Transcript Announcements

Protista and simple Metazoa
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
Today
•Prokaryotes versus eukaryotes
• Endosymbiosis
•Different protists
•Simple metazoa
•Evolution of body cavities
Prokaryotes versus Eukaryotes
• Eukaryotes possess true nucleus, membrane bound
organelles and a cytoskeleton
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
Phylogeny of protists
Sporozoa
Ciliophora
Fungus like protists
prokaryotes
Plant like protists
Cilia
Mastigophora
Spores
sarcodina
choloroplast
Flagella
Pseudopodia
Mitochodria
Nuclear membrane
ATP
DNA
RNA
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
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
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
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
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.
Phylogeny of metazoans
Coelomates
Protostome
Acoelomates
Porifera
Deuterostome
Schizocoelom
Spiral cleavage
Pseudocoelomates
Enterocoelm
Cnidaria
pseudocoelom
Mouth and anus
Spiral cleavage
Mouth and anus
Bilateral symmetry
Organ level (mesoderm)
Multicelularity
Tissue level
multicelularity
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
Evolution of body cavities
Evolution of body cavities
Acoelomates
Evolution of body cavities
Pseudocoelomates
Evolution of body cavities
Schizocoelom
=
Protostome
Evolution of body cavities
Enterocoelom
=
Deutrostome
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
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
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)
Simple Metazoa
4- Pseudocoelomates
-organ level of organization
-pseudocoelom
-nematoda (roundworms)
e.g C.elegans (free living)
Ascaris lumbricoides (parasitic)
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
Dissecting Ascaris female