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
9.
10.
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
14.
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
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