Plant Diversity Exam 1

A. 1. Euglenoids

Many species of euglenoids are strictly heterotrophic. One third have green chloroplasts derived from secondary endosymbiosis of a green algal cell. Euglenoids thrive in nutrient rich water, such as those associated with decaying organic matter, and are often used as environmental indicators of such conditions (primarily fresh water, but some marine). Reproduction is by cell division (mitosis).

bacillium

rod

Monophyly

A single cut prunes the group from the tree. MCRA and ALL descendants

Closest Relative

Any taxon in a group is equally related to all taxa in the sister group. Don't count nodes!

II. B. 1. 3) Explain how, over time, a plant with a heteromorphic alternation of generations could evolve into a plant without a gametophytic generation at all.

As n (the haploid gametophyte) gets smaller and smaller as more time is spent in the 2n (diploid sporophyte), eventually a gametic life cycle is reached where meiosis just directly creates gametes.

Explain why photosynthesis from 3.4-2.2 BYA contributes to global cooling, but results in little free O2 in the atmosphere.

CO2 was being removed from the atmosphere and forming limestone. (thus the cooling) O2 wasn't able to start really building up until 2.7-2.2 BYA. Before that, it precipitates iron in water and is not released into the atmosphere.

A. 6. Bacillariophyceae (diatoms)

Diatoms have the greatest biomass and species diversity of all phytoplankton in marine and fresh waters. They account for up to 25% of the total primary productivity on earth, and are the single most importnat component of aquatic food chains. Diatom cell walls consist of two frustules made of silica, one that overlaps the other. Reproduction is both asexual and sexual (gametic meiosis), with pennate diatoms have isogamous gametes and centric diatoms with oogamous gametes. Large deposits of diatomaceous earth (diatomite) are industrially important and provide evidence of the vast numbers of these microscopic cells. Because diatoms divide rapidly and are immersed in their surroundings, they are good indicators of ecological conditions; pollution or nutrients released today will impact numbers observed tomorrow. Diatoms are 'Stramenopiles' and share a common ancestor with brown algae and some other groups.

Taxonomic Hierarchy

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

II. 6) Discuss how the marine food base can be smaller in biomass than the consumer trophic levels that feed upon it.

Due to the high reproduction rate of the phytoplankton. They get rapidly eaten by the primary consumers (zooplankton), so their biomass at any point in time is small. However, they reproduce so fast that, despite their low steady-state biomass, they have high primary productivity that can support large numbers of zooplankton.

Isomorphic vs Heteromorphic

Isomorphic= gametophyte and sporophyte look the same Heteromorphic= gametophyte and sporophyte look different

Know the three sexual life cycles.

Pink Sheet!!

What is meant by alternation of generations?

The generations are alternately sexual (meiosis and syngamy) and asexual (mitosis).

Clade

all taxa descended from a common ancestor

cyano

blue

phaeo

brown

Apomorphy

derived character trait -shared by more than one thing = synapomorphy -autapomorphy = unique to one spieces

chryso

gold

chloro

green

crypto

hidden

rhodo

red

hapto

to fasten

plankton

wanderer

2- What is the principal difference between a heterotroph and an autotroph, and what role did each play on the early Earth? 3- Why is the evolution of photosynthesis thought to be such an important event in the evolution of life in general? (Chapter 1, pg 2)

2- Autotroph: make own energy source. Heterotroph: dependent on outside source of organic molecules for energy. The competition for food drove the evolution of autotrophs. Now sun energy could transferred and used for life on earth. 3- Photosynthesis altered earth's atmosphere, which in turn influenced the evolution of life.

Why are cyanobacteria appropriately classified as bacteria rather than with photosynthetic protists?

Protists are single celled, cyanobacteria can be multicellular.

II. B. 1) Characterize Phaeophyceae, Rhodophyta, and Chlorophytes with respect to species diversity, habitat, flagella, food storage, pigments, and cell wall components

.Phaeophyceae: Brown Algae -1500 species -marine, flourish in cold ocean water -2 flagella (only in reproductive cells); heterokont means short smooth and long hairy flagella -laminarin storage -Chl A and C, Fucoxanthin (carrotenoid) -cellulose, surrounded by mucilaginous algin matrix Rhodophyta: Red Algae -4000-6000 species -warm, marine, tropical water -no flagella at any point -floridean starch -chlorophyll a, carrotenoids, phycobolins -cellulose with agar and carrageenan (deposits of calcium carbonate in coralline algae) Chlorophytes: Green Algae -17,000 species -freshwater and marine -none or 2+ , equal or unequal, smooth -starch in chloroplasts -chlorphyll A and B, carrotenoids -noncellulose or cellulose

Explain the differences between the four categories of fossils described above. (Fossils)

1) CASTS involve an organism being surrounded by sediments, and then the organism rotting away leaving a mold. The mold, or area vacated, is filled with other sediments providing a simple cast of the organism, much like you could make out of plaster. These provide information about superficial structure, shape, and sometimes finer surface details. 2) COMPRESSION fossils form when the organism or part is surrounded by sediments and compressed flat over geologic time by the weight of the sediments. A carbonaceous film is often all that remains of the organism, but surface details are often apparent and can be observed in detail with scanning electron microscopy. 3) IMPRESSION fossils are similar to compression fossils, except only an impression is left with no organism remains present. Again surface details may be apparent, but not of the quality and detail available with may compression fossils. 4) PERMINERALIZATIONS (petrified) are formed over long periods of time, with the organism tissue infiltrated by silica or various carbonate compounds (minerals) that crystallize. Petrified fossils can reveal amazing exterior and interior structure including details at the cellular level. 5) TRACE fossils (ichnofossils) evidence life, but are not of the organisms themselves. Footprints, burrows, dung,, nests, and even mineral deposits formed through life processes are examples of trace fossils.

II. 9) When light is absorbed by a photosynthetic pigment, one of three things can occur, what are these?

1) Flourescence (release red light, or heat) 2) Pass energy to next molecule by it 3) Chl A in rxn center can send electrons up to the ETC.

