1. Kingdom Animalia
Multicellular, heterotrophic eukaryotes
Capable of controlled locomotion
Unique tissue: nervous and muscle
35 phyla
> 1 million described species
million estimated number of species
(See Table 32.1 for a more complete list of common characteristics)

2. Arose from a colonial flagellated protistan
Animal Origins
Arose from a colonial flagellated protistan
Colonial Theory (Haeckel)
Coordination and cooperation between cells
Common features between animals and protists

3. Proterospongia haeckeli
An extant colonial
choanoflagellate
Note cellular specialization
- flagellated cells
- amoeboid cells

5. Supporting Evidence for Colonial Theory
Flagellated sperm cells throughout Metazoa
Flagellated body cells among lower Metazoa
True eggs and sperm in phytoflagellates
Phytoflagellates and colonial organization

6. Animal Origins
Despite their morphological diversity, animals are monophyletic

7. Supporting Evidence
Flagellated sperm
Early stages of embryology
Common themes in animal body plans
Despite their morphological diversity, animals are monophyletic

8. Key Features in Animal Diversity
Level of organization
Symmetry
Body plan
Embryological development
Understanding differences and patterns evident in animal kingdom = understanding of animal macroevolution

10. Levels of Organization
Ancestral form had some specialized cells and some cooperation between cells
Subkingdom Parazoa, which includes the sponges, lack tissues
Evolution of tissues was next step in animal evolution
Compartmentalization into specialized “regions” was the next step

11. Organ Systems Organs Tissues Specialized Cells With increasing
specialization, eventually
see regionalization
Organs
Tissues
Specialized Cells

13. Fig. 32.8

14. Symmetry
How many planes can a body be divided into along its long axis and still get mirror images?

17. Animals that move in one direction have bilateral symmetry; can be divided into similar halves on only one plane.
The plane runs from the anterior end to the posterior end (tail).
A plane at right angle to the midline divides animals into dorsal and ventral (belly) surfaces.

18. Radial symmetry – typically in sessile animals (all or part of their life cycle)
Bilateral symmetry is associated with cephalization

19. Fig. 32.8

20. Body Plans
Attributes considered for all animals
Presence or absence of different tissue types
Type of symmetry
Presence or absence of a true body cavity

21. Body Plans – Bilateral Animals
All animals based on one of three body plans
Different body plans provide different adaptive advantages
Apparent trend - increased potential body size
Body cavity is area between body wall and internal organs

22. Body Plans – Bilateral Animals
Embryological development of tissues
Ectoderm
Mesoderm
Endoderm

23. Fig. 32.4c
Acoelomate

24. Fig. 32.4b
Pseudocoelomate

25. Fig. 32.4a
Eucoelomate

27. Acoelomate - cavity filled with tissue
Pseudocoelomate - cavity filled with liquid
Coelomate - cavity filled with fluid and organs supported by membranes

28. Fig. 32.8

29. Embryology and Developmental Biology

30. All animals go
through the same
initial stages of
embryonic development
(see Fig. 32.3)

31. Protostomes (“mouth first”): the blastopore develops into the mouth.
Deuterostomes (“mouth second”): the blastopore develops into the anus; the mouth develops later.

32. Embryological Development
Protostomes
spiral cleavage
determinate cleavage
mesoderm develops by cell sloughing
Deuterostomes
radial cleavage
indeterminate cleavage
mesoderm develops from tissue folds

33. Fig. 32.5

34. Fig. 32.8

35. Cambrian Explosion
All animal phyla except one appeared in a geological instant 545 mya
Some groups disappeared?
Why such diversity is so short a period of time (20 million years)?

36. Molecular View of Animal Phylogeny
Genomes and Proteomes – Hox genes and patterning of body axis in vertebrates
Feature Investigation – Taxonomic relationship of arthropods

38. See Table 32.2
Will be helpful for Chapters 33-34
For second Animal Diversity lab

39. Fig. 32.8