Thomas Henry Huxley was an English biologist and prominent advocate for Charles Darwin's theory of evolution. He was known as "Darwin's Bulldog" for his fierce defense of the theory. Huxley also made significant contributions to the fields of comparative anatomy and paleontology. He was a strong proponent of scientific education and played a key role in the development of the British education system. Huxley's work and influence had a lasting impact on the fields of biology and education.