Biology by sandeep sir

 

Biological classification  Biological classification is defined as the process of grouping the organisms according to certain similarities Linnaeus proposed the two kingdoms of classification.  He classified organism into animal kingdom as Animalia and plant kingdom as Plantae.  There were certain limitations associated with two kingdom classification such as- it does not differentiate between eukaryotes and prokaryotes, unicellular and multicellular organisms, and photosynthetic and non-photosynthetic organisms.  Five kingdom classifications  R.H. Whittaker proposed the five kingdoms of classification.  The five kingdoms classification is as follows-  Monera,  Protista,  Fungi,  Plantae, and  Animalia.  The classification was based on thallus organization, cell structure, mode of nutrition, phylogenetic relationship, and reproduction.           Fig.1. Five kingdom classifications  Kingdom Monera...

हिम्मत रखो क्योंकि जब तुम्हारी हिम्मत साथ होगी तो हर परिस्थिति तुम्से हार जाएगी  

SEXUAL REPRODUCTION IN FLOWERING PLANTS Sexual reproduction is the process of development of new organisms from two parents through fusion of male and female gamete.  The flower is the main structure concerned with reproduction. The reproductive organs or the sporophylls are produced within the flowers.  The sporophylls are of two types microsporophylls (stamen) and megasporophylls (carpel)  Carpel is distinguished as ovary bearing ovule, style and stigma.  Stamen is distinguished as filament, anther and connective. The whole process of sexual reproduction in flowering plants can be divided into three steps:-  Pre-fertilization  Double fertilization  Post-fertilization  PRE-FERTILISATION: STRUCTURE AND EVENTS  The pre-fertilization events can be studied under following points:-  Pollen grain formation  Embryo sac formation  Pollination Pollen pistil interaction  POLLEN GRAIN FORMATION  Male reproductive unit (Stamen...