Outline the method for dating rocks and fossils using radioisotopes Chubby womem adult chat free
D.4.4 Outline the trends illustrated by the fossils of Australopithecus including A. The expected frequency of the heterozygous genotype is 2pq. D.5.5 Describe how the evolution of one species into another species involves the accumulation of many advantageous alleles in the gene pool of a population over a period of time. The chance of inheriting two copies of the second of the two alleles is (q)(q).Using relative dating the fossil is compared to something for which an age is already known.For example if you have a fossil trilobite and it was found in the Wheeler Formation.The same rock formation also contains a type of trilobite that was known to live 415 to 425 million years ago.Since the rock formation contains both types of fossils the ago of the rock formation must be in the overlapping date range of 415 to 420 million years.Then after another 5,000 years half of the remaining parent isotope will have decayed.While people are most familiar with carbon dating, carbon dating is rarely applicable to fossils.
But, how can we determine how old a rock formation is, if it hasn’t previously been dated?
sapiens: .1 million years – large brain, flat face, reduced teeth, reduced robustness, chin D.5.4 State that adaptations (or micro-evolutionary steps) may occur as the result of an allele frequency increasing in a population over a period of time. p squared = frequency of homozygous dominants p squared = (.463)(.463) = .214 2pq = frequency of heterozygotes 2pq = 2 (.463)(.537) = .497 If there is random mating in a population, the chance of inheriting two copies of the first of the two alleles is (p)(p).
erectus: .4 - 1.8 million years – more complex tools so meat significant part of diet and changed teeth. neanderthensis .5 million years – larger brains and bones, larger teeth and jaw, shorter limbs for the cold H. If q = frequency of t allele, q squared = .288 so q = .537 If p = frequency of T allele, p = (1 - q) = .463 The frequency of homozygous dominants (TT) and heterozygotes (Tt) can be calculated.
This uses radioactive minerals that occur in rocks and fossils almost like a geological clock.
It’s often much easier to date volcanic rocks than the fossils themselves or the sedimentary rocks they are found in.