CLASS X BIOLOGY

Revise three chapters : Reproduction Heredity and Evolution Our Environment Complete your practical file and submit after winter break. Try to attempt the CBSE sample paper questions from the syllabus covered so far..Check the following link-   CBSE Science sample paper SA II (2016-17)           Check your answers here:       Marking scheme of sample paper Complete the following questions in your notebook. DAV Public School , Kailash Hills Class X Heredity and Evolution & Our environment Q1 . The genotype of green coloured Tomato plants is denoted as GG and that of purple stemmed Tomato plants as gg. When the two are crossed: a) What colour of stem would you expect in F1 progeny? b) Give the percentage of purple stemmed plants if F1 are self pollinated. c) In what ratio would you find the genotypes GG and Gg in the F2 progeny? Q2 .From the list given below, select the character which can be acquired ...

Topics discussed: Biodegradable and non biodegradable substances Waste management Ecosystem- types                     components- abiotic, biotic( producers, consumers, decomposers) Food chain , food web, trophic levels 10% law of energy transfer Length of food chain possible Biomagnification Ozone depletion Biomagnification

Natural selection Genetic drift Microevolution Speciation pictorially Speciation continued... Understanding Homologous and Analogous Interactive Understanding of Homologous ... Artificial Selection

Class XB : Prepare a poster (A3 sheet) on the following topics: Four students will prepare one poster  i) Global warming   ii) Ozone depletion iii) Rain water harvesting iv) Biological magnification v) The magical 3- Reduce, Recycle and Reuse vi) Organic farming vii) Biodegradable vs Non Biodegradable substances viii) Vanamahotsava : Benefits  of growing Plants. ix) Greenhouse and greenhouse effect x) Vermicomposting/ Composting Assessment criteria: Content appropriateness - 5 marks Presentation: Neatness - 1 mark                       Border (preferrably black)- 1 mark                      Proper Heading- 1 mark                      Creativity- 2 marks Write your names on the back side of the poster.

Origin of Life: Evolution can explain formation of many species ultimately from a single  species in the past. But origin of life (first species) needs further explanation. Oparin and Haldane  proposed  biochemical theory of evolution : Chemical evolution : Formation of simple organic substances (amino acids,  glucose, nucleotides) from inorganic substances CH4, NH3, H2S on  primitive Earth. Biological/ Organic Evolution : Formation of first primitive cell using organic  molecules. Evolution of different forms of life forms from simple unicellular  prokaryotic organism Miller and Urey experiment : They simulated primitive earth. Primitive reducing atmosphere             Gases like H2S, NH3, CH4 Evaporation from hot oceans                Boiling water in flask Lightening   ...