List of Biology exceptions and irregularities

  1. Egg laying mammal: Mammals nurture their young ones with their specialized glands that produce milk. But, Platypus is one of the exception that lays eggs. They belong to the order monotremata and there are 5 living sppecies that are all indegenious to Australia and New Guinea.
  2. Fish with lungs: Fish normally breathe by taking in water by mouth, passing them through thin lines of cells and expelling water out through gills (openings on side of the body). But, some fish (Lungfish), do have lungs that they use to breathe, like amphibians, that lets them breathe out of water!
  1. Exon/intron gene structure: is the property of eukaryotes, however yeasts, which are unicellular eukaryotes, do not have any introns in them (mostly mono-exonic genes). Similarly, several species of cynobacteria, γ subdivision of purple bacteria (proteobacteria) have been identified, that do have self splicing introns in them.
  2. Star codons: AUG is considered as universal start codon, which codes for the first amino-acid (methionine) of the translated product. However, the universal start codon is not universal at all! It has been shown that other variations of this codon (NUG) is more frequently used in various organisms as a start codon.


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