Discuss the three-fold value of understanding the life cycle of an organism.

1) differences in reproductive structures are important clues for identification. 2) life cycles aid in understanding "weak points" for biological control 3) life cycles affect genetic variation important for conservation decisions as well as adaptation by organisms to changing environment.

1- What are the two critical events in sexual reproduction in eukaryotes? WHY? 4- In what ways is meiosis different from mitosis? (Chapter 8, pg 173)

1- meiosis and fertilization. Halves and then restores the chromosome number. Increases diversity other than just mutations. 4- Mitosis creates two identical daughter cells that each contain the same number of chromosomes as their parent cell. Meiosis results in four haploid cells.

1- What is the relationship between haploid and diploid chromosome numbers and meiosis and fertilization? 2- Describe the events that occur during crossing-over, and explain why this process is important. 4- List the advantages and disadvantages of sexual and asexual reproduction. (Chapter 8, pg 152)

1- meiosis splits a diploid (2n) organism to result in a halploid organism (n). Fertilization (syngamy) is the fusion of two haploids (n) to form a diploid (2n) 2- results in chromatids that are complete but have a different representation of genes than they had originally 3- Sexual Repro- Adv: increase sexual diversity Dis: must find opposite gender Asexual Repro- Adv: don't need to find partner Dis: only genetic diversity via mutation

1- Expound upon the phytoplankton as the "great meadow of the sea." 3- Pellicle, stigma, contractile vacuole, paramylon, pyrenoid. These are entities found in Euglena. What is the function of each? 4- What do the organisms Karenia brevis and Gonyaulax tamarensis have in common? 5- What pigments do the diatoms, chrysophytes, xanthophytes, and brown algae have in common?Which of these pigments is responsible for the color of these algae? 7- The diatoms may be characterized as "the algae that live in glass houses." Explain. 8- Some kelps have the most highly differentiated bodies among the algae. In what ways? 9- Fucus has a life cycle that is, in someways, similar to our own. Explain. 11- Distinguish between each of the following: oogonium and antheridium; homothallic and heterothallic; pinnate and centric; phycoplast and phragmoplast. (Chapter 15, pg 365)

1- phytoplankton, are the beginning of the food chain for the heterotrophic organisms. In the sea, most small and some large fish, as well as most of the great whales, feed on the plankton, and still larger fish feed on the smaller fish. In this way, the "great meadow of the sea," as the phytoplankton is sometimes called, can be likened to the meadows of the land, serving as the source of nourishment for heterotrophic organisms. 3- pellicle: a thin layer supporting the cell membrane stigma:(big and red) Mark/spot, senses light to move to correct level in the water column. Contains crytochromes. contractile Vacuole: Water wants to go into the cell via osmosis. Takes extra water and squeezes water out of the cell. paramylon: enables the organisms to survive in low-light conditions pyrenoid: a protein body in the chloroplasts of algae that is involved in carbon fixation and starch formation and storage. 4- Both dinoflagellates that produce neurotoxins 5- Chlorophylls A and C, carotenoids; mainly fucoxanthin (except xanthophyceae; yellow green) which accounts for their color. 7- cell walls composed of transparent, opaline silica. Diatom cell walls are ornamented by intricate and striking patterns of silica. 8- differentiated into regions known as the holdfast, stipe, and blade, with a meristematic region located between the blade and stipe 9- Fucus and Sargassum and some other brown algae grow by means of repeated divisions from a single apical cell, not from a meristem located within the body, as is characteristic of the kelps. GAMETIC life cycle. 11- Distinguish between: -oogonium (gamete producing "container" for eggs) VS antheridium (gamete producting "container" for sperm) -homothallic (the possession, within a single organism, of the resources to reproduce sexually) VS heterothallic (sexes that reside in different individuals) -pinnate (bilateral symmetry) VS centric (radial symmetry) -SEE PIC phycoplast (microtubule structure observed during cytokinesis in members of the Chlorophyceae) VS phragmoplast (A structure that forms in plant cells during late cytokinesis and serves as a scaffold for cell plate assembly and subsequent formation of a new cell wall separating the two daughter cells)

1- Of what ecological importance are algae? 2- In what ways are the euglenoids, cryptomonads, and dinoflagellates similar? Why is it difficult to classify these organisms on the basis of how they obtain their food? 3- What are the distinctive features of the phylum Haptophyta, and how are Haptophyta important in global climate control? 4- What are the basic characteristics of the brown algae? The red algae? 5- What characteristics of the green algae have led botanists to conclude that the charophycean green algae are the protist group from which the bryophytes and vascular plants have evolved? (Chapter 15, pg 317)

1- see other answer 2- 3- 4- 5-

2- Why is the term "hierarchical" used to describe taxonomic categories? Name the principal categories between the levels of species and kingdom. 3- What is cladistic analysis? What does a cladogram represent? 5- Name the three kingdoms of multicellular eukaryotes, and give the major identifying characteristics of each. (Chapter 12, pg 234)

2- Hierarchy: system or organization in which groups are ranked one above the other according to status. Domain, Kindgom, Phylum, Class, Order, Family, Genus, Species 3- Analysis: uses phylogenetic relations and evolutionary history to construct a cladogram. Cladogram: branching diagram showing the phylogenetic relationship between a number of species 5- Animalia, Plantae, Fungi

Describe the environment of the early earth after the formation of the second atmosphere. What problems existed that would prevent complex life? (Time Line)

2nd atmosphere developed from volcanic outgasing after the first atmosphere was lost. -N2 (mostly nitrogen) -CO2 (10-100x more than today; made the earth too hot to sustain life) -H2O vapor (produces some O2, but 1/100,000,000 compared to today's oxygen concentration; oxygen is needed to sustain complex life [complexity requires more energy, aerobic = 36 ATP])

II. A. 5. 1) Explain/define the underlined terms/concepts from the previous three groups. 3. haptonema 3. coccoliths 4. important food source for zooplankton 4. seconday endosymbiosis of a red algal cell 5. mixotophic

