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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…
[email protected] (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
1)
2)
3)
4)
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
3.
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 ___________ ______
4.
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 cladethe ______________ – containing …
Ramifications of studies involving Drosophila
melanogaster and Caenorhabditis elegans
Similarities between traditional and
molecular phylogeny
1.
2.
3.
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.
4.
Molecular phylogeny also agrees that the echinoderms
and chordates belong to a clade called the
_______________.
2 key differences between
traditional and molecular phylogeny
1.
Division of protostomes into 2 clades


2.
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…