Question: who are the two naturalists who first came up with the theory of natural selection
[{'answer': 'Charles Darwin', 'provenance': [{'wikipedia_id': '21501970', 'title': 'History of evolutionary thought', 'start_paragraph_id': 2, 'start_character': 8, 'end_paragraph_id': 2, 'end_character': 22, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'Alfred Russel Wallace', 'provenance': [{'wikipedia_id': '21501970', 'title': 'History of evolutionary thought', 'start_paragraph_id': 2, 'start_character': 27, 'end_paragraph_id': 2, 'end_character': 48, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '21501970', 'title': 'History of evolutionary thought', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 1581, 'bleu_score': 0.965953122219079, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14898218272078740816}, 'section': 'Section::::Abstract.'}]}]