This is the current Technology tree, it follows a very simple set of guidelines
1: You start with all Tier 0 techs, unless you choose otherwise
2: Each "Branch" or Field of technology is separate, they tier up separately
3: To reach the next tier in a branch/field you need 1 tech from the prior tier (Tier 1-> Tier 2 -> Tier 3)
4: You must meet all Prerequisites of a tech to research it
5: If spending tech points, each technology is worth 1 tech point
For further information on the handling of technological research, please see the corresponding mechanics page.