- Parthenogenesie
Eg: rotifers, crustaceans, insects, fishes, desert lizards, etc
- Polyspermy
There are 4 Main Types of Cleavage:
1. Radial Holoblastic:
2. Spiral Holoblastic
3. Discoidal Meroblastic
4. Rotational Holoblastic
There is also SUPERFICIAL in insects
Cleavage in Invertebrates:
1. Radial or regulative
2. Spiral
- Protostomia: 'mouth-first'
- Deuterostomia: 'mouth-second'
There are 4 Types of Yolk:
1. Isolecithal: starfish and human
2. Mesolecithal: frog
3. Telolecithal: birds
4. Centrolecithal: insects
What is Cleavage?
: process of nucleus and cell division in zygote.
Blastula: is a hollow mass of cells
- Blastocoel
What is Gastrula?
: having 2 layers of cells with an opening
- Invagination:
- Archenteron:
- Coelomic Vesicles
- Now gastrula is an embryo and has 3 germ layers:
1. Ectoderm: body surface, epithelial cells, nervous system
2. Endodermis: epithelial cells of G.I. tract
3. Mesodermis: muscles, reproductive, peritoneum
-Diploblastic
- Triploblastic
Know the fate of blastopore in Protostomes and Deuterostomes
Formation of the Coelom
1. Schizocoelous
2. Enterocoelous
Advance chordates from Schizocoelous
Amniotes and the Amniotic Egg:
- Reptiles, birds, and mammals
- Amnion:
- Allantois:
- Chorion:
- Chorioallantoic membrane
33 Hours
Procen
Mesen
Rhomben
|
48 Hours
Prosen
Mesence
Myelence
|
72 Hours
Telence
Dience
Mesence
Metence
Myelence
|
96 Hours
Telence
Dience
Mesence
Metence
Myelen
|
Forebrains = prosencephalon
Midbrains = mesencephalon = include optic lobes
Hindbrain = rhombencephalon = medula
- Before 48 hours, there is porcen and NO dience
- After 48 hours there is prosen and there is deince
- At 72 hours procen becomes telence
- At 48 hours there is No telence
Animal Like Protista
- First life on earth about 3.5 billion years ago
- Protista kingdom
- Protozoa Subkingdon
Animal Like Because
A. No cell wall
B. In some way motile
C. Ingest their food
We will discuss 3 Phyla out of 7 Phuyla
Sarcomastigophora
Apicomplexa
Ciliophora
Main Characteristics of Protozoan Phyla:
1. Unicellular
2. Microscopic
3. No germ layers
4. Specialized organs
5. Free-living
Mutualism
Commensalism
Parasitism
6. Some sessile, pseudopodia, flagella, cilia
7. All types of nutrition: autotrophic, heterotrophic
8. Aquatic or terrestrial
9. Asexual and sexual reproduction
There have most of the organelles that other eucaryotic cells posses
- Mitochondria
- Endoplasmic Reticulum
- Golgi apparatus
- Vesicles
- Chloroplast
- Vacuoles
- Ectoplasm and endoplasm
Locomotion:
1. Cilia and flagella: 9+2
2. Pseudopodia:
Ectoplasm: transparent or hyaline, colliod
Endoplasm: more granular, more fluid
A. Lobopodia: large extension of cells body
B. Limax: whole body moves
C. Filopodia: thin extensions
D. Reticulopodia: rejoin to form a netlike mesh
E. Axopodia: supported by axial rods
Excretion and Osmoregulation:
By contractile vacuole:
1. Small vesicles join the contractile vacuole
2. Then contractile vacuole joins the cell membrane
In ciliates it is more complex:
1. Excretory pore leads to outside and they are surrounded by ampulla
2. Ampulla fills up and discharge the water to the outside
Nutrition:
A. Autotrophs: order Euglenida
B. Heterotrophs:
- Phagocytosis
- Lysosomes
- Food vacuole
- Exocytosis the waste material
- Cilia have cytoproct for expulsion of waste
- Pinocytosis
Reproduction:
A. Fission:
a. Binary fission:
b. Budding in cilia
c. Multiple fission
Sporogony: development of spores or sporozoites within occyst
Schizogony: when cytokinesis is preceded by several nuclear division
B. Sexual Reporduction
a. Isogametes
b. Anisogamete
c. Syngamy: fertilization of an individual gamete by another
d. Autogamy: gametic nuclei fuse to form zygote within the same organism that produced them
e. Conjugation: exchange of gametic nuclei between paired organisms
Encystment and Excystment:
Formation of cyst. Not in paramecium
Excape from cyst in called excystment
Phylum Sarcomastigophora:
Some mastigophorans can use psuedopodia and flagella.
