The Baha'i Faith teaches that religious truths, just as scientific concepts, are relative and our understanding is evolved and perfected by each revelation. The essence of religion and science are in harmony and it is only our perception of one or the other that may seem as a conflict. As the primary purpose of both is the pursuit of perfection and knowledge, nothing scientific or religious should be perceived or portrayed as absolute and undeniable truth. One scientific example that comes to mind is "the ether" the existence of which seemed certain until recently. Therefore, progress and evolution are not possible if we perceive our current understanding of "evolution" to be absolute and perfect.
Generally speaking, it can be said that "knowledge" is transferred in four ways. Traditions, values passed on to future generations, intellection or science the source of new discoveries and progress, inspiration manifested in the form of great discoveries and inventions, or beautiful writings and poetry, and revelation; and arguably the first three are various manifestations of the last which is the true source of knowledge in this world.
It is my humble understanding of the Baha'i writings that man has always existed and has no beginning and no end, that it has been created in the likeness and image of God and the dawning place of all His perfections, even if on distant planets or evolved from other forms, but always as its own species and not a random selective evolution of another. Since our perceptions of revelation, the source of guidance for every age may vary on the issue, the best approach may always be to refer to the writings and fortunately the writings of 'Abdul'-Bahá discuss this topic quite well:
"MAN AND EVOLUTION
Certain European philosophers agree that the species grows and develops, and that even change and alteration are also possible. One of the proofs that they give for this theory is that through the attentive study and verification of the science of geology it has become clear that the existence of the vegetable preceded that of the animal, and that of the animal preceded that of man. They admit that both the vegetable and the animal species have changed, for in some of the strata of the earth they have discovered plants which existed in the past and are now extinct; they have progressed, grown in strength, their form and appearance have changed, and so the species have altered. In the same way, in the strata of the earth there are some species of animals which have changed and are transformed. One of these animals is the serpent. There are indications that the serpent once had feet; but through the lapse of time those members have disappeared. In the same way, in the vertebral column of man there is an indication which amounts to a proof that, like other animals, he once had a tail. At one time that member was useful, but when man developed it was no longer of use, and therefore it gradually disappeared. As the serpent took refuge under the ground, and became a creeping animal, it was no longer in need of feet, so they disappeared; but their traces survive. The principal argument is this: that the existence of traces of members proves that they once existed; and as now they are no longer of service, they have gradually disappeared. Therefore while the perfect and necessary members have remained, those which are unnecessary have gradually disappeared by the modification of the species, but the traces of them continue.
The first answer to this argument is the fact that the animal having preceded man is not a proof of the evolution, change, and alteration of the species, nor that man was raised from the animal world to the human world. For while the individual appearance of these different beings is certain, it is possible that man came into existence after the animal. So when we examine the vegetable kingdom, we see that the fruits of the different trees do not arrive at maturity at one time; on the contrary, some come first and others afterwards. This priority does not prove that the later fruit of one tree was produced from the earlier fruit of another tree.
Secondly, these slight signs and traces of members have perhaps a great reason of which the mind is not yet cognizant. How many things exist of which we do not yet know the reason! So the science of physiology, that is to say the knowledge of the composition of the members, records that the reason and cause of the difference in the colors of animals, and of the hair of men, of the redness of the lips, and of the variety of the colors of birds, is still unknown; it is secret and hidden. But it is known that the pupil of the eye is black, so as to attract the rays of the sun; for if it were another color, that is, uniformly white, it would not attract the rays of the sun. Therefore, as the reason of the things we have mentioned is unknown, it is possible that the reason and the wisdom of these traces of members, whether they be in the animal or man, are equally unknown. Certainly there is a reason, even though it is not known.
Thirdly, let us suppose that there was a time when some animals, or even man, possessed some members which have now disappeared; this is not a sufficient proof of the change and evolution of the species. For man, from the beginning of the embryonic period till he reaches the degree of maturity, goes through different forms and appearances. His aspect, his form, his appearance, and color change; he passes from one form to another, and from one appearance to another. Nevertheless, from the beginning of the embryonic period he is of the species of man; that is to say, an embryo of a man, and not of an animal; but this is not at first apparent, but later it becomes visible and evident. For example, let us suppose that man once resembled the animal, and that now he has progressed and changed; supposing this to be true, it is still not a proof of the change of species; no, as before mentioned, it is merely like the change and alteration of the embryo of man until it reaches the degree of reason and perfection. We will state it more clearly: let us suppose that there was a time when man walked on his hands and feet, or had a tail; this change and alteration is like that of the fetus in the womb of the mother; although it changes in all ways, and grows and develops until it reaches the perfect form, from the beginning it is a special species. We also see in the vegetable kingdom that the original species of the genus do not change and alter, but the form, color, and bulk will change and alter, or even progress.
To recapitulate: as man in the womb of the mother passes from form to form, from shape to shape, changes and develops, and is still the human species from the beginning of the embryonic period -- in the same way man, from the beginning of his existence in the matrix of the world, is also a distinct species, that is, man, and has gradually evolved from one form to another. Therefore this change of appearance, this evolution of members, this development and growth, even though we admit the reality of growth and progress, does not prevent the species from being original. Man from the beginning was in this perfect form and composition, and possessed capacity and aptitude for acquiring material and spiritual perfections, and was the manifestation of these words, "We will make man in Our image and likeness." He has only become more pleasing, more beautiful, and more graceful. Civilization has brought him out of his wild state, just as the wild fruits which are cultivated by a gardener became finer, sweeter, and acquire more freshness and delicacy.
The gardeners of the world of humanity are the Prophets of God."
(Abdul-Bahá, Baha'i World Faith - Abdul-Bahá Section, p. 307)
