Question

Which one of the following theories is supported by the distribution patterns of extinct flora such as \textit{Glossopteris across South America, Africa, and Australia, and extant marsupial mammals across South America and Australia?}

• A. Darwin’s theory of natural selection
• B. Wegener’s theory of continental drift
• C. Levins’ theory of metapopulations
• D. MacArthur and Wilson’s theory of island biogeography

Hint:

To explain biogeographical patterns:
1. Continental drift provides evidence for shared distributions of extinct and extant species across continents.
2. Consider historical connections between landmasses to understand fossil distributions.
3. Theories like natural selection and island biogeography address other evolutionary and ecological processes.

Answer 1

The Correct Option is B

Step 1: Understanding the context. The distribution of extinct flora like \textit{Glossopteris} and extant marsupial mammals across continents suggests a historical connection between these landmasses. This pattern cannot be explained by random dispersal but is consistent with the theory that these continents were once connected. Step 2: Wegener’s theory of continental drift. Wegener’s theory of continental drift posits that the continents were once joined together in a supercontinent called Pangaea, which later broke apart. This explains:
The presence of \textit{Glossopteris} fossils across South America, Africa, and Australia, as these regions were once part of Pangaea.
The distribution of marsupial mammals, which originated when these continents were connected and later evolved in isolation after the continents drifted apart. Step 3: Evaluate the options. Option (A): Incorrect. Darwin’s theory of natural selection explains evolution by adaptation to environments but does not directly address biogeographical distributions.
Option (B): Correct. Wegener’s theory of continental drift explains the shared distribution patterns of extinct flora and fauna across separated continents.
Option (C): Incorrect. Levins’ theory of metapopulations describes population dynamics in fragmented habitats and is not relevant to continental-scale patterns.
Option (D): Incorrect. MacArthur and Wilson’s theory of island biogeography deals with species diversity on islands, not continental-scale distributions.