Human earth shapers/ETHS101/Ecology and Evolution/Niches

=Overview= In this Learning Pathway, we start learning how species respond to environmental change by exploring some basic ideas about ecology and evolution. We will consider these ideas:


 * 1) Niches. This reflects the idea that different species are adapted to different kinds of environments - we say that species have different niches. This is extremely important because it means (a) that species can only live in certain places, and (b) when the environment changes species may not be able to live where they do - for instance when the climate changes, or when forests have been cleared.
 * 2) Then we explore what happens to species when the environment changes. This is called '"the four ways"' because every response can be placed into four categories (tolerance, range shift, evolution or extinction). For every species on earth, the balance of the four ways describes the species' past and determines its future, especially if one realises that humans are evolutionary agents.
 * 3) Then we consider one of these four ways in a little more detail. This is evolution. This is because evolution explains how we have come to have so many species, and what those species are like.

Ecological Niches

 * Niches: Are the range of environmental conditions in which a species can exist.

We live in a period of dramatic climate change and other environmental change. What will this do to species? To understand how we can (or cannot) predict how species will respond, we need a little bit of theory to build our science around.

How the living organisms of the world will respond to environmental change pivots on the idea of the ecological niche. We all know that different parts of the world have different climates and landscapes and that different species live in these different regions (think polar bears in the Arctic and jaguars in the jungles of South America). These different species live in these different environments at least partly because they are adapted to their local environment. In that case, we then say that these different species have different niches. Niches are not places, they are the range of environmental conditions in which a species can exist.