In the dense forests of eastern Congo, two explorers made an intriguing discovery: a shrew that was unusually large, about the size of a small rat, and covered in dense fur. Despite its size, it had the typical features of a shrew, such as a pointed nose and dark coloring.
The explorers were surprised by the shrew’s size, as it was significantly larger than typical shrews. The local residents demonstrated the shrew’s remarkable resilience by placing it on the ground and having a full-grown man stand on it for five minutes. Astonishingly, the shrew walked away unharmed, a feat that would have been impossible for any other rodent of similar size.
Intrigued by this resilience, the explorers collected several specimens for further study. Upon dissecting one, they discovered that the shrew’s vertebral column was unlike any other. While most mammals, including humans, have five lumbar vertebrae, the hero shrew boasts ten to eleven, each with numerous processes that interlock, providing exceptional strength and flexibility.
This unique structure extends into the thoracic region, making the hero shrew’s backbone the most unusual among its mammalian relatives. For over a century, the hero shrew was considered a single species with this distinctive backbone.
Evolution is often seen as a gradual process with transitional forms bridging different stages. However, the hero shrew presented a mystery, as there were no known transitional forms linking it to other shrews. This changed two years ago when researchers discovered another species of hero shrew in the Congo. This new species had fewer lumbar vertebrae—eight instead of ten or eleven—suggesting it might be an intermediate form, a “missing link” in the evolutionary chain.
The most intriguing question is what advantage this unique backbone provides. A hypothesis emerged from a conversation at the American Society of Mammologists meetings. Local residents in the Congo mentioned seeing hero shrews near palm trees, where they harvested beetle grubs. It was speculated that the shrew might use its strong back to wedge itself between the palm trunk and leaf base, prying them apart to access food sources unavailable to other predators. This would effectively make the shrew’s backbone a natural crowbar.
When the new species of hero shrew was discovered, the researchers were eager to share their findings and publish the hypothesis. Although the behavior has not been directly observed, this is how science progresses: by proposing ideas and encouraging further observation and experimentation.
The discovery of the new hero shrew species was a significant moment, with only one specimen, the holotype, existing in any museum worldwide. Holding this unique specimen was a thrilling experience, highlighting the excitement and honor of contributing to scientific knowledge.
This discovery not only enriches our understanding of evolutionary biology but also exemplifies the endless curiosity and wonder that drive scientific exploration.
Examine and compare the vertebral columns of different mammals, including the hero shrew. Create a detailed diagram highlighting the differences in vertebrae count and structure. Discuss how these differences might relate to each species’ lifestyle and environment.
Develop an evolutionary timeline for the hero shrew, incorporating the discovery of the new species. Include potential transitional forms and hypothesize about the evolutionary pressures that might have led to the unique vertebral structure. Present your timeline to the class.
Engage in a debate about the hypothesis that the hero shrew uses its backbone as a natural crowbar. Form teams to argue for and against this hypothesis, using evidence from the article and additional research. Conclude with a class discussion on the importance of hypotheses in scientific discovery.
Simulate a field research expedition to the Congo to study the hero shrew. Plan your research objectives, methods for observing the shrew in its natural habitat, and potential challenges. Present your research plan to the class, highlighting how you would test the crowbar hypothesis.
Write a mock scientific paper on the discovery of the new hero shrew species. Include sections on background, methods, results, and discussion. Peer review each other’s papers, providing constructive feedback on clarity, scientific accuracy, and hypothesis testing.
Here’s a sanitized version of the transcript:
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Two explorers in eastern Congo observed a shrew that was the size of a small rat and very furry. In all other respects, it resembled a typical shrew, with a pointed nose and black coloring.
– That seems quite large for a shrew. Rat size? Okay.
– Yes, it was indeed large. Small rat size, which is significant for a shrew.
– Yes, this was a big shrew. The explorers remarked, “That’s an interesting shrew,” and the local residents responded, “Watch this.” They placed a living shrew on the ground, and a full-grown man stood on it for five minutes before stepping off. Remarkably, the animal walked away. If it had been any other rodent or shrew of that size, it would have been crushed.
The explorers collected several specimens and decided to dissect one to examine its vertebral column. It resembled a Triscuit. Let me show you what the next largest shrew looks like. Just like humans, there are five lumbar vertebrae, with one or two processes sticking out on either side, along with a dorsal process. This is a hero shrew, which has ten to eleven lumbar vertebrae, and each vertebra has ten to twenty processes protruding from the sides, interlocked together. While our lumbar vertebrae are larger than those of this shrew, they generally look similar. Animals like camels and bats have lumbar vertebrae that appear relatively the same.