3 (haptophyta) haptonema- (nema = thread) used to acquire food particles, near flagella 3. (haptophyta) coccoliths- alternate morphology of the haptophyta. (lith = stone) tiny round calcareous platelet (calcium carbonate), numbers of which form the spherical shells of coccolithophores. 4. (cryptophyta) important food source for zooplankton: all other ocean life need phytoplankton to survive 4. (cryptophyta) seconday endosymbiosis of a red algal cell: BEST evidence of secondary endosymbiosis (evidence= DNA, nucleomorph, 4 membranes, pigments) 5. (chrysophyceae) mixotophic: capable of photosynthesis AND eating things via phagocytosis (can ingest things 2-3x their size and increase their volume 30x)

3- What role did oxygen play in the evolution of life on Earth? 5- Plants enter our lives in innumerable ways other than as sources of food. How many ways can you list?Have you thanked a green plant today? (Chapter 1, pg 15)

3- Some oxygen converted to ozone and absorbed ultra-violet rays (destructive to life). Allowed for break down of molecules via respiration. Once there was abundant free oxygen, we finally see the appearance of eukaryotic cells. 5- clothes, walls, paper, pencil, agar, pretty much everything...

II. B. 2. 3) What are the Archaeplastida and what is the significance of this name?

ancient - plastids A major line of eukaryotes with mitochondria, comprising the land plants (come from green algae), green and red algae, and a small group called the glaucophytes.

II. A. 6. 2) Life cycle (pg 332)

diploid organism --> meiosis (sexual reproduction) --> gametes (egg, sperm) --> syngamy --> zygote (auxospore) --> new diploid frustules (asexual reprodcution) *repeat* Frustules are dividing asexually, one smaller and one bigger side. then once it reaches minimum size, sexual reproduction is stimulated

II. 8) What are primary products of the light-dependent and light-independent reactions of photosynthesis? How are these related?

Light Dependent: electron released and sent to ETC and used to produce ATP (from ADP) and NADPH (from NADP+) and O2 is produced as a byproduct. Light Independent: ATP and NADPH drive conversion of CO2 into (CH2O)n (carbohydrates) Independent rxn requires the products of the light-dependent reactions to function. The light-independent molecules depend on the energy carrier molecules, ATP and NADPH, to drive the construction of new carbohydrate molecules.

A. Phytoplankton

Phytoplankton encompass the unicellular and unicellular colonial organisms that form the base of aquatic food chains; most groups of algae have at least some species that would be classified as phytoplankton. Cyanobacteria are an important phytoplankton component, but here the focus is only on the eukaryotic groups. Listed below are algal groups composed entirely or primarily of unicellular or unicellular colonial members. Note that in many cases, these groups are not closely related. Some groups have formal taxonomic names (in parenthesis, 15-1) implying monophyly of those groups, while monophyly of others in uncertain at present.

Use differences in unicellular vs multicellular stages to unambiguously distinguish between zygotic, sporic, and gametic life cycles.

Pink Handout!!!

eu

true

Polytomies

unresolved nodes because date conflicts or is lacking; in theory should be able to resolve with more data

Memorize group, plastid origin, and evidence chart. (Endosymbiosis)

Green Handout!!!

gleno

eye

II. A. 6. 4) What is a stramenopile and where does this term come from? What algal groups are stramenopiles? (note: heterokonts is an alternative name also used for this group)

"Straw Hair" Heterokonts = different - flagella Most are algae, ranging from the giant multicellular kelp to the unicellular diatoms, which are a primary component of plankton. -Bacillanaphyceae = diatoms -Phaeophyceae = brown algae

II. 2) What reliable features may be trusted to distinguish the various algal groups?

-2 categories based on size 1) Phytoplankton: unicellular or microscopic colonies. Cyanobacteria fall under this category, but they are NOT algae. 2) Macroalgae: Large, multicellular Diversity of form: photosynthetic pigments, structural features (cell wall, materials composing them), flagella (most have at least one at some point in their lives), food storage, reproduction.

Introduction

-ALGAE is a generic term for autotrophic eukaryotic organisms that produce oxygen as a byproduct of photosynthesis, but lack the defining features of true plants (as in, algae are not part of the kingdom Plantae). -"Algae" is a functional definition and not a term that describes a monophyletic group of organisms. -CYANOBACTERIA have been called "blue-green algae", but because they are prokaryotes, they are classified in Domain Bacteria apart from all other photosynthetic organsims. Eukaryotic algae belong to Domain Eukarya with various relationships to other organisms in an informal group called PROTISTS. -Protists are sometimes classified in a formal kingdom Protista, but since this kingdom is clearly not monophyletic, your textbook does not use that formal name, and we will not either. Most importantly, !!!while all algae are protists, not all protists are algae!!! in fact, most aren't. Within every planktonic group considered below, heterotrophic, non-photosynthetic species also exist that are not algae by definition. Some of the photosynthetic plankton may also obtain nutrients through phagocytosis or osmosis, giing rise to a condition called mixotrophy.

II. A. 2. 1) Key terms: Karenia (Gymnodinium), theca, zooxanthellae, cysts, tertiary endosymbiosis, toxic blooms (pg. 323)

-Karenia (Gymnodinium): The organism responsible for Florida red tides is the dinoflagellate Karenia -theca: cellulose case or sheath -zooxanthellae: golden/yellow, symbiotic flagellates that live within animals (e.g. coral, octopus). Photosynthesize and provide energy to organism. -cysts: dinoflagellates lose theca and can live through difficult times -tertiary endosymbiosis: various sources, ONLY dinoflagellates, the engulfment of an alga containing a secondary plastid -toxic blooms: colonies of algae grow out of control

Introduction 2) Are algae monophyletic? Protists? Explain.

