Answer:
The reasons are explained below -
Explanation:
The large finches living on the Galapagos islands are different from the original source population from a nearby islands because of the following reasons -
- A natural selection favored only the large finches because they are more fit to the current environmental conditions.
- A genetic drift has been occurred in the two populations living on the nearby islands.
- Due to the separation of habitat on both the islands, the gene flow between the two islands is reduced.
All the above listed reasons are responsible for the difference in the finches found on the two islands.
 
        
             
        
        
        
This question is incomplete as the specific food chain is not provided. In general, a food chain will have a primary producer at the base of the chain. This is an organism that is able to utilise a form of energy to convert carbon dioxide in the atmosphere to a carbohydrate. For terrestrial food chains, these are typically plants, who by utilising the energy from the sun, are able to convert carbon dioxide to carbohydrates. The subsequent level in the food chain may be a primary consumer, typically herbivores, that consume plant matter. Subsequent links in the chain would typically be secondary consumers, who would be carnivores, omnivores or decomposers. Carnivores would typically be predators and would be at the apex of the food chain. Energy is lost from one link to the subsequent link in the food chain, through basic respiration and inefficient energy transfer from one link to another. This explains why more resources (land, water and air) are required to grow meat rather than plant matter. More of the sun's energy is available within the lower trophic levels in a food chain, before much of it is lost as energy moves up the food chain. An easy example to illustrate this is that much of the livestock raised in the USA is fed grain. If people rather ate the grain than the livestock, they could obtain all their required energy from a smaller amount of grain then would be needed to raise the meat they require. 
        
             
        
        
        
old useful paper that someone threw in the trash