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Lecture 56

BIOL 1001 Lecture Notes - Lecture 56: Overexploitation, Introduced Species, Genetic Drift

Course Code
BIOL 1001
Tamara Kelly

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April 3rd Note
Increased spp richness increases productivity & stability
Increases stability of community to disturbances
Increases species richness, increases productivity & stability is improved – resistance &
resilience- ability to withstand disturbance & recover quickly from disturbance
Biodiversity has health benefits for humans -treatments from wild plants
Metapopulations forms when individuals from a species occupy small patches of habitat & from
independent populations
- Humans are fragmenting the environment & therefore more species are being forced into
- Throughout time, each population within metapopulation is expected to go extinct
- Migration from nearby populations is critical for reestablishment of subpopulations &
overall metapopulations is maintained at stable number of individuals
Ecosystem services
Ecosystem services: what the environment provides that humans take for advantage. We obtain
them for free from the environment but they are worth a lot if we had to perform service
- Detoxifies & decomposes waste
- Purifies air & H20
- Pollinate crops
- Creates & preserves soils
Essential chemicals cycle through the ecosystem- carbon, nitrogen, phosphorus
Population: group of interbreeding individuals that are all the same spp
Metapopulation: smaller, independent populations connected by migrants
Many spp are forced into metapopulations by habitat destructions
Metapopulations balanced by extinction & recolonizations due to immigration
Smaller metapopulations are likely to go extinct more likely b/c susceptible to drift, inbreeding,
susceptible to pathogen & disease
Gene flow & recolonization occurs when populations go extinct
Local populations within metapopulations are islands of habitats
- Island: patch of habitat surrounded by environment, not suitable for island species
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