1. A hot spot is basically a mantle plum. This is a place in the upper mantle that has much higher activity, higher temperature and pressure. This contributes to the mantle plum to be able to propel magma through the crust much more easily and manifest itself on the surface.
The hot spots create volcanic activity. Unlike the other places that have volcanic activities though, the hot spots are not related with the pate boundaries, but instead they can appear pretty much everywhere. It is more common that a hot spot is located in the interior of a plate, rather than on its boundary or near a boundary.
The hot spots mange to create the most massive volcanoes on Earth. They are very large, very high, but tend to not be steep. They are also volcanoes that are very active, often nonstop with decades or even more.
2. The hot spots manage to create volcanoes, often in the middle of the oceans. As the magma reaches the ocean floor, because it is in such a high amount, it manages to lift up much more oceanic crust that another type of volcano. As the oceanic crust is lifted upwards it comes out over the sea level. Because it occupies such a large area and such a large pieces of crust is alleviated, around the volcanic islands the ocean is actually very shallow.
Because the ocean is shallow around the hot spot volcanoes, it means that the sunlight can penetrate to the bottom or almost to the bottom of the ocean. This provides conditions for photosynthesis, sot he producers thrive. The producers are the basis for all ecosystems, so when they thrive, they attract consumers. Little by little, more and more consumers of different trophic levels are attracted, so more and more organisms start to live in those places. Apart from being a good place for the marine life to develop, the hot pots are also isolated when ti comes to the conditions they provide, so not just that there is a big biodiversity, but there is also a big diversification.
