Question

Ostriches are a large flightless African bird with solid bones and very powerful hindlegs for running and kicking. Rheas are from South America. Other than the fact that they are about half the size of an ostrich, their physical features are almost identical to ostriches. Which conclusion is NOT supported by the observations concerning ostriches and rheas?

A) Ostriches and rheas are probably close relatives, since their features are very similar.
B) Ostriches and rheas may have evolved from a common ancestor, since they have so many similar features.
C) The similarity of ostriches and rheas suggests that Africa and South America may have been joined at one time.
D) Ostriches and rheas started off as different species, but have evolved over time to become identical to each other.

Answer 1

D) Ostriches and rheas started off as different species, but have evolved over time to become identical to each other.

Answer 2

The correct answer is D) Ostriches and rheas started off as different species, but have evolved over time to become identical to each other.

Step-by-step explanation:

Genetical and phenotypical similarities occur in the case different organisms are related, this implies if two species of birds like rheas and ostriches share many visible traits (phenotype), it is likely these are related genetically and therefore these are the result of evolution from a common ancestor. This occurs because according to the evolution theory, species we know today are the result of speciation in which one ancestral species leads to multiple species due to changes in the environment and other natural phenomena, this makes the species share similarities with related species.

However, this does not suggest "Ostriches and rheas started off as different species, but have evolved over time to become identical to each other" because as previously mentioned the most common path in evolution is for a species to derive into other similar species and common traits are an evidence of this, rather than for two separate species to become identical over time even if they are not related.