Origins of nocturnal habits in modern-day birds: how did modern birds become both diurnal and nocturnal creatures?

Evolutionary Origin of Nocturnality in Birds

by Yonghua Wu

Summarized by: Ana Jimenez Bustos is a geology undergraduate student at the University of South Florida. She plans to attend graduate school in a field related to volcanology, possibly planetary geology. Once she has her degree, she would like to teach and continue to do research in volcanology or planetary geology. Outside of school, she enjoys eclectic, noisy music, her dog Miranda, and loves reading and learning about birds and parrots. 

What data were used? This study compiled data from scientific literature that analyzed genomes, physical characteristics such as eye sizes, ear structure, and anatomy of fossils of ancient and modern birds. Molecular, genetic, morphologic, and evolutionary data was used to determine whether the origin of these nocturnal habits (or the habit of being active at night) was based on a common ancestor or if it evolved along the way. The active and inactive genes (genes that are ‘turned on’ or ‘turned off’ in creatures’ bodies) of eyes involved in light reception and transport were used to try to understand when birds began to live, hunt, and forage in the dark. The study analyzed the compilation of these articles’ conclusions to try to determine whether nocturnality in birds was a trait inherited from a common ancestor or if it evolved side by side in different bird species.

Methods: This study used an array of existing scientific literature to study the evolutionary origin of nocturnality in extant bird species. By analyzing existing scientific literature, the study drew conclusions regarding ancient and modern bird habits.  

Results: It is likely that the nocturnal habits of birds evolved from a common ancestor, representing some of the earliest birds. This hypothesis is supported by the morphology of existing birds, such as large eye to body ratio when compared to other vertebrates because larger eyes allow more light into the retina for clearer nocturnal vision. In addition, these birds have a relatively advanced hearing apparatus that could have evolved from the need to communicate in the dark. The lack of certain organs like the parietal eye in crocodilians and birds (today found only in lizards), which is a light sensitive organ connected to the part of the brain responsible for hormone regulation, suggests that birds had a nocturnal origin, as this organ would have been rendered useless in the dark; the ancestors of birds lost this organ millions of years ago. 

In addition, certain genes that are related to detecting movement (specifically, GRK1 and SLC24A1) are thought to have been present in the common ancestor of birds. These genes would have helped to avoid predation in low-light conditions and support the hypothesis that their ancestor was at the very least both diurnal and nocturnal. 

Activity of birds and phylogeny based on reviewed and published studies. Taxa in red present species with true nocturnality, while taxa in green contain species with occasional nocturnal habits.

Specific adaptations to nocturnal life present in modern birds likely evolved independently from each other. Owls’ asymmetric ears, for example, evolved to precisely locate prey in the dark. This trait was likely not preset in the owls’ ancestors. The deactivation of specific genes related to color vision in nocturnal birds was also likely an evolutionary adaptation to the lack of need for color vision in birds that hunt and forage in the dark. This mutation is present in owls, kiwis, and nocturnal parrots. Some modern birds such as nightjars (Caprimulgiformes) have also evolved a tapetum, which is an extra layer in the back of the eye that reflects light back into the retina. This structure often gives eyes a “shiny” look when flashed with bright lights and can help to give animal clearer vision at night. 

Genetic and morphological evidence suggests that it is possible that birds evolved nocturnal habits in parallel to each other, but it is still possible that the common ancestor of all modern birds was both diurnal and nocturnal. Since the activity patterns of modern birds’ ancestors are still mostly unknown more analysis is needed to understand the habits of ancestral birds. 

Why is the study important? Nocturnality of mammalian creatures is largely understood to have evolved to avoid competition and predation from creatures that lurked during the day, but the origin of nocturnality in birds is not so well understood. Did ancient avian (bird) ancestors also have diurnal and nocturnal habits or was it a trait that was picked up along the evolutionary road? Did this nocturnality evolve in several different species or was it inherited from a single ancestor? Studying extant nocturnal birds and birds that have a combination of diurnal and nocturnal habits may help shed light on the evolutionary history of these behaviors. Understanding these behaviors in birds (or avian dinosaurs) can also help understand the behavior of non-avian dinosaurs like other theropods such as Tyrannosaurus rex the distant past. 

The big picture: This study addresses the origins of nocturnal behavior in birds. It suggests that these habits were present in extremely distant relationships going all the way back to the time of the non-avian dinosaurs. Understanding the habits of modern-day bird ancestors can help understand how ancient birds, and even dinosaurs like Tyrannosaurus or Velociraptor, lived in the past. Previous studies have been absolutist in their approach by classifying ancient birds and their ancestors as either nocturnal or fully diurnal, but the complete story may be significantly more complex and requires more studies to fully understand. Analyzing molecular, morphological, and phylogenetic relationships together can provide a better picture of the origin of these behaviors.  

