A young entomologist is trying to increase body hairs in Drosophila. His original population has a mean of 7.5 hairs, and he selects flies with a mean of 10 hairs to inter-mate and produce his next generation. The mean number of hairs in the resulting population was 9.

1. What is the narrow-sense heritability (h2) for number of body hairs in this Drosophila population (show your work)?

2. What would have been the mean number of body hairs in the next population if she had selected individuals with a mean of 8.5 hairs?

3. If she wanted a mean of 10 hairs in the progeny, what should have been the mean number of hairs in the individuals selected as parents?

Explanation:

1) homologous features:

these are the features or structures that have a similar structure in several different organisms but function in a unique way in all of them. these structures indicate anatomical similarities as well as the same ancestry of different organisms. for example, the forelimb of birds, humans, dogs, and whales, perform different functions in all these organisms. but when we analyze the layout of bones or layout of the arrangement, we find that it is very similar across all of them. this indicates that, the ancestor of all these organisms was, but with the passage of time when organism dispersed, and environmental conditions changed, it was evolved into different organisms as per favorable conditions.

2) molecular biology:

as we know that all living organisms are a compilation of billions and trillions of unique biological molecules, that group in a unique fashion to constitute the whole organism. interestingly, some biological molecules and the process of their formation can provide sound evidences of evolution. for example, DNA, a sequence of nucleotides in DNA, amino acids, the process of transcription, translation, etc.

the study of evolution through molecular uniformity has led to the foundation of a novel branch of evolution called phylogenetics. the sequence of nucleotides in DNA is used to find the best possible ancestor of any organism. for example, phylogenetic analysis has found that the origin of eukaryotes is from prokaryotes over the period of time.

3) fossil records:

fossils are the preserved remains of previously living organisms or their traces, dating from the distant past. this doesn't mean that fossils represent the complete skeleton of an organism because many organisms don't even fossilize and those who fossilize don't have complete remains. nonetheless, the fossils that humans have collected offer unique insights into evolution over long timescales. for example, the study of horse fossils has enabled the scientists to reconstruct a large, branching "family tree" for horses and their now-extinct relatives.

parasites can detrimentally affect their host, but also must not allow their host to die before they can complete their life cycle. some parasites have complex life cycles with many different hosts, and have had to find ways of persisting in many different environments during the change from one host to another. ectoparasites live outside the body of the host, and can more easily  disperse, but are  more exposed to predators, parasites, parasitoids. endoparasites live inside the body of the host, and are therefore protected from the outside environment. but they can be  attacked by the host's immune system. they have therefore developed  mechanisms for dispersal such as  complex life cycles.

transcription is a process in which information is rewritten. it is something our cells must do, in a more specialized and narrowly defined way. in biology, transcription is the process of copying out the dna sequence of a gene in the similar alphabet of rna. it needs to happen in the nucleus because that's where the dna is. dna is always inside the nucleus unless the cell is dividing.

transcription is the first step in gene expression, which involves copying a gene's dna sequence to make an rna molecule. transcription is performed by rna polymerases. it has three stages: initiation, elongation, and termination. rna molecules must be processed after transcription in eukaryotes.

explanation:

long version:

the protein synthesis consists two processes which are, transcription and translation. transcription takes place in the nucleus. it uses dna as a template to make an rna molecule. rna then leaves the nucleus and goes to a ribosome in the cytoplasm, where translation occurs. transcription is the first part of the central dogma of molecular biology: dna → rna. it is the transfer of genetic instructions in dna to messenger rna (mrna). during transcription, a strand of mrna is made that is complementary to a strand of dna.  

these three stages are:

  initiation: in which   is the beginning of transcription.occuring when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

    elongation: in which is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

    termination: in which is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.