1) Describe how comparing the anatomy of living species provides evidence of evolution.
A: Comparisons of the anatomy of different types of organisms often reveal basic similarities in body structures even though the structure's functions may differ between organisms. For example, sometimes bones are present in an organism but are deducted in size and either have no use of have a less important function that they do in other, related organisms. Such structures, which are considered to be evidence of an organism's evolutionary past, are called vestigial structures.
2) State how comparing the amino acid sequence of a protein can provide evident that evolution has taken place.
A: If evolution has taken place, then, in general, species descended from a recent common ancestor should have fewer amino acid differences between their proteins than do species that share a common ancestor in the more distant past.
To compare the amino acid sequence of a protein, scientists use a method called sequence alignment. This involves aligning the amino acid sequences of proteins from different species and looking for similarities and differences. The more similar the amino acid sequences are, the more closely related the species are considered to be.
To get the amino acid sequence of a protein, scientists first need to identify the gene that codes for that protein. This can be done through various methods such as experimental techniques or analyzing genetic data already available. Once the gene is identified, scientists can determine the sequence of nucleotides in the DNA.
To convert the DNA sequence into an amino acid sequence, scientists use a process called translation. During translation, the sequence of nucleotides in the DNA is "read" in groups of three called codons. Each codon corresponds to a specific amino acid. By translating the DNA sequence, scientists can obtain the corresponding amino acid sequence of the protein.
To compare the amino acid sequences of proteins from different species, scientists use bioinformatics tools. These tools allow for efficient and accurate alignment of protein sequences. The alignment process involves determining which amino acids are similar or different at each position in the sequence.
Once the alignment is complete, scientists can analyze the similarities and differences in the amino acid sequences. If the amino acid sequences are very similar, it suggests that the species share a recent common ancestor. On the other hand, if the sequences are significantly different, it indicates that the species share a common ancestor in the more distant past.
By comparing the amino acid sequences of proteins from different species, scientists can gain insights into the evolutionary relationships between these species. This information helps build a phylogenetic tree, which represents the evolutionary history and relatedness of different organisms.