Transcript Chapter 10: Architectural Pattern of an Animal

Chapter 9:
Architectural Pattern
of an Animal
Metazoans
 32
Phyla of multicellular animals
– Survivors of 100 phyla from the
Cambrian explosion 600 million
years ago.
Heterotrophy
 Cannot
make own food
 Filter feed in ocean or find food
Mobility

Muscle cells
 Swim, crawl, walk, run and fly
 Some sessile(do not move)
Multicellularity

Daphnia to large whale
 More than one cell
Organization and Complexity

Parenchyma?
 Stroma?
Diploidy

Adults have 2 copies of each chromosome
 One from mother and one from father
Sexual reproduction

Gametes from 2 separate parents
 Can also see asexual reproduction in the
animal kingdom - budding

No cell wall - mobility
 Eukaryotic – nucleus and other membrane
bound organelles
Blastula Formation

Zygote forms blastula
 Hollow ball of cells
 Develop into 3 distinct layers
 Ectoderm/endoderm/mesoderm
 These layers give rise to all other
tissues/organs
Zygote - Gastrula

Found in all animals but sponges
 One cell – 8 cells – blastula – layers
 Process is called cleavage
 Takes 3 hours to reach blastula
 Second process the blastula begins to
collapse inward while cells move to
position - gastrulation

Cell begin to vary in size and form the 3
primary tissues
 Now at embryo stage
 Evidence of common ancestor
Blastopore

Opening to the gut where the inward
bending begins
 First opening that forms in the gastrula
 During
embryonic development
germ layers become differentiated
into four tissues.
– Epithelial
– Connective
– Muscular
– Nervous

The development of an animal embryo
follows one of two different patterns
 Protostome – The blastopore develops into
mouth-most invertebrates
 Deuterostome-The blastopore develops into
the anus – Echinoderms and Chordates
Animal Body Plans
 Limited
by ancestral history.
 Shaped by habitat and way of life.
Animal Symmetry
 Arrangement
of body parts with
reference to same axis of body.
 Most animals have symmetry.
 Sponges do not.
– Asymmetrical
Asymmetry

Without symmetry
 Spherical
Symmetry
– Any plane passing through the center
divides the body into mirrored
halves.
– Protozoa
 Radial
Symmetry
– Divided into similar halves by more
than two planes passing through one
main axis.
– Tubular, vase or bowl shape.
– Some sponges, Hydras, Jellyfish
 Biradial
Symmetry
– Some parts are paired rather than
radial.
 Echinoderms
– Larvae are Bilateral
– Become secondarily radial as adults.
Bilateral Symmetry
 Divided
along a sagital plane into
two mirrored portions-right and
left halves
 Better fitted for directional
movement-forward
 Associated with cephalization

Sagittal
 Transverse
 Frontal

Draw your own
squirrel and label
now
Animal Body Regions
– head end
 Posterior – tail end
 Dorsal – back side
 Ventral – front or belly side
 Medial – midline of the body
 Lateral – the side of body
 Anterior
– farther from the middle of
the body
 Proximal – parts near a reference
point
 Pectoral – chest region
 Pelvic – hip region or area
supported by hind legs
 Distal
Body Cavities
 Bilateral
animals can be grouped
according to their body cavity type
or lack of body cavity.
 Coelom – in more complex
animals the main body cavity.
 A fluid filled space that surrounds
the gut.
 Provides
a “tube within a tube”
arrangement.
 Allows body flexibility.
 Provides a space for visceral
organs or internal organs.
size and complexity –
more cells exposed to surface
exchange.
 Hydrostatic skeleton in many
animals.
 Greater
– Worms

Coelom forms differently in protostomes
and deuterostomes
 Some inverts or protostomes lack a coelom
Cephalization
 Differentiation
of a head or head
region.
 Bilaterally symmetrical animals.
 Most efficient position for sensing
the environmental and responding
to it.
THE END
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