Chapter 6 Classifying Nature’s Diversity

Overview

Life on Earth is extremely diverse, with an estimated ten million species or more. Why is life so diverse and so prolific? How do we describe this diversity? How can we begin to understand it? As Charles Darwin observed, every living species has so great a tendency to reproduce that, if left unchecked, there would soon be no standing room left on Earth for all its progeny. As we saw in Chapter 5, species can also undergo speciation: splitting and thus creating additional species. This process has been going on so long and so frequently as to have produced the many millions of species alive today, plus an even greater number of species that have become extinct in the past. In this chapter, we will describe certain innovations that greatly increased the ability of biological species to succeed in life and to speciate further.

Chapter Outline

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Review Questions

THE PURPOSE of these review quizzes is to guide students in where their knowledge and understanding is strong, where it is weak, and where time should best be spent in studying.

CHAPTER 6:

  1. What is the Linnaean system?  What is cladistics, and how does it differ from other approaches to classification?  (If you cannot explain these things, or if you are not sure, then you need to reread Section 6.1.)
  2. How do prokaryotic cells differ from eukaryotic cells?    (If you cannot explain this, or if you are not sure, then you need to reread Section 6.2.)
  3. What are some of the several kinds of prokaryotic organisms?  How do they differ from one another?  What innovations characterized evolution within the Archaea and Eubacteria?  (If you cannot explain these things, or if you are not sure, then you need to reread Section 6.3.)
  4. What are some of the advantages of compartmentalization?  What are some of the advantages of regional specialization within the parts of cells?  What are some advantages of multicellularity, and how do we think multicellular organisms evolved?  (If you cannot explain these things, or if you are not sure, then you need to reread Section 6.2.)
  5. How do we think eukaryotic cells first arose?  What were the steps in this process?   What is the evidence for this process?  (If you cannot explain these things, or if you are not sure, then you need to reread Section 6.4.)
  6. How are eukaryotic organisms now classified?  Why did our classification change?  What groups are now recognized?  What key innovations may have occurred more than once?  (If you cannot explain these things, or if you are not sure, then you need to reread Section 6.4.)
  7. Some of the major events that characterized evolution within the animal kingdom include the evolution of separate body tissues, bilateral symmetry, body cavities, ecdysis, segmental organization, filter feeding, a notochord, and pharyngeal gill slits.  Why did each of these evolve, and what circumstances favored their evolution?  How do these innovations explain the currently recognized phyla and groups of phyla?   (If you cannot explain these things, or if you are not sure, then you need to reread Section 6.4.)
  8. What are the major characteristics of primates?  Why did these evolve?  How do humans differ from other primates, and why did these differences evolve?  What major changes have taken place during human evolution?  (If you cannot explain these things, or if you are not sure, then you need to reread Section 6.5.)

Open Response Study Questions

These questions are designed to assess your understanding of the topics explored in this chapter. You can use these questions in three ways:

Before you start …

Read through the questions before you read the chapter to help prime you to read the text more carefully and strategically. Remember that you are just starting out on your learning journey, so don’t feel disheartened if you don’t know how to answer them yet!

Whilst you read …

As you work through the chapter, have another go at answering the questions to see how you are progressing. You can also answer the questions with the textbook open in front of you, in order to create model answers that can be used to refer back to later.

At the end …

Answer the questions once you have finished reading to see what you have learned. Check your responses against your model answers and use these to identify any gaps in your understanding.

DEFINITIONS:

In your own words, define ANY TWO of the following terms:

clade      animal          Ecdysozoa       Cell Theory     deuterostome     ectoderm        

endosymbiosis             gastrula           monophyletic              planktonic            pseudopod       hominins        

ESSAYS:

Answer any two of the following questions.  Make sure to answer all parts of any question you choose.

1. Explain at least five important differences between prokaryotic and eukaryotic cells.

2. Explain at least three separate pieces the evidence that support the theory of endosymbiosis.

3. Explain the evidence for the unity of the taxon Archaeplastida, and for the distinctness of plants within that taxon.

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Bibliography

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Brocks, J.J., et al. 1999. Archaean molecular fossils and the early rise of eucaryotes. Science 285: 1033-1036.

Brusca, R.C., and G.L. Brusca. 1990. Invertebrates. Sunderland, MA: Sinauer.

Carroll, R.L. 1988. Vertebrate Paleontology and Evolution. New York: W.H. Freeman.

Ciccarelli, F. D., et al.  2006. Toward Automatic Reconstruction of a Highly Resolved Tree of Life. Science. 311 (5765): 1283–1287. Bibcode:2006Sci…311.1283C.   CiteSeerX 10.1.1.381.9514. doi:10.1126/science.1123061. PMID 16513982.

Clarkson, E.N.K. 1998. Invertebrate Paleontology and Evolution, 4th ed. New York: Chapman and Hall.

Colbert, E.H., M. Morales, and E.C. Minkoff. 2001. Colbert’s Evolution of the Vertebrates, a History of the Backboned Animals Through Time. New York: Wiley-Liss.

