{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture20_Extinctions

Morphological selectivity individuals possessing

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

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: — whole clades affected or not. Morphological selectivity — individuals possessing certain morphological easy to visualize, difficult to interpret features are more vulnerable Ecological selectivity — spets affected more than generalists Biogeographic selectivity — widespread taxa tend to survive more than geographically restricted taxa tropic > temperate Periodicity of extinctions Pattern of 26 million year cycles in families of marine invertebrates (Raup and Sepkoski, 1984) - Is it real? Implies a common cause for mass extinctions - is there evidence? carnivores > herbivores large > small all patterns dependent on quality of stratigraphic record; FADs and LADs assumed true Part 2: Mass Extinctions Patterns of mass extinctions, attributed to various causes: Catastrophic extinction Abrupt and global changes cause synchronous extinctions at a geological boundary, with few if any survivors Stepped mass extinction Groups of species sensitive to change become extinct first, with more robust groups becoming extinct in subsequent episodes Graded mass extinction Rate of extinction increases beyond bac...
View Full 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