1. The Eukaryotes: Algae and Protozoa
Chapter 12, part B
The Eukaryotes: Algae and Protozoa

2. Mitochondrion degenerates
The Three-Domain System
Eukarya
Origin of mitochondria
Fungi
Animals
Bacteria
Origin of chloroplasts
Amebae
Mitochondria
Slime molds
Archaea
Cyanobacteria
Plants
Ciliates
Extreme
halophiles
Proteobacteria
Green
algae
Chloroplasts
Methanogens
Dinoflagellates
Hyperthermophiles
Diatoms
Gram-positive
bacteria
Euglenozoa
Thermotoga
Giardia
Horizontal gene transfer
occurred within the
community of early cells.
Mitochondrion degenerates
Nucleoplasm grows larger

3. Kingdom Protista - Subkingdom Algae (plant-like)
Eukaryotic
Unicellular
Filamentous – form chains of cells
Multicellular (thallic) - thallus (body)
of multicellular algae usually consists of:
branched holdfast
stem like stipes
leaf like blades.

4. Subkingdom Algae (plant-like)
Most Algae are photoautotrophs.
Photosynthesized algae have chloroplasts (Chlorophyll α)
Fungal-like algae are chemoheterotrophs
Cellulose wall
Most algae are found in the ocean
Their location depend on:
wavelength of light
appropriate nutrients
surfaces on which to grow
Algae reproduce:
Asexually by cell division
Fragmentation
Sexually
Algae are classified according to:
rRNA
pigments
their structures

5. Sexual reproduction of Algae
 Isogamy is the form of sexual reproduction in which the gametes produced are identical in shape, size and motility. 
Conjugation - less commonly
isogametes may be non-motile structures
(Spirogyra sp.).
Resting filaments of alga cells.
Formation of conjugation tubes between two adjacent filaments.
Cytoplasmic contents of each cell form a compact mass, representing an isogamete.  The isogametes from one filament migrate through the conjugation tubes into the adjacent filament.
Heterogamy - two different types of gametes are produced. .                                       
Figure 12.12b

6. Chrysophyta
Pyrrophyta
Table 12.4

7. Phylum Phaeophyta Brown algae (kelp) : Phylum Rhodophyta Red algae
Most phaeophytes live in salt water
Harvested for algin
Phylum Rhodophyta
Red algae
Live in salt water
Harvested for agar and carrageenan
Phylum Chlorophyta
Green algae
Gave rise to plants
Figure 12.11b

8. Pectin and silica cell walls (glass cell walls) Unicellular
Phylum Chrysophyta:
Diatoms
live in salt and fresh water
Pectin and silica cell walls (glass cell walls)
Unicellular
All photosynthetic Chlorophyll a and c, carotene, xanthophylls
Store oil
Fossilized diatoms formed oil – petroleum reserves
Figure 12.13

9. Water molds (fungi like).
Phylum Pyrrophyta
Dinoflagellte
Have two flagella,
Live in salt water,
Some are bioluminescent.
Phylum Oomycota
Water molds (fungi like).
These organisms grow as cottony, mold-like filaments.
The filaments have cellulose-based cell walls, but no chitin as the walls of true fungi have.
They produce flagellated gametes (sex cells) that require an aquatic environment for dispersal.

10. Roles of Algae in Nature
Algae are the primary producers in aquatic food chains.
Planktonic algae (phytoplankton) produce most of the molecular oxygen in the Earth’s atmosphere.
Petroleum is the fossil remains of planktonic algae.
Unicellular algae are symbionts in such animals as Tridacna
- Tridacna is a genus of large and gigantic saltwater clams .

11. Subkingdom Protozoa (Animal-like protists)
Protozoa (in Greek proto = first and zoa = animals) - commonly show characteristics usually associated with animals
Unicellular
Many of them are motile,
Heterotrophs
Have complex cells
No cell wall (usually a pellicle )
A cytostome (digestion)
An anal pore (excretion)
Ubiquitous throughout aqueous environments and the soil
Many protozoa are free living
Some are important as parasites and cause serious infections
can infect any human tissue, include intracellular and extracellular parasites
they spread using a variety of strategies
some produce cysts to survive outside the body
spread by insects
spread during human sexual contact
Symbiotic of multicellular animals.

