4.7 Biodiversity Flashcards
Define biodiversity
- The variation that exists within and between all forms of life
- Biodiversity looks at the range of genes, species and habitats within a particular region
Define ecosystem diversity.
The range of different habitats within a particular region.
Define species diversity.
The range of different species in a community.
Define genetic diversity.
Number of different alleles of genes in a population of a species.
Why should biodiversity be maintained?
- moral and ethical
- ecological stability
- environmental
- economic (medicine/tourism)
- aesthetic
- agricultural
Define species richness.
The number of species in a community.
What is an index of diversity?
Species diversity looks at the number of different species in an area but also the evenness of abundance across the different species
What is the index of diversity formula?
D = N(N-1) / Σ n(n-1)
Farming techniques … biodiversity
reduce
Techniques to improve biodiversity in agricultural ecosystems.
- use of organic fertilisers
- using nitrogen-fixing crops
- creating ponds
- planting trees/hedges
Why is it difficult to find the balance between conservation and farming?
- maintaining biodiversity can be expensive or labour/time intensive
- e.g. stopping the use of pesticides would decrease yield and therefore profit
How can biodiversity by investigated?
- comparison of characteristics BUT genetic diversity can only be implied
- comparing DNA base sequence
- comparing mRNA base sequence
- comparing the amino acid sequence of the proteins encoded by DNA and mRNA
If standard deviations don’t overlap, results are …
significant.
phylogenetic classification
- arranges species into groups according to their origins and relationships
- species further away = less closely related
- species closer= more closely related
what is genetic drift?
- change in allele frequency in the gene pool due to chance
causes of evolution
- mutations
- change in gene pool due to emigration/ immigration
- sexual reproduction
- genetic drift
- natural selection
what is the bottleneck effect?
- occurs when natural disasters reduce a population
- DECREASE IN: no. of individuals & genetic diversity
- INCREASE IN: genetic drift
what is the founder effect?
- when a group of individuals break off from a larger population establish a colony
- DECREASE IN: no. of individuals & genetic diversity
- INCREASE IN: genetic drift
small population VS large population in response to genetic drift
small: random events have bigger impact
- allele frequencies change dramatically
- high suspectability to genetic drift