Citation: Wu, Y. (2020). Evolutionary origin of nocturnality in birds. ELS, 483-489. doi:10.1002/9780470015902.a0029073

Oldest preserved DNA gives new insight on mammoth evolution and speciation

Million-year-old DNA sheds light on the genomic history of mammoths.

By: Tom van der Valk, Patrícia Pečnerová, David Díez-del-Molino

Summarized by: Amanda Gaskins, a senior at the University of South Florida studying geology and astronomy. After she graduates, she plans on continuing her education and obtaining her master’s degree in Geological Oceanography, where she hopes to find ways to combat the effect of global warming on coral reefs. In her free time, she loves to spend time in nature and read mystery novels.

What data were used? A team of scientists made paleogenetic (i.e., studying the DNA preserved in fossils) history by extracting what turned out to be the oldest genome data from the molar teeth belonging to three different mammoth species. 

Methods: To reveal the age and makeup of the mammoth’s genetic data, the authors isolated the DNA from molars found in the Siberian permafrost. Fortunately, the cold temperatures of Siberia reduced the effects of DNA break down throughout time. From there, they used methods that maximized the restoration of short fragments of DNA. The authors utilized biostratigraphy, a branch of stratigraphy that involves correlating and assigning the relative ages of rock strata by using the fossil fauna captured within them, in order to gain an idea of when the mammoths lived. They did this by correlating the fossil remains found at the Siberian site with fossils at locations where absolute dates are available. Moreover, in order to observe how these species of mammoths adapted to their cold environment in Siberia, the authors compared the genomes of the woolly mammoth descendants with those of the ancient specimens. 

Results: Through their experiments, the authors were able obtain ages for each of the three mammoths under speculation; each mammoth specimen is discussed here using a nickname given to them by researchers. The youngest of the mammoth group, nicknamed Chukochya, lived approximately 680,000 years ago. By examining the nuclear DNA that is contained within every cell nucleus of a eukaryotic organism, the team was able to construct a phylogenetic (evolutionary) tree (Figure 1) and discovered that Chukochya actually shares a common ancestor with the wooly mammoth. This confirms the hypothesis that Chukochya was a representative of an early form of the woolly mammoth. Adycha is the second-oldest mammoth of the group, whose life span aged back 1.34 million years ago amidst the early Pleistocene. It lived before Chukochya but is an ancestor to the woolly mammoths. The oldest mammoth of the bunch was dubbed Krestovka, with mitochondrial genome (DNA found only in the mitochondria in the cell) dating confirming that it roamed the earth 1.65 Mya in the early Pleistocene.

Figure 1. This figure is a visual of mammoth evolution throughout time. The three points on the timeline represent the three species of mammoths (represented here by their nicknames) that the authors have sequenced the DNA from.

Why is this study important?: This study provides an excellent example of the potential that ancient paleogenomics have to help uncover the mysteries of evolutionary processes like speciation, in which populations evolve and develop into distinct species. Not much research has been done on deep-time paleogenomics with respect to speciation, as it would require a sample with a long range of genome time sequences, ranging at least a million years old, which the vast majority of fossils do not preserve. The previous oldest genomic data on record was recovered from a horse specimen dating back only 780-560 thousand years ago. The experiment also gives insight on the potential of utilizing DNA as a component of biostratigraphy to help correlate the ages of the rocks and fossils contained within them.

The big picture: Overall, this study shed light on the evolution of mammoths while breaking records in paleogenomic history by uncovering the most ancient DNA sample ever analyzed, pushing our knowledge of genomics all the way back into the Ice Age. The ideas and methods displayed in this experiment will be beneficial in future studies regarding temporal data.

Citation: van der Valk, T., Pečnerová, P., Díez-del-Molino, D. et al. Million-year-old DNA sheds light on the genomic history of mammoths. Nature 591, 265–269 (2021). https://doi-org.ezproxy.lib.usf.edu/10.1038/s41586-021-03224-9

Ymke Temmerman, Ing. Water manager/ Aquatic ecotechnologist and MSc student Aquaculture and Marine Resources Management.

Ymke during a field trip to Texel where she just did some field work at The Slutter

What is your favorite part about being a scientist and how did you get interested in science in general?
From a young age, I was always very curious, wanting to learn as much as possible about everything related to the ocean. I always tried to learn more and continue to look for new things to discover. I grew up close to the coast in the Netherlands and till this very day, I still enjoy the nature there and it always feels like coming home. Part of the reason I got so interested in the ocean is the mystery that is part of it, the fact that on the beaches and along the coast, we only see a glimpse of the life beneath the surface. So when the time came to make a decision about what I wanted to study, the choice for water management/aquatic ecotechnology at a university located close to the coast was one that was directly related to my passion for the coasts. During my studies, the passion and enthusiasm for science only grew. The contrast between theory, lab work and boots in the mud is something I enjoyed and still do. During my first internships at the research institutes NIOZ (Royal Netherlands Institute for Sea Research) and Wageningen Marine Research, I really got to experience doing research. These were amazing experiences, with fieldwork, experiments and a lot of new knowledge which ranged from small worms at the bottom of the North Sea to invasive species in industrial harbors. During these periods, I learned that the part I love about science is the continuous exploration of what seems like endless topics. And that with doing research, you contribute to knowledge. Because science to me is exploring new things of which the stories should be shared not only among scientist but with as many people as possible, especially the next generations that will need it to do better.