The Scutisorex has the most unusual mammalian backbone within its group due to its unique morphology, which even extends into the thoracic region.
– Yes, you can see that it’s expanded as well. Why? We didn’t know, and we may still not know, but that’s part of the story. For over 100 years since its discovery, the hero shrew has been classified as a single species, while all other shrews have a backbone that looks different.
– Many people think of evolution as a process where forms at different stages look completely distinct, but there are transitional forms in between that demonstrate gradual change.
– The missing links.
– Exactly.
– However, there were no links from this form to that form. Some suggested that perhaps this change occurred directly from one form to another. Two years ago in the Congo, we discovered another species of hero shrew. This one has fewer lumbar vertebrae—eight compared to the ten to eleven in the previous form.
– Mmhmm. You can also see that the processes on this one are fewer and larger than those on the other.
– Ohhhh. So, we have a form that may represent an intermediate stage between the two. The missing link.
– Now, the most intriguing aspect of this story is what advantage this backbone provides to the animal.
– Mhmm. I recall a conversation I had at the American Society of Mammologists meetings in Missouri about 15 years ago with Lynn Robbins. He mentioned that when he was in the Congo, local residents told him where to find hero shrews. They said, “Oh, come with us to the palm trees to harvest beetle grubs, as we always see them running around the base of the palm trees.” Lynn thought about how these people were pulling the bracts of the palm trees away from the trunk to access the large beetle grubs. Perhaps Scutisorex is inserting itself between the trunk and the leaf base, bending its back to pry the leaf base away and access concentrated food sources that would be inaccessible to other predators. So, it has a built-in crowbar.
When I realized we had discovered a new species of hero shrew, I called him up. I hadn’t spoken to him since the meetings.
– Yes. I said, “Lynn! You have to join us on this,” and this is the perfect opportunity to publish this hypothesis.
– Mhmm. Because neither of us has observed Scutisorex doing this, so this is purely a hypothesis.
– Mhmm. But that’s how science works.
– Yes. You present the idea, and other scientists will make observations to see if it holds true.
– How many of these do we have here? We probably have twenty.
– Twenty? That seems like a lot.
– Yes. How many of these exist? Just one. This one.
– This is the holotype. It’s the only one in any museum in the world.
– And you’re holding it right there.
– Right here, in my left hand. This is so exciting!
– Oh yes, I feel honored to be talking to you right now, knowing that—
– You can hold it. Oh my god. This is it. This is the only one. This is so exciting. This is science.
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This version maintains the essence of the conversation while removing any informal language or phrases that could be considered inappropriate.
Shrew – A small, insectivorous mammal known for its high metabolic rate and pointed snout, often used in ecological studies to understand food chain dynamics. – In the study of forest ecosystems, the shrew plays a crucial role in controlling insect populations.
Resilience – The ability of an ecosystem or organism to recover from disturbances or changes in environmental conditions. – Coral reefs exhibit remarkable resilience, often bouncing back from bleaching events if conditions stabilize.
Anatomy – The branch of biology concerned with the study of the structure of organisms and their parts. – Understanding the anatomy of the human heart is essential for medical students learning about cardiovascular health.
Vertebrae – The series of small bones forming the backbone, which protect the spinal cord and provide structural support. – The vertebrae of mammals are adapted to support various modes of locomotion, from running to swimming.
Evolution – The process by which different kinds of living organisms are thought to have developed and diversified from earlier forms during the history of the earth. – The evolution of antibiotic resistance in bacteria is a significant concern in modern medicine.
Species – A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding. – The discovery of a new species of frog in the Amazon rainforest highlights the region’s biodiversity.
Advantage – A beneficial trait or characteristic that improves an organism’s chances of survival and reproduction in its environment. – The ability to camouflage provides a significant advantage to prey animals in avoiding predators.
Discovery – The act of finding or learning something for the first time, often leading to new scientific insights or understanding. – The discovery of CRISPR technology has revolutionized genetic engineering and biotechnology.
Hypothesis – A proposed explanation for a phenomenon, based on limited evidence, serving as a starting point for further investigation. – The hypothesis that climate change affects migration patterns in birds is currently being tested through longitudinal studies.
Science – The systematic study of the structure and behavior of the physical and natural world through observation and experiment. – Science has provided us with a deeper understanding of the universe, from the smallest particles to the vastness of space.