-Neither is monophyletic -For algae...cyanobacteria have been called "blue-green algae", but because they are prokaryotes, they are classified in Domain Bacteria apart from all other photosynthetic organsims. Eukaryotic algae belong to Domain Eukarya -For protists... sometimes classified in a formal kingdom Protista, but this kingdom is clearly not monophyletic. Most importantly, !!!while all algae are protists, not all protists are algae!!! in fact, most aren't. -Animalia, Plantae, and Bacteria are monophyletic, but some members of the Kingdom Protista are more closely related to one of the first three kingdoms than protists.

Standard Endings

-Phylum: -ophyta -Class: -opsida -Order: -ales -Family: -aceae

II. 7) Distinguish between primary and accessory photosynthetic pigments -- how do each of these function?

-Primary Pigment: Chlorophyll A; must be in ALL photosynthetic organisms. (Red Algae only have CHL A) Can do three things with energy from light: 1) Flourescence (release red light, or heat) 2) Pass energy to next molecule by it 3) Chl A in rxn center can send electrons up to the ETC. -Accessory Pigments: a pigment that is not directly involved in photosynthetic energy transduction but serves to broaden the range of light that can be used in photosynthesis. Chlorophyll B, Chlorophyll C, Carotenoids, Phycobilins

II. B. 2. 2) Discuss the economic and ecological role of red algae.

-agar gels for DNA or bacterial growth -thickening in dairy products like milk -sunbelt granola bars (smooth chocolate layer)

Introduction 1) What are algae? To what higher taxonomic group do they belong?

-autotrophic eukaryotic organisms that produce oxygen as a byproduct of photosynthesis, but lack the defining features of true plants -"Algae" is a functional definition and a term that describes a polyphyletic group of organisms -Kingdom Protista and Bacteria, Animal, Fungi all share common ancestor. EUKARYA. All algae are protists.

II. B. 1. 1) Key terms: blade, stipe, holdfast, plasmodesmata, algin.

-balde: generally flattened structure that typically forms the principal bulk of the thallus -stipe: stem-like part of the thallus (simple differentiated tissue) -holdfast: a root-like structure that anchors aquatic sessile organisms -plasmodesmata: call to cell connection; a narrow thread of cytoplasm that passes through the cell walls of adjacent plant cells and allows communication between them -algin: distributed widely in the cell walls of brown algae, where through binding with water it forms a viscous gum (alginate used for paper, dental molds, etc)

II. B. 2. 1) Key ideas: coralline algae, phycobolin, ocean depth, agar, carrageenan.

-coralline aglae: have calcium carbonate in them -phycobolin: give red color by absorbing higher energy wavelengths of blue and green light -ocean depth: grow to depths of 800 feet -agar and carrageenan: walls are covered in this and can sluff off

II. A. 6. 1) Key terms: frustule, oogamy, isogamy, anisogamy, gametic meiosis (pg 254)

-frustule: hard and porous cell wall or external layer of diatoms. The frustule is composed almost purely of silica, coated with layer of organic substance. 2 per diatom cell -oogamy: female gamete is significantly larger than the male gamete and is non-motile. The male gametes are typically highly motile and are usually tasked with all of the travel (centric diatoms- radial symmetry) -isogamy: sexual reproduction by the fusion of similar gametes. (pennate diatoms- bilateral symmetry) -anisogamy: sexual reproduction by the fusion of dissimilar gametes. -gametic meiosis:

I. 4) Identify/define the following terms: heterocyst, akinete, unicellular colony, gas vesicle, asexual reproduction, fission, stromatolite.

-heterocyst: A transparent, thick-walled, nitrogen- fixing cell (specialized and enlarged) that forms in the filaments of certain cyanobacteria. Lack photosystem II -akinete: vegetative cell that is transformed into a thick-walled resistant spore in cyanobacteria -unicellular colony: because they are bacteria, they are quite small and usually unicellular, though they often grow in colonies large enough to see. Only colonies can fix nitrogen!! -gas vesicle: bright, irregularly shaped structures called gas vesicles. These vesicles provide and regulate the buoyancy of the organisms, thus allowing them to float at certain levels in the water. When numerous cyanobacteria become unable to regulate their gas vesicles properly—for example, because of extreme fluctuations of temperature or oxygen supply—they may float to the surface of the body of water and form visible masses called "blooms." Some cyanobacteria that form blooms secrete chemical substances that are toxic to other organisms, causing large numbers of deaths. -asexual reproduction: reproductive process (fission or budding) that doesn't involve the union of gametes -fission: (1) Asexual reproduction involving the division of a single-celled individual into two new single-celled individuals of equal size; (2) the division of plastids and mitochondria -stromatolite: Stromatolites are produced when flourishing colonies of cyanobacteria bind calcium carbonate into domed structures

II. A. 6. 5) Diatoms can reproduce sexually and asexually, but asexual reproduction is most common. What cues are used to stimulate reproduction in diatoms? Which cue is specific to diatoms and which is more general to other unicellular, sexual algae?

-minimal size (of frustule for stramenopiles?) -decreasing availability of nutrients

II. B. 3. 2) What evidence supports the view that green algae gave rise to the land plants?

-plants have a sporic life cycle, which could have come from sporic green algae or zygotic green algae -both have starch as their ood/energy storage molecule -chlorophyll a and b -cell walls, when present, are made of cellulose.

II. 5) Ocean areas differ in their productivity of marine life. Discuss the reasons for the high productivity of continental shelves and areas of cold-water upwelling.

