iv. Dicots 1. Netlike venation pattern in leaves 2. Multiples of four or five flower parts 3. Seeds contain two cotyledons 4. Vascular bundles arranged as a ring in the stem 5. Root system involved a taproot 6. Pollen grain with three openings c. Flower structure and function i. Sepals 1. Protect developing flower while in the bud ii. Petals 1. Often colorful to attract pollinators iii. Anther 1. Part of the stamen that produces the male sex cells iv. Filament 1. Stalk fo the stamen that holds up the anther v. Stigma 1. Sticky top of the carpel where pollen lands vi. Style 1. Structure of the carpel that supports the stigma
vii. Ovary 1. Base of the carpel, in which the female sex cells develop viii. Female part of the flower is called the carpel and the male part is called the stamen 1. d. Pollination and fertilization i. Two different generations 1. Gametophyte generation a. Haploidic cells b. Production of gametes by mitosis c. Example i. Production of flowers where haploid spores develop to form gametophytes 2. Sporophyte generation a. Diploidal cells b. Production of spores by meiosis c. Example i. Cherry tree grew from a zygote and produced new cells by mitosis e. Pollination i. Process by which pollen is placed on the female stigma 1. Pollen can be carried by many means a. Wind b. Insects c. Birds d. Water e. Other animals 2. Mutualistic relationship with pollinators a. Flowers of plants attract vectors such as birds and bees and further heavily scented flower can attract vectors at night ii. Two general types of pollination 1. Self-pollination a. Pollen from the anther of the same plant falls upon its own stigma which results in less genetic variation within a species
2. Cross-pollination a. Pollen is carried from the anther of one plant via a vector to the stigma of a different plant of the same species. This event increases variation between plants and within the species itself and thus may results in offspring with better fitness. However, the only problems with cross pollination is the pollen not reaching the female stigma due to distance. iii. Fertilization 1. Fertilization takes place in the ovules in the flower when male and female sex cells unite to form a diploid zygote 2. Pollen tube growth and fertilization a. Pollen germinates to produce a pollen tube b. Pollen tube grows down the style of the carpel c. Growing pollen tube is the nucleus that will produce the sperm d. Pollen tube completes its growth by entering an opening at the bottom of the ovary e. Sperm moves from the tube to combine with the egg of the ovule to form a zygote f. Zygote develops surrounding tissue to compose the seed and the ovary around the ovule matures into a fruit which encloses and protects the seeds iv. The seed 1. Means by which an embryo can be dispersed to distant location 2. Dicotyledonous plants and associated seed parts a. Testa i. Touch, protective outer coat b. Cotyledons i. Seed leaves that function as nutrient storage structures c. Micropyle i. A scar at the opening where the pollen tube entered the ovule d.
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