Lauren and Alessandro


How do we define a species?

Initial Model:



In order to determine a species, a large number of biotic creatures must share a common ancestor, must have similar characteristics, and must be their own division of animals because they have a distinguishing trait.


  • Monarch butterflies and viceroy butterflies are very similar in physical appearance, however, they are not able to reproduce together.
  • Monarch-Butterfly-Pismo-Beach.jpg
    Monarch Butterfly
Viceroy Butterfly
  • Biological Species Concept states that two organisms must produce viable offspring to be considered a species.
  • Morphological Species Concept states that 2 organisms must be similar to be considered a species.
  • Two creatures found in the same genus could be species.

Final Model:



Our initial claim was correct because in order to for a group of creatures to be their own species, they must be very similar to each other, must be different from other animals and must belong to the same class, however a key piece of information was left out which was that the creatures must be able to breed with each other and produce viable offspring. This clause is especially important because in the instance of the viceroy and monarch butterflies, it would be hard to tell them apart if not for their breeding habits. The monarch and the viceroy look almost identical to each other (through the mimicry of the viceroy) and are difficult to tell apart except for the fact that they cannot interbreed, thus making them two separate species.


Badgley, Catherine. (2002) The Process of Speciation. From accessed on
November 29, 2011.

McGowan, Alistair. (2008) Species concepts. From accessed on November 29, 2011

Harris, Louis. (1998) Species Examples. From accessed on November 29, 2011