Phenotypic And Genotypic Variation Flashcards
What is incomplete dominance?
Incomplete dominance is a situation where neither gene is completely dominant and so in heterozygous individuals containing both alleles there will be a resulting medium. Red flower crossed with white flower = pink flower
What is plasticity?
Unlike animals plants cannot move and thus have to adapt to environments. This adaption is called plasticity
What does the term ecad mean?
A variant showing adaptation to a particular habitat and in which the adaptive characters are not genetically determined, but are imposed by environmental factors.
Give an example of an experiment done on phenotypic plasticity.
Miner et al. 2005
Morphological plasticity in tadpoles
Predator exposure results in large colourful tail
Lack of predators results in relatively small and less colourful tail
Give an example of phenotypic changes in plant structure
Leaves may become narrower in environmental extremes. This results in a reduced surface area and therefore reduced water loss and heat load required to maintain temperature close to air temperature.
Leaf orientation is another method the plant may use
What are the 2 divisions of environmental factors and what is meant by each?
Biotic factors - effects of other living organisms, including those of the same species
Abiotic factors - physical parameters of the environment
Give examples of abiotic factors that can affect plants
Radiation Temperature Water Gasses Minerals Mechanical effects (wind, burial, snow etc.)
Give examples of biotic factors that can affect plants
Other plants
Micro organisms
Animals
Anthropogenic factors (pollution, agrochemicals etc.)
What is heterophylly?
An example of plasticity in which fluctuating water levels in an environment can cause phenotypic changes in the plant.
Eg. Water crowfoot (Ranunculus aquatilis) has different leaves dependent on water level - submerged leaves offer less resistance to water currents floating leaves much wider
What is an ecotype?
Genetically distinct geographic population (race) within a species, adapted to specific environmental conditions. Typically exhibit phenotypic differences stemming from environmental heterogeneity and are capable of interbreeding with other geographically adjacent ecotypes
What is an ecocline?
Consists of ecotypes or forms of species that exhibit gradual phenotypic and/or genetic differences over a geographical area, typically as a result of environmental heterogeneity
Example of industrial melanism?
Peppered moth (Biston betularia)
What does plasticity effect?
All levels of ecological organisation - demographic parameters, direct and indirect species interactions (competition, predation, coexistence) and ultimately carbon and nutrient cycles
Give examples of plasticity in individual environments
East Africa - herbivory by elephants and giraffes induce longer and more numerous protective spines on Acacia drepanolobium
Barnacles exposed to greater water velocities produce shorter feeding appendices (Marchinko 2003)
Plants alter roots
Give an example of plasticity having indirect actions on another organism
Peacor and Werner (2001) - presence of dragonfly larvae reduced foraging behaviour by tadpoles and subsequently increased algae population
