CHALLENGE OF THE MIND PROJECT
Nathan Wong
Joseph Leidy,
The Father of American Paleontology
Culpepper
Pre-Ap English I, Period 1
January 15, 2025
Table of Contents
Page 3 ……………………………………………………………………………. Abstract
Page 4-5 …………………………………………………………Background Information
Page 6-7 ….…………………………………………………………… Major Contributions
Page 8 ………………………………………………………………………………Challenges
Page 9 ……………………………………………………………………… Final Comments
Page 10 …………………………………………………………………… Works Cited
Abstract
Joseph Leidy was a Paleontologist, biologist, zoologist, professor, and parasitologist who was born on September 9th 1823 and died on April 30th, 1891. He discovered the Hadrosaurus, the national dinosaur of New Jersey and the mosasaur, the largest marine reptile. Leidy also found parasites in undercooked pork products and insects can carry diseases. He helped create new departments in the University of Pennsylvania such as the department of biology, zoology, and anatomy. He was the head chairman of the board of curators and a professor at the university of Swarthmore. He was a US military surgeon during the civil war, in which he wrote about the human liver. He wrote over 600 publications and documents stating his claims and discoveries, some include “Cretaceous Reptiles of New Jersey (And a few tidbits from elsewhere)”, “On the fossil horse of America” and “A Flora and Fauna within living animals”. He studied and did papers over the anatomy of the sloth, locust, lemur, and mollusks. Leidy traveled all over the US, and he found rhizopods, ammonites, ancient mammals, and reptiles. Joseph Leidy is one of the pioneers in science, he made many contributions to the universities and museums that he supported and worked for.
Background Information
Joseph Leidy was a leading figure in the paleontology, parasitology, and anatomy fields. He was born to Philip Leidy and Cathrine Mellick on September 9th 1823. As a young man, Leidy was interested in natural history and he had a talent with anatomy (Harvard). During the civil war, he put his talents to use as an union army surgeon (Philadelphia). He got his Medical degree in 1844 and began to pursue his goals. As Leidy practiced as a physician, he also studied the anatomy of many creatures such as locusts, mollusks, and sloths. He then published his findings and was invited to join the Boston Society of Natural Sciences and the Academy of Natural Sciences of Philadelphia (Harvard). He lectured at the Franklin Medical College in 1846 to 1853, until he was appointed as the professor of anatomy at the University of Pennsylvania. In 1864, he married Anna Harden and they had one adoptive child, Alwina. He then went on to become a part of the College of Physicians in Philadelphia in 1851 (Philadelphia). From 1870 through 1885, Leidy was the professor of Natural History at Swarthmore College, in 1874 he accepted the Hershey Professorship at Harvard. Leidy also became the director of the University of Pennsylvania's first Department of Biology as well as Zoology, and Anatomy (Harvard). Leidy was also the president of the Wagner Free Institute of Science from 1881 to 1891, at that same time he became the chairman for the board of curators. He died on April 30, 1891 (Philadelphia). Joseph Leidy was the founder of paleontology in the United States, he had about 600 books and publications including “On the fossil horse of America” and “A Flora and Fauna within living animals” where he appointed himself as a leader in Parasitology (Harvard). He had made contributions to every field he worked on and is a leading role for his research.
Major Contributions
One of Joseph Leidy’s greatest discoveries in his entire career was the discovery of Hadosaurus. It was said to be a large herbivore around the Cretaceous era with a bill-like snout, and they traveled in herds (EBSCO). On his adventures, Leidy recordedly found seagoing Crocodilians and partial Harosaurus fossils (Smithsonian). Three years later Hadrosaurus was completed with more searching around, and Leidy had found the first recorded complete dinosaur fossil skeleton (Britannica). After Leidy’s discovery, it sparked the “bone wars” hosting dinosaur celebrities like stegasaurus, allosaurus, and Triceratops. His discovery benefited paleontology as a whole because at first most believed that dinosaurs were mammal-like creatures, but thanks to Leidy’s findings, it proved that dinosaurs were more bird-like and they were also related to ducks with the bill of hadrosaurus (Smithsonian). Joseph Leidy’s second great discovery was the mosasaur. He discovered it on his same journey to find hadrosaurus, and it was one of the first marine reptiles to ever be found in the US (EBCSO). The Mosasaur was said to be the largest marine reptile on earth, Mosasaur was smaller than its movie counterpart, being more closely related to monitor lizards and snakes, it is said that it was half the length of a football field and had a tail similar to a shark. Leidy found it in New Jersey and the residents believed at first that mosasaur was a whale, crocodile, or some sort of fish, but thanks to Leidy (and other research from paleontologists) that mosasaur was in fact a reptile. Other than paleontology, Joseph Leidy made many contributions to parasitology, zoology, and