Noah's Ark was too small...

Biblical scholars say that Noah's Ark measured about 300 cubits long, 50 cubits wide, and 30 cubits high. We can argue about which cubit to use but let's say Noah used the Roman cubit which is about 0.4445 m. That translates to an ark that measures 133.2 x 22.2 x 13.32 cubic meters. Athanasius Kircher, a German Jesuit who published Arca Noe in Tres Libros Digesta in 1675, said that the ark only has 150 kinds of birds, and roughly the same number of animals from the other vertebrate groups. This of course, did not include the fishes since they don't need a boat, or those that arose from spontaneous generation. During the 17th century then, the animals did fit snugly in Noah's Ark, not to mention his grinding mills.

By the end of the 17th century however, 500 species of birds, 150 species of quadrupeds, and roughly 10,000 species of invertebrates were recognized by science. By then, the ark is overcrowded. Now, we know that there about 5,498 species of mammals, 10,027 birds, 9,084 reptiles and 6,638 amphibians (Hoffman et al., 2010). You can tell me to exclude the marine mammals and the birds that spend most of their lives in open ocean but they still won't fit in Noah's Ark, however he calibrated his cubits. Especially if they came in pairs. Even if there were only a pair of rice-field rats in there.

Linnaeus solved this problem by saying that the Ark should be interpreted symbolically, rather than literally. He who has described, named, and catalogued about 6,000 species would know that biological reality does not reconcile with the Biblical story.

Taken literally, or metaphorically, with the way we're consuming our resources, perhaps given a few years, life on Earth will fit again in Noah's Ark.