-runoff brings nutrients to the continental shelf -cold water upwells also bring nutrients in concentrated amounts Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water towards the ocean surface, replacing the warmer, usually nutrient-depleted surface water. The nutrient-rich upwelled water stimulates the growth and reproduction

3- In what ways are the cyanobacteria ecologically important? (Chapter 13, pg 256)

13- especially important in global carbon and nitrogen cycles. e.g. rice planting

5- Describe the role of endosymbiosis in the origin of eukaryotic cells. 6- The life cycle of organisms that undergo sporic meiosis is referred to as analternation of generations. Explain. (Chapter 12, pg 255)

5- Most experts believe that the process of establishing an endosymbiotic relationship was preceded by the evolution of a prokaryotic host cell into a primitive phagocyte (meaning "eating cell")—a cell capable of engulfing large particles such as bacteria. It is likely that the ancestral host cell was a wall-less heterotroph living in an environment that provided it with food. Such cells would need a flexible plasma membrane capable of enveloping bulky food particles by folding inward A phagocyte now exists that can prey on bacteria, but the phagocyte still lacks mitochondria. The next step is for the phagocyte not to digest the bacterial precursors of the mitochondria (or chloroplasts) but to adopt them, establishing a symbiotic ("living together") relationship. Transformation of an endosymbiont into an organelle usually involved loss of the endosymbiont's cell wall (if any existed) and other unneeded structures. In the course of evolution, the DNA of the endosymbiont and many of its functions were gradually transferred to the host's nucleus. Hence, the genomes of modern mitochondria and chloroplasts are quite small compared with the nuclear genome. Although the mitochondrion or chloroplast cannot live outside a eukaryotic cell, both are self-replicating organelles that have retained many of the characteristics of their prokaryotic ancestors. Mitochondria are widely accepted to have evolved from an alpha-proteobacterium in a common ancestor of all existing (extant) eukaryotes. By contrast, the chloroplasts of the algae (see Chapter 15) are universally believed to have evolved from cyanobacterial endosymbionts by three major types of endo- symbiosis. The land plants, in turn, inherited their chloroplasts from green algae. 6- A diploid (2n) sporophyte undergoes meiosis to produce haploid (1n) reproductive cells, often called spores. Haploid cells undergo mitosis to produce a gametophyte. The gametophyte produces haploid gametes which fuse to form a diploid zygotic sporophyte.

Write the balanced photosynthetic equation given in class and explain the dual role of photosynthesis by early prokaryotes (with supporting detail) in making the earth inhabitable by eukaryotic organisms. (Time Line)

6CO2 + 6H2O [+ENERGY] <=> C6H12O6 + 6O2 -Removal of CO2 from the atomosphere -begins to lower global temperature -sugar synthesis and organism structure not immediately decomposed (=> oil, etc) -Build up of O2 in the atmostphere -beginning 2.7-2.2 BYA; before the O2 precipitates iron in water -enables aerobic respiration (more efficient, 36 ATP vs 2 ATP in anaerobic) -enable sterol synthesis (component of flexible membranes - allows phagocytosis) -ozone (O3) production filters solar radiation (sufficient amount by .45 BYA)

Discuss the advantages and disadvantages of multicellularity.

Advantages: A multicellular organism has a longer lifespan than an unicellular organism and since it has multiple cells, it can perform more functions than a unicellular organism.They can do lots of other things that a unicellular organism can not because it has more cells to complete more jobs. Disadvantages: due to such a complex composition and functioning they require a large amount of energy

I. 1) Why aren't cyanobacteria algae?

Algae by definition are eukaryotic. Cyanobacteria (though their common name is 'blue green algae') are prokaryotic (no defined nucleus or membrane bound organelles) photosynthesizing bacteria.

Explain how and why cyanobacteria heterocysts affect rice production in asia.

Among cyanobacteria that fix nitrogen are free-living species such as Trichodesmium, which lives in certain tropi-cal oceans. Trichodesmium accounts for about a quarter of the total nitrogen fixed there, an enormous amount. Symbiotic cya-nobacteria are likewise very important in nitrogen fixation. In the warmer parts of Asia, rice was often grown continuously on the same land, without the addition of fertilizers, because of the presence of nitrogen-fixing cyanobacteria in the rice paddies Here, the cyanobacteria, especially members of the genus Anabaena (Figure 13-14), often occur in association with the small, floating water fern Azolla, which forms masses on the paddies. N availability to plants is increased due to application of cyanobacteria in agriculture ecosystems, particularly the rice fields. No additional fertilizer needed, and can reuse the land.

I. Cyanobacteria

Among the most ancient autotrophs. Through photosynthesis, they undoubtedly influenced the early evolution of many forms of life. [NOTE: Prochlorophytes are independent, specialized lineages within the cyanobacteria radiation that evolved chlorophyll b independently from each other and from the chlorophyll b found in true plants]

B. 1. Phaeophyceae (brown algae)

Brown algae are stramenopiles and share a common ancestor with diatoms. Some borwn algae are small filaments, but most are larger with leaf-like blades, stem like stipes, and root like holdfasts. None are unicellular, so this groups does not contain any phytoplankton. Some are over 180 feet long and even have specialized cells for transporting food from blades to the holdfasts. Most have tiny plasmodesmata or channels that connect the protoplasm from adjacent cells. Brown algae include the kelps and most common seaweeds of cold, temperate waters. Algin, derived from the cell walls, is used similarly to agar and carrageenan (from red algae, see below) in food and industry. Some brown algae have sporic meiosis with an isomorphic alternation of generations. Others have heteromorphic generations with microscopic gametophytes. Yet others have gametic meiosis and do not alternate between generations (pg. 254; 338-339)

What advantages do colonies have over strictly unicellular life forms?

Cell differentiation is now possible. Nutrients can be transferred to where they are more needed.

I. 6) Discuss the endosymbiotic hypothesis regarding the origin of eukaryotic organelles; what role do cyanobacteria have in this hypothesis?

