2022---evolutionary-remnants--we-carry-on-5-traces-of-the-past Online

"Those are your [2]. For mammals like cats, dogs, and our early primate ancestors, those muscles are vital [2]. They allow them to pivot their ears toward a sound without moving their heavy heads, helping them pinpoint predators or prey [2]. We have larger, more flexible necks now, so we just turn our heads. Most of us lost the neural wiring to use those muscles, but the physical remnants are still there [2]."

"Perfect timing," Dr. Aris smiled, pointing to Leo's forearm. "There is number five: [1]. When you get cold or scared, tiny muscles at the base of your hair follicles contract [1]. For a furry mammal or a bird, this puffs up their coat or feathers [1]. It traps a layer of air to keep them warm, or makes them look much bigger and fiercer to a threatening predator [1]. Since we lost most of our thick body hair, the reflex does absolutely nothing to keep us warm or scare off enemies. It just makes our skin look like a plucked chicken [1]." "Those are your [2]

"The , or tailbone, is actually a fusion of three to five vertebrae [2]. It is the absolute remnant of a lost tail [2]. Around four weeks into human embryonic development, we actually have a distinct tail [2]! But as the embryo grows, those cells are programmed to die back, leaving only that small, fused base [2]. For our ancestors, tails provided balance in the trees [2]. For you, it serves as an anchor for some pelvic muscles, but it's a far cry from what it used to be [2]." We have larger, more flexible necks now, so

"There it is," the doctor pointed. "That is the tendon of the [2]. About 14% of people don't even have it anymore [2]. Millions of years ago, when our ancestors spent their days swinging through the canopy or climbing trees to escape predators, that muscle gave them a powerful grip [2]. Today, we use door handles and steering wheels, so it is just a leftover [2]." "There is number five: [1]

Leo sat on the edge of the examination table, rubbing his sore jaw. The dentist had just told him that his wisdom teeth were coming in crooked and needed to be removed.

"Precisely," Dr. Aris nodded. "And it's not the only one. Have you ever seen someone who can wiggle their ears?" "Yeah, my cousin can do it. It looks ridiculous."

Leo did as he was told. A thick, cord-like tendon popped up in the center of his wrist.