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.





Cheers

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

View more OpenOffice presentations from Dr samuel Aylward.

Cheers