BIOL 1120 Lecture Notes - Lecture 21: Parthenogenesis, Endosperm, Meiosis
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Chapter 41: Plant Reproduction
I. Flower Characteristics via Coevolution
A. Plants and insects have coevolved.
1. Plants with structures that were more enticing to insects were favored (3 basic attractants for
a. Some plants offered a __________ incentive.
b. Some plants offered a ________________.
i. Scent of a receptive female
ii. Shape of a receptive female
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c. Other plants provided a _________ for developing insect larvae.
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2. Insects that recognized and located particular plants had a competitive edge.
B. Insects are effective carriers of pollen from flower to flower as they visit to gather food.
II. Flower Components (Fig. 41.11, p. p. 837)
A. The specialized parts of the flower grow from the modified end of the floral shoot—the
1. Non- fertile components
a. ________ (collectively called the _____) are the outermost green, leaflike parts.
b. _______ (collectively called the __________) are the colored parts located between the
reproductive structures and the sepals.
2. Fertile components
a. _________ (male parts) are located inside the corolla.
i. Often the stamen consists of a slender stalk (_____________) capped with an __________.
ii. Inside the anthers are pollen sacs in which pollen grains develop.
b. ___________ (female parts) collectively called the __________.
i. Located in the central part of the flower
ii. Vessel-shaped structure with an expanded lower chamber (______), slender column
(_____), and upper surface (______) for pollen landing.
iii. In the ovary eggs develop, fertilization occurs, and seeds mature.
B. Flowers differ from the other tissues of the plant in their fragrance and colors (carotenoids and
anthocyanins), which are attractive to pollinators.
C. ________________ have all four of the above floral parts.
D. _____________________ are lacking at least one of the four floral parts.
E. ______________ have both male and female parts.
F.___________________ lack the parts of one sex (may, or may not, be on the same plant)
1. ______________ plants have male (staminate) and female (pistilate) flowers on the same plant
(ex. corn, cucurbits, pines, etc.).
2. __________ plants have male and female flowers on separate plants (ex. hollies, gingkoes,
mulberries, willows, etc.).
III. Male Gametophyte (Pollen grain) Formation (Fig. 41.15, p. 839)
A. Diploid _______________________ in the anthers divides by meiosis to form four haploid
B. Each microspore will divide to form _______________ each containing two cells .
1. One cell (_____________) in each pollen grain will produce 2 sperm cells.
2. The other cell (_________) will form the pollen tube.
IV. Female Gametophyte (Embryo sac) Formation (Fig. 41.15, p. 839)
A. Diploid _________________________ in an ovule divides by meiosis to produce haploid
B. One of which will undergo mitosis three times to produce a cell with eight nuclei.
C. The nuclei migrate to different parts of the cell resulting in an _______ ______ with seven cells
(Fig. 41.17, p. 840).
1. One cell has two nuclei and will become the __________ which will eventually provide
nutrition for the embryo.
2. Another cell will be the egg.
V. From Pollination to Fertilization (Fig. 41.26, p. 846-847)
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