Ymke on a mudflat on Texel taking samples during an excursion

What do you do?
At the moment, I am finishing up my Masters in Aquaculture and Marine Resources Management. Within this program I am focusing on ecology and marine resources. The marine resources part is mainly about the services provided to us by the ocean (e.g. fish, coastal protection) and how to use these services in a sustainable way. For example, how fishing could be sustainable or how oyster reefs can be used for coastal protection. The ecological aspect is more about how these coastal and marine systems work and how different species contribute to keeping them healthy. Before my adventure at the university started, I did a Bachelors in Water Management in the middle of the Southwestern Delta of the Netherlands. During this study, I focused on ecology from rivers to oceans, learning about how to work together with nature to protect us against flooding. Other topics included climate change and the importance of water, where some countries have too much, others don’t have enough.

In addition to my studies, I am also active as an ambassador for the Dutch Wavemakers. This organization aims to educate the next generation worldwide about sufficient and clean water but also about water safety. We want to achieve this by collaborating with water athletes and students, hoping to make young people enthusiastic about water sports and water studies.  Next to this, we also hope to motivate the young generation to take action and be the change they like to see.

Ymke in Shanghai on a trip for the Dutch Wavemakers to participate in the Wetskills challenge 2019

What are your data and how do you obtain them?
We, as Dutch Wavemakers, communicate these important topics of water safety and scarcity with a positive attitude. We are convinced that it is not fruitful to keep pointing fingers at each other, since solutions are not often born from conflict. Instead we have a solution oriented approach in which we, of course, also talk about the problems but instead of focusing on doom scenarios we try to set out a positive future perspective. From experience, I know that this is way more effective in the long run when it comes to activating people. If they see the type of positive impact they can have as an individual, and if they spread the word with the same positivity as we do, this small action might become a big movement, leading to a real change in mindset.

How does your research contribute to the understanding of climate change, and the betterment of society in general?
As a Dutch Wavemaker, but also as someone with passion for the ocean, I hope to contribute to a positive change in which we start to see the ocean as a companion instead of an enemy or endless resource. As an ambassador I am involved in multiple projects that aim to create awareness for problems like plastic pollution, changing ecosystems and of course, the effects of climate change on our oceans and coastal zones. One of them is the SDG 14 alliance, which focuses on achieving the United Nations’ sustainable development goal 14: Life below water. Here we hope to create more awareness about pollution, sustainable fisheries, increasing biodiversity and protection of the oceans, with the focus on the younger generations. Next to these projects, we also visit all different types of events where we teach the younger generations about the impacts of too much water, but also about the importance of having enough water. We do this with the help of fun little activities in which the children can participate. In this way, children learn about large scale problems like too much water in cities because of the lack of green spaces.

Measuring temperature for an experiment during Ymke’s Bachelors thesis

What advice do you have for aspiring scientists?
Stay curious! As long as you remain curious and eager to learn new things, there is always a way for you to get there. Don’t be afraid to ask questions, there are always people in your surroundings that would be happy to answer them for you. Especially if it is something that you are really passionate about! And remember you will never be too old to learn new things, because a world without new things to discover would be a bit boring, if you ask me!

Was it possible for trilobites to live in brackish water?

Were all trilobites fully marine? Trilobite expansion into brackish water during the early Palaeozoic

By: M. Gabriela Mángano , Luis A. Buatois, Beatriz G. Waisfeld, Diego F. Muñoz, N. Emilio Vaccari and Ricardo A. Astini

Summarized by: Abby McAleer, a senior at the University of South Florida.  She is majoring in geology with a minor in geographic informational systems. After graduation she plans to get a job in conservation or become an elementary school science teacher. In her free time, Abby loves to hike and travel with her friends. 

What data were used? Trilobite trace fossils (meaning, the marks left behind by an organism, separate from a body fossil) from the early Paleozoic were used along with stratigraphic sections from four ancient estuary (an area where fresh and sea water mix) sites. The specimens were found in sediment structures located in Northwest Argentina.  

Methods: The methods used in this study were a combination of ancient estuary outcrop identification, analysis of the different sediment types from these outcrops, and an analysis of the tracks, burrows, and trace fossils of the trilobites to compare fully marine trilobite fossils to fossils of trilobites found in brackish waters. The ancient estuary sediments were identified by dividing the valley systems of the Paleozoic Northwest Argentina Basin into 3 estuary zones; inner fluvio-estuarine (closer to the river), middle estuarine, and outer estuarine (closer to the ocean). The ancient estuary sediments were examined in a stratigraphic log, which describes the vertical changes of sediments from bottom to top in a particular area. Additionally, an analysis of how the fossil record of trilobites was altered by sedimentary processes was preformed to create a connection between paleobiology and the stratigraphic layers of the outcrops. Lastly, body fossil analysis was preformed on the trilobites to compare characteristics of offshore and onshore assemblages (deeper and shallower water, respectively). 

