bioticfactors. Living things include bacteria, algae, fungi, plants (Figure18.1) and ani-
mals, includinginvertebrates(Figure18.2), animals without backbones andvertebrates
(Figure18.3), animals with backbones.
Figure 18.1: The horsetailEquisetumis a primitive plant. ( 16 )Physical and chemical features areabioticfactors. Abiotic factors include resources living
organisms need like light, oxygen, water, carbon dioxide, good soil, and nitrogen, phospho-
rous and other nutrients. Abiotic factors also include environmental features that are not
materials or living things, like living space and the right temperature range.
Organisms must make a living, just like a lawyer or a ballet dancer. This means that each
individual organism must acquire enough food energy to live and hopefully reproduce. A
species’ way of making a living is called itsniche. An example of a niche is making a living
as a top carnivore, an animal that eats other animals, but is not eaten by any other animals.
This niche can be filled by a lion in a savanna, a wolf in the tundra, or a tuna in the oceans.