Ten concepts (biotic potential, population stability, limited (natural) resources, limited survival, variation within a population, origin of variation, variation is inherited, differential survival, change in population, and origin of species) related to natural selection are represented on the CINS (two questions per concept).
To complete the Concept Frame, therefore, students needed to make an inference regarding the origin of variation in tobacco populations.
The twenty items in CINS consist of 10 natural selection concepts (biotic potential, natural resources, population stability, change in a population, limited survival, origin of variation, variation inheritable, origin of species, variation within a population, and differential survival) using three different contexts (the evolution of finches, guppies, and lizards).
A third section demonstrates the origin of variation through mutation (but not genetic recombination through sexual reproduction).
Students engaged in building and evaluating models that illustrated the origin of variation in a population of snails displaying a wide variety of shell colors and patterns.
We can use again the genetic origin of variation as an example.
the genetic origin of variation within a population (random mutations) and. the relative nature of fitness (dependent on phenotypes and the environment).
The important point is that this is a two-step process: first, the origin of variation by random mutation, and second, the non-random sorting of variation due to its effects on survival and reproduction (Mayr 2001).
Several students (22.6%) completed the frame with a correct explanation of the genetic origin of variation in the context of Avida-ED, but not of tobacco plants (Fig. 6), which we may interpret as an inability to transfer a principle across distinct cases of evolution.
A thermodynamic model is developed to understand the origin of variation in the microstructure of ZrO2 film formed on zirconium alloys and its effects on corrosion resistance.
When such mutations arise in a population of organisms, they serve as the origin of variation upon which natural selection can act.
