I guess today wasn't really a real lesson since it was the first lesson.I think it was more about the teacher introducing and explaining to us about what Elective Geography actually is.And also what there is to learn about it.However,I have typed out what I have learnt about the chapter we've started learning.
Natural Vegetation refers to plants that grow naturally in a place with little or no human inference.An ecosystem is a community of living organisms.Thus,natural vegetation plays an important role.It ensures that in an ecosystem,animals and people do not starve to death as trees and other plants provide food and shelter for them (for example,forest ecosystem).
There are 3 kinds of Natural Vegetation (biomes):
-Forests
-Grasslands
-Deserts
For Tropical forests,there are 5 kinds of layers: the Emergent layer,Canopy layer,Understorey layer,Shrub layer and Undergrowth layer.There are epiphytes,lianas and parasitic plants in there.Tropical rainforests are extremely dense.The trees are evergreen (the leaves remain green all year)and have large and broad,waxy leaves with drip tips as this helps to protect the plants from disease due to high temperates and rainfall promote rapid growth of bacteria.The barks of trees are thin and smooth and the roots are shallow and spread widely (buttress roots).
For Tropical Monsoon forests,there are 3 main kinds of layers: the Canopy layer,Understorey layer and Undergrowth.Plant growth is abundant in the tropical monsoon forest but it is less dense than the tropical rainforest.The leaves there are deciduous.They are shed to minimise water loss through transpiration.The barks of the trees are thick and coarse so that the trees can be protected against the heat and dryness during the try season.The branches are found around the middle.
For Mangrove forests,rhere are 3 different horizontal zones of mangrove species: the Coastal zone,Middle zone and Inland zone.A Mangrove forest is dense and luxuriant due to high temperatures and rainfall.The undergrowth is sparse.It is also evergreen and due to high rainfall throughout the year,the leaves are broad and have drip tips.The surface of the leaves are thich and leathery to reduce water loss through transpiration.Some species (eg. Avicennia) are salt excreters as this is their way of adapting specially to grow in salt water by regulating the amount of salt in the tree.
Tropical Rainforests 
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Tropical Monsoon Rainforests
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Mangrove Forests
(Please click the pictures to see bigger ones)
