Early correspondence shows that he always liked school, and was always seeking meaning—seeking to do something with his life. In 1876, he had the chance to attend high school in Columbus, Wisconsin, which had opened that year. Like many youth, he struggled with what to do with his life. After attending a year of high school, he began to teach at a Hampden school, while continuing his studies. In 1879, he attended college at the Oshkosh Normal School (now the University of Wisconsin-Oshkosh). He left there after only one year due to financial reasons, and took a job teaching in Columbus, Wisconsin. He hoped to earn enough money to go back to college.
In 1881, he took a job as a teacher in Oconto, Wisconsin. There, he continued to read voraciously, and had a particular attraction for science. It was here that he started to develop a passion for helping people understand science. He believed that science was the key to the future of society, and that if people could be taught to think with the reasoned, thoughtful, unbiased critical perspective of science, that much suffering in the world could be alleviated.
Ritter needed to earn money for school, and so became a schoolteacher and tutor to pay for his tuition. After a few years of alternatively taking classes and teaching to earn money, he graduated with his BA in 1888. The next year he received a scholarship to go to Harvard University for his MA and Ph.D. in zoology.
He spent a few summers at Marine Laboratories, and in 1891 was given a job teaching biology at the University of California in Berkeley.
Joseph LeConte was the chair of all the scientific fields at the university. In the fall of 1891, following the growing trend of science specialization, the science department was divided into four departments, and Ritter was appointed the chair of the new zoology department.
It was also in 1891 that he married a Berkeley physician, Mary Bennett.
Ritter was chosen to be among the elite scientists of the 1899 Harriman Alaska Expedition. Chosen for his knowledge of marine biology in general and marine invertebrates in particular, he accompanied the group of scientists on their exploration of Alaska.
Consequently, his plan to teach marine biology was to actually take his students to the ocean so they could study living creatures in their natural environment. He wanted to set up a permanent laboratory to study the biology along the Pacific coast, as well as be a "classroom" for his students.
Ritter searched for eleven years for an appropriate place for a permanent marine biological laboratory. He spent summers at various places along the coast with students. His goal was frustrated by lack of money and lack of an appropriate place.
Then, in 1903 Ritter was introduced to newspaper magnate E. W. Scripps. Together with Scripps' half-sister, Ellen Browning Scripps, they formed the Marine Biological Association of San Diego with Ritter as the Scientific Director. Two years later, they arranged for the purchase of a site in La Jolla, north of San Diego (the same site where the Scripps Institution of Oceanography is today).
Scripps paid for continuing projects of Ritter. By 1907 they were constructing the first laboratory on the site.
After World War I, Scripps and Ritter became convinced that nations needed a forum to rationally work out their differences, rather than going to war. They became great advocates for the League of Nations, believing it could be an alternative to war.
Both Ritter and Scripps believed that science had become too parochial. Many scientists had no desire to solve human problems or even share their insights with the laity. Many scientists felt that sharing their scientific discoveries with the popular media would somehow soil their pure discovery. Ritter and Scripps, on the other hand, believed that it was critical to share these scientific discoveries, and by doing so, would help people to "think like a scientist"—with a reasoned thoughtfulness. By the end of 1920, Ritter and Scripps had come to the conclusion that a newspaper would be the best avenue for sharing these scientific discoveries. With Scripps funding, and Ritter as the scientific director, they started the Science Service in Washington DC, using a newspaper format (now Science News) to share science information and discoveries.
On the other hand, the school of thought called vitalism said that there was something different in life than in non-life. There was a vital force—a spiritual force—that made life. Rocks did not have the vital force. Humans did. The vitalists and the mechanists entered endless debates and wrote endless papers advocating their perspective.
According to Ernst Mayr, Ritter introduced the third school of thought: organicism. While the term "organicism" had been used before, Ritter was the first to use it for biological purposes and to create a theory of it. Organicism believed that life was interrelationships between living things, living in a complex web. Today, organicism might be called systems theory. In 1918, Ritter wrote his organicist tome, The Unity of the Organism, which he believed was his magnum opus.
The University of California awarded him the Doctor of Laws degree in 1933.7 He continued to be a tireless advocate of evolution, science education, and human service. He continued to write, finishing his last published book, The California Woodpecker and I, at the age of 81. At the time of his death, on January 10, 1944 he had 5 book-length unpublished manuscripts written, and parts of many other books and articles. 8 His literary executor, Edna Bailey, consolidated his manuscripts and published sections of them, posthumously, under the title Charles Darwin and the Golden Rule.