Chapter 29 2.27.08

Chapter 29 2.27.08 - Chapter 29 1 Honors Biology Book Notes...

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Chapter 29 1 Honors Biology Book Notes Chapter 29 – Green Plants 2/27/08 - Green Plants o Consist of (1) Green algae – important photosynthetic organisms in aquatic environments (2) Green plants – important photosynthetic organisms in terrestrial environments o Green algae studied along with plants because (1) They are closest living relatives to plants (2) Transition from aquatic to terrestrial environment occurred when land plants evolved from algae o First terrestrial organisms, fungi/animals moved to terrestrial environment because they eat plants o Ecosystem : consists of all organisms in a particular area along with physical components of environment [atmosphere, precipitation, etc.] Plants provide ecosystem services – add to physical components of an ecosystem (1) Plants produce oxygen (2) Build soil by providing food for decomposers and add organic matter to soil, which improves soil’s ability to (3) Plants hold soil – roots hold soil and prevent erosion, keep nutrients in soil (4) Plant tissue retains water o Leaves soften impact of rainfall on ground o Roots hold soil in place during rainstorm o Organic matter increases soil’s water-retaining capacity (5) Moderate local climate – plants increase relative humidity/decrease temperature through shade and decrease wind impact Dominant primary producers in terrestrial ecosystems Key to carbon cycle in terrestrial environments – they fix more CO2 than they produce through cellular respiration o Plant Domestication Artificial selection : process our ancestors followed by actively selecting seeds from individuals that exhibited “edible” traits, and used only selected seeds to grow next generation Artificial selection is responsible for original domestication of crop varieties o Plants provide sources of energy – coal is compressed decaying plant matter [peat]
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Chapter 29 2 o Challenges to forests (1) Reducing demand for wood products through recycling and efficient use of timber (2) Sustaining productivity of forests after repeated logging o Bioprospecting (chemical prospecting): effort to find naturally occurring compounds for drugs, insecticides, fungicides, etc. Many plant-derived drugs are produced by plants to deter herbivores Leading anticancer drugs (vincristine/vinblastine) derived from tropical rosy periwinkle o Paths to discover new plants (1) Biologists grow plants hydroscopically (in liquid culture rather than in soil) and expose root cells to bacterial cell wall fragments/toxins from fungus, then collect purified defensive substances extracted by plant (2) Ethnobotanists: biologists who specialize in study of how humans use plants Work as fast as possible in rainforests/indigenous healers b/ c settlers overpopulating there areas o To estimate plant phylogenies, biologists; (1) Compare fundamental morphological features of various green algae/green plants
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This note was uploaded on 04/07/2008 for the course BIO 1111 taught by Professor Hassan during the Spring '08 term at Temple.

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Chapter 29 2.27.08 - Chapter 29 1 Honors Biology Book Notes...

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