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heridity

this is a biology lesson for secondary level students

SudarshanaElapatha
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heridity

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  1. Inheritance • of organisms • Sudarshana Elapatha • National Dip. In Teaching

  2. Derive a quality or characteristic from one's parents is known as inheritance

  3. Heredity . The passing down characteristics genetically from one generation to another is called heredity.

  4. Phenotype The observable characteristics of an individual resulting from the interaction of its genotype with the environment.

  5. Genotype The genetic constitution of an individual organism.

  6. Inherited characters Skin colour (Brown / tan ) Hair colour (Black/Brown) Colour of the Eyes (Black/Brown) Nature of hair (Curly/Strait) Nature of the ear lobes(Free or not) Right-handedness Inability to roll the tongue Nature of hands are folded, Height

  7. Hereditary features that are rarely met Syndactyly - Two adjacent fingers are bound together to some distance by a fold of skin. Polydactyly - Possession of 6 fingers or toes. Albinism - Possession of a very white skin, blonde hair, and white eye lashes Brown or blue eyes -

  8. Non-inherited characters • Characters that are dependent on • Climatic differences, • Environmental conditions • Nutrition • Exercise or activities • Explore to harmful rays • Diseases are not inherited characters. • They are called Non-inherited characters

  9. How are characters inherited from generation to generation?

  10. When a black child was born to white parents what will happen?...

  11. among the parents is expressed through the • child. A hidden character

  12. generationsby chromosomes • Inherited characters are transformed through

  13. Genes which are carried by Responsible for . ( • inheritance of characters Chromosomes are

  14. Mendel’s • experiment

  15. Mendel used garden pea plants Pisumsativum for his experiment.

  16. He carried out his experiments according to the scientific method giving special attention to the following points

  17. Selecting a suitable organism Hybridization of only one character at a time (mono hybridization) Planning simple experiments and recording all the observations continuously and regularly Developing hypothesis based on the observations and rechecking the hypothesis

  18. Special characters selecting Garden pea

  19. Having contrasting characters

  20. Pure line of characters are protected • due to occurrence of Natural reproduction by self pollination

  21. It was possible to produce by cross pollination seeds

  22. They had a short life cycle

  23. offspring Hybridized plants produced fertile

  24. were Seeds • germinated easily

  25. Experiment Done by Mendel

  26. In the ratio

  27. Based on his observations, Mendel disclosed

  28. There are two factors controlling each contrasting trait of an organism

  29. When gametes from these factors separate and only one factor entersa gamete

  30. In a monohybrid, of the morphological ratio between the dominant and recessive traits is 3:1 in the F2 generation

  31. In this F2 generation the ratio among homozygous dominant pairs heterozygous pairs: homozygous recessive pairs is 1:2:1 and is also known as the genotype ratio

  32. In heredity the male and female organisms selected for hybridization is known as the parental generation (P).

  33. Their offspring is known as filial generation (F).

  34. The first generation of offspring is F1 while the second generation is F2.

  35. Gene linkage occurs when two or more genes are linked on the same chromosome, they are called linked genes.

  36. Linked genes on X or Y Chromosomes are known as Sex linked genes

  37. Haemophiliaand colour blindness are sex linked genes on X chromosomes.

  38. The genotype colourblindness XcXc or XcY The heterozygous genotype XCXc acts as carries of the disease.

  39. The genotype Haemophilia XhY The heterozygous genotype XHXh is a carrier female

  40. Incomplete dominance

  41. The four ‘O’ clock flowers ( Mirabilis jalapa) bear flowers coloured

  42. Prominent homozygous produce flowers

  43. Recessive homozygous produce flowers

  44. Heterozygous genotype Rr produces magenta Coloured flowers. Because the dominant gene (R) is incapable of completely overriding the recessive gene(r).

  45. This phenomena is known as incomplete dominance

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