what challenges did it face?
There were serious scientific objections to the process of natural selection as the key mechanism of evolution.
On the Origin of Species
There were serious scientific objections to the process of natural selection as the key mechanism of evolution, including Karl von Nägeli's insistence that a trivial characteristic with no adaptive advantage could not be developed by selection. 
who was the first scientist to state that species change over time Lamarck. who was this person? He was a soldier, biologist, and academic. he is best known for which works? "Hydrogéologie" and "Memoirs of Physics and Natural History", to name a few. is he connected to darwin by any way? His theory is cited in textbooks to contrast with Darwinism. what does this last mentioned term means? It is a theory of biological evolution. regarding the works of the former person; what is referred by the first mentioned? UNANSWERABLE is there any book related to this person? Flore françoise. what is it about? UNANSWERABLE who was darwin? He was an English naturalist, geologist and biologist. what do you mean by this second last term? A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes the Earth and other terrestrial planets, as well as the processes that shape them. is there any book of the person in context on this subject? Yes, the "Beagle" collections. can you state what is it about? It had expert descriptions of the collections he had made during the "Beagle" voyage. did he publish anything? Yes, On the Origin of Species. did he publish any paper on this jointly with someone? Yes, with Wallace. what was its impact on scientific community? Scientific readers were already aware of arguments that species changed through processes that were subject to laws of nature.
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On the Origin of Species [SEP] Challenges to natural selection
There were serious scientific objections to the process of natural selection as the key mechanism of evolution, including Karl von Nägeli's insistence that a trivial characteristic with no adaptive advantage could not be developed by selection. Darwin conceded that these could be linked to adaptive characteristics. His estimate that the age of the Earth allowed gradual evolution was disputed by William Thomson (later awarded the title Lord Kelvin), who calculated that it had cooled in less than 100 million years. Darwin accepted blending inheritance, but Fleeming Jenkin calculated that as it mixed traits, natural selection could not accumulate useful traits.