Describe various biogeographical evidences.
Describe various biogeographical evidences.
Biogeographical evidences suggests that the species restricted in widely separated region show similarity of ancestry.
Habitat isolation had probably restricted these organisms to a particular geography on the earth.
- This can be explained with the help of following processes.
$\Rightarrow \quad$ Adaptive Radiation : The process of evolution of different species starting from a point in a geographical area and finally radiating to other area of geography (habitats) is called adaptive radiation.
Example of adaption radiation are :
$(i)$ Darwin's Finches : Darwin observed an amazing diversity of creatures in Galapagos island.
There he saw the small black birds that amazed him the most later called as Darwin finches.
They represent one of the best examples of adaptive radiation.
He observed that there were many varieties of
finches in the same island and all the varieties have evolved on the island itself from original seed eating finches.
He explained that after originating from a common ancestral seed eating stock the finches must have radiated to different geographical areas and under gene adaptive changes, especially in the type of beaks.
Therefore, due to the alterations in beaks gradually, some become insectivorous and some vegetarian.
Living in isolation for long the new kind of finches emerged that could function and survive in new habitat.
Similar Questions
Lemur and Spotted cuscus exhibit
Lemur and Spotted cuscus exhibit
Assertion : Darwin's finches show a variety of beaks suited for eating large seeds, flying insects and cactus seeds.
Reason : Ancestral seed-eating stock of Darwin's finches radiated out from South American mainland to different geographical areas of the Galapagos Islands, where they found competitor-free new habitats.
Assertion : Darwin's finches show a variety of beaks suited for eating large seeds, flying insects and cactus seeds.
Reason : Ancestral seed-eating stock of Darwin's finches radiated out from South American mainland to different geographical areas of the Galapagos Islands, where they found competitor-free new habitats.
- [AIIMS 2005]
The original birds were ________, from which the various Darwin’s finches arose.
The original birds were ________, from which the various Darwin’s finches arose.
$A$ : Spotted cuscus and marsupial mole are the examples of marsupial radiation.
$R$ : Both are found in Australian region.
$A$ : Spotted cuscus and marsupial mole are the examples of marsupial radiation.
$R$ : Both are found in Australian region.
The diversity in the type of beaks of finches adapted of different feeding habits on the Galapages islands as observed by Darwin, provides evidence for
The diversity in the type of beaks of finches adapted of different feeding habits on the Galapages islands as observed by Darwin, provides evidence for