Unit 4 Flashcards
(56 cards)
What is the definition of biodiversity?
the number and variety of organisms within the area
What is the definition of species diversity?
no. of different species and the relevant abundance of each species in a community
high species diversity = high ecosystem health
What is the definition of ecosystem/habitat diversity?
variation in the ecosystems found in the region or the variation in ecosystems across the planet
What is the definition of genetic diversity?
variety of genes present that control the inheritable characteristics within a population
What factors may cause there to be a relationship between latitude and species diversity?
- temp = hotter near the equator
- weather = increased latitudes have cold and harsh conditions
- light availability
- nutrients and co2 availability
How can global biodiversity be measured?
by the ‘Living Planet Index’ (LPI) which shows a decline of 58% between 1970 and 2012
What are the 5 different human activities that threaten biodiversity?
- habitat loss and degradation
- species overexploitation
- pollution
- invasive species and disease
- climate change
What is the definition of a direct threat?
are immediate human activities that have a direct impact on the area in which the activities are undertaken
What is the definition of an indirect threat?
are human activities which may impact ecosystems globally through the consequences of these actions
What are examples of direct threats?
- habitat loss by agriculture
- species overexploitation
- whaling
What are examples of indirect threats?
- temp change due to climate change
- invasive species and disease
- oil spills
- plastic pollution
- burning fossil fuels
What are some examples of local threats to biodiversity?
- land use change
- resource exploitation (fishing)
- pollution, waste disposal, degradation of local habitat
What is the definition of anthropogenic climate change?
climate change enhanced by human activity
What are some examples of global threats to biodiversity?
- climate change
- oil spills
- waterborne disease
- coral bleaching
Where are tropical rainforests found and how much of the worlds plant and animal species does it contain?
about half the plants and animals in the world
found between 25 degrees N/S of the equator
100 years ago, what % of the Earth’s land did tropical rainforests cover, compared to now?
100 years ago = 15%
now = les than 3%
What is the main cause for deforestation of tropical rainforests?
80% of deforestation is due to agriculture
Why was deforestation increasing in the Amazon?
- push for development
- provided economic growth
- one hectare was being cleared every minute
In 2024, when the new president was elected as the Brazilian president, how much did deforestation decrease by in the first 6 months?
34% decrease
What is driving the increased demand for the need to clear tropical rainforests?
increased population = increased affluence = increased demand
What is the cause and the impacts of logging in the rainforest?
- hardwoods are valuable
- road building for illegal logging
impacts = once cleared forest can’t recover
= Brazil and Indonesia 70 - 80% of logging is illegal
What is the cause and the impacts of cattle grazing in the rainforest?
cause - land sold to farmers
- Brazilian beef in high demand
impacts = Brazil is the largest exporter of beef (more cows than people) 232 million to 210 million in 2020
What is the cause and impacts of palm oil in the rainforest?
cause - 33% of products in super markets contain palm oil
- can be used in biofuel
impacts = Indonesia and Malaysia produce over 80% of the world’s palm oil
= contributes 4% of worlds greenhouse gases
What are the causes and impacts of mining in the rainforest?
cause - income e.g. Indonesia mineral deposits form 19% of their exports
impacts = Brazil is the world’s largest iron mine
