chapter 24 introduction to animals
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Chapter 24 Introduction to Animals. Section 1: Animal Characteristics. Section 2: Animal Body Plans. Section 3: Sponges and Cnidarians. Introduction to Animals. Chapter 24. 24.2 Animal Body Plans. Evolution of Animal Body Plans . - PowerPoint PPT PresentationTRANSCRIPT
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Chapter 24 Introduction to Animals
Section 1: Animal Characteristics
Section 2: Animal Body Plans
Section 3: Sponges and Cnidarians
24.2 Animal Body PlansIntroduction to Animals
Evolution of Animal Body Plans Anatomical
features in animals’ body plans mark the branching points on the evolutionary tree.
Chapter 24
24.2 Animal Body PlansIntroduction to Animals
Evolution of Animal Body Plans
Relationships on this tree are inferred by studying similarities in embryological development and shared anatomical features.
Chapter 24
Introduction to Animals
Symmetry Similarity or balance among body structures of organisms
24.2 Animal Body PlansChapter 24
Introduction to Animals
Symmetry TYPES OF SYMMETRY
Asymmetry – No tissue and irregular in shape Radial symmetry –
Has a top and a bottom but no sides Can be divided on multiple planes
24.2 Animal Body PlansChapter 24
Introduction to Animals
Symmetry TYPES OF SYMMETRY Bilateral symmetry –
Can be divided on one plane to show a mirror image on each side.
Has a top, bottom and sides.
24.2 Animal Body PlansChapter 24
Introduction to Animals
Cephalization Animals with bilateral symmetry tend to
have a posterior (tail-end) and anterior (head-end).
They also have a tendency to concentrate nervous tissue and sensory organs at the anterior end of the animal
24.2 Animal Body PlansChapter 24
Introduction to Animals
Body Cavities Coelomates
Have a fluid-filled cavity with tissue formed from mesodermthat lines and encloses the organs in the coelom
24.2 Animal Body PlansChapter 24
Introduction to Animals
Body Cavities Pseudocoelomates
Have a fluid-filled body cavity that develops between the mesoderm andthe endoderm rather than developing entirely within the mesoderm
24.2 Animal Body PlansChapter 24
Introduction to Animals
Body Cavities Acoelomates
Have solid bodies without a fluid-filled body cavity between the gut and the body wall
24.2 Animal Body PlansChapter 24
Introduction to Animals
Development in Coelomate Animals
Protostomes The mouth develops from the first opening in
the gastrula.
Deuterostomes The anus develops from the first opening in
the gastrula.
24.2 Animal Body PlansChapter 24
Introduction to AnimalsChapter 24
Introduction to Animals
Segmentation Segmented animals can be “put together”
from a succession of similar parts.
Can survive damage to one segment
Movement is more effective
24.2 Animal Body PlansChapter 24