The syllabus for Paper II of UPSC Zoology Optional subject is as follows:

Section A: Non-Chordata and Chordata
1. Non-Chordata
- Classification, organization, and characters of phylum Porifera, Coelenterata, Platyhelminthes, Aschelminthes, Annelida, and Arthropoda.
- Comparative study of parasitic helminths and arthropods.
- Physiological, ecological, and economic importance of non-chordates.

2. Chordata
- Classification and general characters of chordates.
- Comparative anatomy and functional anatomy of different systems of vertebrates.
- Comparative study of the different groups of vertebrates - Pisces, Amphibia, Reptilia, Aves, and Mammalia.
- Adaptive radiation, origin, and evolution of chordates.
- Physiology, ecology, and economic importance of chordates.

Section B: Cell Biology and Genetics
1. Cell Biology
- Structure and functions of the cell, including the cell cycle, cell division, and cell differentiation.
- Ultrastructure and functions of cellular organelles.
- Prokaryotic and eukaryotic cells - structure, reproduction, and functions.
- Cell membrane, cell adhesion, and cell-cell interaction.
- Cell signaling and signal transduction mechanisms.
- Cell cycle regulation and cell death.

2. Genetics
- Mendel's laws of inheritance and their extensions.
- Gene interactions, gene mapping, and recombination.
- Chromosomes - structure, organization, and behavior during mitosis and meiosis.
- Linkage and crossing over, sex determination, and sex-linked inheritance.
- Mutation - types, causes, and effects.
- Genetic disorders and their molecular basis.
- Genetics of microorganisms, plants, and animals.
- Molecular genetics techniques and applications.

Section C: Evolution, Systematics, and Ecology
1. Evolution
- Theories of evolution - Lamarckism, Darwinism, Neo-Darwinism.
- Natural selection, adaptation, and speciation.
- Origin and evolution of life on Earth.
- Human evolution and its significance.

2. Systematics
- Principles and methods of taxonomy and systematics.
- Classification and nomenclature of animals.
- Zoological parks, museums, and collections.

3. Ecology
- Ecological concepts and principles.
- Ecosystem structure and function.
- Population ecology and community ecology.
- Biodiversity - conservation and management.
- Ecological factors and their influence on animal distribution and behavior.

In conclusion, the syllabus for Paper II of UPSC Zoology Optional subject covers topics related to non-chordata and chordata, cell biology and genetics, and evolution, systematics, and ecology. Understanding the concepts and knowledge of these areas will help candidates in answering the questions effectively in the examination.