Kingdom

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Kingdom Animalia
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Characteristic Of Animals
Most are Motile at some point in life cycle
No Cell Walls
Multicellular
Heterotrophic
Eukaryotic
Dominant Generation is Diploid
Heterogametic
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Animals are grouped according to the presence or
absence of a backbone.
34 animal phyla
Animals with backbones are called vertebrates
while animals without backbones are called
invertebrates.
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Cell Structure and Specialization

• Animal cells lack cell walls that provide
  structural supports for plants and fungi.
• The multicellular bodies of animals are held
  together with the extracellular proteins,
  especially collagen.
• Other structural proteins create several types of
  intercellular junctions
• tight junctions, desmosomes, gap junctions.
• Animals have 2 unique types of tissues
• nervous tissue - impulse conduction
• muscle tissue- movement

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Embryonic development

• Consist of 3 basic stages
• 1. Cleavage-
• -After fertilization the zygote undergoes
  cleavage, a succession mitotic cell divisions,
  leading to the formation of a multicellular,
  hollow ball of cells called the blastula
• 2. Gastrulation
• 3. Organogenesis

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• Development
• Blastula
• Each cell is called a blastomere.
• Center blastocoel

Fig 32-2

• During gastrulation, part of the embryo folds
  inward, forming the blind pouch characteristic of
  the gastrula.

• This produces two tissue layers the endoderm as
  the inner layer and the ectoderm as the outer
  layer

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Stages of Development

• Some animals develop directly through transient
  stages into adults, but others have distinct
  larval stages.
• Metamorphosis

Sexually immature stage that is morphologically
distinct from the adult, usually eats different
foods, and may live in a different habitat from
the adult.
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Gastrovascular Cavity- Gut
two-way
One-way
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Cephalization
An evolutionary trend toward the concentration of
sensory equipment on the anterior end.
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• Classification Criteria

Traditionally classified based on anatomical
features and embryonic development
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1-Body Symmetry
Symmetry is the arrangement of body parts around
a central point or line.

1. Asymmetry
2. Radial
3. Bilateral

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1-Body Symmetry

• The symmetry of an animal generally fits its
  lifestyle.
• Radial animals are sessile or planktonic and need
  to meet the environment equally well from all
  sides.
• Animals that move actively are bilateral, such
  that the head end is usually first to encounter
  food, danger, and other stimuli.

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2- Germ Layers
Ectoderm - outer Mesoderm - middle
Endoderm -inner
(Viscera)
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2- Germ Layers

• Diploblastic
• 2 germ layers
• Porifera Cnidarian
• Triploblastic
• 3 germ layers
• All other phyla

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3- Body Cavities

• Acoelomates lack a body cavity or coelom
• a coelom is a body cavity lined by mesoderm.

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1. Pseudocoelomates possess a pseudocoelom body
   cavity is incompletely lined by mesoderm.

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1. Coelomates possess a coelom completely lined with
   mesoderm.

Body cavity between the digestive tract and body
wall it is lined by mesoderm
allows digestive system to move independent of
body wall
coelomic fluid assists respiration and
circulation by diffusing nutrients, and excretion
by accumulating wastes
cavity may serve as a storage area for eggs and
sperm
fluid protects internal organs and also serves as
a hydrostatic skeleton
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• A body cavity has many functions.
• Fluid cushions the internal organs
• Fluid of the body cavity can function as a
  hydrostatic skeleton against which muscles can
  work.

1. The present of the cavity enables the internal
   organs to grow and move independently of the
   outer body wall.

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Coelomates are either Protostomes or Deuterostomes

• During early development of the zygote, cell
  division (cleavage) is very orderly.
• Two specific patterns of cleavage.
• Spiral Protostomes
• Slight angle to the vertical axis of the embryo
• First infolding (blastopore) becomes the mouth
• Cells future decided by 4-cell stage
• Radial Deuterostomes
• Parallel to the vertical axis of the embryo
• Blastopore becomes the anus
• Each cells retain ability to develop into an
  embryo.

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• This phylogenetic tree is bases on nucleotide
  sequences from the small subunit ribosomal RNA.