Socrates

Could be considered as the father of philosophy.

He is the one who questioned everything and everyone in his time including god.

Agora is  where they / he discussed politics, arts and philosophy.

He never left a record of his saying.

Thanks to his student Plato his thinking revibrates to modern time.

He believed in afterlife. He postulated if there is afterlife, there is probability of life before and reincarnation.

There was no writing left behind from his time.
His student Plato probably recorded verbatim the discussion he had with his teacher.
In later life Plato was critical of his teacher and contributed his line of thinking to philosophy.

He had followers and haters.

There were three accusers.

Charges of impiety.
1. Going against the God.
2. Homosexuality.

Sentence   Death Penalty.

Chosen by 501 citizens by drawing lots.

1. 260              Yes
2. 220               No
3.    21              Abstained

He was given poison to drink.

When asked about helping him to escape from prison cell he said;
Breaking one law is breaking all the laws.

Plato had known to say;
"We lost the best upright man in history".

Plato

He came from an aristocratic family and lived up to 80 years.
Creator of the Academy in Athens.
Learned mathematics from Pythogarus.

Many individuals influenced his thinking.
Socrates was his teacher.

Dialogue was his way of discussing a topic. His interests branched to philosophy, metaphysics, ethics, logics and religion.

His theory of form (physical word) and non form, most likely the behaviour of mind and abstract thinking lead to the foundation of Western philosophy, which the modern scholars still discuss to present day.

He left behind volumes of writing and most of them were probably came down from the interpretation of Socrates thinking.
His earlier writings are supposed to be coming form his teacher Socrates but in his later life probably after the death of his teacher, he was critical of his teacher and made his own line of thinking.

He is known as the student becoming the teacher.

Founding of the Academy and preservation of thinking that predated him was his monumental contribution to philosophy to begin with but later branched in to other disciplines in education.

His efforts of educating, the human mind by dialogue continues.

Aristotle

He was the father of empiricism.
His curiosity led to vast strides in history of philosophy.
Quest for knowledge and open inquiry were his bona fide.
His interest were science, philosophy and human understanding.
Plato was his teacher.
His seat of knowledge was Venice in Greece.
He travelled a lot and debated his opinions with contemporary intellectuals.
He questioned the authenticity of existing beliefs.
His independent thinking sometimes diverted him from his teacher's idealism.
He delved into metaphysics, logics, ethics and politics.
Founded the lyceum in Athens.
Lyceum expanded into teaching, arts, science, physics and philosophy.
He encouraged research and development.
He was the mentor to the young prince Alexander the Great and ended as his wiser council.
His allurance  to knowledge, virtue and philosophy laid the foundation for modern education.

Wallace, Huxley, Hooker and Darwin

Darwin is not the only one who postulated that theory of evolution.

There were three other figures who influenced Darwin.

Darwin doubted himself of his theory of evolution and the natural selection.

Some were called frenemy.

If not for his friendly companions which were only a few Darwin would have not published his monumental work.
He had many critics and enemies and the Church spearheaded the attacks.

The success of science is collaboration, and the lack of it is the Church's contribution.

Alfred Russel Wallace, 14 years younger had postulated a similar geological postulation of species distribution while working in Indonesia. He studied Geology. anthropology, ecology and astrobiology.
He was a surveyor by profession which helped his naturalistic tendency. He briefly taught surveying and map making in Leister.
His friend and traveling companion went to Amazon jungle to study natural selection that was congruent with geological barriers . He met tragedy after tragedy of his brother dying and the shipwreck and losing of his collection insects.
However he came back to England and made a series of publications.
He subsequently went to East Asia (Indonesia) for further studies.

The Wallace Line separating the Australasia from Asia was his creation.
Joseph Dalton Hooker was a botanist and a explorer. He was a good friend of Darwin. He was the director of the Royal Botanical Garden of Kew, following his father who was the director.
Thomas Henry Huxley was a biologist, anthropologist and a comparative anatomist. He was called Darwin's bulldog due to his close adherence to Darwin's theory of evolution. 
In 1996 a dinobird called sinosauropteryx was discovered in South America. Primitive feathers similar to birds were found with the specimen.
The theory of origin of birds from dinosaur was in existence from the 19th century.