Chloroplasts come from cyanobacteria. • primary endosymbiosis, cyanobacterial cells ingested by the eukaryotic host evolve into primary plastids, each of which is bounded by an envelope consisting of two membranes Most prokaryotes contain a rigid cell wall, so it is likely that an initial step in the transformation of a prokaryote to a eukaryotic cell was the loss of the prokaryote's ability to form a cell wall. (b), (c) This free-living, naked form now had the ability to increase in size, change shape, and engulf extracellular objects by infolding of the plasma membrane (endocytosis), resulting in the formation of endocytic vesicles. (d), (e) Internalization of a patch of the plasma membrane to which DNA was attached was the probable precursor of the nucleus. The primitive phagocyte eventually acquired a true nucleus containing an increased quantity of DNA. A cytoskeleton must also have developed to provide inner support for the wall-less cell and to play a role in movement, of both the cell itself and its internal components. (f) The mitochondria of the eukaryotic cell had their origin as bacterial endosymbionts, which ultimately transferred most of their DNA to the host's nucleus. (g) Chloroplasts also are the descendants of bacteria. They, too, ultimately transferred most of their DNA to the host's nucleus. (h) The photosynthetic eukaryotic cell contains a complex endomembrane system and a variety of other internal structures, such as the peroxisomes, mitochondria, and chloroplasts depicted here

Explain why the chloroplasts of ALL photosynthetic organisms can be traced to a single common ancestor, whereas photosynthetic eukaryotes are polyphyletic. (Endosymbiosis)

Chloroplasts originated from primary symbiosis when a free-living bacteria was originally phagocitized. There are photosynthetic prokaryotes, so eukaryotes would exclude the common ancestor and include various taxa that hard their plastid via secondary or tertiary endosymbiosis.

A. 5. Chrysophyceae (golden algae)

Chrysophytes are stramenopiles closely related to Bacillariophyceae adn Phaeophyceae, and share a similar golden brown color of chloroplasts. Many are mixotrophic, capable of ingesting food 2-3 times their own size and increasing their volume 30 times their normal size to hold the food they hae ingested.

II. B. 3. 4) Recognize distinguishing features in from and reproduction of Clamydomonas, Volvox, Oedogonium, Ulothrix, Ulva, and Spirogyra. (They genera represent increasing complexity from unicellular to colony forms, to multicellularity with different solutions to reproduction. Chances are we won't get to cover them in class... the true scholars will read a little about them and enjoy the wonder of green algal diversity :)

Clamydomonas: ZYGOTIC Two flagellated haploid cells "hug" with flagella and merge into one diploid zygote. It can immeidately divide by meiosis or form a zygospore (thick walled to resist harsh conditions e.g. no nutrients) which can rest and then undergo meiosis to form haploids. Volvox: COLONY FORMING Individual cells look like clamydomonas. Ulothrix: ZYGOTIC, MULTICELLULAR Long chain of rectangular haploid cells. One cell starts forming gametes by mitosis. They are released from cell and isogamous gametes fuse to form zygote, which can either rest or go through meiosis. Oedogonium: OOGAMOUS (egg and sperm) *only other oogamous algae are marine diatoms* Long chain of rectangular haploid cells, but one gametic container for sperm (antheridium) and another for egg (oogonium)

Explain how a living thing may eventually become fossilized, including permineralized, and why the fossil record is incomplete. (Fossils)

Could become fossilized via the 5 types of fossilization. Many lived in conditions that made fossilization unlikely. Even with good conditions, plant parts such as leaves, stems, fruits, seeds, and pollen grains, are more likely to be preserved as fragments. Only a fraction of the fossils have been found.

A. 4. Cryptophyta (Cryptomonads)

Cryptomonads derive their name from their extremely small size and they are most abundant in both marine and freshwaters that are cold or deep. Despite their small size, !!they are a very important food source for zooplankton!! Autotrophic cryptomonads apparently received their chloroplasts via !!secondary endosymbiosis of a red algal cell!!; some of the bet evidence for secondary endosymbiosis is found here.

I. 5) Describe the influence/interactions of cyanobacteria on/with other life forms (symbiosis) and importance in ecological roles such as global carbon and nitrogen cycles.

Cyanobacteria occur as symbionts within the bodies of a vast number of species: amoebas, some sponges, flagellated protozoa, diatoms, green algae that lack chlorophyll, other cya-nobacteria, mosses, liverworts, vascular plants, and oomycetes. This is in addition to their familiar role as the photosynthetic partner in many lichens (see Chapter 14). Some symbiotic cyanobacteria lack a cell wall, in which case they function as chloroplasts. The symbiotic cyanobacterium divides at the same time as its host cell by a process similar to chloroplast division. Stromatolite abundance in the fossil record is evidence that such environmental conditions were prevalent in the past, when cyanobacteria played the decisive role in elevating the level of free oxygen in the atmosphere of the early Earth. Many genera of cyanobacteria can fix nitrogen, converting nitrogen gas to ammonium, a form in which the nitrogen is available for biological reactions.

II. B. 1. 2) What determines the relative amount of time spent in the haploid or diploid generation during the course of evolution?

Diploid should be bigger because then more spores can be made, so more meiosis occurs. This allows organisms to overcome lethal recessive alleles in the genome. Spend less time in the gametophyte (haploid) and more time in the sporophyte (diploid). HETEROMORPHIC Advantage to being diploid = duplicate genome to overcome recessive lethal alleles. GAMETIC IS THE BEST.

II. A. 1) Characterize Euglenoids, Dinoflagellates, and Diatoms with respect to species diversity, habitat, flagella, food storage, pigments, and cell wall components.

Euglenoids: -800-1000 -mostly freshwater, some marine -usually 2, 1 forward, 1 behind stub -paramylon -most have none, or chl a and b, carotenoids -flexible or rigid protein strips under plasma membrane Dinoflagellates: -4000 -mostly marine, some freshwater, some in symbiotic relationships -none (except in gametes) or 2 (1 longitudinal, 1 transverse) -starch -none in many, chl a and c, carotenoids (peridinin) -vesicles beneath plasma membrane, with or without cellulose plates Diatoms: -10,000-12,000 -marine and freshwater -none or 1; only in male centric gametes -chrysolaminarin -none, or chlorophylls a and c, carotenoids (fucoxanthin) -silica

II. Algae

Eukaryotic protists, primarily aquatic, and likely to be found wherever liquid water and light co-occur. Characteristics used to differentiate between algal groups include pigments (chlorophyll and accessory pigments- pgs 126-129), cell wall composition, number and insertion of flagella, food storage molecules, morphology (shape, structure), and to some extent habitat. SEE FIG 15-1 Though neglected in daily thought, algae are extremely important ecologically and economically. Algae are a major component of the base of all aquatic food chains. they have contributed much to the formation of an oxygen rich atmosphere both by O2 synthesis and by removing CO2 that is not immediately available for decomposition (via sedimentation, etc. pgs 140-141). They have contributed to fossil fuel deposits, limestone, diatomaceous earth deposits, reef building, and toxic tides. Some are also valued for direct human consumption or for byproducts used in food and industrial manufacturing.

