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18.1 Finding Order in Diversity

Questions Answers

1. What is the problem with using common names to describe and categories organisms? There can be many of them, and they might refer to different species.
2. What is binomial nomenclature? Which two parts of an organism’s classification are used? Google your favorite plant or animal and report its binomial (scientific) name. A two word naming system where each species has its own specific name.

Ophiocordyceps unilateralis

3. The scientific name for some species of llama is “Llama glama”. Did that fun fact make you smile? Oui.
4. Put the following terms in the correct order from most general to most specific (Containing the largest number of organisms to containing the smallest number of organisms):

order, phylum, genus, kingdom, species, family, class

Kingdom, phylum, class, order, family, genus, species.  
(King phillip came over from germany saturday.)
5. Linnaeus’s strategy of classification focused mostly on physical similarities and differences. Is there a problem with that? What characteristics might scientists use today to classify organisms more accurately? There is a problem because scientists won’t know which traits to categorize by.  Today scientists might use DNA testing for more accurate results.



18.2 Modern Evolutionary Classification

Questions Answers

1. What is phylogeny? The evolutionary history of lineages.
2. The terms “clade” and “monophyletic group” can both be used for the same thing. What specific groups of organisms are these terms referring to? Ones that have a common ancestor.
3. i. What is the function of a cladogram?

ii.How is speciation represented in a cladogram?

  1. A cladogram is a graph that shows a common ancestor and species breaking out by adaptations to form new species.
  2. It is represented by two endpoints  
4. According to the cladogram on page 517, which species is more closely related to crocodiles: birds, or lizards? birds
5i.  What is a derived character?

ii. Give an example of a derived character

iii. Give an example of a trait that would NOT be considered a derived character, and explain why

  1. A derived character is a trait in somethings most recent common ancestor and was passed down to its descendants.
  2. Snout jaws on dogs and wolves
  3. Hair on humans and apes because it is not a specific trait.
6. Look at the cladogram on page 519.

Briefly explain what information a cladogram can tell you, and at least one piece of information that a cladogram cannot tell you.

It can tell us what points species evolved from, but it can not tell us why they evolved the way they did.
7. Our classification system still has its weaknesses, but sometimes we must classify organisms in ways that do not align with cladistics.

Explain why the class reptilia is not considered a clade.

Reptilia is not a clade because there is another class with birds in it.  Reptilia would only be a clade if birds were included in the class.
8. A scientist may use a cladogram as a tool to hypothesize evolutionary relationships. How might a scientist test to see if his or her cladogram is correct? (Hint: page 521) A scientist would take DNA samples of all the species on the cladogram and compare the changes to see if they were correct.



18.3 Building the Tree of Life

Questions Answers

1. The late 1800s was when scientists began to realize that there is more to life than plants and animals, and another key kingdom – the protists – was created. What major piece of technology to you think led to this new way of looking at life? Modern microscopes?
2. Explain the change from the single kingdom “Monera” to “Eubacteria” and “Archaebacteria”. Scientists looked at the genetics and realized that there were some differences
3. We (lovingly) refer to the protists as the random group of organisms that don’t really fit anywhere else. Use the term “monophyletic groups” to explain this in a more scientifically accurate way.

Hint: Don’t know what a monophyletic group is?  Revisit section 18.2

Protists are their oun monophyletic group because they have a different common ancestor than the other kingdoms.
4. Briefly describe the main characteristics of the three domains. Bacteria; unicellular and prokaryotic, have peptidoglycan in their cell walls.

Archaebacteria: unicellular and prokaryotic.   Lack peptidoglycan and have unusual lipids.

Eukarya;  Have a nucleus.  

5. It seems strange that the Bacteria and Archaea domains each only have one kingdom. Why can’t scientists put bacteria and archaea into one domain, branching away from eukarya at one point and then separating from each other later?

In other words, why would this be wrong:

Hint: Think about how we read cladograms

They evolved to have a nucleus, that would imply that the bacterias evolved to not have one.  
THey cannot be their own kingdom because there are too many differences between them.
6. Name and briefly describe the four kingdoms within the domain Eukarya. Fungi  heterotrophs with cell walls containing chitin.  Feed on dead matter by secreting enzymes. Mostly multicellular.

Plantae  Autotrophs with cell walls containing cellulose.  Nonmotile and use photosynthesis to create food.

Protista  Mostly unicellular, some are synesthetic while others are heterotrophic.  Many look like other kingdoms.

Animalia  Multicellular and heterotrophs.  No cell walls and can move around.  


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