1354 articles, 26 from 1998 alone. And this database found articles going all the way back to 1964. Just looking at the tiles I could see that the majority of the articles were research reports rather than editorials or review articles. And each article had links that would lead to more related articles. All totaled there could be as many 2000 articles or more that report on research into abiogenesis. Go check it out for yourself.
I've already dealt with the origin of sex in a different post, but there are dozens of research articles that deal with the origin of sex, as Glenn demonstrated.
Another misconception seems to be the way natural selection works. You almost seem to imply that natural selection creates species that are nearly perfectly adapted to their niches, such that even a minor reduction in that adaptation would either be eliminated by natural selection or cause the species to be eliminated. In point of fact, however, no species is nearly perfected adapted to its niche and most are not even well adapted, but they seem to survive well enough. In fact, it isn't a good idea, evolutionarily speaking, to become too well adapted to a particular niche, because if you do you will become extinct if that niche disappears for some reason, such as a change in the local environment. The most successful species are those that are not particularly well adapted to any one niche, but are flexible enough to exploit a number of niches. That way if any one niche disappears the species is not threatened with extinction.
In the case of the ancestors of the whales, the land dwelling mammals were probably exploiting the margins of the sea for food. Some began looking for food further out into the water and those were the ones natural selection began to modify. The first stage was probably something similar to a beaver, capable of moving around in the water but still pretty much designed to live and work on land. The next stage would probably be something similar to an otter, better adapted for living and working in water, but still adapted to life on land. The next stage after that would probably be something similar to a sea lion, now much better adapted for life in the sea, but still able to get around on land. When finally the proto-whale was able to mate and give birth in the water, it could finally advance to the dolphin stage (or the manatee stage in the case of the sirenae), and complete its adaptation to a completely aquatic existence.
The point is that each stage of whale evolution could have been adapted for an amphibious life of varying degrees, without compromising the species' adaptation to land or sea. There is no hindrance here to evolution.
Kevin L. O'Brien