DNA replication is semi-conservative because only one half of the DNA helix is replicated
Evidence for evolution, in other words evidence of common descent, include fossils, which have shown a (fairly) steady change in morphology over time for some species. An example would be horse hooves: we have fossils that show when they were still three toed, then two toed, then one toe in our present day horses. Another piece of evidence is vestigial organs. An example of vestigial organs is wings in some flightless birds, such as the kiwi. Their ancestors used it in order to fly across the marine barrier into New Zealand, but natural selection and random genetic drift made them quickly lose the ability to fly. Nonetheless, they still have their wings, however small. It can be assumed that eventually, their wings would be reduced to small stubs fused to other nearby bones, as has been observed in their cousins.
Answer:
<u>the bottleneck effect</u>
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Explanation:
Genetic drift has an important impact on the small populations. mutations, which are spontaneous heritable changes in the genetic code, made up of DNA. Here, mutations accumulate over time in a group, modifying the distribution of alleles or various forms of a gene. Natural selection may result in a loss of diversity in a population called genetic drift; one trait's allelic frequency rises while others become less prevalent. Typically such differences exist because of occurrences of mutation and recombination.
Some mutations or alleles may become extinct from the population.
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Variants of a gene accumulate and are transmitted across generations; the frequencies of these occurrences are altered and become more stable in genetic drift- they become genetically distinct and may eventually form a new species after isolation. This may be further compounded through other phenomena such as the founder effect where a group separates and genetic diversity decreases; and the bottleneck effect where barriers to reproduction or the die-off a population increases genetic drift.
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Answer:
PpDD and PpDd
Explanation:
Pigmented eyes (P) are dominant to non-pigmented (p), and dimpled chins (D) are dominant to Non-dimpled chins (d).
The <u>possible genotypes of a pigment-eyed, dimple-chinned person</u> would be PPDD, PpDd, PPDd, PpDD while a blue-eyed person without a dimpled chin would have the genotype ppdd.
The genotype of a blue-eyed, dimpled chin child would be either of ppDd or ppDD, but in this case, the mother is ppdd and as such, the child cannot have two copies of D allele. Hence, the genotype of the child can only be ppDd.
In order for the child to have blue eyes (pp), it means that the father has to have the non-pigmented allele (p). This also means that the father is heterozygous for eye pigmentation (Pp).
<em>Hence, the genotype of the father is now limited to </em><em>PpDD</em> <em>and </em><em>PpDd</em>.
Answer:
The three parts of the cell theory are: cells are the smallest unit of life; all cells come from preexisting cells; and living thing is made up of one or more cell.
