Class X - Notes

Home Page Chapter 13 – Our Environment Introduction The environment includes everything around us—living (biotic) and non-living (abiotic) components. Humans depend on the environment for survival but also impact it significantly. This chapter studies ecosystems, energy flow, waste generation, and the impact of human activities. 1. Ecosystem, Types and Its Components Ecosystem : An ecosystem is a functional unit of nature where living organisms interact with each other and the physical environment. Types : a) Natural Ecosystem : An ecosystem which exits in nature on its own without any human interference is called natural ecosystem. E.g – desert, grassland, forest, ponds, lakes, estuaries, rivers and oceans. b) Artificial Ecosystem : An ecosystem which is created and maintained by humans is called artificial ecosystem. E.g : Aquariums, botanical gardens, parks, field crops, etc are artificial ecosystem. Components of an Ecosystem 1. Biotic Components (Living...

 Home Page Chapter 10: The Human Eye and the Colourful World 1. The Human Eye The human eye is a natural optical device that helps us to see objects around us.   Draw Human Eye from figure 11.1 Ncert Book Structure of Human Eye: Eye Ball : Its spherical in shape with diameter 2.3 cm. Cornea: Transparent front part where light enters. It bends light towards the lens. Aqueous Humour: A transparent liquid filled in the space between cornea and eye lens. Iris: It is the dark muscular diaphragm between the cornea and the lens. Pupil: It is the small hole between the iris through which light enters. Lens: Convex, transparent, flexible structure located behind the iris. Ciliary Muscles: Muscles holding the lens in position. Vitreous Humour : A liquid filled in the space between the eye lens and retina. Retina: Screen where the image is formed. It contains light-sensitive cells (rods and cones)...