Over 2 million species of life exist on Earth; each with unique physical characteristics, behaviors, and habitats. With so much biodiversity, comprehending how every organism came from a common ancestor is challenging. The idea of a “common ancestor” comes from Darwin’s theory of evolution. More than merely an idea or proposal, Darwin’s theory is supported by immense evidence and agreed upon by scientists all over the world. The evidence for evolution can be divided into five categories; embryology, geographic distribution, homologous structures, fossils, and biochemistry. The documentary, “What Darwin Never Knew” covers the vast evidence for Darwin’s theory as applied to each of the five categories of evidence.
Embryology in relation to evolution is how closely related species share similar developmental stages. One example presented in “What Darwin Never Knew” is a connection between fish and human embryos. In both human and fish embryos, slits exist near the neck at a particular stage. In fish, the slits develop into gills, while in humans the slits develop into ears. Although fish and humans are very biologically different, the existence of a shared feature (neck slits) as an embryo suggests that fish and humans are related species and therefore descend from a common ancestor. Moreover, some organisms possess structures only as embryos which suggest the organism descended from an ancestor with the structure. For example snake embryos were shown to have signs of legs, an anatomical structure which is not possessed by snakes, suggesting snakes evolved from creatures possessing legs.
For more on how embryology provides evidence for evolution:
Species which evolved from ancestors in similar geographic regions are more closely related and share anatomical features. One of the first things Darwin noticed when visiting the Galapagos Islands was how tortoise shells were unique to each of the islands. Because the tortoises on the various islands had evolved in isolation from tortoises on other islands, the unique selective pressures of each island caused the tortoises to develop different traits based on geographic location. The beaks of finches on the Galapagos also differed by island, providing further evidence for the role geography plays in evolution. Around the world, different regions provide different selective pressures driving the evolution of species. Sickle cell disease, a disease affecting red blood cells’ ability to carry oxygen to the body is more common in regions with high rates of malaria. Sickle cell disease is so common in such regions because being a carrier of sickle cell disease actually provides a selective advantage against malaria, increasing fitness. Since being a heterozygote increases fitness, genes for sickle cell disease continue to be passed down in areas with high malaria rates creating uneven geographic distribution.
Here is a map showing where malaria is most common in Africa compared to where the allele for sickle cell disease is most common:
Some anatomical features are shared by organisms which appear very different. One homologous structure shared by turtles, fish, and four limbed mammals is limbs. Human limbs, turtle legs, and fish fins come from the same genes and, despite having different functions, have very similar structures suggesting humans, turtles, and fish evolved from a common ancestor.
More on homologous structures:
Fossils can also provide scientists with information about how species have evolved over time. In Argentina, Darwin found shockingly large sloth fossils and armadillo fossils. Darwin observed that the sloth and armadillos currently living in Argentina were much smaller than the fossils suggesting a change in environment caused armadillos and sloths to evolve smaller over time. Additionally, scientists found a 375 million year old flat headed fish fossil which helped the scientists understand how the first land animals evolved. The fossil (called Tiktaalik) possessed arm-like fins, providing evidence for how fish evolved to have limbs and live on land. Fossils of organisms such as Tiktaalik which appear to be “in-between” one type of species and another give scientists an idea of how such different types of organisms emerged.
More on the evolutionary link provided by the Tiktaalik:
The final point of evolutionary evidence has only been accessible to humans through scientific innovation in more recent times. Being able to study the actual DNA sequences of organisms has provided more evidence of connection between species. Additionally, studying biochemistry teaches scientists about many of the shared proteins and chemical compounds among species. Melanin, for example, is a pigment produced by the same gene (MCR1) in many different organisms. However, one of the most groundbreaking evolutionary discoveries in biochemistry has to do with non-protein coding genes. Hox genes determine where structures will be built. Hox genes are the reason why structures like human limbs and fish fins can be coded for by the exact same genes but appear so different. The simple switching on or off of a Hox gene can cause an entire structure such as a limb to be built or not built, allowing evolutionary changes to occur at a much more realistic pace than previously observed. Read more on Hox genes here:
Evolution is clearly supported by countless pieces of biological evidence and can be used to understand the history of how humans, and the entire planet, came to be. However, the mechanisms of evolution are still occurring and taking great effect on society. How can we use the things we have learned about the evolution of plants, animals, and other organisms to learn more about our planet and to solve global issues today?
