Superficial similarities in structures that have the same function can seem like they are evidence of a common ancestor, but they are not. An example of this is the convergent evolution of wings in insects as well as in birds. What are these types of structures called

Distinguishing between Similar Traits

Similar traits can be either homologous structures that share an embryonic origin or analogous structures that share a function.

LEARNING OBJECTIVES

Explain the difference between homologous and analogous structures

KEY TAKEAWAYSKey PointsOrganisms may be very closely related, even though they look quite different, due to a minor genetic change that caused a major morphological difference.Unrelated organisms may appear very similar because both organisms developed common adaptations that evolved within similar environmental conditions.To determine the phylogeny of an organism, scientists must determine whether a similarity is homologous or analogous.The advancement of DNA technology, the area of molecular systematics, describes the use of information on the molecular level, including DNA analysis.Key Termsanalogous: when similar similar physical features occur in organisms because of environmental constraints and not due to a close evolutionary relationshiphomologous: when similar physical features and genomes stem from developmental similarities that are based on evolutionphylogeny: the evolutionary history of an organismmolecular systematics: molecular phylogenetics is the analysis of hereditary molecular differences, mainly in DNA sequences, to gain information on an organism’s evolutionary relationships

the answer would be 3

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.