What is Evolution?
Evolution is a surprisingly easy to understand process. At the highest level, it describes a change in trait frequency in a population over time. To recap what those words mean, a "population" is just a group of genetically similar organisms that live in roughly the same place. A "trait" is an expressed characteristic or feature of an individual within a population (for instance, having green eyes, or brown hair). For each trait, there's a certain number of organisms in the population that possess it, and a certain amount that do not- the ratio between the two is the "trait frequency". As organisms in the population reproduce, the trait frequency can change. So, as you can see, evolution as a process is not something that can happen to single organism, or within the lifetime of a single organism.
The first part of the process of evolution is the generation of the diversity of traits in a population itself. This occurs through the process of "mutation": a usually random process that occurs during (or affecting) replication that changes the genetic makeup of an organism's resulting offspring. These mutations can either be silent- have no impact on the expressed traits, or they can be active- resulting in a change to a trait, or potentially the emergence of a brand new trait that did not exist in the prior generation. With mutations, every generation will have a differing diversity of traits compared with their parents.
Once the substrate- the set of traits- is established, evolution can begin its work on this set of traits through the alteration of the frequencies of each trait. This can sometimes just occur through random chance- this is known as "genetic drift". For instance, maybe a trait that started as 50/50 shifts to 55/45 due to random effects. This small change might then snowball- if there's more organisms with the trait, then it's more likely that an organism with the trait will reproduce and pass on the trait. Another method of evolution is sexual selection in sexually reproducing organisms. Let's say there's some trait which is attractive to potential mates. Possession of the trait then increases the likelihood of mating and then passing on the trait to the next generation.
However, the most familiar mechanism by which evolution occurs is natural selection. In natural selection, organisms with traits that are not useful for its survival in a particular environment will die before they can pass on the trait. Only the organisms with traits that are beneficial (or at the very least neutral) to their survival in the particular environment will be able to pass them on to the next generation. For instance, let's say that there is a 50/50 distribution of a trait that allows for an organism to camouflage, and a predator moves into the environment. The predator will begin to eat the organisms that can't camouflage more often than the ones that can. By the time the organisms get to reproduction, the ratio of traits may be more like 70/30. With more reproducing organisms having the camouflage trait, more organisms in the next generation will possess it as well, leading to its proliferation.
What is Our Plan?
Our plan is to do outreach, especially to adults who might only have taken an evolution class a long time ago, and communicate the ideas expressed above, and how simple they are to understand.
A common way to illustrate the ideas of evolution that we make use of is the "marble model". In the marble model, we have multiple glass jars and 10 blue marbles and 10 green marbles. The blue marbles represent organisms in a population possessing some trait, while the green marbles represent organisms that lack the trait (or have a different contrasting trait). The marbles are numbered so we can use a random number generator to randomly select the marbles that will "reproduce" in the next generation. For each generation, we will fill the next glass jar appropriately. This model can be used to easily show how genetic drift and natural selection play out in a visually intuitive and obvious way.
The goal is of course to increase literacy in this fundamental topic of biology. It's very difficult to understand anything in biology without the context of evolution, as it essentially provides the "why" behind every biological structure and function. Why do we age? Why do whales get less cancer than humans in spite having more cells? Why do trees look the way they do? Why do humans have organs that don't do much of anything? These and more are all explainable only by making reference to the evolutionary history and mechanisms that gave rise to these traits. By understanding evolution, we can understand much more about ourselves and the world around us, and make meaningful progress in addressing medical and biological issues.