Chapter 8 Concepts
Phenotypic variation comes about from the interaction between genes and the
Natural selection acts on phenotypic variation, producing differential survival and
Theodosius Dobzhansky
Nothing in biology makes sense
except in the light of evolution
Questions (Group Activity)
At what level of ecological organization is evolution essential to ecology?
What evidence can you use to support your conclusion?
What are the mechanisms that created the evidence that you cited?
Examples Used
Potentilla glandulosa (Fig 8.4, pp. 188-189)
Chuckwalla (Fig 8.8, 8.10, pp. 190-191)
Type of Natural Selection (Fig 8.15)
Importance of Variability (Fig. 8.21, 8.22, pp. 202-205)
Key Points
Genotypes, and consequently, phenotypes vary in a population
Population size and dispersal capabilities can influence genotypic variability
Variation in phenotypes leads to differential survival and reproduction
Observations of both natural populations and transplanted populations support this