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13. organism and populations

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Chapter: Organisms and Populations 1. Introduction to Ecology Ecology: Study of interactions among organisms and between organisms and their physical (abiotic) environment. History of Ecology: Reiter: First used the term Ecology. E. Haeckel: Introduced and developed the concept of ecology. Levels of Organisation in the Living World Living organisms show different levels of organisation, from simple to complex: Macromolecules → Cells → Tissues → Organs → Organisms → Populations → Communities → Ecosystems → Biomes 2. Ecological Hierarchy Ecological hierarchy: Ecological grouping of organisms into levels of increasing biological complexity. There are four major sequential levels: 1. Organism An individual living being. Basic unit of ecological hierarchy. 2. Population Organisms of the same kind (same species) inhabiting a particular geographical area. 3. Community Several populations of different species living in a particular area. These populations interact with one another. 4. Biome A ...
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worm

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English Std 11th Appreciation

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2.1: Cherry Tree:  The title of the poem is “Cherry Tree”, written by the famous Indian author and poet Ruskin Bond. The central theme of the poem is the beauty of nature, patience, determination, survival and the joy of nurturing a tree. The poem describes how the poet plants a cherry seed and forgets about it. Despite facing several difficulties, such as goats eating its leaves, damage caused by a grass cutter and heavy monsoon rains, the small plant survives and gradually grows into a beautiful cherry tree. After eight years, the poet feels extremely happy and proud to see the tree bearing fruits and beautiful pink blossoms. The poet has used various figures of speech such as personification, alliteration and metaphor to make the poem more meaningful and attractive. The language of the poem is simple, descriptive, rhythmic and full of natural imagery. The poem is written in a narrative style and does not follow a fixed rhyme scheme. The poem gives us the valuable message that pa...
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Bio PYQs

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Chapter no 11:  Enhancement Of Food Production  
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Kapoor Sir's Notes

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घर जाने की उसने विदा ली। सबसे ‘टाटा-टाटा, बाय-बाय’ कर ली। अब वह उड़ने को हुई, बेचारी उलझकर रह गई। “अरे! मैं फँस गई!” वह चिल्लाई। नीलू ने उसकी पुकार सुनी। दूसरी चिड़ियों ने भी बात सुनी। बहेलिया ठगा-सा रह गया। सोच रहा था, ‘पंछियों ने यह किया?’ क्या करता वह बेचारा? एकता के आगे था हारा। चिड़े-चिड़ियाँ तनिक न सकुचे। सीधे दादी माँ के घर पहुँचे। चिंतित दादी बैठी मुँह लटकाए। बुरे विचार मन में आए। चिंकी की आँखों में आँसू थे। उदास हो रहे चुसकू-मुसकू थे। दादी माँ का चरखा शांत। सबका मन हो रहा क्लांत।
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7. plant growth and minerals Nutrition

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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...
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Kingdom Animalia: HRK

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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...
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