Biodiversity and Genetic Variation
Angel L., Ashely A., Melissa S.
Genotype: The particular allele combination of an
individual
Phenotype: The expressed characteristic or trait of
an organism that results from the genotype
Gene Pool: collection of alleles found in all of the
individuals in a population
Genetic Drift: a change in the gene pool of a
population due to chance
Introductory
Terms
Genetic Variation-Two Sources
 Mutation is due to random chance in the DNA gene
 Can form new allele
 Can be passed on to offspring if in gametes
 Recombination forms new combinations of alleles
 During meiosis
 Parent alleles arranged in new ways
Genetic variation increases chance of survival
 Genetic variation=phenotypic variation
 Genetic variation is stored in a population’s gene pool
 Made up of all the alleles in a population
 Allele combinations form when organisms of that population reproduce
 Allele frequencies measure genetic variation
 Measures how common an allele is in a population
Genetic Drift
 Genetic Drift causes a loss in genetic variation
 Common in small populations
 Bottleneck Effect: drastic reduction in the size of a population due to a natural
event or disaster
 Founder’s Effect: when a new colony is started by the few members of a surviving
population
 Can occur after bottleneck event
 Reduced genetic variation from original population
Biodiversity
 The variety of life in an area that is determined by the number of different species
in that area
 Increases the stability of an ecosystem and contributes to the health of the
biosphere
 Species richness: the number of species in a given area
 Species evenness: evaluation of an ecosystem to determine if one species
dominates an area or if all species are equally represented
Importance
 Charles Darwin recognized the importance of genetic variation in evolution via
natural selection
 A population evolves through the differential reproductive success of its variant
members
 This natural selection results in adaption, the accumulation of favorable genetic
variations
 Differences give individuals different a ability to survive and reproduce allowing
evolution
Genes and
Biodiversity
 https://youtu.be/XOxsjdB4-ZQ