12. Protozoa life cycle An individual protozoan is both male and female.
Two stages of parasitic protozoa
Trophozoites - actively feed and multiply are frequently
Cysts are stages with a protective membrane or thickened wall.
Protozoan cysts that must survive outside the host usually have more resistant walls than cysts that form in tissues.
Cysts convert back to trophozoite
Reproduction
Asexual reproduction
Binary fission, the most common form of reproduction, is asexual; multiple asexual division occurs in some forms.
Budding, or schizogony.
Sexual reproduction
Conjugation - During ciliate conjugation, two haploid nuclei fuse to produce a zygote.
Gametas - haploid
Reproductive cyst - oocyst
Table 12.1

13. Protozoa classification
Protozoa have traditionally been divided on the basis of their means of locomotion, although this is no longer believed to represent genuine relationships:
Flagellates
flagella - long hairlike projections
Amoeboids
ameboid movement by pseudopods, which means "false foot"
Ciliates
Cilia - tiny hairlike projections
Sporozoans
Apicomplexa
Myxozoa
Microsporidia

14. Phylum Archaeozoa Chemoheterotrophs No mitochondria, mitosome
Multiple flagella
Giardia lamblia
intestinal parasite of humans and other animals.
Phylogenetic studies suggest that the first eukaryotic cells may have been similar to Giardia and other archaezoans.
Trichomonas vaginalis (no cyst stage)
Figure 12.17b-d

15. Phylum Microspora Nosema No mitochondria Nonmotile Spore formation
Obligate Intracellular parasites
Nosema
Diarrhea
Kerato-conjunctivitis

16. Phylum Euglenozoa
Flagellates: The flagellates are motile by means of whip-like structures called flagella, attached to the surface of the cell.
Photoautotrophs
Intermediate between algae and protozoa
No cell wall – pellicle instead
Eye spot
Chlorophyll α
Euglenoids Euglena
Chemoheterotrophs
Naegleria
Flagellated and amoeboid forms, meningoencephalitis
Trypanosoma
Undulating membrane, parasitic in humans and other mammals, in which they cause a tropical fever known as sleeping sickness.
transmitted through the bite of the tsetse fly (vector).
Leishmania
Flagellated form in sand fly vector, ovoid form in vertebrate host

17. Phylum Amoebozoa
Amebas: The amebas are motile by means of pseudopodia, or “false feet.”
Pseudopodia are projections of the cytoplasm and plasma membrane that form on the edge of the ameba. The cytoplasm flows into the pseudopod, moving the ameba forward
Ameba proteus-
It lives in fresh water, where it feeds
on other protozoa and bacteria
Entamoeba –
This is a parasitic ameba that causes severe gastrointestinal disease in humans.
Comes by drinking contaminated water.
In the intestine, the cysts break open and release actively growing cells called trophozoites.
Acanthamoeba
Amoeba proteus
Figure 12.18a

18. Phylum Ciliophora (ciliates)
They are motile by means of cilia. - Paramecium
Cilia are short, hair-like structures that cover the surface of the ciliate cell.
The beat back and forth in unison, propelling the cell rapidly through the water.
Complex cells
Balantidium coli is the only human parasite
Figure 12.20

19. Phylum of Apicomplexa Nonmotile Intracellular parasites
Complex life cycle with both sexual and asexual stages.
Different stages often develop in different host species.
Plasmodium
Malaria
The sexual stage occurs in the salivary glands of the Anopheles mosquito
Asexual reproduction - in the blood of the mammalian host.
Babesia
Cryptosporidium
Cyclospora
Toxoplasma:
This parasite is transmitted to humans via the oral route, by eating contaminated beef or from contact with cat feces.

20. The Life Cycle of Plasmodium vivax2 3 8 7 6
Figure 12.18

21. Slime Molds Slime molds have been found all over the world
Have both fungal and amoeba-like qualities
Feed on microorganisms that live in any type of dead plant material.
Usually found in soil, lawns, and on the forest floor, commonly on deciduous logs.
Slime mold

22. Slime Molds Phylum Myxomycota “Acellular” slime molds (Physarium )
The body form of this organism during most of its life is a multinucleated mass of cytoplasm (called a plasmodium, a type of coenocytium).
At certain times, especially when growth conditions are unfavorable, it can form stalks, called sporangia, that grow from the plasmodium.
Spores form at the end of the sporangia and are released into the environment, where they may encounter more favorable growth conditions.

23. Slime Molds Phylum Dictyostelida and Phylum Acrasid
Cellular slime molds.
Consist of ameba-like cells each containing a single nucleus.
Chemical signals from the cells can cause them to aggregate into a mass that resembles a plasmodium, although the individual nuclei remain separated by their plasma membranes.
Some cells become spores

24. Arthropods as Vectors
Jointed-legged animals, including ticks and insects, belong to the Phylum Arthropoda.
Arthropods that carry diseases are called vectors.
Mechanical transmission
Biological transmission
Microbe multiplies in vector
Definitive host
Microbe’s sexual reproduction in vector
Elimination of vector borne diseases is best done by the control or eradication of the vectors.
Figure 12.33

25. Learning objectives List the defining characteristics of algae.
List the outstanding characteristics of the phyla of algae
List the defining characteristics of protozoa.
Describe the outstanding characteristics of phyla of protozoa
Compare and contrast cellular slime molds and plasmodial slime molds.
Define arthropod vector.