YES. Zoology is best optional if u have a background in zoology or life sciences.
Questions are straight forward: questions are directly picked from syllabus so donot have to think about the question in exam to find central idea or theme like in some optionals pub ad etc. just look at the question and bang!!! Evolution Zoology Class Notes For IAS AND IFOS Examination 2017-18
Figures and diagrams: this is the best part as it fetches more marks as compared to writing. also when u hv less time in exam(happens most of time) and more questions to answer drawing a diag take less time and fetches more marks as compared to writing in words.
Marks assured: In this along with other optionals like botany one can be assured of marks and predict it if all or most of the points with neat n labelled diag is drawn. Believe me some predictability is bliss in civil services exam coz most of gs in prelims and mains are unpredictable and even if u think u have written good answers in gs still u cannot be sure how much u will get!!!
However there are certain preconditions:
1. you should hv crammed the maximum portion u can and revised it a day before exam. keep all the diag in miniature format at one place and keep on revising it till the time of entering the hall.
2. some hate drawing diagrams during graduation, thats why they dont take zoology as an optional. even if u donot draw very good diags just draw an average diag but it should be neat and label it properly.
3. we hv to do 5 out of 8 questions so choose the question whch have maximum diags to fetch more marks.
4. Donot leave physiology questions as they all have diagrams and earn good marks. dev biology questions fetches less marks as they have less matter and diagrams are tough. and cover full syllabous here- Evolution Zoology Photo copay Class Notes For IAS AND IFOS Examination.
think zoology has great potential. U hv the matter with u – read revise n cram, go to exam and just write it down. No worries!!! GS questions are set in a such manner to bring everyone at the same level. Here writing practise matters(this could be a separate quora question).Therefore largely differences in marks can arise due to optionals. it can make u in or out or an IAS or group b officer.For zoo or life science graduate taking zoo as an optional is like a certificate from upsc titled “welcome to civil service” provided u fulfil the above conditions which is not very tough. Afterall we are studying zoo since class 11. So u can easily convert it into marks. Have that confidence. read more- EVOLUTION ZOOLOGY PRINTED CLASS NOTES FOR IAS AND IFOS EXAMINATION