Class 12 Biology Practical Notes

• Important biology practical class 12 for Intermediate part-II students.
• Estimation of pyramids of numbers using simple techniques. 
• Investigation of adaptive features of hydrophytes, halophytes, mesophytes and xerophytes from fresh material.
• Important 12 class biology practical book for Intermediate part-II students.
• Investigation of water content of soil samples.
• Sampling of a grass and community by quadrat method. 
• Important 12 practical book biology for Intermediate part-II students.
• Study of development of chick embryo 48 over 72 hours after incubation.
• Study of ductless glands (pancreas, thyroid) using microscopic sections. 
• Important biology 12 practical book for Intermediate part-II students.
• Study of simple muscle twitch using frog's muscle.
• Study of skeleton of frog.
• Important biology class 12 practical book for Intermediate part-II students.
• Study of structure of hen's egg.
• INVESTIGATION OF ADAPTIVE FEATURES OF HYDROPHYTES, HALOPHYTES, MESOPHYTES AND XEROPHYTES FROM FRESH MATERIAL
• ECOLOGICALADAPTATIONS IN PLANTS:
• Important biology class 12 practical copy for Intermediate part-II students.
• Modification in Morphological, anatomical, physiological and reproductive characters of plants that help them in surviving in their particular habitat successfully are termed ecological adaptations. 
• Important practical file class 12 biology for Intermediate part-II students.
• Most important, factor in the habitat that forces modifications in characters of plants is availability of water. Thus plants are classified into following ecological groups.
• Important biology lab practical class 12 for Intermediate part-II students.
• (a) Hydrophytes,  (b) Halophytes,  (c) Mesophytes,  (d) Xerophytes
• (a) Hydrophytes:  Hydrophytes are the plants which grow in water reservoirs, like ponds lakes streams or rivers. 
• Important biology practical 12 for Intermediate part-II students.
• Materials: Beaker, Microscope, Hand lens, Forceps, Prepared sli , Fresh plants or preserved plants.
•  Habitat and Habit: Hydrophytes grow inside water, moist and swampy banks photosynthetic, green, weak stem plants.
• Important biology practical book 12 for Intermediate part-II students.
• Hydrophytic Adaptations: There are modifications in morphological, anatomical, physiological and reproductive characters of plants that help them in surviving successfully in habitat having excess of water.
• Important class 12 biology practical copy for Intermediate part-II students.
• 1. Bark cuticle or periderm is absent because plant parts are not exposed to high temperature or hard soil.  2. Stem is modified into rhizome, stolen etc. because long, hard, erect stem is not needed to keep leaves in the atmosphere.  3. Roots are absent or poorly developed in varying degrees. Lamina is reduced, ribbon like, petioles absent. 
• Important class 12 practical biology for Intermediate part-II students.
• 4. Mechanical tissues are absent or highly reduced.  5. Solute potential of cells is quite high to reduce excess absorption of water.  6. Photosynthesis is limited by poor light, poor gaseous exchange and poor nutrient availability. 
• Important class 12 practical book biology for Intermediate part-II students.
• 7. Fruits and seed are usually covered with waxy, gelatinuous or mucilagenous covering to protect them from rot in water.  8. Fruits and seed are quite light in weight. So that they can float and be distributed by water. 
• Important practical biology class 12 for Intermediate part-II students.
• 9. Seeds are produce in very large numbers to ensure enough survival in hydric conditions.
• (b) Halophytes: Halophytes are plants which grow in localities (Area) with high concentration of salts like. NaCl, MgCl₂, MgSO, and abundance of water in the soil. Halophytes cannot use this water due to high salinity.
• Important practical 12 biology for Intermediate part-II students.
• Materials:  Halophytes plants, slides, compound microscope, beakers, lens, dissecting box.
• Examples:  Phizophora, portulaca chenopodium album (Bathu, goosefoot), suaeda fruiticosa (saloonak buti) suaeda monoica, salsola foetida (Lana or saltwort).
• Important practical book biology class 12 for Intermediate part-II students.
• Habitat and Habit:  Plants are grow in water logged and saline area (water and salt rich). Plants are shurbs photosynthetic stems, leaves are reduced.
• Important practical book class 12 biology for Intermediate part-II students.
• Ecological Adaptations: 1. Root system is extensive, usually shallow due to water logging of soil. Root have much lateral branching.  2. Pneumatophores (Breathing roots) are common. These roots grow upward in the air, they have pores at their tips and special absorbing tissue. These roots helps in gaseous exchanges and absorption. 
• Important practical book of biology class 12 for Intermediate part-II students.
• 3. Stem are generally succulent due to water storage tissues in cortex. Very thick cuticle waxy covering and thick walled epidermis reduces transpiration.  4. Much water storage tissue is presents in leaves between outer epidermis and mesophyll.  
• Important practical book of class 12 biology for Intermediate part-II students.
• 5. Stomata generally present on the lower surface only are sunken into urn-shaped chambers.  6. Much aerenchymatous tissue develops in Cortex and Mesophyll to increase gaseous exchange in the condition of water excess in the habitat.
• Important practical copy biology class 12 for Intermediate part-II students.
•   7. Solute potential is very low in cells and plants protoplasm is highly salt-tolerant in general.
• Important practical copy class 12 biology for Intermediate part-II students.