Which terrestrial and marine environments characteristically contain few species? Explain why each of these environments has a low diversity.

Terrestrial environments that characteristically contain few species are deserts and polar regions (such as the tundra). Marine environments with low species diversity include deep ocean floors and polar aquatic regions.

Deserts are characterized by extremely low rainfall and harsh climate conditions, making them uninhabitable for many species. The scarcity of water means that plants have to adapt to survive in these conditions, leading to a lower diversity of plant life. Additionally, the reduced plant diversity results in a lower diversity of herbivorous and predatory animal species that depend on plants as a food source.

In polar terrestrial regions (like the tundra), cold temperatures and freezing conditions make it difficult for most plant and animal species to survive. The short growing season and permanently frozen soil layers (permafrost) limit the types of plant life able to grow and thrive, thereby reducing overall species diversity. As with deserts, fewer plant species directly affect the diversity of herbivores and predators, resulting in a low range of animal species as well.

The deep ocean floor is typically characterized by high pressure, low temperature, and complete darkness. The absence of sunlight in these depths severely restricts the process of photosynthesis. This results in a limited availability of primary producers, such as algae and plants, to support a food chain. With low primary production, the support for higher trophic levels is also limited, resulting in a low species diversity in these extreme environments.

Polar aquatic regions have many similarities with their terrestrial counterparts in terms of the extreme cold and inhospitable conditions. As a result, the species diversity is generally low in these regions. In polar aquatic habitats, the low temperature and the presence of sea ice for much of the year create a challenging environment for life to thrive, limiting the variety of organisms that can survive and reproduce in these conditions. In summary, environments such as deserts, polar regions (terrestrial and aquatic), and deep ocean floors are characterized by low species diversity due to their challenging living conditions such as lack of water, low temperatures, poor availability of nutrients, and darkness. These factors create barriers for the survival and proliferation of a wide variety of plant and animal species, thus limiting species diversity in these habitats.