The document summarizes key characteristics of the Kingdom Animalia. To be an animal, an organism must be multicellular, heterotrophic, reproduce sexually, lack cell walls, be motile during some stage of life, have rapid responses to stimuli, and contain two unique tissues: nervous and muscle tissue. Over time, animals evolved increasing complexity in their cellular organization, body plans, degree of centralization, body cavities, segmentation, and digestive systems. The evolutionary origin of animals is believed to have started from colonial protists in the sea that underwent cell specialization, leading to the first multicellular organisms.

1. Kingdom Animalia

2. In order to be in the Kingdom Animalia, an
organism must be considered:
 Multicellular
 Heterotrophic
 Typically reproduce sexually
 Lack cell wall
 Motile during some life stage
 Rapid response to external stimuli
 Have 2 types of tissues only found in
animals: nervous tissue and muscle
tissue

3. Over time, animals
increased in complexity
 Level of cellular organization and
specialization
 Type of symmetry of body plan
 Degree of cephalization
 Presence and type of body cavity
 Presence of segmentation
 Structure of digestive system

4. Key Term: Cephalization
 A concentration of nervous tissue and
feeding mechanisms in the head
region that serves to integrate the
activities of the nervous system

5. Evolutionary Origin of
Animals
 Animals are
thought to have
arisen from the
sea, from colonial
protists

6. It is believed that some
of these protists
colonies began to fold
inward, creating a
gastrula-like
protosome.
In this stage, cell
specialization
occurred, paving the
way for the evolution of
true multi-cellular
organisms

7. Cell Specialization and
Tissue Formation
 First cell divisions
are known as
cleavages
 Several cleavages
produces a small
hollow ball of cells

8.  As they continue to
divide, the cells get
pushed towarsd the
interior, creating a
BLASTULA
 Differentiation (ie. Cells
become specialized)
occurs in late stages of
blastula

11. 3 Types of Tissue
 Endoderm:
 Gives rise to: liver pancreas, lungs,
lining of digestive tract
 Found in the inner layer

12. 3 Types of Tissue
 Mesoderm:
 Gives rise to: notochord, lining of
coelem, muscles, skeleton, circulatory
system
 Found in the middle layer

13. 3 Types of Tissue
 Ectoderm:
 Gives rise to: covering of the body,
central nervous tissue
 Found in the outer layer

15.  If a body cavity is present between the
digestive tract and the outer layer wall
it is referred to as a coelom

16.  This body cavity is lined with the
mesoderm, which produces a circulatory
system in the body (nutrients and oxygen
therefore don’t diffuse into all body cells)

17. Advantages to having a
coelem
 Acts as a cushion for internal organs
 Provides more room for internal
organs to expand
 Allows animal to become larger
 Allows digestive tract to develop
specialized regions and blood vessels

18. 4 types of body plans:
Radial
Symmetry
Spherical
Symmetry
Bilateral
Symmetry
Asymmetry

19. Asymmetry
 Lack symmetry
 No top or bottom
 No sides are mirror images
 Ex. The hydra

20. Spherical
 Arranged around a central point
 Not top, bottom, left or right, head or
rear
 Ex. Sea Urchins

21. Radial
 Arranged around a central axis like
spokes on a wheel
 Has a top and a bottom
 Ex. Starfish

22. Bilateral
 Arranged around a midline
 Left and right sides
 Sides are mirror images
 Ex. Butterfly

23. Key Term: Cephalization
 The concentration of sensory
tissues at anterior end
 Travelling animal can sense food,
danger, and other stimuli
 A head end is an adaptation for
movement (ie. Burrowing)
 More active animals are generally
bilateral and have cephilization

24. Simple Animals
 Porifera
 Cnidaria

25. Worm-like Animals
 Flatworms
 Roundworms
 Segmented Worms

26. Invertebrates
 Mollusca
 Echinodermata

27. Joint-legged animals-
Arthropods
 Crustacea
 Arachnida
 Insecta
 Diplopoda and Chilopoda

28. Internal Skeletons
(chordates)
 Ancestral chordates
 Urachordata (tunicates)

29. Internal Skeletons
(chordates)
 Vertebrates
 Cephalochordata (lancelets)

30. Internal Skeletons
(chordates)
 Vertebrates
 Chodrichthyes (sharks) Tiger Shark
Basking Shark (endangered)

31. Internal Skeletons
(chordates)
 Vertebrates
 Ostekcthyes
 (bony fish)

32. Internal Skeletons
(chordates)
 Vertebrates
 Amphibia
(frogs and
salamanders)
Poisonous Dart Frog

33. Internal Skeletons
(chordates)
 Vertebrates
 Reptilia

34. Internal Skeletons
(chordates)
 Vertebrates
 Aves (birds)
Carara Bird

35. Internal Skeletons
(chordates)
 Vertebrates
 Mammalia