Evolution and survival of the fittest are not the same thing. Evolution refers to the cumulative changes in a population or species through time. Survival of the fittest is a popular term that refers to the process of natural selection, a mechanism that drives evolutionary change.
Most doctors recommend that you wait until the first day of your missed period before taking a home pregnancy test. A missed period is usually one of the first signs of pregnancy. This is usually around two weeks after conception. However, some tests are more sensitive than others and can be taken earlier. Concentrations of hCG are reported in milliInternational Units (mIU) or amounts equal to 1/1000th of an IU per milliliter.
If you use a home pregnancy test after an hCG injection, it is advisable to wait 20 days before interpreting the test as positive or negative. The best way to detect a pregnancy after an hCG injection or shot is the hCG beta blood test. The blood test is much more sensitive than an urine pregnancy test. The blood hCG test can detect a pregnancy as early as 10 days after fertilization with one caveat. You need two tests several days apart. If you are not pregnant, then the blood hCG numbers will be zero or they will decrease. If you are pregnant then they will rise.