Spider Lab Report - Grade: B- PDF

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Summary

Spider Lab Report is a mandatory assignment in Robert Driver's class....

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Robert Driver BIOL 1201 19 February 2019 Identifying Spiders by their Genitalia ABSTRACT In this lab, we looked at spider genitalia in order to figure out if we can classify the spiders genetically. We find out if it is possible for the phylogenetic trees, morphological data, and genetic data to agree in categorizing spiders by their genitalia. INTRODUCTION Phylogenetic trees demonstrate if species show any kind of relationship with one another when it comes to evolution. Spiders that contain different genitalia may not have the ability to reproduce with species. This is known as a prezygotic barrier. These barriers are formed by a genetic drift (Henrich, 2016). Having a barrier means not being able to reproduce and the gene flow gets cut off (Pérez-Barros, 2011). The spiders in this lab show two different genitalia. Either a spider has a one prong or two prong genitalia. These two spiders cannot mate if they do not have the matching prong. Which leads to the hypothesis; the phylogenetic tree, morphological data, and genetic data do not agree when classifying the spiders by their genitalia. METHODS At first, pictures of spider genitalia were looked at in order to sort out which spiders have one or two prongs. The information gathered about the different spider species was put into MEGA in order to be put in a phylogenetic tree to order them genetically. This program sorted the species based on genetics. Lastly, a morphological tree was constructed in order to sort the spiders out by their traits which is one or two prongs.

RESULTS

Figure 1: Genetic Phylogenetic Tree

Figure 2: Morphological Tree

Above in figure 1 is a phylogenetic tree which explains how the spiders are scattered around the tree despite how many prongs they have. There is a variation of species that are not grouped together in a clade because of their one prong or two prongs. In figure 2 is a morphological tree which categorizes the spiders by their traits such as if the spiders have one prong or two prongs. DISSCUSSIONS The hypothesis, which our group has conducted supports the claim: spiders cannot be classified by their traits. To answer the guiding question: phylogenetic tree, morphological data, and genetic data cannot classify the different species of spiders by their genitalia simply because traits do not have anything to due with being related in any type of data. It is shown in figure 1 that despite the spiders having similar traits, they are scattered throughout the phylogenetic tree. Prezygotic barriers enable spiders with different prongs to reproduce and have different genetics (Henrich, 2016). Having similar or different traits does not mean a species is more or less related, but rather is based on the genes that the species carry. CITATIONS Henrich, Tina, and Martin Kalbe. "The role of prezygotic isolation mechanisms in the divergence of two parasite species." BMC Evolutionary Biology, vol. 16, no. 1, 2016. Academic OneFile,

http://link.galegroup.com/apps/doc/A470585589/AONE?

u=ncliveecu&sid=AONE&xid=

cd0a45 dc. Accessed 19 Feb. 2019.

Pérez-barros, P., Calcagno, J. A., & Lovrich, G. A. (2011). Absence of a prezygotic behavioural barrier to gene flow between the two sympatric morphs of the squat lobster munida

gregaria (fabricius, 1793) (decapoda: Anomura: Galatheidae). Helgoland Marine Research, 65(4), 513-523. doi:http://dx.doi.org/10.1007/s10152-010-0240-1...