{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

[BIO 1306] Ch33_Lecture

[BIO 1306] Ch33_Lecture - 33 Deuterostome Animals 33...

Info icon This preview shows pages 1–17. Sign up to view the full content.

View Full Document Right Arrow Icon
33 Deuterostome Animals
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
33 Deuterostome Animals 33.1 What is a Deuterostome? 33.2 What Are the Major Groups of Echinoderms and Hemichordates? 33.3 What New Features Evolved in the Chordates? 33.4 How Did Vertebrates Colonize the Land? 33.5 What Traits Characterize the Primates?
Image of page 2
33.1 What is a Deuterostome? Deuterostomes are characterized by three early developmental patterns: Radial cleavage Mouth forms opposite the blastopore Coelom develops from mesodermal pockets that bud off from the cavity of the gastrula
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
33.1 What is a Deuterostome? The first two are the ancestral states for all bilaterian animals. Evidence from DNA sequencing supports the monophyly of the deuterostomes; echinoderms, hemichordates, and chordates. There are fewer species of deuterostomes than protostomes.
Image of page 4
Figure 33.1 A Current Phylogenetic Tree of the Deuterostomes
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
33.1 What is a Deuterostome? Deuterostomes are triploblastic, coelomate animals with internal skeletons.
Image of page 6
33.1 What is a Deuterostome? Recently discovered fossils of early deuterostomes in China: Homalozoans : skeleton similar to echinoderms, but also bilateral symmetry and pharyngeal gill slits. Vetulicosystids also had pharyngeal gill slits. Yunnanozoans had external gills and a segmented posterior section.
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Figure 33.2 Ancestral Deuterostomes Had External Gills
Image of page 8
33.1 What is a Deuterostome? Bilateral symmetry is the ancestral condition. Echinoderms evolved unique pentaradial symmetry; other deuterostomes retained bilateral symmetry.
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
33.2 What Are the Major Groups of Echinoderms and Hemichordates? Only six of 23 groups of echinoderms known from fossils survive today. Nearly all are marine. Hemichordates: 95 living species Together they are known as the ambulacrarians .
Image of page 10
33.2 What Are the Major Groups of Echinoderms and Hemichordates? Echinoderm larvae have bilateral symmetry, as they develop into adults, it changes to pentaradial symmetry (in fives or multiples of fives). Echinoderms have no head, and move equally well in many directions. They have an oral side containing the mouth, and an aboral side containing the anus.
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Figure 33.3 Evolutionary Innovations of Echinoderms (Part 1)
Image of page 12
Figure 33.3 Evolutionary Innovations of Echinoderms (Part 2)
Image of page 13

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
33.2 What Are the Major Groups of Echinoderms and Hemichordates? Echinoderms have a system of internal calcified plates covered by thin layers of skin and some muscle. The plates fuse to form an internal skeleton.
Image of page 14
33.2 What Are the Major Groups of Echinoderms and Hemichordates? The water vascular system is a network of water-filled canals leading to the tube feet. Functions in gas exchange, locomotion, and feeding. Water enters through the madreporite , which is connected to the ring canal around the esophagus. Other canals radiate out from the ring canal.
Image of page 15

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
33.2 What Are the Major Groups of Echinoderms and Hemichordates?
Image of page 16
Image of page 17
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