Question

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

Short answer

The terrestrial environment with low species diversity is the Arctic Tundra, characterized by extreme cold, short growing season, and low nutrient availability due to permafrost. These harsh conditions make it difficult for most plant and animal species to survive. The marine environment with low species diversity is the Deep Sea, found at depths below 200 meters. Factors contributing to low diversity in the deep sea include lack of sunlight, high pressure, and low nutrient availability. Challenging environmental conditions in both the arctic tundra and the deep sea result in low species diversity in these environments.

Step-by-step solution

Terrestrial Environment: Arctic Tundra

Arctic tundra is an extremely cold, windy, and low precipitation environment characterized by permafrost, a permanently frozen subsoil. The harsh conditions make it difficult for most plant and animal species to survive, which leads to low species diversity in this environment.

Explanation for Low Diversity in Arctic Tundra

There are several factors contributing to the low diversity in the arctic tundra, including: 1. Extreme cold: The low temperatures in the arctic tundra limit the range of plant and animal species that can survive in this harsh environment. 2. Short growing season: The short growing season means plants have a limited amount of time to grow, reproduce, and store energy, making it difficult for many species to thrive. 3. Low nutrient availability: The presence of permafrost and the slow rate of decomposition in cold environments result in low nutrient availability for plants.

Marine Environment: Deep Sea

The deep sea, which is found at depths below 200 meters, is known to contain few species. It is a dark, cold, and high-pressure environment where the availability of sunlight and nutrients is extremely limited. The unique conditions of the deep sea make it challenging for most marine species to survive, leading to low species diversity.

Explanation for Low Diversity in the Deep Sea

Factors that contribute to the low diversity in the deep sea include: 1. Lack of sunlight: Sunlight is crucial for photosynthesis, which is the base of the food chain in marine ecosystems. The absence of sunlight in the deep sea limits the primary productivity and, subsequently, the number of species that can survive in this environment. 2. High pressure: The weight of the overlying water column creates high pressure in the deep sea, which affects the physiology and survival of marine organisms. 3. Low nutrient availability: Nutrients in the deep sea are limited, mainly due to the absence of primary production and the reliance on the "marine snow" – organic matter falling from the surface – as the primary source of nutrients. Overall, it is the challenging environmental conditions in both the arctic tundra and the deep sea that result in low species diversity in these environments.

Key concepts

Arctic Tundra

The Arctic tundra is a unique terrestrial environment, defined by its extreme conditions. Located near the North Pole, it experiences severely cold temperatures and long winters, which create a challenging habitat. One of its key characteristics is the presence of permafrost, which is soil that remains frozen all year round.

Permafrost acts as a barrier that prevents deep root growth, limiting the types of vegetation that can thrive. In addition to extreme cold, the Arctic tundra has a very short growing season, typically lasting only a few weeks to a couple of months. This limited period hinders plant growth and reproduction.

• Low temperatures and harsh winds discourage many species from adapting to such environments.
• The short summer means less time for photosynthesis and nutrient storage by plants.

Nutrient availability is critical, yet it's very limited in the tundra. The slow rate of decomposition due to low temperatures makes recycling of nutrients slow, leading to nutrient-poor soil. Consequently, only specialized and adapted species can survive here, contributing to the low species diversity.

Deep Sea Environments

Deep sea environments are often defined as any part of the ocean below 200 meters from the surface. These zones are known for their extreme conditions, marked by complete darkness, high pressure, and frigid temperatures. Such factors combine to create an environment where few species manage to flourish.

The absence of sunlight is a major limiting factor. Without light, photosynthesis cannot occur, greatly reducing primary productivity and the availability of food resources. As a result, deep sea ecosystems largely depend on organic material, known as "marine snow," that drifts from more productive oceanic layers above.

• High pressure affects the physiological functions of species.
• Low temperatures result in slower metabolic rates.
• Nutrient scarcity limits the variety of surviving organisms.

Specialized adaptations are necessary for survival in these harsh conditions, resulting in distinct fauna capable of coping with limited resources and extreme pressures.

Environmental Conditions

Environmental conditions greatly influence the types of species that can survive in an ecosystem. In both the Arctic tundra and deep sea environments, such conditions are harsh and unforgiving. The extreme temperatures, whether due to extreme cold or high pressure, play a vital role in shaping life.

• In the Arctic tundra, continual cold restricts species that can withstand freezing temperatures.
• In deep sea environments, the lack of light restricts photosynthesis-based food chains.

Each environment requires organisms to have special adaptations to survive. These adaptations could be physical, such as antifreeze proteins in Arctic fish, or behavioral, such as scavenging strategies in deep-sea creatures. Essentially, the challenging environmental conditions are central to understanding why species diversity is low in these locations.

Marine Ecosystems

Marine ecosystems vary widely in their characteristics and biodiversity. While coastal waters teem with life due to abundant sunlight and nutrients, deeper marine ecosystems are less forgiving.

Marine ecosystems like coral reefs have high species diversity because of favorable conditions, such as warm temperatures and sunlight, which facilitate a complex food web. In contrast, deep sea ecosystems support fewer species because of their challenging conditions.

• Coral reefs support diverse life due to ample light and nutrients.
• Deep sea ecosystems are nutrient-poor, affecting biodiversity.

This contrast highlights the impact of environmental factors—light, pressure, temperature, and nutrient availability—on marine biodiversity. Understanding this variance is crucial in studying marine ecosystems and their conservation.