1. Explain why any one species cannot live everywhere.
Any species cannot live everywhere because this would effect the natural balance. Also one species cannot adapt to all the different environments of our planet. For example a marine creature can only live underwater and cannot live on ground.
2. Explain how the activities of some species can lead to: a) an increase b) a decrease in the population size of another species.
Some species act as population controllers of other species. There must be a 'balance' between the two and this is important to a healthy landscape. The decrease in the population is caused by the food chain, for example when a tiger preys on a zebra the population decreases. The increase of the population of a species is caused by the predator when it stops feeding on a species lower than the predator in the food chain. So when the predator stops or reduces the amount of feeding on a species, the population of the species would start to increase.
3. It is seldom possible to count all the individuals in a given space. Explain one method by which biologists can study population densities without obtaining such data.
Scientist barely ever count the amount of individuals in a certain area because it would take too much time. Instead of actually counting the number of individuals in an area they would compare it with other areas where they know the population of individuals. In this way they can roughly estimate the number of individuals in a certain area.
4. What might happen to a rabbit population in an area where there are no predators? If there were a few rabbits in an area with no predators they would over-populate and cause serious damage to the ground. Since they are fast...