Protista and simple Metazoa

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Protista and simple Metazoa
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Announcements

• There will be a quiz next lab on protsista and
  Annelids
• Assignment for this lab include page
  50,63,64,65,66,67,68.
• Make sure you know your four digit number by now

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Today

• Prokaryotes versus eukaryotes
• Endosymbiosis
• Different protists
• Simple metazoa
• Evolution of body cavities

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Prokaryotes versus Eukaryotes

• Eukaryotes possess true nucleus, membrane bound
• organelles and a cytoskeleton

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Endosymbiosis
Eukaryotes evolved from symbiotic association
of different kinds of prokaryotes,each
specialized for different function. Eukaryotes
include unicellular protists and all
multicellular organisms. Symbiosis versus
parasitism
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Phylogeny of protists
Sporozoa
Ciliophora
Plant like protists
Fungus like protists
prokaryotes
Cilia
Mastigophora
Spores
choloroplast
sarcodina
Flagella
Pseudopodia
Mitochodria
Nuclear membrane
DNA
RNA
ATP
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protists

• Unicellular Eukaryotes having different types of
• membrane bound organelles like nucleus,
  mitochondria,
• contractile vacuoles and chloroplasts.
• 1- Animal like protists (protozoa)
• a- Sarcodina e.g Amoeba
• characterize by forming pseudopodia
• b-Mastigophora e.g Trypanosoma
• characterize by having flagella

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protists
C- Ciliophora e.g paramecium
e.g. stentor characterize by presence
cilia D-Sporozoa e.g. Plasmodium malaria
characterize by forming infective
spores 2-Fungus like protists (slime molds)
e.g Dictyostelium spp. characterize by sexual
(diploid) and asexual (haploid) reproduction
depending on the availability of food
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protists
3- plant-like protists (unicellular algae)
e.g Euglena e.g golden brown algae
(phytoplankton) depend on photosynthesis as
energy source characterized by presence of
Chloroplast
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I got the picture
We will examine pond water using the hanging
drop technique Put a drop of pond water on the
slid with depression, cover with cover slip and
examine under microscope Wash the slid when you
are done and bring it back to me
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Metazoans
Multicellular and consume other organisms
Muticellularity permit evolution of specialized
cells, tissues and organs that are able to
perform narrow tasks more efficient than
generalized cell. Grouped according to level
of organization (cellular, tissues and organs)
and presence or absence of body cavities
(coelom). a true coelom is a cavity within the
mesoderm layer and usually filled with fluid.
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Phylogeny of metazoans
Coelomates
Protostome
Deuterostome
Schizocoelom
Spiral cleavage
Pseudocoelomates
Acoelomates
Enterocoelm
Porifera
Cnidaria
pseudocoelom
Mouth and anus
Spiral cleavage
Mouth and anus
Bilateral symmetry
Organ level (mesoderm)
Multicelularity
Tissue level
multicelularity
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Evolution of body cavities
During the embryonic life, there are three
embryonic layers From which the different
tissues and organs differentiate. These are
ectoderm, endoderm and the mesoderm.
Invagination of the mesoderm layer will
eventually result in the formation of body
cavity. According to presence or absence of
body cavity 1-Acoelomate no cavity.
2-Pseudocoelomate cavity between mesoderm and
endoderm.
3-Schizocoelomate true coelom formed by split in
developing
mesoderm. 4-Enterocoelom true coelom
formed by out-pocketing
of the gut
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Evolution of body cavities
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Evolution of body cavities
Acoelomates
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Evolution of body cavities
Pseudocoelomates
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Evolution of body cavities
Schizocoelom Protostome
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Evolution of body cavities
Enterocoelom Deutrostome
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The advantages of the coelom

• - It allows for more extensive growth of the
  organs (digestive tract).
• - It permits the formation of an efficient
  circulatory system
• The fluid in the coelom can transport or move
  materials faster than by
• diffusion. Animals often dump food or wastes
  into the coelom and
• depend on body movement to distribute the
  materials to the
• required areas.
• - The muscles of the digestive tract can become
  independent of the
• muscles of the body wall permitting more
  variation in movement of
• both sets of muscles.
• - The coelom provides a space for gonads to
  develop during breeding
• season or for young to grow in those animals
  which give birth to
• live young

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Simple Metazoa
1- Porifera (sponge) -cellular level of
organization -aquatic organisms - e.g
Grantia 2- Cnideria -tissue level of
organization continuous layer of cells
function as a tissue (epidermis and
gastrodermis) i.e. one unit -radial symmetry
(tentacles) -the medusa and the polyp
architectures - e.g jellyfishes,corals and
hydra
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Simple metazoa
3- Acoelomates -no body cavity -organ level
of organization -bilateral symmetry
-e.g.platyhelminthes(flatworms)
Planaria.Dugesia (free living)
Cestoda..Taenia (parasitic)
Trematoda.Fasciola(parasitic)
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Simple Metazoa
4- Pseudocoelomates -organ level of
organization -pseudocoelom -nematoda
(roundworms) e.g C.elegans (free living)
Ascaris lumbricoides (parasitic)
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I got the picture
start looking at the scopes and answer
questions dissect Ascaris worm -wear gloves
-identify the mouth and anus under dissecting
scope - start dissection from the posterior end
toward the mouth -when you are done, wash your
hands and discard in the orange bucket
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Dissecting Ascaris female