Transcript The Animal Kingdom

The Animal Kingdom
Anatomical Positions
DORSAL
ANTERIOR
POSTERIOR
VENTRAL
Directional Orientation
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Anterior vs. Posterior
Dorsal vs. Ventral
Medial vs. Lateral
Distal vs. Proximal
Inferior vs. Superior
Cephalic vs. Caudal
Aboral vs. Oral
Anatomical Position Review
• Use the proper terms to describe the
relationship between the following body
parts:
– A) hand is ____ to the elbow
– B) knee is ____ to the head
– C) bellybutton is ____ to the spinal cord
– D) heart is ____ to the lungs
– E) head is ____ to the neck (2 terms fit here)
– F) wrist is ____ to the fingers
Characteristics of Animals
• Heterotrophic
• Multicellular
• Movement
• Eukaryotic
Symmetry
• Asymmetry
• Radial Symmetry
• Bilateral Symmetry
Symmetry: Asymmetry
• Irregular shapes
• Do not move
• Sponges
Symmetry: Radial
• Can divide into equal halves
using many planes
• Cnidaria (stinging animals)
• Echinoderms (sea stars)
Symmetry: Bilaterial
• Can only divide into left & right
halves
• Most efficient for movement
– Flatworms
– Roundworms
– Mollusks
– Segmented Worms
– Chordates
Bilaterally Symmetrical Animals
• Platyhelminths
• Chordates
• Fishes
• Herps
• Birds
• Rotifers
• Molluscs
• Arthropods
ALLOWS FOR CEPHALIZATION!
Cephalization
• The process in animals by which nervous
and sensory tissues become concentrated
in the "head."
• Cephalization evolved several times within
the animal kingdom, suggesting that it
offers certain inherent advantages
• the evolution of an advanced degree of
cephalization in animals was associated
with the evolution of a predatory lifestyle.
Benefits of Cephalization
• The anterior end of the animal became
most likely to first encounter food,
predators, and other important features of
the external environment.
• Flatworms (platyhelminthes) are the most
primitive organisms to show cephalization
Loss of Cephalization
• Cephalization has been lost in some
groups.
• Bivalves (Clams, Mussels, etc.)
• Echinoderms (Sea Stars)
Body Plan of Organisms
• General similarities in development and
form and function among members of a
particular phylum
Germ Layers
• Germ layer is a collection of cells found in
an embryo that will give rise to all of the
body’s tissues and organs.
3 Types of Germ Layers
• Ectoderm – outside layer
• Mesoderm – middle layer
• Endoderm – inside layer
LAYER
ORGAN & ORGAN SYSTEM
Ectoderm
Nervous system
Skin
Sensory Organs
Mesoderm
Muscles
Circulatory System
Skeletal System
Reproductive System
Endoderm
Lining of gut and respiratory tracts
Liver
Pancreas
Digestive Glands
Tissue Layer Body Plans
• Diploblastic – ectoderm and endoderm
• Triploblastic - ectoderm, mesoderm and
endoderm
– Acoelomate
– Pseudocoelomate
– Eucoelomate
Animal Development (Embryology)
• Stage 1:
Fertilization
• Sperm (n)
meets Egg
(n) to create
Zygote (2n)
Embryology
• Stage 2: Initial Cleavage
• Cleavage = cell divisions
• The single cell begins to divide into a solid
mass of cells (morula)
Embryology
• Stage 3: Blastulation
• Interior of morula is
pulled away
• Forms blastocoel (hole
middle)
• Once hollow ball of cells
is created, it is now
known as a blastula.
Embryology
• Stage 4: Gastrulation
• Indentation starts at pole of blastula
(blastopore)
What the blastopore becomes…
• Determines if the
organism is a
protostome
(mouth) or
deuterostome
(anus)
Cleavage: Radial vs. Spiral
• In deuterostomes, cleavage is radial
• In protostomes, cleavage is spiral
Embryology
• Stage 5: Determination of Germ Layers
• As cells move into blastopore; cells
differentiate and creates 2 layers of cells
(endoderm & ectoderm)
• The horse-shoe shapes ball is called the
gastrula
Embryology
• Stage 6: Coelom Development
• In gastrula stage, digestive tract is formed
in the middle of the organism
• What surrounds that digestive tract is
called a body cavity (coelom) determines
whether the organism is a acoelomate,
pseudocoelomate or coelomate
• Gastrulation Video
• Invagination
• Creation of Primitive Gut
Protostomes Body Cavities
• Acoelomates – no body cavity
– Platyhelminthes
• Pseudocoelomates – fake body cavity
– Nematodes
Deuterostomes Body Cavities
• All are Coelomates – true body cavity
– Mollusks
– Annelids
– Arthropods
– Echinoderms
– Chordates