Animal Systems
Page 738: Body Symmetry
&
Chapters 27 through 28
What is an animal?
Scientific Definition
Animal: eukaryotes that are multicellular
heterotrophs that do not have a cell wall.
Characteristic
Eukaryotic
So the are not…
Prokaryotes (Bacteria or Archaea)
Multicellular
Heterotrophic
Absent Cell Wall
Protists
Plants and algae
Plants, algae, or fungi
FYI…
• 3-30 million species
• 97% of all species are invertebrates
Invertebrates
• The vast majority of animals are Arthropods (1,170,000 to
10 million species)
• Of all invertebrates, the insects (part of the arthropods) are
by far the most numerous. About 1-30 million+ species
• For comparison, chordates (including mammals) consist of
about 75,000 species
Arthro  “jointed”
+ pod  + “foot” or “leg”
Arthropod “jointed leg”
Chordates
Arthropods
Some terms used to describe animals
Body Symmetry
• Asymmetrical = without symmetry
• Radial Symmetry =
symmetry around a central axis
• Bilateral Symmetry
–can be divided into symmetrical
halves on either side of a plane
Examples of
Asymmetrical
Animals
Porifera (Sponges)
This is a cut
out piece for
marketing
uniformity
Radial
Symmetry
Animals with
Radial Symmetry
Examples of Animals
with Bilateral Symmetry
Body Orientation (used in humans)
• The Anatomical Position: The Do not let this
intimidate you…
anatomical position describes
a person that is standing erect
with the feet facing forwards,
arms hanging to the sides, and
the palms of the hands facing
forward. Directional terms are
always from the patient’s
perspective. When we refer to
the right side we are referring
to the patient’s right side
=
Body Planes of Animals
(including humans)
Term
Sagittal
(or Median)
Frontal
(or Coronal)
Definition
Divides the body into right
and left halves
Divides the body into
anterior and posterior
halves
Transverse
Divides the body into
(or Horizontal) superior and inferior
halves
Directional Terms
• Right and left – Refers to the
Patient’s right or left side
• Proximal – Near, closer to the origin
Distal – Away from, farther from the
origin
• Lateral – Toward the side, away
from the mid-line
Medial – Toward the mid-line,
middle, away from the side
Directional Terms
• Superior – Above, Over
Inferior – Below, Under
• Anterior – In front of, front
Posterior – Behind, toward
the rear
• Ventral – Toward the belly
Dorsal – Toward the back
Directional Terms Quick Check
Term
Definition
1 Superior
2 Inferior
3 Anterior
4 Posterior
5 Lateral
6 Medial
7 Proximal
8 Distal
9 Ventral
10 Dorsal
Directional Terms Quick Check
Term
Superior
Inferior
Anterior
Posterior
Lateral
Medial
Definition
1
Above, Over
2
Below, Under
3
In front of, front
4
Behind, toward the rear
5
Toward the side, away from the mid-line
Toward the mid-line, middle, away from the
6
side
7 Proximal Near, closer to the origin
8 Distal
Away from, farther from the origin
9 Ventral Toward the belly
10 Dorsal
Toward the back
Other animal examples…
Vocabulary
1.
2.
3.
4.
5.
6.
7.
8.
9.
Anatomical Position
Anterior
Asymmetrical
Bilateral Symmetry
Distal
Dorsal
Frontal (or Coronal)
Inferior
Lateral
10.Medial
11.Posterior
12.Proximal
13.Radial Symmetry
14.Right and left
15.Sagittal (or Median)
16.Superior
17.Transverse (or Horizontal)
18.Ventral
Due tomorrow at the beginning of class:
1.Write a story using seven of these words (as they
are used in biology) EXCLUDING right and left.
2.No definitions in your story.
3.I must be able to tell that you know what the word
means from the story.
4.No more than one vocabulary word in a sentence.
5.If I can’t read your handwriting, I wont.
In other words TYPE IT or write legibly.
6.No legible first name, last name, OR period = LATE