End Show Slide 1 of 39 Copyright Pearson Prentice Hall Biology

End Show Slide 2 of 39 Copyright Pearson Prentice Hall 20-4 Plantlike Protists: Red, Brown, and Green Algae

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 3 of 39 Copyright Pearson Prentice Hall 20-4 Plantlike Protists: Red, Brown, and Green Algae The three phyla of algae that are largely multicellular are: red algae brown algae green algae

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 4 of 39 Copyright Pearson Prentice Hall Red Algae What are the distinguishing features of red algae?

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 5 of 39 Copyright Pearson Prentice Hall Red Algae Red algae are able to live at great depths due to their efficiency in harvesting light energy. Red algae contain chlorophyll a and reddish accessory pigments called phycobilins. Phycobilins absorb blue light, enabling red algae to live deep in the ocean.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 6 of 39 Copyright Pearson Prentice Hall Brown Algae What are the distinguishing features of brown algae?

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 7 of 39 Copyright Pearson Prentice Hall Brown algae contain chlorophyll a and c, as well as a brown accessory pigment, fucoxanthin. Brown Algae

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 8 of 39 Copyright Pearson Prentice Hall Brown Algae Brown algae are the largest and most complex of the algae. All are multicellular and most are marine, commonly found in cool, shallow coastal waters of temperate or arctic areas.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 9 of 39 Copyright Pearson Prentice Hall Brown Algae Brown Alga Structure Blades Bladder Stipe Holdfast

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 10 of 39 Copyright Pearson Prentice Hall Brown Algae Fucus, a common brown alga, is made up of a holdfast, stipes, bladders, and blades. The holdfast attaches the alga to rocks. Holdfast Blades

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 11 of 39 Copyright Pearson Prentice Hall Brown Algae The body of Fucus contains: a flattened stemlike structure called a stipe, leaflike structures called blades, and gas-filled bladders that keep the alga afloat and upright. Blades Bladder Stipe

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 12 of 39 Copyright Pearson Prentice Hall Green Algae What are the distinguishing features of green algae?

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 13 of 39 Copyright Pearson Prentice Hall Green Algae Green algae share many characteristics with plants, including their photosynthetic pigments and cell wall composition. Scientists hypothesize that the ancestors of modern land plants looked like certain species of living green algae.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 14 of 39 Copyright Pearson Prentice Hall Green Algae Green algae live in fresh and salt water, and moist land areas. Many species live most of their lives as single cells. Others form colonies, groups of similar cells that are joined together but show few specialized structures. A few are multicellular and have specialized structures.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 15 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae How do multicellular algae reproduce?

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 16 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae The life cycles of many algae include both a diploid and a haploid generation.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 17 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Switching between haploid and diploid stages during a life cycle is known as alternation of generations. Many alga also shift between sexual and asexual reproduction.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 18 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Reproduction in Chlamydomonas The unicellular Chlamydomonas spends most of its life in the haploid stage.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 19 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Reproduction in Chlamydomonas zoospores Mature cell Pairing of plus and minus gametes Zygote Release of haploid cells

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 20 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Asexual Reproduction in Chlamydomonas Mature cell zoospores In suitable living conditions, this haploid cell reproduces asexually, producing cells called zoospores by mitosis. Mitosis

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 21 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae If conditions become unfavorable, Chlamydomonas can also reproduce sexually.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 22 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Sexual Reproduction in Chlamydomonas Release of haploid cells Pairing of plus and minus gametes Zygote

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 23 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Haploid cells undergo mitosis, but release gametes instead of zoospores. The zoospores are of two opposite mating types—plus (+) and minus (-). Pairing of plus and minus gametes

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 24 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae The plus and minus gametes form pairs and fuse, forming a diploid zygote.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 25 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae The zygote grows a thick protective wall. Within this protective wall, Chlamydomonas can survive conditions that otherwise would kill it.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 26 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae When conditions again become favorable, the zygote grows, divides by meiosis, and produces four haploid cells. Release of haploid cells

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 27 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Reproduction in Ulva The life cycle of the green alga Ulva involves alternation of generations. Ulva are gametophytes, or gamete-producing plants.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 28 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Male gametophyte Gametes Female gametophyte Gametes fuse Zygote Sporophyte Spores Mitosis Meiosis Fertilization Mitosis Reproduction in Ulva

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 29 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae The haploid phase of Ulva produces male and female gametes. Gametes Female gametophyte Male gametophyte Fertilization Mitosis

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 30 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Gametes fuse Zygote Sporophyte When male and female gametes fuse, they produce a diploid zygote cell, which grows into a diploid multicellular Ulva.

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 31 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae The diploid Ulva undergoes meiosis to produce haploid reproductive cells called spores. MEIOSIS Spores

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 32 of 39 Copyright Pearson Prentice Hall Reproduction in Green Algae Each spore can grow into a new individual without fusing with another cell. Because the diploid Ulva produces spores it is known as a sporophyte, or spore-producing organism. MEIOSIS Spores

End Show 20-4 Plantlike Protists: Red, Brown, and Green Algae Slide 33 of 39 Copyright Pearson Prentice Hall Ecology of Algae Algae produce half of Earth’s oxygen through photosynthesis. Algae is found in sushi, ice cream, and other foods. Chemicals from algae are used to make plastics, waxes, transistors, deodorants, paints, lubricants, and artificial wood. Agar thickens nutrient mixtures in scientific labs.

End Show - or - Continue to: Click to Launch: Slide 34 of 39 Copyright Pearson Prentice Hall 20-4

End Show Slide 35 of 39 Copyright Pearson Prentice Hall 20-4 Reddish accessory pigments found in red algae are known as a.chlorophyll a. b.phycobilins. c.fucoxanthins. d.chlorophyll c.

End Show Slide 36 of 39 Copyright Pearson Prentice Hall 20-4 The giant kelp belongs to the group known as a.green algae. b.brown algae. c.red algae. d.golden algae.

End Show Slide 37 of 39 Copyright Pearson Prentice Hall 20-4 The life cycles of many algae include a.haploid generations only. b.diploid generations only. c.both haploid and diploid generations. d.only asexual reproduction.

End Show Slide 38 of 39 Copyright Pearson Prentice Hall 20-4 The green alga Chlamydomonas reproduces asexually by producing a.zygotes. b.gametes. c.zoospores. d.holdfasts.

End Show Slide 39 of 39 Copyright Pearson Prentice Hall 20-4 Cells that can grow into new organisms without fusing with another cell are called a.gametes. b.spores. c.gametophytes. d.sporophytes.

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