PART V: STRUGGLE AND COMPETITION

Chapter 19: Escape through Diversity

1. Nature's most severe competition takes place among members of the same species, among individuals that need precisely the same resources to survive.

2. Central to the biologist's view of competition is the concept of "niche." Every species must find a way to make a living in the ecosystem.

3. All organisms need two basic resources, living space and food. Only when both are abundant can organisms avoid competition. In cases where individuals share exactly the same niche, life becomes a zero-sum game.

4. Competition pervades nature, but only occasionally does it take the form of direct competition. From the evolutionary perspective, avoiding conflict makes sense because competition imposes costs. Consequently, individuals able to avoid conflicts with their species-mates tend to reproduce more successfully.

5. For the last 25 years, Jared Diamond has researched the lifeways of New Guinea's 513 bird species. He has found several bird species, all descended from a common ancestor, that now live in strictly separate altitude zones.

6. When two species did not subdivide the available living space, Diamond found that they feed at different times of the day.

7. In other cases, birds limit competition costs by specializing in different foods. Observing the adage "the jack of all trades is the master of none," each of the eight species of pigeons is specialized for a particular size of fruit.

8. Because the trees yield only so many fruits of each size, competition within each species is intense. But to a lesser degree, competition also occurs between populations.

9. Throughout nature, diversity provides a partial escape from direct competition. Members of the same species rely on territories and subtle differences in behavior to escape struggles for survival.

10. Nature's patterns would be easier to decipher if diversity were the exception and not the rule. But life did not evolve so that it might be comprehended more easily by its most intelligent product. The earth's 30 million species provide living testimony to competition's power to create diversity.