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  Practical Notebook Biology Standard XII Biology  Answeres Practical Notebook Standard XII Class-12th science Click here download in PDF 8. Study of plants found in xerophytic and aquatic conditions/habitats.  And comment on their adaptations  Introduction:  Adjustment (acclimatization) of plants and animals for their survival and perpetuation, to their environment by means of special structures or functions, is known as adaptation The plants that can grow and survive in deserts, dry conditions of soil, and high temperature, are called xerophytes.  All xerophytes show adaptations to reduce the loss of water due to transpiration.  Some xerophytes show the presence of stored mucilage in the plant parts that help in retaining water.  Some plants have latex, that helps retain water and seal the place of injury.  E.g.  Euphorbia, Calotropis, Acacia, Opuntia.   The plants that grow in abundance of water are, called hydrophytes.  They are generally adapted to remain buoyant and avoid the dec

  Practical Notebook Biology Standard XII Biology  Answeres Practical Notebook Standard XII Class-12th science Click here download in PDF 8. Study of population density and frequency of different plant populations, by quadrat method.   Aim:  To study population density and frequency of plant population by quadrat method.   Principle:  All the different types of individual plants growing at a particular space or geographical area at a particular time, form (constitutes) the plant population of that area.    It changes from time to time and may increase or decrease due to many different factors.   The number of individuals of a species present per unit area at a given time is called population density.  6. Population density = 4.  The population density (D) can be calculated as D = N / S.  where N Number of individuals of a species and S- Units of space or area (no. of quadrats).  MS  The population density can be determined by marking quadrats of suitable size and recording the number