Results: The presence of trilobite fossils in ancient estuary environments supports the hypothesis that trilobites could handle a change of salinity and still survive. Although the presence of these fossils in the ancient estuary fossil record does not mean that the trilobites permanently inhabited these regions, it leads us to believe that trilobites migrated to these areas for food and possibly a safe place to nest and spawn. It is likely that the realization that tidal influenced estuaries were not fully marine environments helped us come to this conclusion. Figure 1 illustrates the 4 stratigraphic logs that were taken from the ancient estuaries. In this figure, we can see the expansion of the trilobites from marine to brackish water. 

Figure 1. This diagram represents the four stratigraphic logs of the ancient estuaries. In this figure, we can see the expansion of the trilobites from marine to brackish water through the column.

Why is this study important? This study helps us understand that trilobites made evolutionary changes to be able to handle the salinity change to survive, unlike other strictly marine invertebrates, like echinoderms. We can use the findings of this study to better understand the lifestyles of other marine organisms that lived during this time. 

The big picture: Previously, it was believed that trilobites could not handle salinity changes.  After this study, it has been indicated that trilobites were able to migrate to areas with fluctuating salinity for evolutionary advantages. This has helped scientist understand that assumptions of an organism’s tolerance for salinity may need to be reevaluated to limit future biases in paleontological studies.  

Citation: Mángano MG, Buatois LA, Waisfeld BG, Muñoz DF, Vaccari NE, Astini RA. 2021 Were all trilobites fully marine? Trilobite expansion into brackish water during the early Palaeozoic. Proc. R. Soc. B 288: 20202263. https://doi.org/10.1098/rspb.2020.2263

Molecular phylogeny of an elephant-like species

A molecular phylogeny of the extinct South American gomphothere through collagen sequence analysis

By: Michael Buckley, Omar P. Recabarren, Craig Lawless, Nuria Garcia, Mario Pino

Summarized by: Stormie Gosdoski a student at the University of South Florida. She will be receiving her Bachelor of Science in Geology this December, 2020. After school she plans to join the scientific community and put her degree to good use. 

Data: Phylogenetic trees are created to determine the closest possible relationships between species, like a family tree. The phylogenetic tree containing gomphotheres, a group related to modern elephants, was created by analyzing molecular differences across species and determine the relationships between gomphotheres and true elephants and mammoths. One of the most informative ancient biomolecules that scientists can use for this type of study is collagen, which is the most abundant protein in bones and teeth. 

The scientists sampled four different gomphothere fossils belonging to a genus called Notiomastodon from South America. To reduce extraneous variables that could be present in the dataset, all the fossils were taken from the same location: the Pilauco Site in Osorno, Chile. They were also taken from the same layer of sediment. The layers of sediment on Earth can be read like a book, if no other geologic event has altered their positions. The ability to read each layer like a book gives scientists the ability to date the specimens; 13,650 ± 70 years ago to 12,372 ± 42 years ago. The fossils collected from this site included two root molars, a piece of rib, and a skull fragment.

Methods: The bones had fragments removed from them using a diamond-tip Dremel drill. They were then demineralized in hydrochloric acid (meaning, the scientists removed the minerals from the bones). The collagen was extracted from the solution. It was analyzed by a machine called a Matrix Assisted Laser Desorption Ionization Mass Spectrometry Time-of-Flight Mass Spectrometry (MALDI-ToF-MS). This type of equipment is used specifically to find the protein fingerprint of cells (which, just like our fingerprints, are unique to specific groups). The data collected from these methods were compared and searched for on the Swiss-Prot database for any potential matches to the primary protein sequences that are present in the collected data. This database is a protein sequence database. A potential match in the database would mean the species are more closely related. Once the analysis was complete, the scientists then performed a phylogenetic analysis of the data collected. Meaning, they compiled this information and ran the phylogenetic analysis using these new specimens and animals belonging to the closely related proboscideans, the group including elephants and mammoths, in the database as well, to determine relationships of the organisms in question.

Results: The protein fingerprint spectra of the four specimens collected in this study compared to the spectra of woolly mammoth and American mastodon was determined to differ from one another. The collagen fingerprints were similar, but there were three variations observed in the data (figure 1). At this point, using parsimony, Bayesian analysis, and maximum likelihood (the three methods of determining evolutionary relationships) a range of phylogenies was generated. This range compared three extinct proboscideans (Mammuthus, Mammut (the American mastodon), and Notiomastodon) and other closely related mammals. The results of these comparisons showed a closer relationship between Notiomastodon and Mammut. Meaning, the South American gomphothere has a close relationship to the American mastodon (figure 2).

