Read the following passage and answer the items that follow. Your answers to these items should be based on the passage only.
Invasions of exotic species into new geographic areas sometimes occur naturally and without human agency. However, human actions have increased this trickle to a flood. Human caused introductions may occur either accidentally as a consequence of human transport, or intentionally but illegally to serve some private purpose or legitimately to procure some hoped-for public benefit by bringing a pest under control, producing new agricultural products new agricultural products or providing novel recreational opportunities. Many introduced species are assimilated into communities without much obvious effect. However, some have been responsible for dramatic changes to native species and natural communities. For example, the accidental introduction of the brown tree snake Boigairregularis into Guam, an island in the Pacific, has through nest predation reduced 10 endemic forest bird species to the point of extinction.
One of the major reasons for the world’s great biodiversity is the occurrence of centers of endemism so that similar habitats in different parts of the world are occupied by different groups of species that happen to have evolved there. If every species naturally had access to everywhere on the globe, we might expect a relatively small number of successful species to become dominant in each biome. The extent to which this homogenization can happen naturally is restricted by the limited powers of dispersal. By virtue of the transport opportunities offered by humans, these barriers have been breached by an ever-increasing number of exotic species. The effects of introductions have been to convert a hugely diverse range of local community compositions into something much more homogeneous. It would be wrong, however, to conclude that introducing species to a region will inevitably cause a decline in species richness there. For example, there are numerous species of plants, invertebrates and vertebrates found in continental Europe but absent from the British Isles (many because they have so far failed to recolonize after the last glaciations). Their introduction would be likely to significant detrimental effect noted above arises where aggressive species provide a novel challenge to endemic biotas ill-equipped to deal with them.
What the impact of invasion of exotic species on an ecosystem?
Both statement 1 and statement 2 accurately describe impacts of exotic species invasion on an ecosystem, as derived from the passage.
Options A (1 only), B (2 only), and D (Neither 1 nor 2) are incorrect because the passage supports both statements as valid impacts of exotic species invasion. The text clearly illustrates both the extinction of endemic species and the homogenization of community compositions due to such invasions.