Subphylum Mastigophora
A. Phytoflagellates
Eg: Euglena, Chlamydomonas and Volvox
Coral reefs are by zooxanthellae
Some Structures in Euglena:
- Pellicle
- Kinetosome
- Contractile vacuole
- Stigma to locate light?
- Chloroplast
- Paramylon bodies
- Reproduction by binary fission
Some Structures in Volvox:
- Cell wall
- Division of labor
- Asexual and sexual reproduction
- Macrogametes loaded with food
- Microgametes forms sperm to find ovum
- Zygoes multiply and break away
B. Zooflagellates:
Trypanosoma brucei rhodensiense
Trypanosoma brucei gambiese
Trypanosoma burcei brucei
transmitted by tsese fly (Glossina)
Trypanosoma cruzi cause Chagas' disease
- transmitted by kissing bug Triatominae
Leishmania in liver and spleen
- Visceral Leishmaniasis
- Cutaneous Leishmaniasis
- Transmitted by sand fly
Trichonomas vaginalis
Giardia lamblia
Subphylum Sarcodina
Entamoeba histolytica
Entamoeba coli
Entamoeba gingivalis
Forminiferas: shelled amoeba, make up of calcium carbonate, silica and silt radiolarians and heliozoan, silicon
Phylum Apicomplexa:
- Micronemes
- Pseudopodia in some intracellular stages
- Flagella in gametes of some species
- Asexual and sexual cycle
- Some require intermediate host
- Some develop oocyst or spore
Class Sporozoa:
- Most important class
Three Subclasses:
Gregarinia: found in insects
Coccidia:
Piroplasma: in cattle, Texas red-water fever caused by Babesia bigemina
Subclass Coccidia:
- Intracellular
- Eimeria and Isospora cause coccidiosis
- Eimeria tenella in young fowl
Reproduction of Eimeria:
Schizogony --> gametes --> fertilization --> oocyst --> in intestine in feces
Sporogony in oocyst --> 8 sporozoites --> outside of host new host ingest sporulated oocyst
Toxoplasma gondii
In AIDS patients
Definitive host is cat
Possible intermediate host
Plasmodium
Malaria transmitted by mosquitoes
Sporozoites injected to human by insects
Sporozoites in live initiate schizogony
P. falciparum penetrate R.B.C after one generation in liver
In RBC trophozoites feed on HBG
Sexual Reproduction
Microgamests and macrogametes
Mosquitoes ingest gametes
Fertilization --> oocyst
Phylum Ciliophora:
-Mostly freeliving some parasitic, some commensalism, and some colonial
- Some sessile; suctorians
- Larger than most protozoan
- Multinucleated
- Undulating membrane: cilia are fused into a sheet
- Cytostomes (mouth)
- Oral groove
- Two contractile vacuole system
Passage of water and food in paramecium:
Oral groove --> cytostome --> cytopharynx --> food vacuole --> indigestivle out by cytoproct
Reproduction
1. Binary fission: micronucleus divide mitotically and macronucleus elongate and divide amitotically
2. Conjugation
3. Autogamy: self-fertilization
eg: Balantidium coli
Phylogeny:
Apicomplexa from flagellated
Mastigophora from bacteria
Ciliated from flagellated or ?