Question

In: Biology

How reliable are morphological and molecular data in evolutionary studies? What are their weakness? How can...

How reliable are morphological and molecular data in evolutionary studies? What are their weakness? How can they complement each other? Pls provide a reference like a journal article. thanks

Solutions

Expert Solution

The major difference lies in the space of possible states and in the number of relevant levels of granularity and frames of reference. Whereas in molecular data at the nucleotide level the space is limited to only 4 different states (the 4 different nucleotide types), in morphology there is practically no such limitation. Moreover, whereas in molecular data you usually analyse the data either on the granularity level of individual nucleotides or on the level of amino acids. Different frames of reference are usually not used, but sometimes gene arrangement and 3d structure is also considered. In morphology, all different kinds of levels of granularity are considered, from the molecular level to the gross anatomy level. Moreover, different frames of reference can be considered, as for instance a purely spatio-structureal frame as opposed to a functional or a developmental frame.

All this affects the descriptive level as well as the analytical level in phylogenetic investigations. Molecular data can usually be described as a sequence of letters using a 4-letter code. This lends itself to very formalized descriptions of sequences. In morphology, we are dealing with a lack of such formalism. Instead, we are facing different terminological traditions that are often taxon-dependent, where the meaning of terms can vary between different authors and through time and where also homology considerations influenced terminology. No formalized standard exists for morphological descriptions.

In the step of character identification and homology assessment, using molecular data we must align sequences and then each nucleotide position in the sequence is a putative phylogenetic character with a set of 4 different possible character states. This can be easily formalized for phylogenetic algorithms to analyze the data. This is straight forward. In morphology, this step is tricky due to the space of possible states. The delimitation of characters is non-trivial and the different levels of granularity and frames of reference make it even more complicated. We have discussed these differences between morphological and molecular data in some detail in our 'The Linguistic Problem of Morphology' paper (https://www.researchgate.net/publication/215827731_The_linguistic_problem_of_morphology_Structure_versus_homology_and_the_standardization_of_morphological_data).


Related Solutions

How reliable are morphological and molecular data in evolutionary studies? What are their weakness? How can...
How reliable are morphological and molecular data in evolutionary studies? What are their weakness? How can they complement each other?
What are some of the advantages of using molecular data in evolutionary studies
What are some of the advantages of using molecular data in evolutionary studies
Can you think of an example where molecular data would be better for inferring evolutionary relationships?...
Can you think of an example where molecular data would be better for inferring evolutionary relationships? Can you think of an example where morphological data would be better for inferring evolutionary relationships?
a) What are the advantages and disadvantages of morphological and molecular systematic? b) why phylogenetic are...
a) What are the advantages and disadvantages of morphological and molecular systematic? b) why phylogenetic are important with regards to conservation efforts? c) in term of conservation effort, what can scientist do to reduce the risk faced by species?
What evolutionary pressures could have resulted in the morphological adaptations of the robust Australopithecus (also known...
What evolutionary pressures could have resulted in the morphological adaptations of the robust Australopithecus (also known as Paranthropus) (species: Australopithecus aethiopicus, Australopithecus robust, Australopithecus Boise). Why do you think they became extinct?
What criteria can be applied to determine if a selection tool is valid and reliable? How...
What criteria can be applied to determine if a selection tool is valid and reliable? How do we know if a selection tool is good. Explain each of the criteria.
how can you determine whether a source is reliable and trustworthy?
how can you determine whether a source is reliable and trustworthy?
Locate two cultivars of a plant species you are familiar with. How (if possible) can morphological...
Locate two cultivars of a plant species you are familiar with. How (if possible) can morphological tests help you distinguish between the two cultivars? Explain in detail.
morphological description of Vitaceae Description? How are the leaves arranged? What is the shape of the...
morphological description of Vitaceae Description? How are the leaves arranged? What is the shape of the leaf? Leaf type? pinnately compound. palmately compound or simple What other leaf characteristics are important? leaf margins Is the leaf is petiolate, sessile, or clasping? Inflorescence type ? spike raceme panicle corymb umbel helicoid cyme Reproduction? Any information ? synapomorphies of this plant family are?
Explain why data warehouses and data marts are important in healthcare. What is their greatest weakness...
Explain why data warehouses and data marts are important in healthcare. What is their greatest weakness and what is their greatest strength? *Its meant data wearhouse in general. We are talking about healthcare settings.
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT