plant diversity

plant diversity - Trends in plant complexity: origins of...

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Today we begin our examination of plant diversity; focus is on diversity, form, and function of land plants. Eukaryotic common ancestor Rhodophyta (red algae) Chlorophyta (green algae) Charophycean Embryophytes algae (land plants, kingdom Plantae ) Trends in plant complexity: origins of land plants Mainly in marine/freshwater habitats Attributes of land plants in common with their Charophycean algal ancestors: photosynthetic autotrophs : chlorophyll and the photosynthetic apparatus use solar energy to “ fix ” carbon from CO 2 and water cell walls made of cellulose (and other materials) : rigid wall gives support and allows plant cells to ‘use’ hydrostatic pressure, unlike animal cells structural and biochemical details (no need to memorize ) : similarities in chloroplast organization photosynthetic pigments (chlorophyll a and b; carotenes) phragmoplast (structure used to make cell walls in cell division) peroxisome enzymes (present in Charophyceans, absent in other algae) similar sperm cell structure (in land plants that have sperm) ‘rosette’ cellulose synthesizing complexes in plasma membranes chloroplast and nuclear DNA sequence similarities Trends in plant complexity: origins of land plants Attributes (derived traits) of land plants that distinguish them from Charophycean algal ancestors: apical meristems : specialized ‘growth regions’ in above- and below-ground portions of the plant multicellular, dependent embryos (hence, Embryophytes ) : zygotes partially develop into embryos within the tissues of the female parent in an organ called the archegonium -- provides for additional nutrition alternation of generations: both haploid and diploid phases of the life cycle are multicellular unique reproductive structures: multicellular gametangia (reproductive organs that produce gametes) walled spores , protected by tough outer layer Trends in plant complexity: origins of land plants Functional aspects of land plant adaptations: 1. apical meristems Aquatic plants live in a fluid that moves around them to provide
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This note was uploaded on 04/16/2008 for the course BIOL 5b taught by Professor Chappel during the Spring '08 term at UC Riverside.

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plant diversity - Trends in plant complexity: origins of...

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