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Phycology and Phycology Lab Course by Dr. Mohamed Jawad Al-Haidarey Ecological Biogeochemistry / Phycology. Textbooks: Lectures, required reading :. Linda E Graham & Lee W Wilcox (2000) Algae , Prentice-Hall.
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Dr. Mohamed Jawad Al-HaidareyEcological Biogeochemistry / Phycology
Regular attendance of lectures and lab classes is expected. It is further expected that students show up in time. For both the lecture and the lab classes, the student who comes late most will have to bring doughnuts or some food for the next lecture
· Prymensiophytes (Haptophytes)
· Dinophytes (Dinoflagellates)
· Introduction to the Ochrophytes
· Raphidophytes and Chrysophyceans
· Synurophyceans, silicoflagellates, pedinelids, tribophyceans
· Phaeophytes (Brown algae)
· Rhodophytes (Red algae)
· Introduction to the Green algae
· Ecology of macroalgae and periphyton
· Introduction to phycology
· Basics of algal biology
· Reproduction in algae
· The role of algae in biogeochemistry
· Algae in biological associations
· The role of algae in aquatic food webs
· Taxonomy and Systematics of Algae
· Phytoplankton size in ecology
· The physical environment: temperature, light, turbulence
· Growth of phytoplankton
· Losses of phytoplankton
· Swimming and bouyancy
· The origin of eukaryotic algae
PHYCOLOGY=STUDY OF ALGAE
Phycology is the science (gr. logos) of algae (gr. phycos). This discipline deals with the morphology, taxonomy, phylogeny, biology, and ecology of algae in all ecosystems
what is Phycology means? And where are algae abound?
Don’t be Cheat
If you did you are cheater
---No nuclear region and complex organelles—chloroplasts, mitochondria, golgi bodies, and endoplasmic reticula.
-- Cyanobacteria. Chlorophylls are on internal membranes of flattened vesicles called thylakoids-contain photosynthetic pigments. Phycobiliproteins occur in granular structures called phycobilisomes.
---Distinct chlorplast, nuclear region and complex organelles.
--- Thylakoids are grouped into grana
pyrenoids are centers of carbon dioxide fixation within the chloroplasts of algae and hornworts. Pyrenoids are not membrane-bound organelles, but specialized areas of the plastid that contain high levels of ribulose-1,5-bisphosphate carboxylase/oxygenase
granum with a
Stack of thylakoids
Unicellular, Colonial and Filamentous forms.
Colony with constant number of cells, which cannot survive alone; specific „tasks“ among groups of cells is common (is a colony containing a fixed number of cells, with little or no specialization)
Dendroid form: resembling a tree in form or in pattern of growth (Dinobryon).
c. Filaments: daughter cells remain attached after cell division and form a cell chain; adjacent cells share cell wall (distinguish them from linear colonies!); maybe unbranched (uniseriate such as Zygnema and Ulthrix) or branched (regular mutiseriate such as Cladophora or unregulermutiseriate such as Pithophora).
d. Coenocytic or siphonaceaousforms: one large, multinucleate cell without cross walls such as Vaucheria
e. Parenchymatous (such as Ulva ) and algae: mostly macro-scopic algae with tissue of undifferentiated cells and growth originating from a meristem with cell division in three dimensions
; pseudoparenchymatous (such as Batrachospermum) pseudoparenchymatous superficially resemble parenchyma but are composed of apprised filaments
f. Erect thallus forms: Thallus, from LatinizedGreek (thallos), meaning a green shoot or twig, is an undifferentiated vegetative tissue (leaves, roots, and stems) of some non-mobile organisms such as Chara and Nitella.
Source: A Biology of the Algae
By Philip Sze, third edition, WCB MCGraw-Hill
blue pigment –phycocyanin)
Forms of algae
Don’t be Cheat
If you did you are cheater
What is Pyrinoid ?
