For her science fair project, your little sister replicated one of Mendel's experiments. From a P0 pea plant with purple flowers and a pea plant with white flowers, she got 1 purple F1 hybrid (she had forgotten to water, so just one survived). From this self-fertilized F1 she got 8 F2 offspring. 7 were purple and 1 was white, for a 7:1 ratio. Did your little sister just disprove Mendel's laws

No, the 7:1 ratio is close to the expected 6:2 ratio even with the limited sample size.

Explanation:

Let the alleles be P (purple) and W (white).

The possible crosses are

PP x WW, PP x PW, PW x WW, PW x PW

the F1 is PP or PW

one F2 is white so the F1 must be PW and

the F2 are PP, WW, PW and

the expected 8 progeny are 2PP, 2WW, 4PW

Because 7/8 are purple, we can infer that P is dominant and W recessive, so the expectation is 6 purple, 2 white

The observed ratio is similar to the expected ratio, so we can’t say that this result disproves Mendel, particularly with a small sample.

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.    

format change of dna.