Summer SAVY 2023 Session 1, Day 3 – Dabbling with DNA
Day 3: Wednesday was dedicated to learning about the process of evolution. We started by taking the students outside, asking them to make observations of different organisms, and describing a particular characteristic (trait) that is beneficial (adaptive) for that organism. Examples include the fur of squirrels and dogs, bird and insect wings, that many trees drop their leaves in the Fall, and that trees are tall holding their leaves up to the sun. We talked about each of these adaptations, and I stressed to them that when we look at organisms from an evolutionary perspective, we see that traits are often adaptive. Back in the classroom we talked about our opposable thumbs as a beneficial adaptation and watched a video from HHMI about the evolution of lactose tolerance in humans1.
After lunch, we went to the computer lab and ran a simulation of the evolutionary process2. In this simulation they see how a variable population evolves over time, influenced by environmental conditions, the occasional volcanic eruption or disease outbreak, and mutation. They see that changing the initial makeup of the population or the environmental conditions will inevitably lead to a different evolutionary outcome. We contrasted this example of natural selection with an example of artificial selection. We talked about the evolution of dogs from wolves and did some dog breeding. From six hypothetical dog breeds, they were asked to create a new breed for a specific purpose. They generate several pups and again see that there is variation among siblings. Generating a pup with just the right combination of traits is not easy. If they brought that document home, you could ask them to describe what they did. Tomorrow, we focus on the structure of DNA, build a model, and begin our discussion of recent advances in understanding and manipulating DNA; we will also visit a lab on Vanderbilt’s campus working in genomics. Please ensure students are wearing closed-toed shoes to be in compliance with the lab’s policies!