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12 Cards in this Set
- Front
- Back
asexual reproduction
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- budding from roots, aerial portions, fragmentation, apomixis (seeds without fertilization)
- grafting: stock (root), scion (stem grafted to root) |
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disadvantages of asexual reproduction
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- disease can wipe out entire species because they are all genetically identical.
- less diversity |
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adaptations of angiosperms to reproduce sexually
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- flowers
- pollen (no water needed) - seeds - fruit |
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male gametophyte development in the flower
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- happens in a pollen grain
1. microsporocytes (in the anther) - meiosis 2. 4 microspores - mitosis 3. pollen (male gametophyte) |
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female gametophyte development in the flower
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- happens in the ovule
1. megasporocyte (in the ovule) - meiosis 2. 4 megaspores. 1 survives -mitosis 3. 7 cells (8 nuclei) - embryo sac |
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mechanisms to prevent self- fertilization
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- pin: stamen below the stigma
- thrum: stamen above the stigma - dioecious plants - self incompatibility (genetic control) |
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double fertilization
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- 2 sperm nuclei
- 1 fertilizes egg cell. becomes the zygote (2N) - 1 fertilizes the polar nuclei. becomes the endosperm (3N) |
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types of seeds
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- monocots: grasses (corn)
- dicots: common bean. castor bean. - difference is the size and shape of the cotyledon |
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advantages of producing seeds
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- the shell prevents drying out embryo
- save the embryo for when conditions are right. |
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advantages of producing fruit
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- animals eat the fruit. dispense seeds through fecal matter
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early development of a plant
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- germination of the dormant seed. imbibition- bring in water.
- growth of the embryo - gets food from cotyledon. grows towards the light. |
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protection of the apical meristem
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- hypocotyl hook: common bean. happens when sprouting out of the ground.
- coleoptile: protective tube around corn stem. |