BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: Fossils

1.78 Billion Year Old Bacteria: the Origins of Photosynthesis

E. coli Bacteria (7316101966)

Pretty music everyone is aware of the term photosynthesis. We identify photosynthesis as the process plants take to make food by utilizing the sun’s energy. New findings take us back in time to the earliest signs of this process. The article published on January 3 2024 reveals that bacteria fossils hold some of the oldest signs of machinery required for photosynthesis. Cyanobacterias’s invention of photosynthesis is responsible for the oxygen in Earth’s atmosphere which is a large sum of information derived from fossils. 

The bacteria fossils are compression of carbon that don’t contain any mineralized structures such as bone or shells. The fossils also revealed that there are complex structures inside of the microscopic bacteria such as thylakoids which are located inside of the chloroplast and allow photosynthesis to take place. It is exciting to see such old thylakoids inside of the bacteria fossils but it is not unheard of as some researchers believe that thylakoids may have evolved before the Great Oxidation Event which occurred around 2.4 billion years ago and marked a significant increase in Earth’s oxygen levels.

During the period that the bacteria fossils lived in, oxygen levels in Earth’s atmosphere were at a fraction of today’s levels which helps explain why the fossils hint that there may have been small pockets where oxygen was abundant, possibly allowing the evolution of the ancestors of plants and animals. Most of the rocks that scientists believe may harbor fossils similar to the ones discovered have been compressed destroying intracellular structures like thylakoids which makes the findings even more rousing. 

A similar article published the following day identifies the bacteria fossils to be between 1.73 and 1.78 billion years old. Furthermore, the article points out that prior to this discovery, the presence of thylakoids in cyanobacteria was traced back to only around 600 million years ago, but now the earliest evidence of thylakoids in cyanobacteria is 1.2 billion years older. The fossils are also defined as Navifusa Majensis, a presumed type of cyanobacteria. N. majensis fossils add a vital data point in the timeline that aims to discover the exact timing of oxygenic photosynthesis’s evolution.

A second article published on the same day explains that the bacteria fossils “were laid down in mud and squeezed as the mud was transformed into shale over time.” The intriguing part, though, is that the internal structures of the cells were preserved throughout this process. 

To help further explain the job of thylakoids in plant cells, in AP Biology class, we learned about the specifics of the chloroplast, the organelle in plant cells that is responsible for photosynthesis and plants green color. Furthermore, we learned that grana, located below the inner membrane of the chloroplast, are stacks of thylakoids. A large surface area of thylakoid disks results in better productivity in the cell. In the article linked in the previous paragraph, astrobiologist Emmanuelle Javaux is referenced as speaking about “dark lines stacked through tiny sausage-shaped cells” that they believe represent thylakoids. An image in the Cells Notes Packet displays the same description that Javaux is providing with dark rectangles being spread across an image of the chloroplast. 

I believe that these new findings are a great advancement in the mystery that is the evolution of photosynthesis in plants. These findings are one of the first steps of discovering the exact timing of oxygenic photosynthesis’s evolution. I look forward to seeing if more fossils are discovered with thylakoids and other complex structures still intact, what do you think?

 

Love in the World of Paleontology: The Story of Annie Alexander

This is not just a biology story

Annie Montaque Alexander was born on December 29th, 1867. In 1901, she found herself attending a lecture by John C. Merriam on paleontology at Berkeley University. She was hooked instantly and requested to join the fossil explorations.

Annie’s life is defined by traveling. She was an outdoors person and fossil exploration was like a gold mine for her. She took part in explorations to Fossil Lake, Oregon (1901), Shasta County, California (1902 & 1903), and the West Humboldt Range in Nevada (1905). This last expedition discovered a large amount of Triassic ichthyosaur skeletons, including some of the largest in the world. 

An ichthyosaur is any member of an extinct species of aquatic reptiles. They are similar to porpoises in appearance and are distant relatives of lizards and snakes. They are highly specialized, but not dinosaurs. Their remains span almost the entire Mesozoic Era, but are abundant and diverse during the Triassic and Jurassic periods.

She took part in all the hard work and hardships that come with field work, as well as cooking the meals for the trip. These expeditions, as a part of her agreement with Merriam, were all expeditions she financed. 

Her interests were not limited to paleontology. In 1908, Annie helped establish the Museum of Vertebrate Zoology and made up the difference when State appropriations for its construction fell short. She did this all before she had the right to vote. That’s crazy!