Figure 1 This figure is the mass spectrometry of the three species. (Top to bottom) gomphothere (green), mastodon (blue), and woolly mammoth (red). This shows observed peak difference in the spectra between the three species.

Importance: This determination of the relationship between gomphotheres and mastodons can change how scientists interpret the relationships of other species in phylogenetic studies. Are there other relationships that need to be changed? How accurate can the scientific community get with the relationships of species? How does this affect our relationship to other species? How can we use this type of analysis to track our own evolution through time? This relationship is but one small portion of a larger question and we can use this to refine what we already know about ancient and present species.

The Big Picture: As scientists, we cannot rely on what our eyes are seeing to determine the relationships between species. Using molecular analyses can give a better idea of how closely related species are to one another. This type of analysis can also show how elephants have evolved and changed through history. This can give scientists a better understanding of the biology of elephants. Who knows- maybe it could lead to predictions of how the species will evolve in the future?

Figure 2 This is the phylogenetic tree that was generated from the analysis with ancient ancestor Paenungulata at the bottom (yellow) and the branch containing the common ancestor at the focus of the study, Proboscidea (pink). The South American gomphothere (green) is the sister taxon to the American mastodon (blue). It further shows the relationships of the other species. On the left is the geologic time scale, which shows when each species was alive.

Citation: Buckley, M., Recabarren, O. P., Lawless, C., García, N., & Pino, M. (2019). A molecular phylogeny of the extinct South American gomphothere through collagen sequence analysis. Quaternary Science Reviews, 224, 105882.

Jihan Al-Shdifat, Chemist / Organic Biogeochemistry Scientist In-Training

Processing samples after the dive.

What is your favorite part about being a scientist and how did you get interested in science in general? I got into science out of curiosity. Not many people I know are in the sciences which I think called out to me to explore what a scientist does, what do they look like aside from how they are portrayed in popular culture, or in general. I chose chemistry because understanding the universe from a molecular point of view appealed to me. Now, I am focused on oceanographic work employing biogeochemistry tools and techniques.

The best part about being a scientist is that you can allow your curious mind to think freely. There is always so much more to learn. When you’re out doing fieldwork, or simply processing samples in the lab, the thrill you get whenever you’re making a discovery is irreplaceable. This doesn’t mean obtaining purely positive results- insights and observations on negative results and failed experiments make you appreciate the scientific process more. Unlocking life skills in pursuit of science is a thing! I learned SCUBA diving, and programming, because these are requisites needed to tackle the research problem I am working on at the moment.

With my work, I hope to encourage more Filipinos to pursue a career in the sciences.

In laymen’s terms, what do you do? My research involves enumerating the lipids found in microbial mats, the water column and sediments in an area where groundwater bubbles out from the seafloor. These areas have very dynamic chemistries and my objective is to understand how micro- and macroorganisms thrive and adapt to these conditions.

Submarine groundwater discharge research group of the OASIS Lab, UP-MSI collecting biomass, sediment and gas samples.

How does your research/goals/outreach contribute to the understanding of climate change, evolution, paleontology, or to the betterment of society in general? Knowing the lipid composition gives us an understanding of the metabolic processes employed by microorganisms in adapting to their environment. Looking at the adaptation in areas affected by submarine groundwater discharge can very well contribute to assessing how organisms may behave in response to the changing oceans. The research also employs stable isotope measurements to go hand-in-hand with lipid studies. Another goal is to test how paleotemperature proxies behave in tropical climate as most studies are being done in temperate regions.

Leisure dive after sample collection: We make time to have a leisure dive after completing the sample collection dives to appreciate the rich biodiversity in Mabini, Batangas.

What are your data and how do you obtain your data? In other words, is there a certain proxy you work with, a specific fossil group, preexisting datasets, etc.? The data that my research uses are lipid mass spectrometry profiles as well as isotopic compositions from isotope-ratio mass spectrometry analysis. Isotopic data are both compound-specific and bulk analysis. We also perform the standard physico-chemical measurements of the study site, as well as obtain DNA data of the microbial mats we’ve collected from the field. The team is also exploring the use of imaging to profile the microorganisms across the water column.

Bubbles emanating from the seafloor.

What advice do you have for aspiring scientists? Scientists come in all shapes and sizes. As long as you have that curious mind to hold on to, there is no mold that you should follow on how to be one. Find an inspiration and follow it through with hard work and a lot of readings, and you’re good. More importantly, engage people on your work. Science is meant to be communicated to the larger population outside the scientific sphere and now more than ever is citizen science a force we definitely want to tap into.

 

Specifying past climate change through analysis of sand

Paleoclimate and Holocene relative sea-level history of the east coast of India

Study Conducted By: Kakani Nageswara Rao, Shilpa Pandey, Sumiko Kubo, Yoshiki Saito, K. Ch. V. Naga Kumar, Gajji Demudu, Bandaru Hema Malini, Naoko Nagumo, Rei Nakashima, Noboru Sadakata

Summarized by: Scott Martin, a student studying geology at the University of South Florida that will be graduation with a bachelor’s in early December. He plans on working in a government water management position or as a private contractor at an IT firm. He enjoys camping, kayaking, and playing music in his free time.

