INTRODUCTION TO ALGAL CHARACTERISTICS AND DIVERSITY

Phycology and Phycology Lab Course by Dr. Mohamed Jawad Al-Haidarey

Ecological Biogeochemistry / Phycology

1Textbooks: Lectures, required reading:Linda E Graham & Lee W Wilcox (2000) Algae , Prentice-Hall.Marty Kelly & Richard Telford (2007) Common fresh water diatoms of Britain and Ireland.Janet R stein (1975) Hand book of phcological methods, culture methods, and growth measurements. (2007) (1979) (1985)

2Attendance politics: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 .

3Phycology Syllabus

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 Cyanobacteria The origin of eukaryotic algae Euglenophytes

Cryptophytes Prymensiophytes (Haptophytes) Dinophytes (Dinoflagellates) Introduction to the Ochrophytes Diatoms Raphidophytes and Chrysophyceans Synurophyceans, silicoflagellates, pedinelids, tribophyceans Phaeophytes (Brown algae) Rhodophytes (Red algae) Introduction to the Green algae Prasinophyceans Ulvophyceans Trebouxiophyceans Chlorophyceans Charophyceans Ecology of macroalgae and periphyton

4INTRODUCTION TO ALGAL CHARACTERISTICS AND DIVERSITYPHYCOLOGY=STUDY OF ALGAEPhycology 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

5FOSSIL HISTORY OF ALGAE3.5 billion yrs agoCyanobacteriafirst algaeProkaryoteslack membrane bound organellesLater eukaryotes evolvedmitochondria, chloroplasts, and chromosomes containing DNA.6Where are algae abound?

Kelp forest up to 50 m height are the marine equivalent to terrestrial forest; mainly built by brown algae.

Some algae encrust with carbonate, building reef-like structures; Cyanobacteria can from rock-like structures in warm tidal areas: stromatolites.

7Where are algae abound?Algae grow or are attached to animals and serve as camouflage for the animalAlgae live as symbionts in animals such as Hydra, corals, or the protozoan ciliate Paramecium;in corals they are referred to as zooxanthellae

8Where are algae abound?Small algae live on top of larger algae: epiphytonAlgae in free water: phytoplanktonTerrestrial algaeAlgae have adapted to life on land and occur as cryptobiotic crusts in desert and grassland soils or endocryptolithis algae in rocks

9Where are algae abound?Algae live on the snow cover of glaciers and in the brine channels of sea ice.A symbiosis of algae and fungi produced the lichens, which are pioneer plants, help convert rock into soil by excreting acids, stabilize desert soil, are sensitive to air pollution

10Where are algae abound?Algae can cover trees or buildings green or live in the hollow hairs of ice bears

11Algal Blooms

Algae can be so dominant that they discolor the waterHigher amounts of nutrients are usually the causeAlgal blooms can have harmful effects on life and ecosystem:Reduced water clarity causes benthic communities to die offFish kills are common effects50% of algal blooms produce toxins harmful to other organisms, including humansAlgal blooms produce a shift in food web structure and species compositionAlgal blooms can mostly be linked to sewage input or agricultural activities, leading to nutrient pollution: Eutrophication

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We can find Algae in different Size (from some microns to more than 60 meters)We can find Algae in different region (soil, water, animal , plants etc)Some of algae are prokaryotes and others are eukaryotes.Summery of the lecture one1415Summery of the lecture one In the aquatic ecosystems we can find algae as :Attachment:Epipelic / on the clayEpipzamic / on the sandEpilithic / on the rocks.Epiphytic / on the plantsEpizoic / on the animalsEndozoic / in the animals bodyEndophytic / in the plants bodyAs Plankton:Euphytoplankton / all the life cycle is planktonTychophytoplankton / some of the life cycle is plankton16Summery of the lecture one According to environments we can subdivided Algae in to :Halophyts: in region with high salinity.Thermophyts: in region with high temperature.Cryptophyts: in the region with low temperature.In the trrastrial environments we can classified Algae in to :LithophytsEpidaphicsEndodaphicsCasmolithics

Quiz:

Please, in short, Clarified: what is Phycology means? And where are algae abound? Dont be Cheat If you did you are cheater 17Lecture two:18ALGAEHow are algae similar to higher plants?