Apical and intercalary
The reproduction of algae can be discussed under two types, namely, asexual reproduction and sexual reproduction. The former type refers to reproduction in which a new organism is generated from a single parent. In case of sexual type, two haploid sex cells are fused to form a diploid zygote that develops into an organism. Let's discuss in brief about the asexual and sexual reproduction in algae along with examples.
A cell could not keep growing bigger forever. Food molecules could not reach the inside of a large cell fast enough to keep it alive. So when a cell reached a certain size it had to divide into two smaller cells called daughters. The daughters grew and, when they reached that certain size, they too divided, this processes called binary fission.
But this caused a problem, Why?.
Hormogonia in Oscillatoria
2. Another method of asexual reproduction in algae is by formation of spores; the algal species Ulothrix, Chlamydomonas and Chlorella reproduce by this method. Depending upon the algal species, the spores can be produced in normal vegetative cells or specialized cells called sporangia. They are either motile called zoo spores or non motile called akinete spores.
As already mentioned, sexual reproduction takes place by the union of male and female gametes. The gametes may be identical in shape and size called isogamy or different called heterogamy. Some of the simplest forms of algae like Spirogyra reproduce by the conjugation method of sexual reproduction. In the process of conjugation, two filamentous strands (or two organisms) of the same algae species exchange genetic material through the conjugation tube. Among two strands, one acts as a donor and another serves as a receiver. After exchanging the genetic material, two strands separate from each other. The receiver then give rise to a diploid organism.
Isogamy: is the form of sexual reproduction in which the gametes produced are identical in shape, size and motility. There is no structural distinction between "male" and "female" gametes. Pairs of isogametes align themselves with their flagellar poles touching and after several seconds, the motile gametes fuse to form a single, non-motile, diploid zygote.
Isogametes, less commonly, may be non-motile structures. A specific example exhibiting non-motile isogametes is the reproductive process known as conjugation, in Figure below, the conjugating Spirogyra identify the four stages of the process as outlined.
Isogamy in Spirogyra sp.
B. Formation of conjugation tubes between two adjacent filaments.
C. 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.
The two isogametes unite to form a zygote. Each zygote eventually undergoes meiosis to form four haploid cells. One haploid cell will form a new filament by mitosis, the other three degenerate.
In heterogamy, two different types of gametes are produced. The male gamete, the sperm cell, is typically very small, highly motile and is produced in very large numbers. The female gamete, the egg cell, is much larger and non-motile, called Oogamy. Fewer female gametes are produced but each is usually afforded some protection. Heterogametes are also produced by higher plants and animals.
Oedogonium sp. is a green alga that produces heterogametes. The figure bellow illustrates the life cycle of this alga. You can locate a mature egg cell and the small male filaments, which are the site of sperm production, the egg cells and male filaments are usually adjacent to one another on the same algal strand.
=part of the filament
breaks off from the rest and forms a new one.
Zoospores after losing their flagella,
form new filaments. No sexual fusion.
d, e, and f are aplanospores
g, and h are hypnospores
K is autospores.
L is Isogamous, m is Anisogamous, and n is Oogamous
Three different types of life cycle, depending on when miosis occurs, the type of cells produced, and if there is more than one free-living stage present in the life-cycle.The life cycles in algae
Life-cycle III (Diplobiontic life cycle):three multicellular phases, the gametophyte and one or more sporophyte(s)
1. Color has been an important means of classifying algae, and gives many groups their names. However, other characteristics, such as type of photosynthetic food reserve, flagella type, cell wall structure and composition, and life history, have been important in further distinguishing the algal divisions.
Locomotion in algae is largely based on the action of flagella. The figure below illustrates the wide variety of flagella present in the algae. The primary distinctions used for classification are the number of flagella, their location on the cell, and their morphology. Two major types of flagella are recognized: the smooth, or acronematic, and the hairy, or pleuronematic, types. The smooth flagella generally moves by whiplash motion and the hairy flagella moves by a pulling motion.