What data were used: Data from specific kinds of particles, carbon dating, and results of analysis of ancient pollens found within sand columns.

Methods: First, columns of sand were collected from the Kolleru Lake in India. Then, the chemical composition of the sand was identified, carbon dating was done on some of the plant samples and shells within the sand, and the pollen samples within the sand columns were identified. 

Results: It was found that the bottom of the core, which represents about 18,400 years ago, shows signs of being a dried freshwater body that most likely became more arid (i.e., drier) due to a dry spell in the area around that time. We can assume this because in the sand cores, authors found pollen spores from plants that live in arid environments and rocks that are only able to be found in areas where salt water evaporated. The freshwater lakes would have become saltier as they evaporated and eventually start leaving behind evaporite (i.e., rocks and minerals formed during evaporation) deposits. Then, around 8,000 years ago, the climate in the area changed to that of a tidal zone. This is an area that is underwater when the tide is high and above water when the tide is low. The evidence that as found that points to the area being a tidal zone is the color of the sand itself, shells of mollusks that live in tidal areas, and pollen from mangrove trees. At around 4,900 years ago the area changed again and shows evidence of being a completely freshwater area as it is today.

This figure shows the area being studied in relation to the rest of India. The yellow lines are the depth underwater in that spot, so anywhere the line labeled 5 is touching is 5 meters below sea level. The star labeled KK, the triangle labeled DP, and the dots labeled MW and PN are all locations in which sand columns were taken for this study. Note that the yellow lines are not past coastlines but show depth below the current waterline.

Why is this study important?: This study deepened our understanding of the climate of the past in India as well as how the sea level changed in the area as the global climate did. Understanding more of the specifics of how sea level changes with climate allows for more preparation to be done in coastal cities globally. The change in climate that was analyzed during this study is the Earth’s natural cycle of climate change that is in place due to the slight changes in its tilt and path around the sun.

The big picture: The results from this study will allow for climate models being used in the future to be more accurate since the data that was collected covered thousands of years. This allowed for the study of climate change throughout time as well as the potential causes and effects that the changes in climate had on the area. While this study looked at how natural climate change affected the area, human-induced climate change is altering that cycle and the data on how climate change from the past affected specific rehions could better prepare us to handle to affects of the human-driven climate change that is occurring today.

Citation: Nageswara Rao, K., Pandey, S., Kubo, S. et al. Paleoclimate and Holocene relative sea-level history of the east coast of India. J Paleolimnol 64, 71–89 (2020). https://doi.org/10.1007/s10933-020-00124-2

The Change in Tanystropheus Species Due to Resource Availability

Aquatic Habits and Niche Partitioning in the Extraordinarily Long-Necked Triassic Reptile Tanystropheus

By: Stephan N.F. Spiekman, James M. Neenan, Nicholas C. Fraser, Vincent Fernandez, Olivier Rieppel, Stefania Nosotti, Torsten M. Scheyer

Summarized by: Sarah Kreisle, a geology major at the University of South Florida minoring in GIS. She is a senior planning to graduate December 2020. Afterwards, she plans on staying local to further her knowledge in Florida geology and seek a job or internship offering experience in the field. In her free time, she enjoys hiking and kayaking.  

What data were used? Researchers used fossilized remains of Triassic reptiles Tanystropheus hydroides and Tanystropheus longobardicus, most of which were found at the Besano Formation of Monte San Giorgio, Switzerland. 

Methods: Using digital modeling, both T. hydroides and T. longobardicus were re-created virtually, using dislodged and deformed parts from the original skull. After virtual re-construction, these specimens were analyzed for similarities and differences. Additionally, records of stomach contents and skeletal were used to compare and reconstruct diet and environments.

Results: After examination, the two species were found to have similarities between the shapes of their skulls, but diverged in their dietary patterns, evidenced by slight morphological differences in the skull, and skeletal size. In T. hydroides and T.longobardicus they found that its jawbone curved and allowed for the nasal area to sit on the top side of the body. The snout was very flat and plate-like, which is a similar feature to the present-day crocodile. In T. longobardicus, the snout still sits on top of the skull, but is less prominent than T. hydroides. When looking at the shape of skulls in both T. hydroides and T.longobardicus, the snout was curved and flat with their breathing capability on top, in order to swim more efficiently. It was very likely that these creatures were shallow water dwellers since their nasal cavities were not built to endure pressure at great depths. Due to their lengthy necks, they were likely to pounce on food rather than chase after it. A long neck made it much harder to move around with ease. The long necks of the T. hydroides were able to give them an advantage when stalking prey and causing less obvious movements that might alarm the prey. Using the re-creation of the skull, it is observed that the teeth of T. hydroides were more likely to snap at food, rather than suck food from a shell. Scientists can tell from the fang-like teeth, that it was grabbing and holding its prey. In past specimens, there has been evidence of squid-like creatures and fish scales collected from the stomach contents. Conversely, T.longobardicus was more likely to use its shorter teeth for eating soft shelled invertebrates or plants. Their teeth are tricuspid teeth (i.e., teeth with three cusps), which are also present among animals that eat both plant and animal matter. Though T. hydroides is very similar to T. longobardicus, the biggest difference between them is their size. T. longobardicus was less than half the size of T. hydroides. Likely, these creatures were eating different resources available over time, changing the amount of energy they required to survive. It is possible that these two species lived together in the same aquatic environment and deviated from each other in order to survive on available food sources. 

