2.1: Species and Populations

In this section we will look at the concepts of  the species, populations and habitats. We will investigate the relationships between biotic and abiotic factor in the ecosystem as well as build an understanding of the niche and how that is defined by the resources available to each species. We will also examine the interactions involved in competition – predation, herbivory, parasitism, mutualism and disease.

From that foundation we will look at how these interactions describe the development of populations and the limits to population growth as carrying capacity.

Use the following slide share to start building an understanding of this topic before preceding to each of the sub topics to gain a greater depth.

Before you move to the start of reviewing this topic, there is a short quiz below that will help you gain an understanding of what you may or may not already know.

1. When a population exceeds the carrying capacity of the environment that supports it, which process often restores the equilibrium?


2. The main difference between S and J population growth curves is that


3. parasite, infecting the organs of its host, spreads from host to host more rapidly when the host population, in a given area, is higher. Assuming infection with the parasite reduces fertility, this would be an example of control of the host population through


4. Which is most likely to be an internal density dependent factor regulating a population of herbivores?


5. An ecological niche is


6. In an area of grassland, a sudden severe frost reduces the population of butterflies. Of what is this frost an example?


7. Which interaction would benefit both organisms in a relationship?


Question 1 of 7