Evolution Blog

The Hardy Weinburg Equation is used to calculate the genetic variation of a population at equilibrium. By equilibrium, it is assumed that there is no mutation, no selection, random mating, and a large population . This creates a null hypothesis that is used to measure whether the observed genotypic frequencies are similar or differ from the estimated frequencies from the equation.  There are 30 white roses in a population of 600 red roses. White roses are recessive and red roses are dominant. 1. What percentage of the population are white roses? 2. What percentage of roses are heterozygous for this trait? 3. What are the frequencies of the dominant and recessive alleles?

One of the misconceptions I had about mutations before actually learning in depth about them was that they weren't a good thing. It has been interesting to learn that mutations can lead to diseases, but in most cases are also vital for a species to survive and reproduce. Some concepts, such as phylogenetic trees can still trip me up. When they're already made, I can read them and understand them fairly easily. However, when given only written and out-of-order information, they can still confuse me.  Both of these concepts have come gradually to me. There is a lot to learn about mutations, which makes that topic interesting to learn about. With phylogenetic trees, practice using them and creating my own is something I still have to actively practice.  

An animal is said to exhibit altruism when their behaviors are putting themselves at risk, but are benefitting other organisms. Another way to think about altruism, is if an organism exhibits altruistic behavior, they are reducing their own reproductive fitness while at the same time increasing other organisms' reproductive fitness. That is, the respective number of offspring each organism would potentially produce.  For example, vervet monkeys give off warning calls when a predator is near in order to warn fellow monkeys. However, in making these calls they are actively putting themselves at risk to the predator itself.  This example also brings up the the theory of kin selection, which is as simple as it sounds. Kin selection is the theory that organisms are more altruistic towards members of their own species , rather than those who are not.  This short video shows how different calls made by the vervet monkeys indicate different types of predators. Give it a watch!

     The most recent example of adaptations on the micro scale that we have discussed is that of Soapberry bugs in Florida and in Texas. In Florida, soapberry bugs used to have long beaks in order to feed on larger soapberry plants. That is, until about 50 years ago when an invasive species of smaller soapberry plants was introduced to the state. Because the plants were smaller, the soapberry bugs did not need their long beaks to reach the seeds of the soapberry plants anymore. Instead, they adapted to the new species of plants and in less than 50 years, soapberry bugs in Florida now have short beaks.     The opposite adaptation occurred in Texas. Here, soapberry bugs used to have short beaks, but with the introduction of a larger soapberry plant, the bugs have adapted longer beaks.     Shown above is an illustration of the two new host plants (invasive species) and their change in sizes relative to each location Shown above is an example of ...

The variation that I found most interesting is the hybridization of species. As young scientists, most of what we learn relates to the fact that a species is its own, and cannot cross breed with other species. Because of this, when I think of hybrid species, I tend to think of hybrids as fictional creatures shown on Vampire Diaries or Teen Wolf. However, hybrid species are in fact real and are nothing like the powerful creatures we see on shows.  Hybridization of a species occurs when two different species mate to form a completely new species, who is reproductively isolation from those two parent species. An example of this are the Heliconius butterflies. Researchers believe there are at least 39 known species of Heliconius species, meaning they are able to interbreed to create brand new species.  Shown above are a few different species of the same Heliconius genus of butterflies. As you can tell, they are all similar in wing shape, but their patterns are quite different.

 A phylogenetic tree is a diagram that shows evolutionary relationships among organisms. There are many different phylogenetic trees because there are SO many different species of organisms. The branching pattern on these "trees" represents how a species evolved from a series of common ancestors.  The diagram shown above is an example of a monophyletic tree. The group that is circled is the monophyletic group, who all came from the same ancestor. However, each one of these organisms has a characteristic that makes it different than the other organisms in this group. (Note that this is not an accurate representation of the actual genetic relationships of these animals) The diagram shown above is an example of a paraphyletic tree. All of the animals listed make up a paraphyletic group. Paraphyletic groups do not share a common ancestor. For example, the panda and its descendants are not genetically related to the ostrich and its descendants.

       I was not aware that evolution occurs on both macro and micro scales. It does make sense that the two scales are intertwined though, because if they weren’t, all of the evolutionary history would be completely random and wouldn’t be traceable. The part I do wonder about, however, is at what point does the evolution of an organism transition from micro to macro. I understand microevolution is what is happening “now,” but how long is actually considered “now” and when does it become macroevolution?      In the video with Grant Ernhart, I was completely blown away by the visuals he used. It is easy to think about how long the Earth has been alive, but seeing it on that scale, I realized I truly had no idea. The biggest thing that surprised me was how long photosynthesis had been taking place with no other real life-forms. Also, what an absolute “short” period of time that humans have been around. I would love to learn more in depth about how after ...