Figure 1 Both species in this picture are depicted to be different structurally, which could mean different food source and possible early competition for food. The skull of T. hydroides shows long curved teeth that would have gripped prey, whereas the skull of T. longobardicus had the short, tricuspid teeth. The tricuspid teeth are much easier to grind food, in both plants and meat. The skeleton of T. hydroides shows a significant size difference from T. longobardicus. The picture in the bottom right corner depicts that the small skeleton of the T. lonobardicus was mature due to the growth lines seen.

Why is this study important? This study is important because it displays niche partitioning, or natural selection driven by resource use. In examining these two species’ tooth alteration, stomach contents, and size difference, we see how very closely related organisms have evolved in different paths due to resource needs. This shift in consumption patterns may also indicate a time period in which competition for food sources was high. We can therefore hypothesize that while these species could have been descended from a recent common ancestor, they have since changed physically and behaviorally due to their environments. 

The big picture: Many other species have been defined by the process of niche partitioning and will most likely continue in the future as our environment readily changes. These changes further cause increased competition in the food web. Change in size of the Tanystropheus could have been due to the amount of energy available to them in food. Teeth and other characteristics of the genus Tanystropheus can explain features of animals in existence today. Learning about Tanystropheus will help us learn more about creatures during the Triassic and surrounding periods. 

Citation: Spiekman, S. N. F., Neenan, J. M., Fraser, N. C., Fernandez, V., Rieppel, O., Nosotti, S., & Scheyer, T. M. (2020). Aquatic Habits and Niche Partitioning in the Extraordinarily Long-Necked Triassic Reptile Tanystropheus. Current Biology30(19), 3889. https://doi-org.ezproxy.lib.usf.edu/10.1016/j.cub.2020.07.025

Marie-Charlott Petersdorf, Biology Master’s Student

Hello folks! My name is Marie-Charlott and currently I am working on my master’s thesis in theoretical ecology. To be honest, I never expected to get this far in my scientific career and everyday when I get up in the morning (when coffee is involved) I am happy to contribute some knowledge to our scientific world.

What is your favourite part about being a scientist, and how did you get interested in science in general?
Well, I have kind of a romanticised story of how I decided I want to be a scientist; when I was a child, I was obsessed with animal documentaries, atlases about animals and especially with dolphins. I had tons of books about the life of the ocean (spoiler alert: I changed to bears!) When I graduated high school, I did not really know what I wanted to do with my life or where I could see myself in the future. I decided to apply for all kinds of studies that I thought might be suitable for me at universities all around my hometown. Eventually I only got accepted at the University of Cologne for the bachelor’s program in biology. I had my very first big mind-blowing moment when I sat in a lecture of inorganic chemistry and the professor explained to us that all matter on our planet, as far as we are concerned, is made of the same quality: atoms. It is only the protons, neurons and electrons that make the difference. Only these three things determine how matter is and how it is able to react. At this very moment, I fell in love with science in general. I could not believe how great everything around us actually appears to be, how many fantastic secrets are out there to uncover. I decided I want to get to know and contribute AS MUCH AS I COULD. And since that moment, many more mind-blowing moments like this followed. And I undoubtedly believe this will never stop for the rest of my life. 

Science also literally saved my life and gave me a place to belong to. Both of my parents passed away during my Bachelor’s studies and I was lost in this big world. I found support and passion in working for something bigger than me, something that is real and can be proven. It gave me stability. 

What I truly love about science and the scientific community: No matter who you are, where you came from, who you love or who you decide to be: We all agree on the general principles of logic, causality and reproducibility. We all work for the same goal.

How does your research contribute to the understanding of climate change, evolution, palaeontology, or to the betterment of society in general? 
It is not a secret anymore that humanity contributed well to destroy its own home planet by climate change, globalisation, urbanisation, biodiversity- and ecosystem loss. There is undoubtedly an immense amount of work to do – and I started with my master thesis at a point where I try to understand what went wrong in our approach to maintain species diversity so far. Many biodiversity conservation programs were designed to reintroduce species into their natural habitat to maintain ecosystem workability when they disappeared. Unfortunately, many of them failed and the programs were not successful. But how do we investigate the reasons for a failed reintroduction? Interview the released animals one by one? 

