The Phylogeny of Caminalcules

Using a large sheet of paper, construct a phylogenetic tree for the Caminalcules.  Use a meter stick to draw 20 equally spaced horizontal line on the paper.  Each line will be used to indicate an interval of one million years.  Label each line so that the one at the bottom of the paper represents an age of 19 million years and the top line represents the present (0 years).

Cut out all the Caminalcules (including the living species).  Put them in piles according to their age (the number in parentheses).  Beginning with the oldest fossils, arrange the Caminalcules according to their evolutionary relationship.  Figure 4 shows how to get started.

Figure 4

Hints, Suggestions and Warnings

a.     Draw lines faintly in pencil to indicate the path of evolution.  Only after your instructor has checked your tree should you glue the figures in place and darken the lines.

b.     Branching should involve only two lines at a time:
Like this                                                 Not this

 

 

c.     Some living forms are also found in the fossil record.

d.     There are gaps in the fossil record for some lineages.  Also, some species went extinct without leaving any descendants (remember the dinosaurs, Fig. 1).

e.     The Caminalcules were numbered at random; the numbers provide no clues to evolutionary relationships.

f.      There is only one correct phylogenetic tree in this exercise.  This is because of the way that Joseph Camin derived his imaginary animals.  He started with the most primitive form (#73) and gradually modified it using a process that mimics evolution in real organisms.  After you complete your phylogeny compare it with Camin's original.

LIVING CAMINALCULES

FOSSIL CAMINALCULES          (numbers in parentheses indicate age in millions of years)


 

Cammanicules Questions

1. Some lineages are very extensive throughout time, some lineages stop abruptly.  How would Darwin explain this phenomenon?

 

1. Some lineages (e.g. the descendants of species 58) changed very little over time.  A good example of this would be “living fossils” like the horseshoe crab or cockroach.  Again, discuss How Darwin would explain this in the fossil record.

1. Some Caminalcules went extinct without leaving descendents. In the real world, what factors might increase or decrease the probability of a species going extinct?

 

1. Describe two examples of vestigial structures that you can find among the Caminalcules.  These are structures that have been reduced to the point that they are virtually useless.  Ear muscles and the tail bones are examples of vestigial structures in our own species. 

1. Explain how vestigial structures provide clues about a species’ evolutionary past.  Illustrate your argument with vestigial structures found in humans or other real species.

 

1. Creature 57 has developed claws from its ancestors. What hypothetical purpose might these have had for that creature?

1. How would Lamark explain the emergence of these claws?

 

1. If we were to do detailed analysis of the structures of these creatures, which creatures would we expect to see homologous structures.  Explain your answer.

1. Would we expect find these fossils in the same area, like from a single river bed, spread out across a continent, or from multiple continents.  Justify your answer with an explanation of biogeography.

 

1.  Creatures 10 and 24 have fat abdomens.  Why would Darwin still say these creatures still have a high degree of fitness?

1. If we were to do a DNA analysis of the following creatures: 2,3,13,20 and 24, which would we expect to be the most similar.  Explain why.

 

1. Why would biologists what to find DNA samples of the different creatures?  How would that data be used to correct mistakes in the arrangements or phylogeny?