Elephants and Evidence of Evolution

     One of Darwin’s key predictions of evolution was that species change through time. This is dubbed as microevolution. When considering current evidence of evolution, I like to think about how humans have affected the evolution of other species. Most effects are done inadvertently. As I said in one of my previous posts, I love elephants. I remember reading a couple years ago that the amount of poaching of elephants in Africa for their ivory tusks has led to more elephants not developing trunks. Humans have poached and killed the elephants that have tusks to take their ivory, but they do not kill the elephants that do not have tusks. The poachers have thus selected for the tusk-less elephants. National Geographic reported that between 1977 and 1992, 90% of elephants living in a national park in Mozambique were killed for their ivory. Before 1992, 96-98% of female elephants developed tusks, but after 1992, only about 32% of female elephants developed tusks. Even more significantly, in Addo Elephant National Park in South Africa, it is reported that up to 98% of female elephants do NOT develop tusks in the early 2000s. Elephants have a very long gestational period and live very long lives compared to almost every other animal on the planet. The fact that this change has occurred in such a short amount of time is remarkable. 

Some may regard this evolution as a good thing for the species given that female elephants will not be hunted and killed for their ivory if they do not possess tusks. Both the females and males of African elephants develop tusks, while only a small percentage of Asian male elephants develop tusks. According to EleAid.com, about 50% of Asian females develop short tusks that do not have pulp inside. However, tusks do serve a variety of purposes from lifting objects, helping to gather food like stripping bark from trees, digging, and for protection from other animals. Tusks also act as a guard for the trunk itself. One can argue that these species are still thriving without their tusks, but I would argue that it’s important to preserve this characteristic for the benefit of elephants. Elephants live in matriarchal groups, so it is especially important that female elephants have the protection that tusks can afford them. We have caused this change, but we can also help restore this feature. Overall, the characteristics of the African elephant have changed over a relatively short amount of time due to selection. 

Switching topics, another fact that possibly supports the theory of evolution is that all organisms on earth have a genetic code, and their genetic information is stored in DNA and RNA. This supports Darwin’s prediction that species are not independent but are connected by descent from a common ancestor. Interestingly, humans share common genetic factors with other organisms. Humans possess one copy of a gene called p53 that suppresses cancer, and elephants have 20 copies of the p53 gene. Researchers have reasoned that these additional copies have given elephants enhanced fighting powers against cancer compared to humans. The fact that humans and elephants share this gene, that they both have genes at all, points to the conclusion that we share a common ancestor. 



Sources

Mental Floss - "Elephants Are Evolving Without Tusks Thanks to Poaching"

YouTube - SciSchow - "7 Animals That Evolved at Hyperspeed — Because of Us" 

 EleAid - "Elephant Tusks"

World Wildlife Fund - "What is ivory and why does it belong on elephants?" 

Comments

  1. Hunter HiegertFebruary 11, 2021 at 11:55 AM

    Great blog post Erin! While I am aware of elephants being constantly poached due to their ivory, I was oblivious as to how widespread and impactful poaching truly is. I loved that you implemented statistical data to clearly convey how the poachers are changing the population of elephant's evolutionary path. Finally, I found it interesting how you concluded your post by comparing elephants genetic makeup to that of humans. To me it acted as a bridge to not only show our similarity to animals as diverse as elephants, but also to emphasize the importance of preserving animals like these as they may not be as different from us as it seems!

    ReplyDelete
  2. MichiFebruary 17, 2021 at 7:54 AM

    Fantastic post! I learned a bunch that I did not know about before!

    ReplyDelete

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