The documentary’s most powerful revelation was the existence of Hox genes, master regulatory genes that act like a genetic blueprint for body plans. These genes are astonishingly conserved across wildly different species: the same Hox gene that positions a mouse’s limb also patterns a fruit fly’s wing. What changes evolution is not always which genes an organism has, but when, where, and how much those genes are expressed.
I also learned about the concept of genetic switches, which are short DNA sequences that act like dimmers on a light, turning genes on or off in specific cells at specific times. A single switch mutation can produce dramatic physical changes, like the loss of the stickleback fish’s armor plates, without affecting the underlying gene itself.
Finally, the documentary illustrated how the diversity of life all originates from one common ancestral limb structure, shaped by tweaks to the same underlying developmental genes. The sheer economy of evolution is stunning.
What Was Interesting
The stickleback fish segment genuinely surprised me. Scientists were able to trace a specific armor, and that same mutation had evolved dozens of times independently in different freshwater populations worldwide. Seeing evolution unfold on a timescale scientists could study, with a molecular mechanism they could pinpoint, made natural selection feel real in a way textbook examples don’t.
I was also struck by the section on the human brain. The documentary suggested that relatively few genetic changes separate our genome from a chimpanzee’s, yet the behavioral and cognitive differences are enormous. It raises profound questions about what “complexity” really means genetically. It’s not about having more genes; it’s about the sophistication of the genetic network.
Connections to Class
Natural Selection & Adaptation
The documentary directly illustrated selection acting on genetic variation, the stickleback’s armor loss being selected for in predator-free freshwater, exactly paralleling what we discussed with Darwin’s finches and trait variation.
Curious Question:
If Hox genes are nearly identical across species, what specifically in the regulatory network around them produces such dramatically different body plans? Is there a limit to how many body plan “archetypes” are possible?
Ethics has been around since the first human civilizations, with written ethical frameworks emerging in Asia as early as 1500 B.C.E.. Throughout the centuries, ethics has evolved to reflect more modern understandings of equality and justice, but certain frameworks like the virtues framework have remained relatively unchanged. What has changed, however, is the situations in which ethics needs to be applied. Bioethics is a rapidly growing field that attempts to address the complicated moral questions proposed by the astounding advancements in medicine, life sciences, and technology that have been developing. Bioethics considers whether everything that we theoreticallycando, such as cloning or human genetic editing or the use of stem cells is something that weshould do, and involves the principles of nonmaleficence (don’t do bad), beneficence (do good), respect for autonomy, and justice (making sure that everyone is treated fairly). Some frameworks used in bioethical decision making are The Utilitarian Approach, which is focused on which option does more good than harm, The Common Good Approach, which is focused on how actions affect the community life, The Rights Approach, which centers on respecting the fundamental rights of individuals, The Justice Approach, which involves treating individuals equally, and The Virtue Approach, which asks the question “What kind of person would I be if I did the action in question?”.
Superintelligence!
We got the opportunity to apply these principles and approaches in several ways. One of the first things that we did to practice our bioethical decision making was to watch a TedTalk and come up with an ethical argument about the benefits or drawbacks of the technology being discussed. I chose the talk “What happens when our computers get smarter than we are?” by Nick Bostram because I don’t know as much about AI ethics, aside from the dramatized apocalypses I’ve seen on TV, and I’m very worried about the loss of natural human intelligence due to AI. Bostrom argues that if there are only relatively small differences between the minds of humans and chimpanzees, but yet a very dramatic difference between the capabilities of the two species, then further small changes to the human brain and how we humans think could have very major consequences for humanity. He suggests that although the initial development of AI would take many years and lots of hard work, the AI would then quickly move past human intelligence, and then that superintelligent computer would be the last invention that humanity ever needed to make. He reasons that superintelligence is like an optimization process, and that to control AI, which he suggests would quickly go beyond human control, superintelligence would need to be motivated to please humans and learn human values.
