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Characteristics of Algae:. Plantlike members of the kingdom Protista Eukaryotes Most unicellular, but some multicellular Autotrophic

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1. Algae Kingdom Protista Developed by Adam F Sprague

3.  Structure of Algal Cells: The body of algae is called the thallus  Algae may  be unicellular, colonial, filamentous, or multicellular Unicellular algae are single-celled & make up phytoplankton (a population of photosynthetic organisms that begins many aquatic food chains) Phytoplankton make much world's carbohydrates & are the major producers of oxygen

4. Unicellular AlgaeChlamydomonas

5. Structure of Algal Cells: Colonial algae consist of groups of cells working together Some colonial algal cells may specialize for movement, feeding, or reproduction showing for division of labor 

6. Colonial algae

7. Structure of Algal Cells: Filamentous algae have slender, rod-shaped thallus arranged in rows joined end-to-end Holdfasts are specialized structures in some filamentous algae that attaches the algae so it can grow toward sunlight at the surface

8. Filamentous algae Enteromorpha

9. Structure of Algal Cells: Multicellular algae often have a large, complex leaf-like thallus & may have stem-like sections and air bladders  Macrocystis is among the largest multicellular algae

10. Structure of algae vs. seagrass

11. Air Bladders

12. Multicellular algae Macrocystis

13. Kelp beds

14. Classification: Algae are classified into 7 phyla, based on color, type of chlorophyll, form of food-storage substance, and cell wall composition All phyla contain chlorophyll a All algae live in water or moist areas (ponds, seas, moist soil, ice...) Act as producers making food & oxygen Many species of algae reproduce sexually and asexually Sexual reproduction in algae is often triggered by environmental stress

15. Chlorophyta (green Algae): 7000 species May be unicellular, multicellular, or colonial Include Spirogyra, Ulva, & Chlamydomonas Contain chlorophyll a & chlorophyll b and carotenoids (orange & yellow pigments) as accessory pigments Store food as starch Cell walls mainly cellulose, but some marine forms add CaCO3 Habitat may be freshwater, moist surfaces, or marine environments Some have whip-like flagella for movement May live symbiotically as lichens Thought to have given rise to terrestrial plants

16. Phaeophyta (brown algae): 1500 species Contain chlorophyll a & chlorophyll c and fucoxanthin (brown pigment) as accessory pigments Most are multicellular growing in cooler marine habitats Include kelps & seaweeds Largest protists Specialized rootlike holdfasts anchor thallus to rocks Specialized air bladders keep leaflike blades afloat near surface to get light for photosynthesis Stemlike structures are called the stipe and support the blades Store food as a carbohydrate called laminarin Include Laminaria & Fucus

17. Rhodophyta (red algae): 4000 species Multicellular algae that mainly grow deep in warm marine waters Some freshwater species exist Highly branched thallus Contain chlorophyll a & phycobilins (red pigments) to trap sunlight for photosynthesis Store food as starch Cell walls contain cellulose and agar (used as a base in culture dishes to grow microbes) Some species contain carageenan in their cell walls used for gelatin capsules & in some cheeses

18. Dinoflagellata or Pyrrophyta (dinoflagellates): 1100 species Major producers in marine habitats Small, unicellular organisms making up plankton Many are photosynthetic, but some are colorless heterotrophs Photosynthetic dinoflagellates are yellow to brown in color due to chlorophyll a & c and carotenoids

19. Bacillariophyta (diatoms): 11,500 species Abundant in marine & freshwater habitats Called phytoplankton & start many aquatic food chains Contain chlorophyll a & c, carotenoids (orange pigments), & xanthophyll (yellow pigments) Store food as starch & contain mainly cellulose in their cell walls Lack cilia & flagella

20. Freshwater algae Chrysophyta (golden algae) Euglenophyta

21. Common Marine algae of Barnegat Bay

22. Enteromorpha

23. Ulva

24. Agardhiella

25. fucus

26. spongomorpha

27. Ceramium( Banded Red Weed)

28. Codium

29. Sargassum

30. There are numerous types of marine algae found throughout our back bay areas, this has just been a sample of what you will find.

31. Reproduction in Unicellular Algae

32. Asexual Phase Algae absorbs its flagellum Haploid algal cell then divides mitotically from 2 to 3 times From 4 - 8  haploid flagellated cells called zoospores develop in this parent cell Zoospores break out of the parent cell & eventually grow to full size

33. Sexual Phase Haploid cells dividing mitotically to produce either “plus” or “minus” gametes A plus gamete and a minus gamete come into contact with one another, shed their cell walls, and fuse to form a diploid zygote This resting stage of a zygote is called a zygospore & an withstand bad environmental conditions When conditions are bad, the thick wall opens and the living zoospore emerges

35. Reproduction in Multicellular Algae: Oedogonium is a multicellular, filamentous green algae with specialized cells called gametangia that form gametes The male gametangia or antheridium makes sperm, & the female gametangia or oogonium makes eggs Sperm are released into the water & swim to the egg to fertilize them The fertilized egg or zygote is released from the oogonium & forms thick-walled zoospores Zoospores undergo meiosis so one cell attaches to the bottom & develops a holdfast while the other zoospores divide & form a filament

37. Spirogyra, another filamentous green algae, reproduces by conjugation

38. Two filaments align side by side, their adjacent cell walls dissolve, & a conjugation tube forms between them Fertilization occurs when a + gamete cell moves through the tube & fuses to the - gamete cell  Zygote forms a thick walled spore (sporangium) that breaks away from the parent & forms a new filament

39. Ulva The leaflike algae Ulva has a sexual reproductive cycle characterized by a pattern called alternation of generations  Alternation of generations has two distinct multicellular phases- a haploid, gamete-producing phase called a gametophyte and a diploid, spore-producing phase called a sporophyte Alternation of Generation also occurs in more complex land plants, but the gametophyte & sporophyte do not resemble each other

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