Question

Phylogenetic Reconstruction Question.

Describe the following types of data used in modern phylogenetic analyses and list the limitations of the type of data if they exist.

a) Morphology

b) Development

c) Paleontology

d) Behavior

e) Molecular Data

Answer 1

a) In morphology refers to the comparative morphology that is the study of the plane of body organization and its structures between groups of organisms. For example, the bones of a human arm, the fins of a whale and the wings of a bat are distinguished by their size, shape and function. The limitations of this is that there may be confusion when the organisms are classified. An example of this is that of the actinomycetes and fungi degrading organic matter because having a similar morphology was thought to belong to the same group (altough the actinomycetes are related to bacteria) the similarities they have is due to the "convergent evolution" because by sharing the same ecological niche they evolve in a similar way.

b) Development refers to the way they grow, the best example to illustrate this is how insects develop: There are insects with life cycles holometabolos (which go through the phases of egg, larva, pupa and adult) and hemimetabolos (cycle in which there is only egg, nymphs [that are like miniature adults] and adults). The limitations also show that by morphology can be confused and put a related species with another (when in fact they are not)

c) Paleontology It refers to the interpretation of the fossil record and can be done in a similar way to morphological interpretation. The limitations are: Although there are more than 250,000 known species judging from the current range of biodiversity, there must have been many more species. The fossil record will never be complete because there is little chance of finding evidence of an extinct species because at least one specimen should have been buried delicately before it decomposed or was devoured. In addition, it would have had to escape erosion, lava and other forces of nature and would have had to be exposed on the walls of a canyon after a river or glacier had made its way through layers of sedimentary rock. ditionally, not all prehistoric species are easy to preserve. Unlike the spiny fish and hard shell molluscs, neither jellyfish nor worms appear so frequently in fossil records.

d) Behavior It refers to their habits, that is, whether they are diurnal or nocturnal, the food they have (hervibors, carnivores, omnivores) etc. The limitation that it has is again the confusion that can arise when classifying species, since there are butterflies of dirino habits and butterflies of nocturnal habits (and although they are related they can be classified in different groups)

e)Molecular data: It refers to the sequences of biomolecules such as DNA, RNA (ribosomal, messenger or transfer). Although this may be the most reliable of all the limitation that it has is that it requires a lot of work to sequence the genome of a single cell (especially if it is eukaryotic because they are several chromosomes and are "disordered"). Nowadays, computer technologies help a lot to perform those tasks, however, there are many efforts to make these sequencing.