Oh hell I'm drinking so let's do this.

So evolutionary biologists sometimes use terms without clear definitions. For instance, "convergent evolution". While organisms may be *similar*, at what point are they considered convergent? Let's talk about charismatic electric fishes 1/

From the tropics! These fishes have been considered convergent in nearly all biological aspects, from genes to development to external morphology. But we have to consider that organisms can be convergent at multiple levels, but it's not required. 2/

For example, birds and bats both have functional flight, but they don't build their wings in the same ways. This means functional convergence but not morphological convergence.

We can break morph convergence into a few descriptions: complete, incomplete, or parallel evolution.3/

Complete: unrelated taxa are nearly identical in terms of morphology

Incomplete: unrelated taxa see more morphologically similar than their ancestors

Parallel: organisms are evolving in similar ways, leading to parallel trajectories in shape space 4/

In electric fishes, scientists have described external morphology as being incredibly similar. But does external morph match internal morph?

I used 3D geometric morphometrics to analyze skull shape across Gymnotiformes (South America) and Mormyridae (Africa) 5/

Results show that these species do NOT overlap in shape space. We have "convergence" but not identical morphologies. Instead, these species are building similar external morphologies by changing their skull bones in different ways. 6/

We have to consider "convergence" at different biological levels. We can think about genetics, development, morphology, and function. Organisms can be convergent in multiple ways, but it's not required. 7/

We also have to think about organisms as a mosaic. They're a combination of traits, some convergent and some divergent with other taxa. If we call organisms as a whole "convergent," it's going to break down. CHARACTERISTICS or TRAITS of organisms are convergent. 8/

These traits should also be examined at multiple levels to determine how truly convergent taxa are. An integrative approach can give us a holistic look at organisms and their evolution. 9/

THAT SAID, these are (in a sense) my opinions. I'm totally up for discussion, debate (respectful), AND collaboration!

Convergence is my jam and I'm so excited about it! 10/

If you'd like to see more, I'll be defending my dissertation THIS WEDNESDAY over zoom. Let me know if you'd like a link! I'm not sharing publicly but can DM you if you're interested.

Thanks for sticking around! -Kassandra fin/