Intermediate and transitional forms

Intermediate and transitional forms - Intermediate and...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
. Intermediate and transitional forms: the possible morphologies of predicted common ancestors All fossilized animals found should conform to the standard phylogenetic tree. If all organisms are united by descent from a common ancestor, then there is one single true historical phylogeny for all organisms. Similarly, there is one single true historical genealogy for any individual human. It directly follows that if there is a unique universal phylogeny, then all organisms, both past and present, fit in that phylogeny uniquely. Since the standard phylogenetic tree is the best approximation of the true historical phylogeny, we expect that all fossilized animals should conform to the standard phylogenetic tree within the error of our scientific methods. Every node shared between two branches in a phylogeny or cladogram represents a predicted common ancestor; thus there are ~29 common ancestors predicted from the tree shown in Figure 1 . Our standard tree shows that the bird grouping is most closely related to the reptilian grouping,
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern