L2 - Human impacts on biodiversity Flashcards
what is the Anthropocene
the current geological epoch marked by significant human impact on Earth’s geology and ecosystems
what epoch preceded the anthropocene
the holocene, a period of relative climatic and environmental stability lasting the last 10,000 years
why is population growth a central issue in the Anthropocene
exponential growth reduces resources per person and stresses Earth’s finite carrying capacity
what was the world population in 2020, and what is it projected to be by 2050?
7.8bn in 2020
9.7bn by 2050
which countries contribute most to global population growth?
India, Nigeria, Democratic Republic of Congo, Pakistan, Ethiopia, Tanzania, USA, Uganda and Indonesia
what percentage of LDC population is projected to increase by 2030
33% reaching 1.9 billion by 2050
which 10 populous countries have fertility rates below the replacement level?
china
USA
brazil
russia
japan
vietnam
germany
iran
thailand
UK
how did early humans impact ecosystems
through hunting, fire use, land use changes and over exploitation of natural resources
what major extinction events correlate with human colonisation
- Africa and SE Asia: 50000 years BP
- Aus = 50000 years BP
- N America = 11000 BP
- New Zealand = 900 years BP
what activities have seen rapid growth since WWII?
population
urbanisation
motor vehicle use
foreign direct investment
fertiliser
consumption
water use
which planetary boundaries have been exceeded
climate change and biodiversity loss
name 3 boundaries with increasing risk
land-system change
freshwater use
interference with N and P cycles
what % of species have been harmed by over exploitation or agriculture
75%
how much of the world’s coral reefs and mangrove areas have been lost
20% of coral reefs
35% of mangroves
by how much have humans increased species extinction rates
by up to 1000 times the background rate
what are the 4 categories of ecosystem services
- Supporting e.g. nutrient cycling, soil formation
- Provisioning e.g. food, freshwater and wood
- Regulating e.g. climate and disease
- cultural e.g. aesthetic and recreational benefits
why are ecosystem services vital
contribute to human well-being by ensuring security, health, social relations and freedom of choice and action
when did conservation biology emerge as a field
in the 1960’s
what is the intrinsic value of biodiversity according to conservation biology
biological diversity has inherent worth, independent of human use
name 2 direct and 2 indirect uses of biodiversity
Direct = food, medicine
Indirect = nutrient cycling, ecosystem services
why is conservation biology considered a value-laden science
it emphasises that diversity is good, extinction is bad and ecosystems should remain complex
evolution must continue