Polyphyly

Excludes MCRA and usually many descendants

What are the limitations of carbon-14 dating and what other reliable absolute dating methods exist? (Fossils)

Half life is only 5, 700 years. Useful for dating recent events, not old fossils. Reliable to about 35,000 years and a max of 50,000-60,000 years. However, fossil evidence shows life at least 3.8 BYA, life on land 450 MYA, so carbon dating not useful for dating the history of life. Variety of other radiometric isotopes exist, like uranium 238 and potassium 40 which allow fossils to be dated millions and even billions of years old with relatively narrow margin of error.

II. A. 2) Define and give an example of secondary and tertiary endosymbiosis with details and evidence supporting these hypotheses.

In the process of secondary endosymbiosis, eukaryoticcells containing plastids are themselves engulfed by anothereukaryotic cell and evolve into secondary plastids (Figure12-13b). Such plastids are characterized by the presence of three or four envelope membranes. Of the algal lineages considered in this book, secondary plastids are found in haptophytes,most cryptomonads, and many euglenoids, dinoflagellates, and stramenopiles. In tertiary endosymbiosis, the eukaryotic cells have a plastid derived from a eukaryotic endosymbiont with a secondary plastid. The envelope of tertiary plastids consists of more than two membranes. Tertiary plastids derived independently from cryptomonad, haptophyte, or diatom endosymbionts with secondary plastids are found in several dinoflagellate species.

B. Macro Algae

Included here are three groups that are not necessarily closely related, but that have at least some large, multicellular species.

II. A. 6. 3) What are the advantages and disadvantages of oogamy compared to isogamy? What features are associated with oogamy (i.e. describe what oogamy is and how it functions)

Large stationary egg, smaller mobile sperm. Disadvantage: -sperm has to travel safely to egg -egg cannot find sperm - isogamy has a numerical advantage in producing as many small gametes as possible -large egg is "tasty" because it's a nutrient rich resource Advantage: -good reason to produce large gametes that will contribute cytoplasmic mass to the zygote. -both gametes don't have to move

Paraphyly

MCRA but not all descendant. Requires more cuts after the MCRA

II. 4) 6CO2 + 6H2O [+energy] <=> C6H12O6 + 6O2 describes and equilibrium interaction (the number of C, O, and H are equal on both sides of the equation). The left to right equation is photosynthesis, and right to left equation is respiration. If the equation is balanced, how does surplus O2 accumulate in the atomosphere?

More photosynthesis occurs than respiration and decomposition. All clothes are product of photosynthesis. Coal deposits, oil, etc. Products of photosynthesis that have been fixed and cannot respire.

A. 2. Dinoflagellates

Most dinoflagellates are characterized by 2 flagella that cause the cells to spin, and a conspicuous groove. Many species have cellulose plates called THECA that are located inside the cell membrane rather than on the outside like cell walls and plates of other algae. Chloroplasts in dinoflagellates have arisen multiple times by secondary or tertiary endosymbiosis; most autotrophic species have the pigments listed in Table 15.1, but a few obtained their chloroplasts from green algae or other phyla and thus have different pigments. -As zooxanthellae, some dinoflagellates are important in coral reef formation. Although several phyla of phytoplankton can produce toxins, dinoflagellates are the most notorious in this ability and Karenia is responsible for the "red tides". Dinoflagellates occur both in marine and fresh waters, and are second only to diatoms as eukaryotic producers at the base of marine food chains. Reproduction can occur by cell division with each daughter cell getting half of the theca and regenerating the other half. Other life cycles are complex and can involve up to at least 24 different stages..

II. B. 3. 3) Where did green algae get their chloroplasts from? What other major algal group are they related to?

Primary endosymbiosis, from cyanobacteria in common ancestor of green and red algae -Red Algae

II. 3) What evidence exists that suggests most algal lineages are primitively heterotrophic?

Primary endosymbiosis. In order for chloroplasts to begin, their primitive ancestors would have had to phagocitized a bacterium, making them heterotrophic. Primary endosymbiosis occurred ONCE resulting in Red Algae, Green Algae, and Glaucophytes. All other organisms with chloroplasts got them from either secondary or tertiary endosymbiosis (which can/has occurred multiple times)

B. 2. Rhodophyta (red algae)

Red algae share common ancestry with green alga (see below) -- unicellular species are ancestral in both groups, so multicellularity evolved independently. The red algae are mostly multicellular and predominantly marine. They are unique among algae in lacking flagella at any stage of the life cycle, and in possessing chlorophyll A as its only chlorophyll molecule. While accessory pigments help some algae protect themselves from too much sun, the phycobolins of red algae absorb the higher energy blue and green wavelengths that penetrate deep water. This enables some red algal species to inhabit water up to 800 feet deep (deeper than any other algae) where light intensity is only .ooo5% that of surface light. "Coralline algae" accumulate calcium compounds on their walls; some of these are important contributors to reef building. Reproduction can be both asexual or sexual, with some sexual cycles including three generations (1 haploid, 1 diploid attached to the haploid gametophyte, and 1 free living diploid sporophyte). Some red algae are eaten directly in eastern countries and the cell wall components agar and acarrageenan are used in food and industry worldwide.

II. A. 2. 2) Explain how rain followed by extended periods of hot, sunny weather and calm seas can lead to red tide and the effects of a red tide on other aquatic organisms and humans.