How are algae different from higher plants?

19SimilaritiesPresence of cell wallmostly cellulosic.Autotrophs/Primary producerscarry out photosynthesisPresence of chlorophyll a

20DifferencesAlgae lack the roots, stems, leaves, and other structures typical of true plants. Algae do not have vascular tissuesnon vascular plantsAlgae do not form embryos within protective coveringsall cells are fertile.Variations in pigments.Variations in cell structureunicellular, colonial and multicellular forms.

21PROKARYOTIC VS EUKARYOTIC ALGAEProkaryotes---No nuclear region and complex organelleschloroplasts, 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.Prokaryote algal cell

Source: http://www.botany.hawaii.edu/faculty/webb/BOT311/Cyanobacteria/Cyanobacteria.htm22Prokaryotic and Eukaryotic AlgaeEukaryotes---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 aStack of thylakoidspyrenoid23Forms of AlgaeBODY OF AN ALGA=THALLUS

DIVERSITY IN MORPHOLOGY----MICROSCOPICUnicellular, Colonial and Filamentous forms.

Source: http://images.google.com/images24Forms of Algae

MACROALGAE25Forms of Algae

MICRO ALGAE26Forms of AlgaeUnicells: single cells, motile with flagellate (like Chlamydomonas and Euglena) or nonmotile (like Diatoms)

272. Multicellular form: the vegetation forms are in six forms:

Colonies: Assemblage of individual cells with variable or constant number of cells that remain constant throughout the colony life in mucilaginous matrix (containing an extracellular matrix made of a gelatinous glycoprotein), these colonies may be motile (like Volvox and Pandorina) or nonmotile (like Scendesmus and Pediastrum).

28 Coenobium: 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)

29b. Aggregations: is aggregation of cells that have ability to simple division (so, its colony but unconstant in form and size), the aggregations are in several types:Palmelloid form: non-motile cells embedded in mucilage (like Tetraspora).

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Dendroid form: resembling a tree in form or in pattern of growth (Dinobryon).31Amoeboid or Rhizopodial form such as Chlorarachnion.

32c. 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 unreguler mutiseriate such as Pithophora).

Cladophora

Pithophora33d. Coenocytic or siphonaceaous forms: one large, multinucleate cell without cross walls such as Vaucheria

34e. 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

35; pseudoparenchymatous (such as Batrachospermum) pseudoparenchymatous superficially resemble parenchyma but are composed of apprised filaments

36f. Erect thallus forms: Thallus, from Latinized Greek (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.

Chara

37CELLULAR ORGANIZATIONFlagella=organs of locomotion.Chloroplast=site of photosynthesis. Thylakoids are present in the chloroplast. The pigments are present in the thylakoids.Pyrenoid-structure associated with chloroplast. Contains ribulose-1,5-bisphosphate Carboxylase, proteins and carbohydrates.Eye-spot=part of chloroplast. Directs the cell towards light.

Source: A Biology of the AlgaeBy Philip Sze, third edition, WCB MCGraw-Hill38Variations in the pigment constitutionChlorophylls (green)Carotenoids (brown, yellow or red)Phycobilins (red pigment-phycoerythrinblue pigment phycocyanin)

39Summery of lecture two:Forms of algaeUnicellularMulticellularMotile (Euglena)Non motile(Chlorella)Colonies 2. AggregationsPalmelloid (Tetraspora)Dendroid (Dinobryon)Amoeboid (Chlororachnion)3.Filaments4. Coenocytic / Vaucheria5.Parenkematus/ Ulva6. Psedoparenkematus / Batrachospermum7. Erect thallus / Chara

4040Quiz of lecture twoWhat is Pyrinoid ?

