This is simply a matter of vocabulary. Introns do not contain coding sequences, while exons do. "Intron" comes from the word "intragenic," meaning between genes, and therefore between exons. During post-transcriptional modification, introns are spliced out of the initial RNA transcript.

The ribosome is where translation happens, but it requires both mRNA and tRNA. mRNA provides the "recipe" for the order of the amino acids in its codons, each of which corresponds to a specific amino acid in the chain, and the tRNA molecules come in and bind appropriately when their anti-codons are complementary to the mRNA codons. tRNA molecules carry the amino acids to the ribosome, where the actual protein chain is then synthesized.

Transcription factors are proteins that bind to the regulator region of genes in eukaryotes and regulate whether a gene is expressed or not. A TATA-box binding protein is recruited after the transcription factors bind to the regulator region, and it eventually recruits RNA polymease. Tyrosine recombinases are not involved in initating eukaryotic gene expression.

Structures that are similar as a result of convergent evolution are referred to as analogous structures, such as the wings of beetles and birds. These animals do not share a common ancestor, and developed the trait for wings independent of one another. Homologous structures arise when two organisms share a trait due to linkage with a common ancestor. For example, legs of a dog and the legs of a cat are considered homologous.

Phylogeny refers to the evolutionary history of a lineage, and can be used to identify common ancestors. Taxonomy is the naming and classification of organisms. Binomial nomenclature is the scientific name for an organism containing its genus and species.

Analogous structures are anatomical structures that have similar functions, but arose independently. Due to environmental stresses and natural selection, organisms of different species evolved and adapted independently, resulting in the existence of body parts with similar functions. This refers to convergent evolution. An example of analogous structures are the wings of several different animals. A moth, hummingbird, and a bat are only extremely distantly evolutionarily related, yet they all have wings of some sort, which serve the common purpose of transportation through air. Homologous structures are body parts that are anatomically similar and may share similar anatomical forms, but are not the result of convergent evolution, rather they are the result of divergent evolution. These commonalities within organisms show descent from a common ancestor. An example of homologous structures are the "arms" of three different mammals, a human, a bat, and a whale. Each "arm" has very similar anatomical organization of bones, but is used for very different functions.

A vestigial trait is an attribute that has lost its function but has been retained through evolution. Examples include the formation of goose bumps in humans and pelvic remnants in boas and pythons. A change in the DNA sequence (genome) of a cell is a mutation. A trait that makes an organism better suited for a habitat is an adaption. Structures that arise in organisms that share a common ancestor, but perform different structures are called homologous structures. An example of a homologous structure is the "arm" of a mammal. Mammals have very similar bone and muscle organization in their arms (whales, humans, bats), but the function of each is much different (swimming, grabbing, flying).

It is believed that all organisms are descended from a common ancestor. Evidence of this includes morphological similarities, vestigial characteristics, and observations made within the fossil record. Recently, phylogenetic trees and cladograms are made using DNA sequence analysis to determine the similarity in the genomes of organisms. 

When parts of an animal serve different functions but have similar placement and bone structure (such as a wolf forearm and a whale flipper) and are derived from a common ancestor, these two structures are homologous. Convergent evolution is a process during which two non-related organisms develop analogous structures that serve the same function but have different structures. The bottleneck effect refers to the decrease in genetic diversity that occurs when a population goes through sudden decline and then expands again. Mendel's laws of inheritance refer to the rules by which different traits, or alleles, are passed on from one generation to the next as discrete units of inheritance called genes.

By definition, vestigial structures are structures that are thought to have had a biological function a long time ago but have since lost that function due to evolutionary changes. The human appendix is considered to be an example of a vestigial structure.

Homologous structures show the existence of a shared ancestry through the observation of structural similarities between different species; however, while a human's hand and a cat's paw are structurally similar, they have very different functions.