Are you implying that there were two bigfoots on the Ark?
...Bigfeet....Bigfootses....
No, you are inferring that all by yourself. I will, however, implicitly state that Noah only took 2 of the "dog kind" on the ark some 4,000 years ago, and from that pair we have the enormous variety we have today. Coyote, wolf, fox, terrier, danes, sheepdog, etc. All dog kind, and most can easily interbreed. Ask any 3 year old, and he will identify them as 'dog'. Thus, those bigfeetses you referred to may be merely a type of mountain ape, who knows? Who cares?
It is quite possible, IMHO, we will find a living dino one day. There are numerous examples of "living fossils" that have not noticibly changed from the fossils found in the rocks we dig up. There are several examples, such as Horseshoe Crabs, Okapi, Cockroaches, Nautilii, etc. Some of these exist in rock dated 400 million years old, yet they appear today, living, identical to there fossils. 400 million years, and no apparent mutation/evolution.
One fascinating example is the The Clacanth, which according to the fossil record, dates back some 410 million years to the Devonian period. This animal was used as a major evolutionary link between the fish and land dwellers, with speculation that it crawled on land and had primitive lungs. Some publications suggested it was the most significant proof of evolution. However, when one was first caught in 1938, speculation was obliterated by fact. It was also discovered that the fish was in evolutionary stasis, and had not changed from it's fossilized ancesors.
Of course, the fish is not millions of years old, nor is the earth. People believe whta they want to, accepting evidence that agrees with their beliefs, and dismissing evidence that does not. Humans cannot be truly impartial and objective, however, that must be our goal.
Does genetic variation occur? Yes, but within kinds. Does Natural Selection occur? Yes, but it reduces the diversity of the gene pool within that kind. Do animals evolve? You must come up with a viable, workable definition you are happy with. I have observed that teachers in school, the Science Channel, and devoted evolutions tend to use varying definition based on their intentions. Does Genetic Mutation occur? Yes, but it is almost always deleterious.
One must make up his or her own mind as to what theory best explains the evidence we have.