I agree that we cannot assume our control over an AI model and use traditional methods to dominate the superintelligence, but I would then suggest that maybe we shouldn’t develop superintelligence at all. However, that is probably unrealistic, as even if the government and big companies moved away from superintelligence, then individuals would still find a way of creating the AI, maybe with even less safety regulations. I worry that we already are losing our ability to think critically because of AI, and think of a world like the one in WALL-E, where humans let AI do all the thinking for us and waste away. Nonetheless, I see all of the benefits of AI, like self-driving cars and improvements in medicine, and would recommend the video because we all need to think about the consequences of AI as a very real and current issue and debate the ethics of superintelligence if we are going to go into the AI age informed. I think that many people would defend superintelligence using the utilitarian approach, saying that the good AI does outweighs the bad, but I would argue that superintelligence could negatively impact the rights of those affected using the rights approach, because AI might start taking away the autonomy of people to make choices, might distort the truth, therefore denying people the right to informed consent, and might impact the right to privacy as well by listening in to people’s private conversations and using the data without permission.
CRISPR, stylistic rendering
We also watched the documentary Human Nature, which was mainly about the creation and ethics of CRISPR. I especially liked the beginning of the documentary, which discussed the mechanism of CRISPR and CRISPR’s connection to yogurt cultures. I was fascinated to hear about how while CRISPR is named for the repeats in bacterial DNA that scientists observed, the spacers that are from the virus that infected the bacteria were actually what was very important in CRISPR-Cas9 acting as an immune system for the bacteria. In terms of ethics, CRISPR raises many concerns, such as how CRISPR could bring about a society where the rich are genetically “superior” to the poor and divisions in society are even more substantial than today. Many people are uneducated about genetics and might assume that genes determine everything about a person, when in fact genes are only a part of a complex network of factors including environmental ones that determine who a person is. I personally don’t think that the CRISPR technology is inherently evil, or that humans are, I just think that in the wrong hands, and without the right regulations, the technology could be used in evil ways, so the field of biotechnology is essential.
Additionally, we practiced our bioethics skills through being given scenarios and then choosing one of two options based on which we thought was more ethical, before explaining our reasoning and why someone might think differently from us. I really liked that we had to come up with counter arguments because there are usually no perfect answers in bioethics and all different opinions have validity. I chose the case study on reporting incidental findings where a woman named Barbara participated in a genetic study to help her son but then found out that she was at high risk for developing Alzheimer’s. I said no, Barbara participated in the study to help her son and had not expressed any interest in learning about her own genetics. The researchers delivered grave news about a disease she cannot prevent. My specific opinion, though, is that the researchers acted unethically by not telling Barbara ahead of time that the study could uncover information about her genome unrelated to her son’s MS. She should have been allowed, using the principle of respect for autonomy, to decide whether she would participate in the study or not knowing that her participation could lead to the uncovering of her genetic predispositions for diseases such as Alzheimer’s, which would have allowed her to give her fully informed consent to the study. Telling Barbara about her risk for a disease with no cure and no preventative measures when she had not expressed interest in learning about her own risk does harm, going against the principle of beneficence, because now Barbara worries all the time about her risk and may be at higher risk for depression or anxiety due to the risk. We learned in class from the genetic counselor presentations that before genetic testing, all family members have to sign a lot of paperwork, ensuring that the individuals know about what genetic risks could be uncovered by the testing, so the researchers should have followed a similar protocol with Barbara. My choice actually was in the minority of votes, with only 40% agreeing with me. I think that’s because I made my choice based on my opinion that the scenario was unethical, with Barbara not being fully informed ahead of time, not because I thought that the researchers were necessarily wrong in telling her.
