Calculating biodiversity Flashcards
What is the issue of species richness?
Measure doesn’t take into account the number of individuals present.
How to calculate biodiversity?
Simpson’s index of diversity.
Takes into account both richness + evenness
What does Simpson’s Index usually result into?
Results in value between 0 and 1.
0 = no diversity
1 = infinite diveristy.
Higher value of Simpson’s Index of diveristy = more diverse the habitat
What do low/high biodiveristy values tell us about habitat?
Low = stress with relatively few ecological niches
Few species –> very specific adaptations for environment.
Relatively simple food webs
Change to environmnet = major effect on ecosystem
High = more ecological niches
Many species in habitat
Complex food webs
Why is genetic biodiveristy important?
Differences in alleles = genetic diveristy.
More alleles present in population = more genetically biodiverse the population.
More G.B = likley to adapt to changes in environment = less likely to become extinct.
More organisms within population that carry advantageous allele – help survive in altered conditions.
What factors positively affect genetic biodiveristy?
Mutations -> creates new allele
Interbreeding between different populations. –> migration from 1 pop + breeds with member from another pop = allele transfer = gene flow
What factors negatively affect genetic biodiversity?
Selective breeding (artifical selection)
Captive breeding programmes in zoos/conservation centres.
Rare breeds –> produce breed of domestic animal/plant where characetristics =less popular –> number of breed fall catastrohphically.
Artificial cloning
Natural selection
Genetic bottlenecks –> few individuals within pop survive an event/change.
Founder effect –> small number create new colony, geographically isolated from OG
**Genetic drift ** –> random nature if alleles being passed from parents to offspring –> frequency of occurance will vary.
How to measure genetic biodiversity?
Measure polymorphism.
proportion of polymorphic gene loci = number if polymorphic gene loci/ total number of loci
Greater proportion of polymorphic gene loci = greater geentic biodiveristy within the population.
What does ‘loci’ refer to?
Refers to position of the gene on a chromosome.
Define monomorphic?
Single allele exists for this gene.
Most genes are monomorphic.
How can gel electrophresis be used to measure genetic biodiveristy?
Separates fragments of DNA based on size.
Smaller the fragments = further the movement through thegel.
Gene loci can be determined
