Biology

Animal Kingdom
Phylum Porifera
➢ Porifera means pore bearers.
➢ Members of this phylum are commonly known as sponges.
➢ Body is perforated with many pores called ostia.
➢ Ostia are mouthlets and allow entry of water.
➢ A larger aperture called osculum allows exit of water.Phylum Porifera
Habit and Habitat
➢ These are generally marine and mostly asymmetrical animals.
➢ Some sponges are found in fresh water also like Spongilla.
➢ Adult sponges are sessile or sedentary but their larvae are motile.
➢ Study of sponges is Parazoology.Phylum Porifera
Habit and Habitat
➢ These are primitive multicellular animals and have cellular level of organisation.
➢ Sponges are on a blind branch of evolutionary tree.
➢ Sponges have evolved from colonial choanoflagellates.
➢ Connecting link between Protozoa and Porifera is Proterospongia.Phylum Porifera
Body Structure
➢ Body wall has two layers i.e.
○ Outer Pinacoderm
○ Inner Choanoderm
➢ In between these two layers, a non-cellular jelly-like layer called mesenchyme is
present.
➢ Body cavity is called spongocoel or paragastric cavity or atrium.Phylum Porifera
MesenchymePhylum Porifera
Body Structure
➢ Pinacoderm has pinacocytes.
➢ Choanoderm has choanocytes.
➢ Choanocytes are also called collared
flagellated cells.
➢ These line the spongocoel and the canals.Phylum Porifera
Gas Exchange
➢ All body systems are absent.
➢ Gas exchange occurs through general body surface.
➢ There are no specialised respiratory structures.Phylum Porifera
Excretory System
➢ Excretion occurs through general body surface.
➢ Specialised excretory structures are absent.
➢ Excretory product is ammonia(Ammonotelic).Phylum Porifera
Food and Feeding
➢ These are microphagous animals.
➢ These feed on microscopic food particles like bacteria, protozoans etc.
➢ Digestion is intracellular.
➢ Food is captured by flagella of choanocytes which digest it partially.
➢ Partially digested food is passed on to trophocytes which digest it completely and
distribute it.Phylum Porifera
Skeletal System
➢ The body is supported by a skeleton made up of spicules or spongin fibres.
➢ Spicules are small needle like structures which are of two types.
○ Calcareous Spicules (made up of CaCO3)
○ Siliceous Spicules (made up of silica)Phylum Porifera
Nervous System
➢ There are no neurons but these are sensitive to external environment.
➢ Pinacocytes are contractile cells.
➢ These can increase or decrease overall surface area of sponge body.Phylum Porifera
Canal System
➢ Sponges have a water transport or canal system.
➢ It is also called aquiferous system.
➢ It is lifeline of sponges.
➢ Water enters through minute pores (ostia) in the body wall into a central cavity,
spongocoel(Paragastric cavity) from where it goes out through the osculum.Phylum Porifera
Canal System
➢ It is a system of pores, chambers and canals through which water circulates.
➢ This pathway of water transport is helpful in
○ food gathering
○ respiratory exchange
○ removal of wastes
○ reproduction.Phylum Porifera
Reproductive System
➢ Sexes are not separate.
➢ These are hermaphrodite animals, i.e., eggs and s***ms are produced by the same
individual.Phylum Porifera
Reproductive System
➢ Reproduction is asexual as well as sexual.
➢ Asexual reproduction is by
○ Fragmentation,
○ Budding
○ Branching
○ Gemmule formation.
➢ Sexual reproduction is by formation of gametes.Phylum Porifera
Fertilisation and Development
➢ Fertilisation is internal.
➢ Scypha sponge is protogynous i.e. ova matures earlier than s***matozoa.
➢ Flagella of choanocytes captures s***m and passes it to ova developing in
mesenchyme.Phylum Porifera
Fertilisation and Development
➢ Development is indirect having a larval stage, which is morphologically distinct
from the adult.
➢ Larvae are ciliated and free swimming.
➢ Larval stages are
○ amphiblastula
○ parenchymula
○ rhagon.Phylum Porifera
Examples
➢ Spongilla (freshwater sponge)
➢ Euspongia (common bath sponge)
➢ Sycon (crown sponge or urn sponge)Phylum Porifera Examples
➢ Hyalonema (glass rope sponge)
➢ Euplectella - Venus’s flower basket (It is given as a wedding gift in Japan).

Good morning
Everyone

7. पोषण (Hindi, Nutrition)

‘बच्चों के सीखने और साझा करने के लिए 100 स्वास्थ्य संदेश’ 8-14 वर्ष की आयु के बच्चों के लिए सरल, विश्वसनीय स्वास्थ्य शिक्षा संदेश हैं । इसलिए इसमें 10-14 साल के युवा किशोर शामिल हैं। हमें लगता है कि 10-14 वर्ष के युवा किशोरों को निश्चित रूप से सूचित किया जाना विशेषत: उपयोगी और महत्वपूर्ण है क्योंकि यह आयु समूह अक्सर अपने परिवार में छोटे बच्चों की देखभाल करता है। साथ ही अपने परिवार की इस तरह सहायता करने के लिए वे जो काम कर रहे हैं उसे मान्यता देना और उसकी प्रशंसा करना महत्वपूर्ण है।

इन 100 संदेशों में 10 प्रमुख स्वास्थ्य विषयों में से प्रत्येक पर 10 संदेश हैं: मलेरिया, अतिसार (डायरिया, दस्त), पोषण, खाँसी-ज़ुकाम और बीमारी, आँत के कीड़े, जल और स्वच्छता, टीकाकरण, एचआईवी और एड्स, दुर्घटनाएँ और चोट, तथा प्रारंभिक शैशव विकास। ये सरल स्वास्थ्य संदेश माता-पिता और स्वास्थ्य शिक्षकों के लिए घर, स्कूलों, क्लबों और क्लिनिकों में बच्चों के साथ उपयोग करने के लिए हैं।

पोषण (nutrition) वह विशिष्ट रचनात्मक उपापचयी क्रिया जिसके अन्तर्गत पादपों में खाद्य्य संश्लेषण तथा स्वांगीकरण(गुण लगना) और विषमपोषी जन्तुओं में भोज्य अवयव के अन्तःग्रहण, पाचन, अवशोषण, स्वांगीकरण द्वारा प्राप्त उर्जा से शारीरिक वृद्धि, मरम्मत, ऊतकों का नवीनीकरण और जैविक क्रियाओं का संचालन होता है, सामूहिक रूप में पोषण कहलाती है। पोषण के अन्तर्गत निम्नलिखित बिन्दुओं पर विचार किया जाता है-

पोषक तत्वों का सेवन,पोषक तत्वों का प्रत्येक दिन के आहार में उचित में रहना,पोषक तत्वों की कमी से शरीर में विकृतिचिह्नों का दिखाई पड़ना। पौधों में श्वसन पत्तियों द्वारा होता है

Happy Rakshabandhan