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Biodiversity
the variety of living things in a given area
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How Biodiversity is Measured
- 1. Genetic Diversity - Genetic variation within a species (variety of different versions of the same genes within a species)
- 2. Species Diversity - # of species
- 3. Species Richness - # of species in an area
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Inbreeding depression
genetically similar parents mate and produce inferior offspring
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Ecological Diversity
richness and complexity of a biological community (number of niches, trophic levels etc)
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Ecosystem diversity
number/variety of ecosystems
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Latitudinal gradient
- species richness increases toward the equator
- Some possible causes:
- High plant productivity: more niches = higher species coexistence
- Climate stability, no glaciation: more time for evolution/speciation
- Diverse habitats increase species diversity and evenness
- Tropical rainforests and drylands, ecotones
- Human disturbance can increase local habitat diversity
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Biodiversity hotspots
have a large number of endangered and threatened species; have a concentration of endemic species; used to prioritize conservation; 34 - most near equator
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Endemic species
species that are unique to that location
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Benefits of biodiversity
- Food
- Wild species can improve food security
- Wild strains can provide disease resistance
- Potential new food crops
- Medicinal value
- Wild species produce $150 billion/year in pharmaceuticals
- Ecosystem services
- Intact ecosystems have increased stability and resilience, and can provide ecosystem services
- Purify air and water
- Detoxify wastes
- Stabilize climate, moderate floods, droughts, wind, temperatures
- Cycle nutrients and renew soil fertility
- Pollination
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Biophilia
humans have emotional bond with other living things
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Threats to Biodiversity
- extinction
- Extirpation = the disappearance of a population from a given area, but not the entire species globally. This can lead to extinction
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Causes of Extinction "HIPPO"
- H: Habitat destruction and fragmentation
- I: Invasive species
- P: Pollution
- P: Population pressure (human)
- O: Overharvesting
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Habitat fragmentation
gradual, piecemeal degradation of habitat; continuous habitats are broken into patches
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Biodiversity Protection
- Conservation biology is one of the few scientific fields that is explicitly goal-directed
- Aim of biological conservation is to prevent individual species (or entire communities) from becoming extinct
- Important concepts for conservation
- Conservation geneticists = study genetic attributes of organisms to infer the status of their populations
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Minimum viable population size
how small a population can become before it runs into problems
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Metapopulations
a network of subpopulations; important in fragmented habitats
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Endangered Species Act (ESA)
- 1937
- primary US legislation for protecting biodiversity
- forbids the government and citizens from taking actions that destroy endangered species or their habitats
- forbids trade in products from endangered species
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Threatened
those likely to become endangered in the foreseeable future
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Endangered
one that is in danger of extinction throughout all or a significant portion of its range
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CITES
- UN Convention on International Trade in Endangered Species of Wild Fauna and Flora
- protects endangered species by banning international transport of their body parts
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Convention on Biological Diversity (1992)
- 3 Goals:
- 1. Conserve biodiversity
- 2. Use biodiversity in a sustainable manner
- 3. Ensure the fair distribution of biodiversity's benefits
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The Red List
[LOL - it is red] species facing high risks of extinction
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Captive breeding
individuals are bred and raised in zoos or other captive facilities with the intention of later re-introductions
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Indicator species
an organism that serves as an index of ecosystem health; help to prioritize communities that need protection
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Keystone species
a species that plays a critical role in a biological community that is out of proportion to its abundance; protecting this can protect the entire ecosystem
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Flagship species
Interesting species used to motivate people to preserve communities and contribute to conservation → “charismatic megafauna”
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Umbrella species
Species which require large blocks of land → preserving the umbrella also preserves the entire community; are often large species
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Habitat protection
recent trend to protect entire system rather than single species
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Ecological restoration
restores degrade areas to some semblance of their former condition
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Debt-for-nature swap
a conservation organization pays off a portion of a developing country’s international debt
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Conservation concession
conservation organizations pay nations to conserve and not sell resources
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Conservation easement
legal document between the land owner and a government or private agency; the owner retains property rights but agrees not to allow certain types of development
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