Transcript Lecture 2

Chapter 3
Animal
Architecture
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Stages of development: Zygote, Blastula, Gastrula
Types of cleavage: Radial (Regulative) v. Spiral (Mosaic)
Symmetry: Aymmetry, Spherical Symmetry, Radial Symmetry, Bilateral
Symmetry
DEVELOPMENT
Figure 3_05
Figure 3_03
Typical of
echinoderms and
chordates
Typical of
molluscs and
annelids
Figure 3_04
Animal Body Plans
• Animal Symmetry
– Symmetry
• Correspondence of size and shape of parts on opposite
sides of a median plane
– Spherical symmetry
• Any plane passing through center divides body into mirrored
halves
• Best suited for floating and rolling
• Found chiefly among some unicellular forms
• Rare in animals
9-6
Body
Plans
– Radial symmetry
• Body divided into similar halves by more than 2 planes
passing through longitudinal axis
• Usually sessile, freely floating, or weakly swimming
animals
• No anterior or posterior end
– Can interact with environment in all directions
9-7
Body
– Bilateral Symmetry
Plans
• Organism can be divided along a sagittal plane into two mirror
portions
– Right and left halves
• Much better fitted for directional (forward) movement
• Associated with cephalization
– Differentiation of a head region with concentration of nervous tissue
and sense organs
• Advantageous to an animal moving through its environment
head first
• Always accompanied by differentiation along an
anteroposterior axis
9-8
Figure 3_01
Body
Plans
• Regions of bilaterally symmetrical animals
– Anterior
• Head end
– Posterior
• Tail end
– Dorsal
• Back side
– Ventral
• Front or belly side
– Medial
• Midline of body
– Lateral
• Sides
9-10
Body
– Distal
Plans
• Parts farther from the middle of body
– Proximal
• Parts are nearer the middle of body
– Frontal plane (coronal plane)
• Divides bilateral body into dorsal and ventral halves
– Sagittal plane
• Divides body into right and left halves
– Transverse plane (cross section)
• Divides body into anterior and posterior portions
9-11
Figure 3_02
Anatomical terminology
Or segmentation: serial repetition of similar body segments (metameres)
along longitudinal axis
METAMERISM
9-14
Deuterstome--“Second mouth”: 1) mouth forms from second opening
2) radial cleavage 3) coelom forms by outpocketing 4) regulative embryo;
Echinoderms, Hemichordates, and tunicates, lancelets and vertebrates in
Chordates
Protostome—”Mouth first”: 1) mouth forms, then anus 2) spiral cleavage
3) coelom forms by splitting 4) mosaic embryo
Two groups: Ecdysozoa—animals that molt & Lophotrochozoa—
lampshells (phylum Brachiopoda), snails (phylum Mollusca), and worms
(phylum Annelida)
DEUTEROSTOME V.
PROTOSTOME
Figure 3_08
Acoelomate—planaria (phylum Platyhelminthes)
Pseducoelomate—nematode (phylum Nematoda)
Coelomate—oligochaete (phylum Annelida)
BODY PLANS
Figure 3_09
Epithelial—lines cavity or covers surface. Skin
Connective—cells and matrix (fibers & ground substance). Blood, lymph,
cartilage, bone
Muscle—contractile. Skeletal, cardiac & smooth
Nervous—excitable. Neurons & glia
FOUR TISSUE TYPES
Figure 3_10
ts of
Metazoan
– Epithelial Tissue
Bodies• Sheet of cells that covers an internal or external
surface
• Avascular
• Function
– Protection
– Absorption
– Secretion
9-21
ts of
Metazoan
• Simple epithelia
Bodies – Single layer of cells
– Found in all metazoa
• Stratified epithelia
– 2 or more cell layers
– Restricted to vertebrates
• Separated from underlying tissues by a basement
membrane
9-22
Figure 3_11a
Found in lungs &
frog skin
Figure 3_11b
Found in kidneys &
glands
Figure 3_11c
Found lining
intestine
Figure 3_12c
Found in skin and orifices
ts of
Metazoan
Bodies
• Connective Tissue
– Widespread in body
– Contains relatively few cells, many fibers, and a
ground substance or matrix
– 2 types of connective tissue proper In vertebrates
– Loose connective tissue
• Contains fibers and both fixed and wandering cells in a
viscous fluid matrix
– Dense connective tissues
– Characterized by densely packed fibers and little matrix
• Connective tissue also includes blood, lymph, cartilage, and
bone
9-27
Figure 3_12a
Figure 3_12d
Guess where this is
found
Figure 3_13a
Loose connective tissue
Figure 3_13b
Dense CT
Figure 3_13c
cartilage
Figure 3_13d
bone
Metazoan
Bodies
• Muscular Tissue
–
–
–
–
–
Most abundant tissue in most animals
Originates from mesoderm
Muscle cell called a muscle fiber
Specialized for contraction
3 types
• Skeletal
– Striated, unbranched, multinuclei, and voluntary
• Cardiac
– Striated, branched, 1-2 nuclei, involuntary
• Smooth
– No striations, unbranched, 1 nucleus, involuntary
9-34
Figure 3_14a
Figure 3_14b
Figure 3_14c
Metazoan
Bodies
• Nervous Tissue
• Specialized to receive stimuli and conduct
impulses from one region to another
• 2 basic cell types
– Neurons
• Structural and functional unit of nervous system
– Neuroglia
• Insulate and support neurons.
9-38
Figure 3_15
Neuron—Dendrites,
soma & axon
TRENDS IN SIZE AND
METABOLIC RATES
Figure 3_16
Figure 3_17