There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved. Charles Darwin (from ‘The Origin of Species’, 1859)  

CHAPTER 32 AN INTRODUCTION TO ANIMAL DIVERSITY Initially Prepared by Brenda Leady, University of Toledo Modified by John Cossel Jr., Northwest Nazarene University

Who is this class? -- Explore the syllabus I want to take advantage of the technology available to enhance your learning. Email -- Best way to get in touch with me… jocossel@nnu.edu (NOT “jcossel”) Internet -- There is a course webpage http://people.nnu.edu/jocossel/ PowerPoint -- Lecture material available off Internet

J.B.S. Haldane The Creator would appear as endowed with a passion for stars, on the one hand, and for beetles on the other, for the simple reason that there are nearly 300,000 species of beetle known, and perhaps more, as compared with somewhat less than 9,000 species of birds and a little over 10,000 species of mammals. Beetles are actually more numerous than the species of any other insect order. That kind of thing is characteristic of nature.

Characteristics Lack… Most have _________, ________, capacity to move at some point in the life cycle Ability to… Specialized ________ ________and _________ system Cells exist in extensive _________ ______ Unique ______ ________

Traditional classifications Most biologists agree kingdom is _____________ Animal ________ are very similar Most likely ancestor a __________ ________ ___________ similar to _____________ About ___ recognized animal phyla

Who are the animal phyla?

Traditional classification based on body plans 4 main morphological and developmental features used

Tissues ________ divided into __________ (no specialized tissues or organs) and __________ (more than one type of tissue and organs)

Symmetry Eumetazoa are _______ __________(Radiata) or ___________ _______________ (Bilateria) Bilateral animals have __________ and _____ and ______ surfaces Radial animals have _______ and _______ sides

Spatial terminology…

Number of cell layers Radial animals have 2 embryonic cell layers ___________ Bilateral animals have 3 germ layers Cell layers develop during _______________ Inner layer – ______________ Outer layer – ______________ ___________ - 3rd layer in bilateral animals Forms muscles and most other organs http://www.youtube.com/watch?v=8v6cXkzlEQA

http://www.youtube.com/watch?v=UgT5rUQ9EmQ

Body cavity ______________– body cavity is completely lined with mesoderm (coelomates) ______________ – coelom is not completely lined by tissue derived from mesoderm (pseudocoelomates) ______________ – lack a body cavity entirely Fluid-filled body cavity can protect internal organs or be used as ___________ ______

Embryonic development Which is which (usually)?!? Spiral cleavage Schizocoelous coelom development Blastopore becomes anus Cleavage is indeterminate- pluripotent stem cells Radial cleavage Enterocoleus coleom development Blastopore becomes mouth Cleavage determinate

Other methods of classification Possession of ____________ Development of _____________ Presence or absence of ___________ (segmentation) Traced to changes in ______ _____

Changes in Hox Gene Expression Control Body Segment Specialization Based on relatively simple changes in the expression patterns of Hox genes Hox genes designated 1-13 Shifts in patterns of gene expression in the embryo along the anteroposterior axis govern transition from one type of vertebra to another and short or long necks Mice, chicken, goose, and snake Illustrates descent with modification

Molecular views of animal diversity Molecular techniques used to classify animals by comparing similarities in the ______ and the _______________ of animals, especially sequences of nucleotides in the gene that encodes RNA of the small ribosomal subunit (________) Advantage generally more objective and subject to more rigorous testing

Aguinaldo and Colleagues Used 18S rDNA to Analyze the Taxonomic Relationships of Arthropods to Other Taxa Sequenced the complete gene encoding SSU rRNA Relationships among 50 species determined Data indicated existence of monophyletic clade- the ______________ – containing … Ramifications of studies involving Drosophila melanogaster and Caenorhabditis elegans

Similarities between traditional and molecular phylogeny The clade called Metazoa is ____________, meaning all animals came from a single common ancestor. At the earliest stages of evolution, molecular phylogeny supports the traditional view of the split between… There is also agreement about an early split between… with most animal phyla belonging to the Bilateria. Molecular phylogeny also agrees that the echinoderms and chordates belong to a clade called the _______________.

2 key differences between traditional and molecular phylogeny Division of protostomes into 2 clades Traditionally split into Deuterostomia and Protostomia based on embryonic development Deuterostomes still separate but protostomes divided into _______________ and __________ Presence or absence of a body cavity Traditionally split into coelomates, pseudocoelomates and acoelomates Molecular evidence indicates presence or absence…