Mostly exist as solitary amoeboid cells When food is short amoeboid cells form

Mostly exist as solitary amoeboid cells when food is

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Mostly exist as solitary amoeboid cells When food is short, amoeboid cells form a slug-likemobileaggregate Some cells dry up and form a stalk supporting an asexual reproductive structure in which other cells develop into spores Decompose rotting organic matter
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Unicellular Algae Algae Are photosynthetic protists . Chloroplasts support aquatic food chains Arefound in plankton . Drift or can swim weakly Dinoflagellates Unicellular algae reinforced by cellulose plates Characteristic spinning movement caused by two flagella in grooves Cause red tides
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Unicellular Algae Diatoms Photosynthetic, unicellular algae Have a unique, glassy cell wall Contain silica Two halves fit together likea box and lid Key sourceof food in all aquatic environments Diatomaceous earth made of thick sediments of fossilized diatoms Green algae Named for pigment in chloroplasts May be unicellular, colonial, or multicellular Some are large and complex enough to qualify as seaweeds
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Seaweeds .
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Chapter 16 Plants, Fungi and the Move onto Land
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PLANT EVOLUTION AND DIVERSITY Plants evolved from green algae Plants and present-day green algaecalled charophyceans probably evolved from a common ancestor Morphological, biochemical, and genetic similarities Adaptations enabling permanent life on land appeared in ancestral green algae about 475 million years ago Early environment suitablefor plant life
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Terrestrial Adaptations of Plants Plants haveadaptations for life on land Plants and algae areboth multicellular photosynthetic eukaryotes A set of derived characteristics distinguishes plants as a clade Plants and algae interact differently with their environments Key adaptations of plants to four challenges of terrestrial life
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Structural Adaptations Supporting theplant body Lignin thickens and strengthens cell walls Maintaining moisture Waxy cuticle covering aerial parts prevents direct gas exchange Stomata control gas exchangeand prevent water loss Obtaining resources from both soil and air Roots provide anchorageand absorb water and minerals fromsoil Leaves absorb CO 2 fromtheair Elongation of apical meristems maximizes exposureto resources Vascular tissue(xylemand phloem) connects subterranean and aerial parts
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ReproductiveAdaptations Reproducing on land Male and female gametangia (protective jackets) surround gamete- producing cells Plants are embryophytes Fertilized egg develops into an embryo whileattached to and nourished by theparent plant All plant lifecycles have alternation of generations Haploid spores areproduced in protectivesporangia
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Highlights of Plant Evolution
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