From chimp to man: it's as easy as 1, 2, 3!

Hi Grashnak, and welcome to EvC. I haven't been here long myself, hope you enjoy the debate as much as I have.
You asked for examples of body parts in the animal kingdom that have no purpose. My pleasure. There are many examples and they are known as vestigial features.
Blue whales, being evolved from land-based, four-legged mammals, have remnants of hind legs, hidden inside their bodies. They serve no purpose to the whale, but are a good example of how evolution works.
Here is an excerpt from the website of the University of Aberdeen's zoology museum;

quote:

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The main propulsive force in whales comes, not from the hind limbs, from the spinal musculature and the tail fluke. The hind limbs, although still present, have become much reduced in size, are fully enclosed within the skin and are invisible from the outside.
In 1881 [Sir John] Struthers published, "On the Bones, Articulations, and Muscles of The Rudimentary Hind-Limb of the Greenland Right-Whale (Balaena mysticetus). J. Anat. and Physiol. XV: 141-321."
In the paper he wrote:
Nothing can be imagined more useless to the animal than rudiments of hind legs entirely buried beneath the skin of a whale, so that one is inclined to suspect that these structures must admit of some other interpretation. Yet, approaching the inquiry with the most skeptical determination, one cannot help being convinced, as the dissection goes on, that these rudiments [in the Right Whale] really are femur and tibia.

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Full link here - http://www.abdn.ac.uk/~nhi708/treasures/bluewhale.php
The page on vestigiality on Wikipedia has plenty more examples, including the wings of ostriches, the eyes of blind mole rats and the wings of certain flightless moths.
Link here - Vestigiality - Wikipedia
Hope this helps and Merry Christmas!

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