CLASS X BIOLOGY

Class X A, B, C Complete notes of chapter "How do organisms reproduce? "- Asexual reproduction, General features of sexual reproduction. Do NCERT questions based on topics covered so far. Class XA  - Submit your report on dengue emphasising on how it affects our health (body functions affected) and suggesting measures as to how you can prevent its spread by ensuring cleanliness in your surroundings. Establish the relationship between environmental phenomenon of global warming and increase in the population of vector (e.g. mosquito) . Also submit your poster to spread awareness about dengue. HAPPY DUSSEHRA ! Enjoy the holidays and at the same time study for your upcoming Unit test..

HOW DO ORGANISM REPRODUCE ? ˜ Reproduction is the process by which living organisms produce new     individuals similar to themselves. ˜ Reproduction ensured continuity of life on earth. ˜ Reproduction – A bridge to hereditary transmission. ˜ It involves continuation of characters from the parents to daughter cells by Copying of DNA (Deoxyribose Nucleic Acid) molecules present in the chromosomes of the cell. ˜ Copying of DNAs is also not a foolproof exercise, even minute changes bring about Variation in the blue print of the offsprings. ˜ The useful variations are retained while the harmful one does not go beyond. ˜ Actually variations help the species to withstand drastic environmental changes, thus save the species from becoming extinct and promotes its survival for a longer time. ˜ This inbuilt tendency of variation is the ‘‘fuel’’ for Evolution.               ...

Keeping in view the recent outbreak of Dengue in Delhi, collect information on Dengue- its causative agent, means of spread, symptoms, how it affects our body functioning ( refer to blood component affected and its function), preventive measures and make a one/two page brief report on it. Also prepare an innovative means to spread awareness about it- a poster/slogan/pamphlet/ poem/ jingle/ skit.  You may work individually or in pairs (or in groups for skit/ play). Activity aims to develop ability of :- identifying the relevant details about the disease. effective presentation in report. creativity in designing/ preparing awareness campaign. sharing of ideas/ cooperation in a group/ pair.(in case of group work) To be submitted and discussed in First week of October.

Revision of chapter Life processes and Control and Coordination  . Doubts from the topics were taken up in the class.

CHAPTER 7 – CONTROL & COORDINATION KEY CONCEPTS & GIST OF THE LESSON ˜  Coordination-The working together of various organs of the body of an organism in a proper       manner to produce appropriate reaction to a stimulus is called coordination.    Example : Withdrawal of hand on touching a hot object. Control and Coordination in Animals It is brought about in all animals with the help of two main systems ( a ) Nervous System ( b ) Endocrine System Nervous System Parts of the Nervous system – (i) Brain (ii) Spinal cord (iii) Nerves (Neurons) Functions ( i ) To receive the information from environment ( ii ) To receive the information from various body parts.      (Stimuli ® Response) ( iii ) To act accordingly through muscles and glands. Stimulus : Any change in environment to which the organisms respond and react is called stimulus. E.g., touching a hot plate. Response : The reacti...