5 Times Evolution Did Its Best

TL;DR

Evolution is not a linear process, but rather a trial and error system that results in inefficient adaptations. This video explores several examples of these inefficiencies, including the limitations of the enzyme RuBisCO in photosynthesis, the necessity for marsupial offspring to climb to their mother's teat, the convoluted path of the recurrent laryngeal nerve, the backwards arrangement of vertebrate eyes, and the challenges faced by the human spine and feet due to bipedalism.

Transcript

[♪ INTRO] So you know that cheesy old picture of human evolution, with an ape getting more and more upright until it proudly steps forth as a human being? You probably know that’s not how evolution works. It doesn’t have a plan; organisms aren’t all headed on a set trajectory toward some imagined biological “perfection”. Evolution just throws every... Read More

Key Insights

• 💦 Evolution does not have a plan and does not strive for perfection, but rather works with what is available.
• ❓ The inefficiencies and quirks in biological adaptations are a result of the trial and error nature of evolution.
• ❓ Adaptations that are sufficient for survival and reproduction persist, even if they are not optimal.
• 😃 Different organisms have evolved alternative solutions to overcome inefficiencies, such as C4 and CAM photosynthesis pathways and cephalopod eyes.

Questions & Answers

Q: Why hasn't evolution improved the efficiency of the RuBisCO enzyme in photosynthesis?

While RuBisCO is inefficient, it still allows organisms to carry out photosynthesis, which is an impressive feat on its own. Evolution works with what it has and as long as a trait is not lethal, it can still be passed down.

Q: What is the evolutionary reason for marsupial offspring having to climb to their mother's teat?

The immediate post-birth climb-and-clamp of marsupial young is still not fully understood. However, one hypothesis suggests that giving birth early allows marsupials to respond to harsh or changing conditions more easily compared to placental mammals.

Q: How did the recurrent laryngeal nerve end up on a convoluted path?

The looping of the recurrent laryngeal nerve around the aorta is a result of the developmental pattern where the nerve forms next to the aorta. This pattern was passed on through evolution, even as animals such as giraffes evolved longer necks.

Q: Why did vertebrate eyes evolve in a convoluted and backwards arrangement?

Vertebrate eyes evolved gradually, and the changes did not have an ideal end point to work towards. The backward arrangement of photoreceptors and nerves in vertebrate eyes is a result of the gradual inside-out development of light detection organs.

Summary & Key Takeaways

• Photosynthesis relies on an enzyme called RuBisCO, which is highly inefficient and wasteful in its process.

• Marsupials have pouches that require their newborn offspring to climb to their mother's teat, but the evolutionary reason for this behavior is still unknown.

• The recurrent laryngeal nerve takes a detour around the aorta, resulting in longer paths and potential engineering screw-ups.

• Vertebrate eyes are arranged in a convoluted manner, leading to an inefficient design compared to cephalopod eyes.

• The human spine and feet have undergone structural changes for bipedalism, resulting in a host of challenges and discomfort.