Chapter 7 of Class 11 Biology, Structural Organisation in Animals, explains how animals are built—from their body tissues to organs and complete organ systems. It focuses on the levels of structural organisation, such as cells, tissues, and organs, in different animals. Important topics include animal tissues, morphology and anatomy of earthworm, cockroach, and frog.
I decided to write about this topic because students often find it confusing due to the large number of scientific terms and animal examples. But once you break it down into simpler sections, it becomes easier to understand. This chapter is very useful, especially for NEET aspirants and board students. It not only builds your knowledge of animal biology but also helps you understand how body systems work in different organisms. Practical questions are often based on diagrams and comparison tables from this chapter. That’s why I think it’s important to review this topic properly and have a downloadable NCERT PDF for regular revision.
What is Structural Organisation in Animals?
This chapter deals with how animals are structured at different levels and how cells come together to form tissues, organs, and finally, functional systems.
1. Animal Tissues
There are four basic types of tissues in animals:
- Epithelial Tissue – Covers body surface and organs (e.g., skin, lining of lungs)
- Connective Tissue – Supports and binds other tissues (e.g., blood, bone, cartilage)
- Muscular Tissue – Responsible for movement (e.g., skeletal, cardiac, smooth muscles)
- Nervous Tissue – Transmits signals and controls body functions (e.g., neurons)
2. Morphology of Earthworm
- Scientific Name: Pheretima posthuma
- Body is segmented
- No skeleton
- Has a closed circulatory system
- Both male and female reproductive organs (hermaphrodite)
3. Anatomy of Cockroach
- Scientific Name: Periplaneta americana
- Body divided into head, thorax, and abdomen
- Open circulatory system
- Separate sexes
- Tracheal system for respiration
4. Anatomy of Frog
- Scientific Name: Rana tigrina
- Moist skin, no scales
- Three-chambered heart
- Well-developed digestive, nervous, and reproductive systems
- Can live both on land and in water (amphibian)
Download PDF
Click here to download NCERT Class 11 Biology Chapter 7: Structural Organisation in Animals PDF
