Figure 18.2: Insects are among the many different types of invertebrates. ( 25 )Every species fills a niche, and niches are almost always filled in an ecosystem.
An organism’shabitatis where it lives. The important characteristics of a habitat include
climate,theavailabilityoffood,waterandotherresources,andotherfactors,suchasweather.
A habitat may be a hole in a cactus or the underside of a fern in a rainforest. It may be a
large area of savanna.
Roles in Ecosystems
There are many different types of ecosystems (Figure18.4). A few examples of some ecosys-
temsarearainforest, chaparral, tundra, anddesert. Thesewordsarethesamewordsusedfor
biomes. This is because climate conditions determine which ecosystems are found in which
location. A particular biome encompasses all of the ecosystems that have similar climate
and organisms.
Different organisms live in each different type of ecosystems. Lizards thrive in deserts, but
no reptiles can survive at all in polar ecosystems. Large animals generally do better in cold
climates than in hot climates. Despite this, every ecosystem has the same general roles
that living creatures fill. It’s just the organisms that fill those niches that are different.
For example, every ecosystem must have some organisms that produce food in the form of
chemical energy. These organisms are primarily algae in the oceans, plants on land, and
bacteria at deep sea hot springs.
The organisms that produce food are extremely important in every ecosystem. The most
fundamental distinction between types of organisms is whether they are able to produce
their own energy or not. Organisms that produce their own food are calledproducers.
In contrast, organisms that use the food energy that was created by producers are named