Why Are Animals Symmetrical?

Animals range in size shape and biology drastically but there is one thing that unifies more than 95% of animals, and every known land animal. Something that almost all animals inherited from an incredibly ancient common ancestor hundreds of millions of years ago. they have a left and a right side which are mirror images of each other. So why is this and why has this made them so successful?

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[kevinwells]

It's also interesting that despite being primarily symmetrical we and other animals have organs that aren't. For example our hearts are only on our left side, our livers on the rights, and the digestive tract is kind of all over the place. It seems that the evolutionary pressure towards symmetry mostly applies to our outside structure and sensory organs.

[timothymoore]

I wish all my bilaterally symmetrical relatives a very pleasant evening.

[barnicskobalazs]

this is such a fundamental thing i never thought about.

[drakeyork]

The answer is simple, it allowed for weight balance, and movement is a lot easier when you aren’t having to counterbalance a large weight on one side while having far less on the other. You would just end up falling over repeatedly which isn’t good when you are trying to move in a singular direction.

[greleti]

I just want to show my appreciation for your video. I was baked and sitting on the couch and thought "why are animals symmetrical" and was delighted to find such a great answer so quickly. thank you

[dinocharlie]

"Bilaterians have a clear direction of movement"
Crabs: "And I took that personally"

[lauramartin]

To be clear - there's tons and tons of organisms that grow in fractals nowadays. They just are all plants. (ex, broccoli and cauliflower)

[rogerwilco]

I was wondering about starfish, but you fortunately addressed that.

[CaffieneKitty]

I swear, I wrote a paper that basically turned into 'why bilateral symmetry works' for my 1st year college Astronomy class back in 1992, (when they foolishly let us pick from a term paper topic list that included "describe the hypothetical evolution of life on another planet" and I am so thrilled to watch this video, because I came to similar realizattions and understandings and this video feels SO VALIDATING for that paper. Thank you! 🙂

[indridmothman]

Whenever I’m articulating a skeleton, this is always super helpful! If I have a bone that I can’t place, I check if it’s symmetrical; if it is, it’ll go somewhere in the middle, and if not, there will be a matching one somewhere!

[DissedRedEngie]

Imagine a jellyfish with a brain. Now, don't ever imagine that again.

[quirijnv]

Flatfish are still born symmetrical though, right?
Their right eye migrates through their body to the other side when they mature.
It's almost like a mini evolution at super speed.

[Spacekid_Productions]

It’s weird that I never wondered this thanks for opening my mind I’m gonna be stuck on this topic for a while 😅🧐

[littlebigcomrade]

Every frustrated artist has asked themselves this once when drawing a face.

[Aeiroq]

I’m blown away by your production, it’s simple, VERY factual and elegantly presented. Can’t wait to watch more of this content. Subscriber earned 🎉😅

[embyrr]

Huh, I never knew echinoderms were bilatarians (which autocorrect wants to render as “BiL Atari and”). You learn something new every day.

[ruthl.]

This is something that I would have never realized even though it's so obvious: that most animals are bilateral (and all the advantages that this brings along).
It's because of things like these that I love this channel.❤️

[--Paws--]

Flounder in development
Symmetry: "Imma head out.."

[DeltaDanner]

The red fish at 9:07 is like: who are you filming? Are you filming me? No? Ok let me just get out of your way then.

[vincentlaw]

that was truly educating, loved it. Made me understand the way we look at the world on a deeper even philosophical level. I think the way how our bodies are build, with a front and back and a center of nerves (brains), must have had an influence on how we think and view the world, how we developed a philosophy of "right" and "wrong", of "forward" and "backward", of truth itself.