What is adaptive radiation? Describe its types.

(N/A) During his voyage,Darwin visited the Galapagos Islands. There,he observed an amazing diversity of creatures. He was particularly amazed by small black birds,which were later called Darwin's Finches.
He observed many varieties of finches on the same island. He realized that all the varieties had evolved on the island itself. From the original seed-eating features,many other forms with altered beaks evolved,enabling them to become insectivorous and vegetarian finches.
The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation.
Types of Adaptive Radiation:
$1$. Divergent Evolution: This occurs when species from a common ancestor evolve into different forms to adapt to different environments (e.g.,Darwin's Finches,Australian Marsupials).
$2$. Convergent Evolution: This occurs when different species,not closely related,evolve similar traits as a result of having to adapt to similar environments or ecological niches (e.g.,Australian Marsupials and Placental Mammals).