adaptations.
Natural selection leads to traits called adaptations, which improve an organisms ability to survive and reproduce.
Genetics, blood type gene has two alleles, each allele has genotype A, B or O. The A and B are dominant, and O is recessive. So allele A combined with allele O is type A. Similarly, BO is type B, AA is type A, BB is type B, OO is type O, and AB is typeAB.
If both parents have type A blood, then the alleles could be AA or AO, thus the allele A frequency is 75%, allele O frequency is 25% for both parents.
So the chance of alleles OO is 25% × 25% = 6.25%,
alleles AA is 75% × 75% = 56.25%,
alleles AO is 75% × 25% = 18.75%,
alleles OA is 25% × 75% = 18.75%.
Since AA, AO and OA are blood type A, and OO is blood type O, thus their child has 6.25% chance to be blood type O and 93.75% chance to be blood type A.
The +/- is called the rhesus factor, with + being dominant, and - being recessive.
So if both parents are -, the kids are always -, otherwise the kids might be + or -.
Child Blood Type Estimate Table:
Father's Blood TypeABABOMother's
Blood
TypeAA/OA/B/AB/OA/B/ABA/OBA/B/AB/OB/OA/B/ABB/OABA/B/ABA/B/ABA/B/
A theory is an idea that has yet to be proven by experimentation. A law is a theory that has been proven correct.
The human circulatory system processes an average of 20 litres of blood per day through capillary filtration, which removes plasma while leaving the blood cells. Roughly 17 litres of the filtered plasma is reabsorbed directly into the blood vessels, while the remaining three litres remain in the interstitial fluid. One of the main functions of the lymph system is to provide an accessory return route to the blood for the surplus three litres
