron ponticum in the UK
the introduction of biological pest control, e.g. cane toads in Australia
Non-native species can be highly problematic as they often have no natural competitors, predators or pathogens that help limit population growth
Without natural population control, populations of non-native species can grow very quickly
Non-native species can negatively affect native species through factors such as competition and disease
How does hunting impact plant and animal species?
Hunting animals for food can result in overexploitation of a natural resource; if populations are hunted so much that they are unable to recover then extinction may result, e.g.
passenger pigeon
dodo
Pyrenean ibex
Harvesting animals for food must be carried out in a sustainable way to ensure that extinctions do not occur, e.g. by implementing sustainable fishing practices
How does habitat loss impact plant and animal species?
Humans cut down forests and drain wetlands to create land for farming, as well as polluting water, soil and air
As their habitat area is reduced a species will:
search for other suitable habitats
compete for the remaining habitat
Eventually the range of habitat can become so small that a species is not able to survive and becomes extinct
How can we control the effect of human activities?
There are many control measures in place across the globe to help mitigate the impact of human activities on plant and animal species; these measures will vary depending on the country and on the impacts that need to be addressed
Examples include:
prohibiting import and export of species
putting restrictions in place to control the impact of humans on animal and plant populations, e.g.
Certain areas cannot be used for agriculture, housing and infrastructure
Policies are in place to ensure environmental tests are carried out before building on undeveloped land
reducing sources of greenhouse gases, for example the burning of fossil fuels for electricity, heat, or transport
increasing the capacity of “sinks” that store greenhouse gases, such as the oceans, forests, and soil
