Pop Quiz 4 Which of the following statements

Pop Quiz! 4. Which of the following statements concerning fertilization in ferns is true? • a. It occurs within the female structure. • b. It requires water. • c. The fertilization product is a seed. • d. It occurs within the female structure; and It requires water. • e. It occurs within the female structure; It requires water; and the fertilization product is a seed. 5. Gametophytes are • a. haploid plants that produce spores. • b. diploid plants that produce spores. • c. haploid plants that produce gametes. • d. diploid plants that produce gametes. • e. diploid or haploid plants that produce gametes.

Pop Quiz! 6. Alternation of generations refers to the • a. expression of recessive traits. • b. presence of a diploid and a haploid generation in the life cycle of plants. • c. presence of the different sexes in two different plants. • d. occurrence of a sexually reproducing diploid stage followed by an asexually reproducing haploid stage during the life cycle of higher plants.

PLANTS! Reproduction Part 2 (lecture 16) (Gymnosperms & Angiosperms)

First Seed Plants • Gymnosperm: conifers – vascular – heterospory • male vs. female gametophytes – seeds • naked seeds (no fruit) – pollen • contain male gametophyte – life cycle dominated by sporophyte stage • coniferous trees you are familiar with are diploid • reduced (microscopic) gametophyte • reduction of gametophyte protects delicate egg & embryo in protective sporophyte – protected from drought & UV radiation

Pollen • Pollen eliminated the water requirement for fertilization – spread through wind & animal Ragweed pollen…oh my itchy eyes!

sporangium & pollen male (pollen) cones female cones pine embryo

Gymnosperm Life Cycle

First Flowering Plants • Angiosperm: flowering plants – vascular – heterospory • male vs. female gametophytes – flower • specialized structure for sexual reproduction – seeds within fruit – pollen – life cycle dominated by sporophyte stage • trees & bushes you are familiar with are diploid • reduced (microscopic) gametophyte

Flower • Modified shoot, modified leaves • Male – sepals – petals – Stamens Stamen Anther Stigma Style Ovary Filament • Filament & anther • Female sepals petals stamens – Carpel • Stigma, style, & ovary Petal carpel Ovule Sepal Carpel

Flowering Plant Pollination • Pollination – transfer of pollen from the anther to a stigma – If pollination occurs, a pollen tube forms – The pollen tube transfers sperm to the ovule which will result in a zygote (new plant) and a 3 n (triploid) nucleus that will form endosperm • Endosperm is the nutrient storing tissue in a seed

Seed & Plant Embryo • Seed offers… – protection for embryo – stored nutrients for growth of embryo cotyledons = “seed” leaves, first leaves of new plant endosperm (3 n) cotyledons embryo (2 n) seed coat

Double Fertilization • Remember: 3 Features of the Angiosperm Cycle – • Flowers, Fruits, & Double Fertilization The Process: – – – Pollination (pollen grain lands on stigma) Tube Nucleus (pollen tube produced down the style) Generative Nucleus (2 sperm form by mitosis) Enters ovary through micropyle 1 sperm fertilizes haploid egg to form zygote; other sperm combines with 2 polar nuclei to form 3 n endosperm (food-storing tissue)

Angiosperm Life Cycle male gametophyte = pollen grain (haploid) dehiscence polar nuclei pollen grains egg cell ovary sac sperm nuclei travel down pollen tube 3 n endosperm female gametophyte = ovary sac (haploid) 2 n zygote double fertilization 2 n embryo new sporophyte in seed (diploid)

Monocots & Dicots • Angiosperm are divided into 2 classes – dicots (eudicot) • 2 cotyledons (seed leaves) • leaves with network of veins • woody plants, trees, shrubs, beans – monocots • 1 cotyledon • leaves with parallel veins • grasses, palms, lilies

Pop Quiz! 1. The heterosporous condition led to evolution of • a. gymnosperms and angiosperms. • b. pollen grains and seeds. • c. male and female plant parts. • d. pollen grains and seeds in male and female plant parts. • e. gymnosperms and angiosperms which bear pollen grains and seeds in male and female plant parts.

Pop Quiz! 2. Which of the following produces no seeds? • a. Cycads • b. Conifers • c. Horsetails • d. Ginkgos • e. Tomato 3. Microspores mature into • a. ovules. • b. seeds. • c. pollen grains. • d. anthers.

Pop Quiz! • 4. Gymnosperms – a. were the first plants not to have swimming sperm and were therefore freed from the need for water to reproduce. – b. are divided into two groups, the monocots and dicots. – c. were the first plants to develop vascular tissues. – d. were the first plants to develop flowers to attract insects.

Pop Quiz! • 5. Which of the following statements about pine cones is correct? – a. Cones are exclusively female structures. – b. Cones are the result of pollination. – c. One type of cone produces microspores. – d. Seeds are enclosed in cones. – e. One type of cone produces microspores; and seeds are enclosed in cones.