Cell division, mitosis and meiosis, role of meiosis in sexual reproduction and natural selection in Galapagos Islands

Hi,

These two videos on the two types of cell divisions are superb. Watch and enjoy.








The function of sexual reproduction and the reason why organisms choose this form over asexual methods is explored in this video. Watch and be wowed.




Sexual reproduction, genetic variation and natural selection resulted in an explosion of phenotypes in the remote Galapagos Islands. More than 13 types of finches evolved to take advantage of the various niches available to them. This was recorded by Charles Darwin, the first scientist study these birds and the father of the theory of evolution.





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Lesson 20: Cells reproducing themselves-mitosis and meiosis

Hi,

This set of 43 slides are very good in explaining the 2 types of cell division. The following points are precisely and concisely explained:

• all cells of the body are not the same, importance of cell specialisation
• copies of cells are made for growth, repair, reproduction etc
• mitosis occurs almost everywhere, 2 identical daughter cells are produced
• meiosis occurs in gonads only, 4 non-identical daughter cells are produced
• mitosis for growth and repair, almost all body cells produced in this way
• meiosis for sexual reproduction, occurs for reproductive purpose
• photomicrograph and line diagrams of different stages of mitosis
• photomicrograph and line diagrams of different stages of meiosis
• interphase, metaphase, anaphase, telophase
• differences between mitosis and meiosis,
  
• importance of meiosis is sexual reproduction
• comparing ageing process with cancer formation
  

Biology Cellular Reproduction 1196898661945653 5

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Lesson 10: Cell division-mitosis and meiosis

Hi,

This is a very good revision material to view. concepts covered include:

• cells divide to increase numbers for growth, repair and reproduction
  
• cell organelles-mitochondria, chloroplast, nucleus, cell membrane
• specialised cells-red blood cell, nerve cell, pollen, guard cell, palisade cell, xylem cell,
• 1 billion cells per hour are replaced in your body by cell division
• blood cells by bone marrow by mitosis
  
• skin cells 100 million per day by mitosis
  
• zygote, 1 cell, grows into baby within 9 months by mitosis
• photographs on mitosis in onion shoot and root tip showing mitosis
• meiosis- in testis, ovary, anther
• fertilisation restores the diploid number in zygote
• mitosis ( 2n--> 4n--> 2n-->2n)
• meiosis (2n--> 4n-->2n-->n)
  
• the sex of child is determined at the point of fertilisation
• fertilisation with y-carrying sperm results in male, fertilisation with x-carrying sperm results in female child.
• meiosis occurs in anther producing pollen, in testis producing sperm, in ovary producing ova, ( or ovule in plant).
  
• self fertilisation less variation than cross fertilisation in plants
• short questions
  

Mitosis and Meiosis

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