Q1. A) If you group all segmented organisms (blue circles), would they form a mo
ID: 67473 • Letter: Q
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Q1. A) If you group all segmented organisms (blue circles), would they form a monophyletic clade? Explain. B) As what type of trait would you classify body segmentation (apomorphy, synapomorphy,plesiomorphy, symplesiomorphy, homoplasy)? Explain you answer. C) Do you think segmentation appeared once in the ancestor of these groups or appeared independently in each group? Explain your answer. D) Do organisms that molt (called ecdysis, includes: Loricifera, Kinorhyncha, Nematoda, Tardigrada, Arthropoda and Onychophora) form a monophyletic group? Explain. E) As what type of trait would you classify the ability to molt (apomorphy, synapomorphy,plesiomorphy, symplesiomorphy, homoplasy)? Explain.
Q2. Some people have suggested that Tardigrades (water bears) come from another planet. Look at the phylogenetic tree, which has been constructed based on DNA and morphological data, to A) explain whether the alien origin of Tardigrades is supported. B) How would the phylogenetic tree look like if Tardigrades were indeed alien?
0 0seg Pseudocoelomates Segmented Eumetazoa Protostomes AcoeloPlatyzoa morpha Deutero- stomes Spiralia Ecdysozoa Lophotrochozoa Bilateria -Metazoa Phylogenetic tree of animal phyla. The red circles depict animal groups that present a trait known as pseudocoelom, while the blue circles depict animal groups that show a pattern of segmentation.Explanation / Answer
B) As what type of trait would you classify body segmentation (apomorphy, synapomorphy,plesiomorphy, symplesiomorphy, homoplasy)? Explain you answer.
An apomorphy or also called separate form or derived state is an innovation whereas Plesiomorphy also called close form or ancestral state are a taxon has retained its ancestors characterize. Aasymplesiomorphy which contain two or more taxa which are not nested within each other. Homoplastic or aslo called an instance of homoplasy shared by two or more organisms and absent from their common ancestor.
C) Do you think segmentation appeared once in the ancestor of these groups or appeared independently in each group? Explain your answer.
As we consider development as continuous process rather than suddetn chage except mutation during developemt and it appears for me that better to conclude that segmentation was appeared once in ancestor and not due to sudden changes in individual group.
D) Do organisms that molt (called ecdysis, includes: Loricifera, Kinorhyncha, Nematoda, Tardigrada, Arthropoda and Onychophora) form a monophyletic group? Explain.
As we wrote in para A that Organism of this clade consists of an ancestral species and all its descendants. Above all organism given in D section looks to evolved from same ancestor and can be grouped in same clade.
E) As what type of trait would you classify the ability to molt (apomorphy, synapomorphy,plesiomorphy, symplesiomorphy, homoplasy)? Explain.
It would be in Plesiomorphy as I feel. Explanation is quite not justified so skipping this part/
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