Annie also took part in many trips to Alaska, where she collected mammal skulls. This is where she discovered a new subspecies of grizzly bear, named Ursus alexandrae after her. 

Also in 1908, Annie met and began traveling with Louise Kellogg. Annie and Louise would live and travel together until Annie’s eventual death in 1950.

Same sex marriage was not legal until 2015. Annie and Louise were a couple living in what is referred to as a “Boston Marriage”. A “Boston marriage” is a term for women living in a marriage-like relationship without any male support. While not all “Boston Marriages” are lesbian relationships in a sexual sense, the term is better described as ‘domestic partnerships’. It is derived from Henry James’s 1886 book detailing a marriage-like relationship between two women. Despite all of this, it’s obvious that Annie and Louise loved each other.

Annie and Louise found themselves on adventures in California, Nevada, New Mexico, Utah, Colorado, Idaho, and Arizona. The heat could get as high as 136 degrees! Crazy to think about heat like that in cold like this!

Annie and Louise collected over twenty thousand specimens of animals, plants, and fossils for the museums. Like Ursus alexandrae, many of the new species were named after Annie, including Hydrotherosaurus alexandrae (Cretaceous plesiosaur), Swollenia alexandrae (grass species), Shastasaurus alexandrae (Triassic ichthyosaur), Alticamelus alexandrae (Miocene camel), and more. Oh, what I’d give to have a dinosaur named after me! Laurasaurus pasqualae. Pretty awesome!

She followed the field and laboratory work of the paleontologists at Berkeley closely and maintained a close relationship with Dr. Merriam and his successors throughout her life. 

The 1900s was not a pleasant time for women in the STEM field and Annie knew this. Even if the only thing separating men from women is a y-chromosome, many people looked down upon women, and still do today. Annie repeatedly complained about the need for a fireproof building for the fossil collections and reestablish a strong paleontology program. She never gave up on her goals. Yet, she often found herself negotiating her pleas. Her gender, as well as the untimely recent depression, led to complications. Still, she never gave up on what she was passionate about and that is admirable.

The research and specimens founded by Annie and Louise contributed to long-term data today. Both Annie and Louise ignored society’s attempts to hold them down and did what they loved in their life. No one could stop them.

I think Annie Alexander is an extremely interesting person. I’ve never heard of her before I did my research. She appreciated scientific research and understood the important questions and problems for studying, despite not being a research scientist herself. She properly documented and preserved her specimens to keep their scientific value. She is a great judge of character and is extremely loyal to the people she trusts. Louise was a lucky lady to have Annie in her life. We all are lucky to have Annie as a person to look up to.

Fossils of Massive Rats Found

Attention fellow biology lovers: it appears our biggest fears have been realized. In East Timor, in Southeast Asia, researchers have found fossils of rats up to ten times larger than modern rats. Fear not, however, as these rats are long gone. Researcher Dr. Julien Louys said that the rats lived tens of thousands of years ago, and that there is evidence of humans actually using them as a source of food. Many of the fossils were found with cut and burn marks. The findings came as a part of a project called From Sunda to Sahul. The purpose of the project team that found the rat fossils was to find when humans started moving through Southeast Asia.

Dr. Louys believes that the rats actually lived in Southeast Asia until about one thousand years ago. He cited their extinction as being cause by the introduction of metal tools into society in Southeast Asia, enabling the inhabitants to destroy forests faster and more completely. The team is working to find the impact of humans on the Southeast Asian Ecosystem, which is directly correlated to the rats. Once they find the exact conditions that existed in the area before the rats extinction, they will have a more exact idea of what happened that left the rats extinct.

The rats themselves are characterized as mega-fauna. Mega-fauna is a term that refers to animals that are abnormally large, and these rats fall under this category. The rats are part of a movement that has seen a mass extinction of mega-fauna animals across the globe. Although the most common explanation for this unfortunate trend is human influence- which undoubtedly played a role- the reality is that hard evidence points to climate change as having a larger impact. As more research takes place, it will become clearer as to the exact reason for extinction of these massive rats in Southeast Asia. What do you think caused the extinction? Feel free to comment!

A sketch of a Deinotherium, a mega-fauna species that went extinct about 12,000 years ago. Image from Wikipedia Commons.

 

 

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