Others might argue that telling Barbara was right because of the principle of beneficence, because telling her could do her good by allowing her to better plan her life and motivating her to continue to maintain a healthy and active lifestyle. People with the view opposite to me might also argue that telling her conforms to the principle of justice because if healthcare providers start deciding what information about genetic risks should be shared with a patient, some patients might unfairly not be told about a genetic risk, while others are told. Additionally, someone might argue that telling Barbara about her genetic risk is essential because healthcare providers shouldn’t ever be allowed to keep information about a patient from that patient, whose autonomy as an individual with a right to know all available information before making future medical decisions would be compromised.
My team’s pGLO transformation lab results!
In class, we got to genetically edit E. coli to make the bacteria glow green under UV light, which was a very exciting hands-on way to apply what we had been learning about biotechnology. I like the logic of the experiment, particularly the use of plates with ampicillin to select for transformed bacteria, since the plasmid that we used for transformation also conferred resistance to the antibiotic. Ethically, I think that the genetic modification of bacteria is not very controversial because no humans or sentient beings are harmed. In fact, connecting with the principle of beneficence, the genetic modification of bacteria can lead to some very positive effects, such as how bacteria can be genetically modified to produce human insulin for people with diabetes.
Overall, I think that bioethics is a very interesting subject that asks us to look deeper at the moral effects of our actions, and I hope to see bioethics continue to grow in the future as technology continues to develop. As someone who hopes to go into biotechnology in the future, I’m glad that I have been exposed to bioethics here at NDB so that I can think about the ethics of new treatments, that, while created with the best of intentions, might have unintended negative consequences.
Here are some links to learn more: If you want to learn more about genetics, check out my posts here and here!
As biotechnology continues to advance, bioethics becomes an increasingly important part of scientific conversation. New technologies have the power to alter living systems, treat disease, and reshape the natural world while also raising important questions about responsibility, safety, and fairness. Bioethics helps guide people and reminds people about how scientific progress should move forward only with careful reflection on the impact on people, society, and the environment.
There are many new biotechnology studies underway worldwide. Looking at the studies from a bioethical perspective can help one determine if the technology is being used in a good way. One study I learned about in a TED Talk was about how using young blood might help reverse aging. Below is a link to the TED Talk: How young blood might help reverse aging. Yes, really. I chose to learn more about reverse aging because I had never heard of how young blood can reverse aging, and I wanted to understand how reverse aging works. The video talked about giving older people younger people’s blood to treat diseases of aging, like Alzheimer’s, which is a type of dementia. According to the CDC, dementia is not a specific disease but overall a term describing a decline in mental ability interfering with daily life, usually affecting memory, thinking, and behavior. An estimated 6.7 million older adults have Alzheimer’s disease in the United States, which is expected to double by 2060. The video explained that as the body ages and becomes sick, the brain is affected because the whole body is connected through blood. Many experiments have been done with mice where older mice were injected with young human plasma. As a result, the old mouse injected with human plasma behaved more like a younger mouse and appeared rejuvenated. Below is a photo of a test a scientist performed where the two mice were put in a maze with only one hole allowing the mice to escape below. The mice were trained to find the hole for several days. As a result, the mouse with the young blood was able to remember and find the hole much faster.
Helping older people reduce age-related diseases like Alzheimer’s can be very beneficial, especially if the younger people are willing to donate blood. Reverse aging by giving older people young blood is ethical because giving the older people the young blood follows the principles of bioethics. For example, respect for autonomy is upheld, as young people have the decision and free will to donate blood or not, and older people have the choice to receive younger blood. Another example is the principle of nonmaleficence. The older patient is not intentionally harmed by receiving the blood, and the younger person donating the blood is also not intentionally harmed. Blood used to help reverse aging also follows a rights-based approach, respecting the rights of those affected, with donors and patients able to choose whether to donate or receive blood.
