Biology topic 4 Biodiversity, species richness, index of diversity

What is biodiversity?

The avariation that exists within and between all forms of life, including diffrences in genes, species and habitats within a reigon

What three levels does biodiversity consider?

Genetic divercity , species divercity and habitat / ecosystem diversity

Together showing how varied life is t different biolifcal scales

How can biodiversity be assessed on a global scale?

By mesuring the number and range of different ecosystems and habitats across earth

How can biodiversity be assessed on a local scale?

By counnting the number of species in a habitat and their relative abundance

Why is biodivercity essential for ecosystem resilience?

High biodeveristy increases the abilty of ecosystems to reisist and recover from enviromental changes , becouse more species means more functional roles and stability

What is ecosystem (habitat) diversity?

VAriety of different ecosystems or habitats within a particular area , each offering unique environmental conditions that support different communities

How does habitat variety affect biodiversity?

Areas with many distinct habitats (e.g forests, wetlands, grassland) support more species and therefore have higher overall biodiversity

Why is a coral reef an example of high ecosystem diversity?

It contains many microhabitats and ecological niches, supporting a wide range of species and interactions

Why do sandy deserts have low ecosystem diversity?

Environmental conditions provide fewer habitat types, supporting fewer species and resulting in lower biodiversity

What is species richeness?

The number of diffrent species present within a community at a given time

Its the simplest measure of species diversity becouse it only counts how many species exist

How does species richness relate to species diversity?

Higher species richness means more species are present so the community is considered more divers but this mesure ignores how many incdividuals each species has

What is an example of a species rich enviroment?

Tropical rain forest, which contains high number of diffrent species and therfore scores highly for species richness

Why can species richness be misleading as a mesure of diversity?

Becouse it only counts species number and does not consider abundance or evenness - a havitat may have many species but very few individuals of each

What key limitation does species richness have?

It ignores population size and distribution, so it cannot show wether species are evenly represented or dominated by a dew abundant species

Why do conservationists prefer an index of diversity over species richness?

Because index of diversity includes both species number and evenness, giving a more accurate picture of how balanced and stable a community is

What does the index of diversity describe?

Shows the relationship between the number of species in a community and the number of individuals in each species , giving a more accurate mesure of divesritu than species richness alone

What two components does the index of diversity take into account?

Species richness - how many different species are present

Species evenness - how evenly individials are distributed among those species together these give fuller picture of diversity

Why can species richness alone be misleading?

BEcsoue it only counts species number and ignors abundance

A habitat may have many species but be dominated by one , making it less diverse than a habitat with fewer species but more even distribution

What is the formula for the index of diversity ?

d=N(N−1) / Σn(n−1)

Where N is the total number of organisms in the community , n is the number of individuals of each species and the zig zag is the sum of

What does N represent in the index of diversity formula?

The total number of organisms in the entire community

What does n represent in the index of diverity formula?

The number of individuals belonging to a single species within a community

What does Σn(n−1) represent ?

The sum of n(n-1) for every species in the community, reflecting how individuals are distributed across species What

What does a larger index diversity value indicate?

Higher level of species diversity meaning many species and / or more even distribution of animals

What is step one when calculating the index of diversity?

Calculate N(N-1) to obtain value A

What is Step 2 when calculating the index of diversity?

Calculate n(n-1) for each species in the comunity

What is step 3 when calculating the index of divesity?

Add all the n(n-1) values together to obtain value B

What is step 4 when calculating the index of diversity?

Divde vlaue A by vlaue B to ge thte final index of diversity