Biodiversity Flashcards
What causes variation within species
Crossing over
Independent segregation
Random fertilization of gametes
Natural selection
favorable characteristics lead to reproductive success to produce offspring that inherit the advantageous characteristics, that can be passed on over many generations until all offspring contain the advantageous allele and can no longer breed with the original species to produce living fertile offspring.
How is genetic diversity measured
By comparing proteins and DNA
All members have same genes but can differ in their alleles
How does genetic diversity increase
Greater number of different alleles which makes species more likely to adapt to environmental changes
Genetic drift
Random changes in allele frequency
Can be Driven by chance not selection
Can cause alleles to disappear = less Genetic variation
Factors affecting genetic diversity
Selective breeding
Founders effect
Genetic bottlenecks
Selective breeding
identifying individuals with desired characteristics and using them to parent the next generation. Unwanted alleles bred out.
Over many generations all individuals will posses desired characteristics
Founders effect
Small group of individuals breaks off from a larger population to establish an isolated from og colony
Carries into small fraction of alleles of population so not all genes pool is present
Genetic bottlenecks
When large genetically diverse population is darwsticslly reduced due to environmental factors
Allele lost = reduced genetic diversity
Biodiversity
Variety of living organisms in a given region
Species diversity
- the number of different species and the abundance of each species within a community
Genetic diversity
difference in DNA / base sequence / difference in alleles / genes / gene pool
Ecosystem diversity
- the range of different habitats within a particular area
Measuring biodiversity 2 ways
Allows comparison to be made between different areas
Slows comparison to be made in same area at diff times
Species diversity measuring
Species richness : number of different species in a given area
Species evenness : comparison of size of population of different species within a particular area
D=N(N-1)/£n(n-1)
D=species diversity index
N=total number of organisms of all species
n=total number of organisms of each species
Advantages of conserving a forest ecosystem
Trees as sustainable resource
Maintain habitats
Maintain diversity
Maintain food chains
Reduce flooding
Impacts of agriculture
Agricultural ecosystems are controlled by humans. Farmers select species for qualities that makes them more productive this reduces genetic diversity of alleles