With many new technologies, there are also cases in which people vote on whether the technology is ethical. The case study I chose was Gene Therapy for Enhancement Purposes by Genetics Generation. The case involved Dr. Anderson and whether to give Kelly the gene therapy for Alzheimer’s, something Kelly does not have. When making a vote, I relied on the principle of justice and the principle of beneficence. The principle of justice concerns fairness in healthcare, with a fair distribution among people affected, and the principle of beneficence concerns the healthcare provider’s duty to help patients. By giving Kelly the treatment, Kelly is taking away the treatment from someone who actually needs the treatment. Also, by giving Kelly the treatment to improve enhancement to get into med school, all the students who are also trying to get into med school are put at a disadvantage, with not an equal chance to get in. However, making a decision is difficult as there are different arguments for people who voted yes. One argument supporting people who voted yes is the principle of bioethics, respect for autonomy. Respect for autonomy is about how an individual has the right and free will to make decisions. Since Kelly has free will to choose to receive gene therapy for Alzheimer’s, Dr. Anderson’s refusal to give Kelly the treatment could seem to violate Kelly’s respect for autonomy. Another argument is the Utilitarian Approach, which emphasizes balancing good over harm. While Kelly may not need the treatment, using the gene therapy to help Kelly get into med school will later allow Kelly to help underserved populations and impoverished areas which lack good healthcare, making people think about how the good outweighs the bad.
A documentary we watched was Human Nature. Human Nature was about CRISPR and how CRISPR can be used to alter, delete, or replace DNA sequences in living organisms. If you want to learn more about CRISPR, check out the article below from CRISPR Therapeutics onGene Editing. One interesting example the documentary included, which involved CRISPR, was in organ transplants. Organ transplants can be extremely difficult because of the possibility of the immune system rejecting the organs. CRISPR can be used to reduce organ transplant rejection by modifying the donor organs. The documentary briefly mentioned the use of CRISPR to modify pig kidneys for use in humans. In the article below from Massachusetts General HospitalWorld’s First Genetically-Edited Pig Kidney Transplant into Living Recipient Performed at Massachusetts General Hospitalone can learn more about the first successful kidney transplant from a pig donor in 2024 and how CRISPR-Cas9 was used to remove harmful pig genes and certain human genes to improve the compatibility of the kidney with humans.
While using CRISPR to help create pig kidneys for human transplantation, there are bioethical concerns, such as the principle of justice. Pig kidneys are extremely expensive, so are only available to wealthy patients, worsening the existing inequalities in the transplant system. Another bioethical concern is the beneficent approach, which emphasizes the welfare and safety of patients. While the donor pig kidneys are potentially lifesaving for patients, the procedure carries high risks, including the potential transmission of unknown pathogens.
Biotechnology is advancing rapidly. A great example of the speedy advances is genetically engineering E.coli to glow green under UV light. We added pQuince, a plasmid containing ara, GFP, and ampr.
The AraC protein is a transcription factor regulating the expression of GFP, the GFP (Green Fluorescent Protein) is what makes the bacteria glow green under UV light, and the ampr makes the ß – Lactamase protein, which makes the bacteria resistant to the antibiotic ampicillin, breaking down the ampicillin present in the agar. My group’s transformation worked out with the genetically engineered bacteria growing green under UV light. Below is a picture of our four plates and the bacteria, and a picture of bacteria glowing under a UV light.
While genetically engineering E.coli may not have as many ethical concerns, the transformation shows what the future may hold, including genetically engineering people’s DNA.
In conclusion, the rapid growth of biotechnology highlights why bioethics must be considered. Technologies such as young blood plasma research, gene therapy, CRISPR gene editing, and even in-class genetic engineering experiments demonstrate how powerful biotechnology has become. While biotechnology has the potential to treat diseases and improve human health, applying bioethical principles helps society evaluate whether these technologies are being used in a way to truly benefit people.
