Well it depends on what you're talking about. In ecology, a population is a group of individual organisms that interbreed in a particular geographical area. When there is gene flow between populations (i.e. through dispersal), the collection of individual populations is called a metapopulation (again in a particular geographical area). Abundance is simply the number of individuals IN a population/metapopulation.
Well, I guess it depends on the animal. For, say, small reptiles, you'd do random quadrats of an area, and produce a distribution map based on what you found in the quadrats. IDK what a "profile sketch" is.