Red tide comes from dinoflagellates. When it rains, the salinity of water is decreased, and the runoff increases the amount of nutrients in the water. The combination of these two things leads to LOTS of reproduction. Warm water and calm seas contribute as well. In the case of red tide, the dinoflagellates contain neurotoxins, which poison aquatic vertebrates and birds. However, shell fish take up the toxins and if humans eat them, it can cause paralysis via neurotoxic poisons.

Differentiate between relative and absolute dating. (Fossils)

Relative Dating- attempts to assign a date based on the layer or strata the fossil was found in, raltive to other layers that have been more precisely dated by absolute means. Absolute Dating- relies on the radioactive decay of a variety of chemicals. e.g. uranium 238 --> lead 206. Half the amount of uranium will decay into lead during its half life, in this case, 4.5 billion years.

II. B. 1. 4) Why does the formal taxonomic name of the red algae end in "phyta" while the formal taxonomic name of the brown algae ends in "phyceae"

Rhodophyta: phylum ending Phaeophyceae: family ending Genetic and ultrastructural evidence place the Phaeophyceae among the heterokonts (Stramenopiles),[16] a large assemblage of organisms that includes both photosynthetic members with plastids (such as the diatoms) as well as non-photosynthetic groups (such as the slime nets and water molds). Although some heterokont relatives of the brown algae lack plastids in their cells, scientists believe this is a result of evolutionary loss of that organelle in those groups rather than independent acquisition by the several photosynthetic members.[17] Thus, all heterokonts are believed to descend from a single heterotrophic ancestor that became photosynthetic when it acquired plastids through endosymbiosis of another unicellular eukaryote. BOTH monophyletic

Summary Table pg 172

SEE PIC

II. A. 1. 1) Draw a euglena cell with the following parts labeled and their function described; stigma, contractile vacuole, flagella.

Stigma: (big and red) Mark/spot, senses light to move to correct level in the water column. Contains crytochromes. Contractile Vacuole: Water wants to go into the cell via osmosis. Takes extra water and squeezes water out of the cell. Flagella: usually two, often unequal with one short and one long Three membranes around chloroplast. SEE PIC

I. 3) Why aren't cyanobacteria colonies equivalent to a multicellular organism?

The cells of cyanobacteria are usually joined only by their walls or by mucilaginous sheaths, so that each cell leads an independent life. Cell to cell connection for transferring nitrogen. Some cells fix nitrogen and cannot photosynthesize. No multicellular organisms that are not eukaryotes (some scientists say this). If something is multicellular, it can't live independently of the other cells. Colonies DO allow specialization and potential escape from predation.

B. 3. Chlorophytes (green algae)

The green algae are diverse in size, shape, and reproductive life cycles, with important phytoplankton representatives and important macroscopic species. Green algae are commonly encountered in both marine and freshwaters; a few are primarily terrestrial and some form important symbiotic relationships with lichens. Many green algae have zygotic life cycles, though some have evolved to sporic life cycles. Some green algae are used as food, and others have contributed significantly to some petroleum deposits. Most significantly, evidence indicates green algae are the group from which the plant kingdom evolved, and these two groups share many features (pg 367)

A. 3. Haptophyta (Haptophytes)

These primarily marine algae received their chloroplasts via secondary endosymbiosis of a red algal cell, and, like red algae and cryptomonads, some species thrice in water more than 200 meters deep. Many species possess a thread like cell extension called haptonema that can hold prey or food particles. Many haptophytes produce external body scales of calcium carbonate called coccoliths; sedimented coccoliths are the major contributor (25%) of ocean floow limestone deposits and thus haptophytes are extremely ecologically important in the carbon cycle. Other species produce large quantities of sulfur containing molecules that are important in cloud formation, acid rain, and climatic cooling.

II. B. 3. 1) Green algae traditionally are referred to the taxonomic group "Chlorophyta". Why specifically does the textbook avoid giving this group a formal taxonomic name?

They are referred to as the Chlorophytes because the monophyletic group also inlcudes land plants. Green algae on their own are paraphyletic.

II. A. 4) How do reproductive rates, intimacy with their environment, and nutrient needs contribute to the usefulness of phytoplankton as water quality biomonitors?

They're very sensitive to nutrients. If there is a depletion, they'll die. If there are excess nutrients, it could result in red tide. Large surface area to volume ratio because they are so small, therefore they respond rapidly. Reproductive rates are fast because they primarily go through asexual reproduction. Measure abundance of phytoplankton in water and compare.

II. A. 5. 2) Understand the importance of calcium carbonate deposition by marine algae as a second means of sequestering CO2 - why is CO2 removal from the atmosphere important?

To allow for global cooling. (side note: DMS cloud formation also important to global cooling)

Answer questions in phylogenetic trees.

White handoout!!!

Sister Groups

descendants on both sides of common ancestor

II. 1) Discuss the contributions of the various algal groups discussed in class to the ecosystem and their importance to man -- provide examples with supporting details.

haptophytes = DMS and coccoliths (taking CO2 out of the atmosphere, we can also harvest limestone, like for chalk), cryptomonads are important food source due to fatty acids (for zooplankton), proteins? diatoms=25% of photosynthesis AND arge deposits of diatomaceous earth (diatomite) are industrially important AND they are good indicators of ecological conditions, red algae (food for deep ocean organisms, we eat some red algae-vitamins, we get agar which we use in biology), brown algae=algin, kelp (brown algae) forests are high in diversity ((Help Come Die R Brown))

Pleisiomorphy

means "near". Primitive at original trait. Traits before any evolution occurred in the group.

monad

one cell

phyto

plant

Nodes

represent hypothetical ancestral species, no longer living

Homoplastic

similar characteristics but not because of shared common ancestry, but independent evolution

dino

to whirl or rotate

I. 2) Describe the various forms of cyanobacteria and identify by name and role any special cell forms.

variations in colony forms, akintetes, heterocysts, etc -fragmentation of the filament -filamentous with basal heterocyst -gelatinous "ball" -plate