IB biology: option C: ecology

what is an indicator species?

an indicator species is an organism used to assess a specific environmental condition.

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In situ conservation may require active management of
nature reserves or national parks.

Ex situ conservation is the preservation of species
outside their natural habitats.

Biographic factors affect species diversity.

Richness and eveness are components of biodiversity.

Indicator Species

how do we calculate biotic index?

total (number of individuals of indicator species x pollution tolerance rating) / total number of organisms in the habitat.

what is in-situ conservation?

conservation in natural habitat

what are examples of in-situ conservation?

national parks/nature reserves,

controlling grazing

controlling access by public

controlling poaching - park rangers

what is ex-situ conservation?

conservation of endangered species outside natural habitat

what are examples of ex-situ conservation?

plant species grown in botanic gardens

seeds of plants stored in seed banks

captive breeding of animals , followed by release of captive – bred individuals into their natural habitats. (reintroduction of species)

what are advantages to in-situ conservation?

conserves natural habitat,

sustainable,

part of long-term management

what are advantages to ex-situ conservation?

species may be too rare to be left in wild,

habitat may have been lost,

carefully controlled conditions

what are the two components to biodiversity?

richness (number of different species present) and evenness (how close in numbers each species is)

how do we calculate simpson’s biodiversity index?

N(N-1) / n(n-1)

what does N mean?

total number of individuals collected

what does n mean?

number of individuals of a species

what are biogeographic factors?

factors that affect species diversity

what is a island biogeography model?

the larger an island is, the greater the biodiversity found here.

why can larger nature parks support higher biodiversity

Biogeographic factors affect species diversity

larger National Parks have a wider range of habitats so support more niches and allow broader realised niches,

larger populations can be supported - show greater genetic diversity.

what are corridor effects?

greenbelts/hedgerows can provide corridors for the migration, foraging and spreading of local species

what are the effects of species isolation?

gene pools become limited and populations are more vulnerable to environmental change

why is the corridor effect important?

it allows species to expand over a larger area and in turn reduce vulnerability to environmental change (move over huge range of environmental conditions)

what is the edge effect?

boundaries between habitats or ecosystems where disturbance can occur and in turn effect species living there.