Alfred Wegener’s theory of continental drift, proposed in the early 20th century, was a pioneering idea suggesting that continents were once part of a supercontinent called Pangaea and have since drifted apart. His theory was supported by various lines of evidence, particularly botanical and fossil findings, but it also faced significant criticism and limitations.
Fossil Distribution:
Polar Wandering:
Rocks of the Same Age:
Tillite Deposits:
Placer Deposits:
Timing of Drift:
Role of Oceans:
Reliance on General Assumptions:
Inadequate Mechanism:
While Wegener’s theory of continental drift was initially met with skepticism, it laid the groundwork for the development of more advanced theories such as plate tectonics. Plate tectonics provided a more comprehensive explanation for the movement of continents, incorporating the roles of oceanic and continental plates, seafloor spreading, and the mechanisms driving these processes. Despite its limitations, Wegener’s theory was a significant milestone in the understanding of Earth's geological history and the dynamic nature of its surface.
Optimal Zone:
Critical Minimum Zone:
Critical Maximum Zone:
1. Distribution in Space
2. Distribution in Time
Mollusca: The green mussel (Mytilus)
Arthropoda: Brine shrimp (Artemia salina), cockroach (Periplaneta)
Birds: Hawks, cuckoo
Mammals: Rats, bats, etc.
Eurytopic animals thrive over a large range, e.g., cockroach.
Stenotopic animals are restricted to a definite area, e.g., Peripatus in arctic areas.
Sweeps Take Bridges:
Filter Bridges:
Corridor Bridges:
In conclusion, understanding animal distribution involves recognizing spatial and temporal patterns, each influenced by geographical, environmental, and historical factors. The various distribution types and patterns offer insights into the diverse ways animals adapt to their surroundings and evolve over time.
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1. What is the Continental Drift Theory proposed by Alfred Wegener? |
2. What evidence supports the Continental Drift Theory? |
3. What are some criticisms of the Continental Drift Theory? |
4. How does botanical evidence support Continental Drift? |
5. What are some drawbacks of the Continental Drift Theory? |
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