Zoological Realms

ZOOGEOGRAPHICAL REALMS

• Zoo-geographicalrealms, also known as biogeographic regions, are areas of the world characterized by distinct and unique patterns of flora and fauna.
• These realms are defined by geographical, climatic, and ecological factors, and they play a crucial role in understanding the distribution of life on Earth.
• They provide insights into the distribution of species, the influence of geological history, and the impact of environmental factors on the evolution of life forms.

1. Major Zoo-Geographical Realms:

• There are several major zoo-geographical realms recognized globally, each with its unique set of ecosystems and species. These include the Nearctic, Neotropical, Palearctic, Ethiopian, Oriental, and Australian realms, among others.

Nearctic

• Encompasses North America, excluding the high Arctic regions.
• Diverse ecosystems ranging from arctic tundras to deserts.
• Iconic species include the American bison and black bears.

Palaearctic

• Covers Europe, Asia (except for the Indian subcontinent), and North Africa.
• Features diverse landscapes, including the Siberian taiga and Mediterranean scrublands.
• Home to species such as the Siberian tiger and European brown bear.

Neotropical

• Encompasses Central and South America, along with the Caribbean.
• Features the Amazon rainforest, one of the most biodiverse regions on Earth.
• Iconic species include jaguars, toucans, and howler monkeys.

Oriental

• Covers South and Southeast Asia, including the Indian subcontinent.
• Home to the Bengal tiger, Asian elephant, and diverse bird species.
• Characterized by tropical rainforests and diverse landscapes.

Ethiopian

• Encompasses sub-Saharan Africa.
• Rich in diverse ecosystems, including savannas and rainforests.
• African elephants, lions, and numerous endemic species.
• Many unique species found only in this realm.

Australian

• Comprises Australia, New Guinea, and nearby islands.
• Known for its marsupial fauna, including kangaroos and koalas.
• Isolated evolution due to geographic isolation is a key feature.

2. Characteristics of Realms:

• Each realm has distinct climatic conditions, vegetation types, and wildlife species.
• For example, the Neotropical realm is known for its diverse rainforests, while the Australian realm is characterized by its unique marsupial fauna.

3. Distribution of Life Forms:

• The distribution of life forms within these realms is often shaped by geological history and the movement of continents.
• The concept of "vicariance" plays a significant role, where species are separated due to the splitting of landmasses.

4. Impact of Continental Drift:

• The theory of continental drift and plate tectonics has had a profound impact on the formation and separation of zoo-geographical realms.
• For example, the joining of South America and North America led to the interaction and competition of fauna from these two realms.

5. Survival of Unique Fauna:

• Some realms have unique and ancient species due to their isolation from other realms.
• For instance, Australia's isolation allowed the survival of marsupials, such as kangaroos and koalas, without competition from placental mammals.

6. Conservation Significance:

• Understanding zoo-geographical realms is essential for conservation efforts.
• Conserving species within these realms helps protect unique biodiversity and ecological systems.