anatomy, he found many causes and origins of diseases and parasitites. He discovered that the horse once roamed the US, and had gone extinct long before Columbus had arrived (Britannica). He also found animals such as sloths, locusts, lemurs, mollusks, and parasites. Leidy was a major helper in anatomy writing down so many bones and ligament publishings for each animal, he also wrote the first thorough paper over the liver. He also discovered prehistoric tigers, lions, camels, and rhinoceros. Leidy’s greatest discoveries to parasitology is the transmission of the parasite that transmits trichinosis through undercooked pork. Today, cooks and chefs make sure to cook pork and bacon the right amount so the parasite does not contaminate the food thanks to his research (Philidelphia). Leidy once fell sick and after his recovery, he wanted to learn how he got such an illness. It turns out that his disease was transmitted through an insect. He did some research and came to the conclusion that protozoa and insects such as flies and mosquitos carry diseases with them and they transmit them through bites, stings, and contamination (Harvard). Thanks to his research, doctors and scientists created bug spray to protect people from bugs such as these, and people take proper precautions to avoid this transmission. Without him, the bone wars wouldn’t exist, where legends like the Tyrannosaurus Rex, Triceratops, and Allosaurus. And, paleontology in the US wouldn’t exist, so no one would have found fossils until the 1900s where they would’ve finally understood its scientific value. Joseph Leidy had completed many things in his lifetime, he also had a lot of challenges that he struggled to overcome during his discoveries.
Challenges
Even though Joseph Leidy had made many contributions in the fields that he worked in, he had to overcome many hardships and failures to achieve such goals. First and foremost, Leidy’s first challenge was the completion of the Hadrosaurus. Leidy took a very long time to complete the Hadrosaurus fossil, he used other bones from different findings which had some pieces that connected and they were paired with other fossils that he had collected over his travels. Also, he would’ve completed the skeleton earlier if the farmer who owned the land hadn’t sold the fossils without knowing the full scientific value and how hard it was for Leidy to find the replacement for the skeleton. He tried searching for replacements for the Hadrosaurus from traveling across the US, and either he found the same fossils that he had already found or they were completely different fossils. He was looking for fossils like missing puzzle pieces and the end goal was more than worth the effort. Leidy is truly a pioneer in his studies and all his trials and errors were not in vain. Without him looking for the certain fossils he wouldn’t have found the mosasaur or other fossils, animals, and so many more accomplishments, so Joseph Leidy's legacy is built on the effort and work that he put in to have a place in history.
Final Comments
Joseph Leidy was a paleontologist who discovered dinosaurs such as Hadrosaurus and mosasaur and he also brought paleontology in the US, started the bone wars, and created the department of biology in the university of pennsylvania. He traveled a lot during his lifetime, and found many specimens, these led to many discoveries. Leidy helped doctors and zoologists with his studies of human and animal anatomy, including sloths, lemurs, and locusts. Leidy also found parasites that lead to diseases and he found ways to prevent them from transmitting.
Learning about Joseph Leidy impacted me by his devotion to the fields he worked in and how much he had to do to be where he is in history. He is an innovator because of these discoveries, and he sparked many discoveries afterwards. Even though some of his discoveries weren't that big today, it was a historical event that everybody was talking about. He truly was the US’s father of paleontology.
For these reasons, the word I chose to represent Joseph Leidy is "persevere". I chose this word because even though he went through so much just to get results for a parasite or a dinosaur, he did it in the name of science and he did it so that the US could experience paleontology.
Works Cited
Belardo, Carolyn. “Last Man Who Knew Everything.” The Academy of Natural Sciences, 27 Aug. 2018, www.anspblog.org/last-man-who-knew-everything/.
“Hadrosaurus | EBSCO.” EBSCO Information Services, Inc. | Www.ebsco.com, 2023, www.ebsco.com/research-starters/anthropology/hadrosaurus.
“Joseph Leidy | American Zoologist.” Encyclopedia Britannica, www.britannica.com/biography/Joseph-Leidy.
“Joseph Leidy Papers - Philadelphia Area Archives.” Upenn.edu, 2025, findingaids.library.upenn.edu/records/CPP_MSS2170-01. Accessed 1 Dec. 2025.
Magazine, Smithsonian, and Riley Black. “Dinosaur Classics: Leidy’s Dinosaur Inventory.” Smithsonian Magazine, 27 June 2011, www.smithsonianmag.com/science-nature/dinosaur-classics-leidys-dinosaur-inventory-23317878/.
Osborn, Henry Fairfield. “Joseph Leidy (1823-1891).” Biographical Memoirs National Academy of Sciences, vol. 7, 2025, p. 1, ui.adsabs.harvard.edu/abs/1913BMNAS...7....1O/abstract. Accessed 1 Dec. 2025.