Scientists have found another, feasible solution to get to the bottom of the matter. 

When we try to model an event or reproduce a mechanism on the computer in a simulation, preparation and evaluation is a dynamic process where we learn from what we model and try to improve this model to get as close as possible to the real event we try to simulate. In my master thesis, I created a simple model based on equations which solution represents the population density of different animal species. My model is not adapted to one species in particular but held general to investigate the event of what we call community closure: A ecosystem loses a species and begins to dynamically re-calibrate itself towards a new equilibrium. The interactions within the system change when one interaction partner just disappears; and this is where I start my investigation. I force one of the species which used to interact as a competitor or as a predator or prey into extinction and then try to reintroduce it back into the system when a new equilibrium is reached. When we find out more about the major forces that keep ecosystems closed, we might find a way to manage some of these factors and tackle the issue of failed reintroduction programs.

One of the biggest problems in nature is: We can only see the system in its status quo as it appears to us right now. Due to environmental uncertainty, it is often hard to approximate what happened in the past and what led to the state we observe right now. This is also what computational models are for: We can play around with our models and maybe are able to reveal completely new phenomena we might also find in nature when we know what to look for.

What advice do you have for aspiring scientists?
Never let anyone else tell you what you are able to do or not. Don’t be afraid to reach for the stars. My Mom used to say: It is always possible if you are willing to work hard, and I truly believe in that. There is nothing you can’t learn, even when you don’t feel apt or suitable for the task. Go for what you are passionate about in life and also learn from your mistakes. A bad grade or a rejected paper do not mean you suck as a scientist. Struggle means improvement and we are all in this together, so don’t worry about one thing in particular you haven’t been perfect at. 

The increasing rate of extinction today and how it affects our future

Vertebrates on the brink as indicators of biological annihilation and the sixth mass extinction

By: Gerardo Ceballos, Paul R. Ehrlich, and Peter H. Raven

Summarized by: Melody Farley, an undergraduate geology student at the University of South Florida in her final semester. Her goal is to use her degree at the Southwest Florida Water Management District to help with the management of water resources in Florida’s systems. She plans on attending graduate school in a few years, after gaining some work experience to determine what she wants to specialize in. When she is not studying geology, she loves to kayak, hike, and enjoy nature with her fiancé.

What data were used? Data was collected from the International Union for Conservation of Nature (IUCN); specifically, the number of individuals in each vertebrate species, as well as the number of species whose endangerment status has been studied was used here.

Methods: This study used the database material from the IUCN to help classify the species studied based on geographical range and number of individuals. From this, they determined the number of vertebrate species with fewer than 1,000 individuals, excluding extinct species. 

Results: 515 vertebrate species were discovered to have fewer than 1,000 individuals, indicating that they are “on the brink” and very susceptible to extinction. This comprises 1.7% of the total terrestrial vertebrate species. Of the 515 vertebrate species on the brink, more than 50% of these species have fewer than 250 individuals, meaning that there are much closer to extinction. Species on the brink are found to be concentrated in regions with higher human interaction. 543 species have gone extinct since 1900. If the 515 species were to join the 543 species that have already gone extinct, the total extinct species in a 150-year span would be 1,058 vertebrate species. Given the last 2 million years’ background rate of extinction, 9 species would be expected to go extinct in this 150-year period. So, the extinction rate would be 117 times faster than previous background rates.

Figure SEQ Figure \* ARABIC 1: This figure shows the population sizes of 5 groups – Mammalia, Aves, Reptilia, Amphibia, and Vertebrates from left to right, with Vertebrates being an aggregation of the first 4. They are categorized by the number of individuals left in the species. Here, you can see that in all 5 groups, at least 50% of the on the brink species have fewer than 250 individuals.

Why is this study important? This study is important because it illustrates the effects that humans are having on different populations around the world. Extinction rates are much higher now than in geologic history, mostly since the development of agriculture approximately 11,000 years ago. Many of the extinction rates have increased even more since the 1800s as human civilizations have become more advanced, showing that an increased competition for resources have expedited the extinction rates in recent history. 

The big picture: Earth’s systems are all part of an important balance. When a species goes extinct and disappears from an ecosystem, simple maintaining services of this ecosystem can be disturbed. If this happens enough times, we could have the collapse of ecosystems that we rely on for survival. Humans require several things to survive: a stable climate, fresh water, crop pollination, and more. Many of these are made possible by healthy and sustained ecosystems. With the continued risk of climate change, species extinction is a bigger problem now than ever, and it is important for humans to consider the effects of their development, and what this means for the future of civilizations.

Citation: Ceballos, G., Ehrlich, P.R., Raven, P.H., “Vertebrates on the Brink as Indicators of Biological Annihilation and the Sixth Mass Extinction.” Proceedings of the National Academy of Sciences, vol. 117, no. 24, 2020, pp. 13596–13602., https://doi.org/10.1073/pnas.1922686117