{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Chapter 32 - An Introduction to Animal Diversity

Chapter 32 - An Introduction to Animal Diversity - Chapter...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 32 Class Notes – An Introduction to Animal Diversity – Page 1 Max Sauberman AP Biology – Mr. Schilp Chapter 32 An Introduction to Animal Diversity Our Kingdom: Biologists have identified 1.3 million living species of animals, and estimates run to as many as 200 million. Distinguishing the Animal Kingdom: Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers. Five criteria comprise a reasonable definition of an animal… 1. Animals are multicellular ingestive heterotrophs a. Taking in organic molecules through ingestion (eating) 2. Animal cells lack cell walls that provide structural support for plants and fungi a. Multicellular bodies are held together by extracellular structural proteins (collagen) b. Animals have intercellular junctions: tight junctions, desmosomes, and gap junctions, that all hold tissues together and are comprised of structural proteins 3. Animals uniquely have nerve cells (impulse connection) and muscle cells (movement) 4. Most animals reproduce sexually, with a dominant diploid stage a. A small flagellated sperm fertilizes a nonmotile egg b. The zygote undergoes cleavage, a succession of mitotic cell divisions, leading to the formation of a multicellular hollow ball of cells: the blastula c. During gastrulation, part of the embryo folds inward, forming layers of embryonic tissues that will develop into adult body parts i. The resulting development stage is a gastrula d. Some animals have a distinct larval stage i. A larva is a sexually immature stage that is morphologically distinct from the adult, usually eats different foods, and may live in a different habitat than the adult ii. Animal larvae undergo metamorphosis and become adults 5. Animals share a unique homeobox-containing family of genes: Hox genes a. All eukaryotes have genes regulating the expression of other genes b. Many of these genes contain common homeobox DNA sequences c. All animals share the unique family of Hox genes d. Hox genes control cell division/differentiation, and produce different morphological features
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
Chapter 32 Class Notes – An Introduction to Animal Diversity – Page 2 e. Hox genes in sponges regulate the formation of channels; in bilaterians, they regulate patterning of the anterior-posterior axis The history of animals: Animals began to diversify over a billion years ago, diverging from the ancestors of fungi as much as 1.5 billion years ago. The common ancestor was probably a colonial flagellated protist and may have resembled modern choanoflagellates. Neoproterozoic Era: The oldest generally accepted animal fossils are only 575 million years old.
Image of page 2
Image of page 3
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