Delson E. 2019. An early dispersal of modern humans from Africa to Greece. Nature, 571(7766): 487-488. doi:10.1038/d41586-019-02075-9 

Erickson, H.P. 2017. The discovery of the prokaryotic cytoskeleton: 25th anniversary. Mol. Biol. Cell 28(3): 357-358. https://dx.doi.org/10.1091%2Fmbc.E16-03-0183

Felsenstein, J. 2003. Inferring Phylogeny. Sunderland, MA: Sinauer.

Fenchel, T. 2002. Origin and Early Evolution of Life. New York: Oxford University Press.

Harvati, K., et al. 2019.  Apidima Cave fossils provide earliest evidence of Homo sapiens in Eurasia.  Nature,  571: 500-504.  https://www.nature.com/articles/s41586-019-1376-z 

Hirt, R.P., and D.S. Horner, editors. 2004. Organelles, Genomes, and Eukaryote Phylogeny. Boca Raton, Fl: CRC Press.

Holt, J.G., et al. 2000. Bergey’s Manual of Determinative Bacteriology, 9th ed. Philadelphia: Lippincott, Williams & Wilkins.

Jørgensen, B.B., and V.A. Gallardo. 1999. Thioploca spp.: filamentous sulfur bacteria with nitrate vacuoles.  FEMS Microbiol. Ecol. 28: 301-313.

Maddison, D. R. and K.-S. Schulz (eds.) 2007. The Tree of Life Web Project. http://tolweb.org

Mayr, E., and P.D. Ashlock. 1991. Principles of Systematic Zoology, 2nd ed. New York: McGraw-Hill.

Margulis, L. 1970. Origin of Eukaryotic Cells. New Haven: Yale University press.

Margulis, L. 1981. Symbiosis in Cell Evolution: Life and its Environment on the Early Earth. San Francisco: W.H. Freeman.

Margulis, L., and D. Sagan. 2002. Acquiring Genomes: A Theory of the Origins of Species. New York: Basic Books.

Nielsen, C. 1995. Animal Evolution: Interrelationships of the Living Phyla. New York: Oxford University Press.

Oren, A., and G.M. Garrity. 2021.  Valid publication of the names of forty-two phyla or prokaryotes.  Int. J. Syst. Evol. Microbiol. 71(10): 5056.  https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijsem.0.005056  https://doi.org/10.1099/ijsem.0.005056

Parks, D.H. et al. (2018). A standardized bacterial taxonomy based on genome phylogeny substantially revises the tree of life. Nature Biotechnology 36(10): 996–1004. bioRxiv 10.1101/256800. doi:10.1038/nbt.4229. PMID 30148503. S2CID 52093100.

Pearson, L.C. 1995. The Diversity and Evolution of Plants. Boca Raton, FL: CRC Press.

Raven, RH., and S.E. Eichhorn. 1999. Biology of Plants, 6th ed. New York: W.H. Freeman, Worth Publishers.

Simonetta, A.M., and S. Conway Morris. 1991. The Early Evolution of Metazoa and the Significance of Problematic Taxa. Cambridge, UK: Cambridge University Press.

Slon V., et al. 2018.  The genome of the offspring of a Neanderthal mother and a Denisovan father.  Nature, 561(7721): 113-116.

Spoor F.  2019.  Elusive cranium of early hominin found.  Nature, 573(7773): 200-202, DOI: 10.1038/d41586-019-02520-9  

Tucci S. et al.  2018.  Evolutionary history and adaptation of a human pigmy population of Flores Island, Indonesia.  Science,  361(6401): 511-516.

Wiley, E.O. 1981. Phylogenetics. The Theory and Practice of Phylogenetic Systematics. New York: Wiley.

Willmer, P. 1990. Invertebrate Relationships. Patterns in Animal Evolution. Cambridge, UK: Cambridge University Press.

Yarza, P., et al. (2008). The All-Species Living Tree project: A 16S rRNA-based phylogenetic tree of all sequenced type strains. Systematic and Applied Microbiology 31(4): 241–250. doi:10.1016/j.syapm.2008.07.001. hdl:10261/103580. PMID 18692976.

SEE:   Bacterial taxonomy article in Wikipedia, incl. phylogeny & ref to Ciccarelli et al [44]

Ciccarelli, F. D., et al.  2006. Toward Automatic Reconstruction of a Highly Resolved Tree of Life. Science. 311 (5765): 1283–1287. Bibcode:2006Sci…311.1283C.   CiteSeerX 10.1.1.381.9514. doi:10.1126/science.1123061. PMID 16513982.      LifePx2.png

See also: 

https://en.wikipedia.org/wiki/%27The_All-Species_Living_Tree%27_Project

https://en.wikipedia.org/wiki/Branching_order_of_bacterial_phyla_(Genome_Taxonomy_Database,_2018)

http://bioweb.uwlax.edu/bio203/f2013/voye_rach/classification.htm

https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijsem.0.005056

            names of 42 prokaryotic phyla (as of October 2021):

Based on Ciccarelli et al. (2006), Yarza et al. (2008), and Parks et al. (2018), with names of bacterial phyla after Oren and Garrity (2021) wherever possible.

Chapter 7
Human Variation