Dont be Cheat If you did you are cheater 41Lecture Three42Growth in algaeDiffuse or generalized growth: (Ulva).Localized growth: Apical growth: (Chara, Cladophora).Basal growth: (Bulbochaete).Intercalary growth: (Laminaria, Oedogonium).Trichothallic growth: (Ectocarpus)

43Growth in algae44

Tricothallic

Apical and intercalaryReproduction in algae 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.

4546First: Asexual Reproduction includes:1. Vegetation reproduction:In unicellular algae: simple cell division some time called binary fission (such as Gleocapsa).In multicellular (colonies, filamentous, thallus, etc) by: Fragmentation such as Microsystis.Hormogonia: A small, motile filament, formed by some Cyanobacteria, that detaches and grows by cell division into a new filament such as Oscillatoria.Propagules: a structure capable of producing a new individual such as Sphacelaria.47Vegetative reproduction

Cell DivisionA 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?.Vegetative reproduction48

Hormogonia in Oscillatoria

49Vegetative reproduction

Propagules

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.5051

Ulotrix There are a lot of types of akinete spores such as:Autospores: immobile spores that cannot develop flagella such as Chlorella. Aplanospores: immobile spores that may nevertheless potentially grow flagella.Hypnospores: A thick-walled resting cyst.Tetraspores: spores produced by a tetrasporophyte, characteristic of red algae.Statospores: spores that are not actively discharged from the algal fruiting bodyAuxospores: A spore in diatom algae that leads to reformation of an enlarged vegetative cell.

52Second: Sexual Reproduction:

53As 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.54Second: Sexual Reproduction:

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.

55Second: Sexual Reproduction:

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.56A. Resting filaments of alga cells.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.57HeterogamyIn 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.58

Heterogamy in Oedogonium sp.SEXUAL REPRODUCTIONISOGAMY-Both gametes have flagella and similar in size and morphology.

ANISOGAMY-Gametes have flagella but are dissimilar in shape and size. One gamete is distinctly smaller than the other one.

OOGAMY-gamete with flagella (sperm) fuses with a larger, non flagellated gamete (egg).59REPRODUCTIONVegetativeCell divisions/Fragmentation=part of the filamentbreaks off from the rest and forms a new one.Asexual ReproductionZoospores after losing their flagella,form new filaments. No sexual fusion.Sexual-Gametes6061

a, b, and c are zoosporesd, e, and f are aplanosporesg, and h are hypnosporesK is autospores.L is Isogamous, m is Anisogamous, and n is Oogamous62Gametes look like vegetative cells or very differentIsogamy: both gametes look identicalAnisogamy: male and female gametes differ morphologicallyOogamy: One gamete is motile (male), one is nonmotile (female)Monecious: both gametes produced by the same individualDiecious: male and female gametes are produced by different individualsHomothallic: gametes from one individual can fuse (self-fertile)Heterothallic gametes from one individual cannot fuse (self-sterile)The life cycles in algae63Three 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.64The life cycles in algaeLife-cycle I (haploid life cycle): major part of life-cycle (vegetative phase) in haploid state, with meiosis upon germination of the zygote (zygotic meiosis)also referred to as haplontic life cycle, a single, predominant haploid phase

65The life cycles in algaeLife-cycle II (Diploid life cycle): vegetative phase is diploid, with meiosis upon formation of gametes (gametic meiosis) also referred to as diplontic life cycle, a single, predominant diploid phase

66The life cycles in algaeLife-cycle III (Diplobiontic life cycle): three multicellular phases, the gametophyte and one or more sporophyte(s)Gametophyte: typically haploid, produces gametes by mitosis Sporophyte: typically diploid, produces spores by meiosis Isomorphic: sporophyte and gametophyte look alike Heteromorphic: sporo- and gametophyte look different

Basis of algal Classificationthe different groups of algae can be classified on the basis of a number of characteristics. 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.67FlagellaLocomotion 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.

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68ECOLOGICAL DIVERSITYLAND---WATERFRESH WATER---MARINE HABITATSFLOATING (PLANKTONIC)BENTHIC (BOTTOM DWELLERS)EPIPHYTES

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