Welcome back to the blog! This post will begin to examine how one of the most significant defining traits of any animal – sex – is determined on a molecular level. Although it may seem better simply to observe physical features and/or behavioral characteristics of an animal in question, it is easier said than done because there can be some grey area and inconsistencies that may not be immediately apparent among different types of animals, especially for ones other than humans and avian species exhibiting explicit differences between sexes (also known as sexual dimorphism) in particular. After all, every organism on Earth shares the same exact genetic language (the ACGT of DNA) and has the same fundamental cellular processes (DNA replication/synthesis in addition to cell growth and division), so as long as the means are available, examining the genome of an animal is arguably more effective and reliable for sex identification in many cases.

Before taking a look at anything in particular, there is a pinch of basic, fundamental background terminology that should first be gone over. For the sake of visualization, the karyotype of an “average” (in this case – no detectable genetic mutations present that result in a chromosomal disorder) human male is provided to the left. A karyotype refers both to a depiction of an individual’s collection of chromosomes and the method by which the depiction can be obtained. The numbering of the chromosomes is generally dependent upon their relative size in comparison to the rest of the chromosomes. This karyotype is stained in such a way that it produces color for contrasting purposes. Additionally, most people know what a chromosome is – a structure that DNA forms when it is condensed for certain specific processes that are out of the scope of this post at the moment. Humans naturally have 46 total chromosomes, or 23 pairs. The final two chromosomes in humans are known as sex chromosomes (as opposed to the other 44 autosomal ones) and are of particular interest for this (and the next) post; as their name implies, together, they determine the biological sex of a person. The differentiation between male and female is significant, so it does make sense that there is a clear name dedicated to this pair.

This post only scratches the surface as not all of the intended content would fit, so this topic will be split into an overflow post following this one! As a preview, the next post will touch on the intriguing and complex sex-determination systems found in humans and other types of animals. Until next time, feel free to theorize about it all. Thanks for reading, and take care!

Hello again! This post is a continuation of my previous post discussing birds invading my garage in hopes of establishing a nation of their own, so feel free to check out part one. The story did not end where I left off!

As previously implied, the newly hatched birds are especially vulnerable. After all, they do not have any feathers and are even unable to open their own eyes. This can be exploited early on in their development to trick them into responding to humans mimicking call sounds of the parents until they finally open their eyes and realize that they were completely tricked, backstabbed, and quite possibly, bamboozled. “Bazinga”, if you will. I swear I had them under my control during the first half of their childhoods. Smaller, backyard birds in general tend to develop at a rapid pace. Eventually, they’ll grow fuzz on their heads. It looks kind of like that one photo of Einstein sticking his tongue out – I expect most people to know exactly what I am talking about right now.

Momma and Papa Birdies were not the only ones to visit, however! Long story short, a larger predator bird threw one of the babies out of the nest and my father and I chose to nurse it for a day before returning it to the nest (picture not included, apologies). Man, I really need to ask Dad for those recordings, huh.

For better or for worse, the hole was sealed when we had our garage door system completely redone. Was this the end of my avian adventures? Nope!

There was also another family of birds directly outside the garage, but they came along much later than the original family – long after the hole was sealed. These birds were chilling in our holiday wreath which is arguably a very clever location for their traditionally stylized nest – a nest that indicated a different species of bird in addition to the blue-colored eggs! Every time I returned home late at night, I could always see the bird watching me with paranoid eyes as I drove by into the garage. We set up a camera to watch over this nest as well, but in the end, it did not turn out as well as the other family because of some parental neglect and premature test flights from babies who were not yet ready to leave the nest, much less fly back up to it (image above).

I wonder how many generations have passed since I last saw them! Wherever they are, I hope that all of them are living their best lives. Can I blame the birds for invading the garage? It was an interesting experience, so no; the weather was quite cold at the time and there must have been many dangerous creepy crawlies outside! In the end, we’re all just little birds trying to spread our wings in this world, right?

Feel free to take a look at this video of the first family of birds (in garage). Without further ado, I hope you enjoy! Things like this are cute unless you are the parent of course.

And so the tale of two bird families staying at my house comes to a conclusion. Well, I definitely prefer this scenario over having bats all over my residency hall – a completely different story for another time. Thanks for reading, and stay safe until next time.