Lec 24: Human impact – Biodiversity loss and its consequences Flashcards
what processes cause biodiversity?
natural selection and speciation
how many species are estimated to exist? How many are identified?
- 7 Million
1. 75 million
Name the 5 drivers of biodiversity loss and an example of each
- habitat loss (tropical forest)
- overexploitation (overfishing)
- pollution (eutrophication)
- climate change (polar bears)
- invasive species (zebra mussels)
how many species have gone extinct in the last 500 years? (well documented cases)
900
Why should we care about biodiversity loss (4)
- ethics
- medical
- ecosystem services (direct, indirect, lifestyle)
- culture
What are the 2 subsets of economic value?
use value
non-use value
What are the types of non-use value
bequest
existence
option
Which species are most important for ecosystem services?
plants, microbes, and insects
not what you think of when you think of biodiversity
Does biomass increase with increased diversity?
Is poly-culture better for biomass?
Generally, there is a correlation between increased biodiversity and increased biomass.
Poly-cultures have higher biomass than mono-culture.
However, the most productive species within a poly-culture would actually be more productive in a mono-culture.
How does diversity affect stability?
increased diversity improves stability
- porfolio effect: the sum of many random things produces a more stable ensemble
- spatial insurance hypothesis: if many sites are considered, the timing of biomass fluctuations can average out across space
How does biodiversity affect pest control?
increases pest control
Where is most of our money being spent? Do these correspond to species most important for ecosystem services?
50% of conservation dollars are being spent on the top 10 species, 95% on vertebrates.
not really. those are bugs, plants, and microbes.
