NARAYANKAR NOTES

7.1 Plant Growth 1. Growth Growth is a characteristic feature of living organisms. It has two aspects: quantitative and qualitative. A. Quantitative Aspect Refers to an increase in length, breadth, size, volume, body mass, dry weight and number of cells. It is a quantitative change (change that can be measured). Growth is the final end product of successful metabolism (chemical reactions occurring inside living organisms). B. Qualitative Aspect Refers to changes in the nature of growth. Development: An ordered change or progress in an organism. Differentiation: A process through which cells become specialised, leading to a higher and more complex state. 2. Definition of Growth Growth is a permanent, irreversible increase in the bulk of an organism, accompanied by a change in form. Permanent: Lasting. Irreversible: Cannot be reversed. Bulk: Overall size or mass of an organism. 3. Growth in Plants In multicellular vascular plants, growth is indeterminate (continues throughout life). Grow...

4.1 Criteria Used for Animal Classification Animals are classified based on the following criteria: 4.2 Animal Body Plan A. Cell Aggregate Plan Cells do not form true tissues or organs. Cells show minimal differentiation and division of labour. Found in Phylum Porifera (sponges). Cells are loosely organised and perform different functions without forming true tissues. B. Blind Sac Body Plan Body is sac-like with a single opening. Digestion occurs inside the sac-like cavity. Ingestion and egestion occur through the same opening. Example: Phylum Cnidaria. C. Tube-within-Tube Body Plan The digestive system forms a tube within the body. Mouth and anus are separate openings at opposite ends of the digestive tract. Food enters through the mouth and undigested waste exits through the anus. Found in Phylum Annelida onwards. 4.3 Animal Classification 1. Phylum Porifera Meaning: Pori = pores; feron = bearing Examples: Scypha, Euspongia (bath sponge), Euplectel...