Plant Overview and Reproduction Pre-AP Biology Mrs. Scott

What Is a Plant? Members of the kingdom Plantae Plants are multicellular eukaryotes Plants have cell walls made of cellulose. Plants develop from multicellular embryos and carry out photosynthesis using the green pigments chlorophyll a and b

Overview of the Plant Kingdom Botanists divide the plant kingdom into four groups based on three important features: Water conducting tissues Seeds Flowers

Bryophytes: Mosses, Liverworts, Hornworts. During at least one stage of their life cycle, bryophytes produce sperm that must swim through water to reach eggs of other individuals. Therefore, they must live in places where there is rainfall or dew for at least part of the year Seedless vascular plants include club mosses, horsetails, and ferns. Like other vascular plants, ferns and their relatives have true roots, leaves, and stems. Seed plants are divided into two groups: Gymnosperms: Cone plants Bear their seeds directly on the surfaces of cones Ex.) conifers, pines, spruces, cycads, ancient ginkgoes and gnetophytestr & Angiosperms: Flowering plants Bear their seeds within a layer of tissue that protects the seed Ex.) grasses, flowering trees shrubs, wild flowers

The Plant Life Cycle Characterized by alternation of generations: the two generations are the haploid (N) gametophyte, or gamete-producing plant, and the diploid (2N) sporophyte, or spore-producing plant.

Monocots and Dicots Monocots and dicots are named for the number of seed leaves, or cotyledons, in the plant embryo. Monocots have one seed leaf, and dicots have two seed leafs

Ultraviolet Flowers

http://www.naturfotograf.com/UV_flowers_list.html

Reproduction of Seed Plants Chapters 24

Life Cycle of Gymnosperms Reproduction in gymnosperms takes place in cones Male cones produce – pollen grains Female cones produce – ovules

Flowers and Fruits Angiosperms have unique reproductive organs known as flowers. Q: Why are flowers evolutionary adaptations? A: they attract animals that pollinate them

Structure of Flowers Flowers are reproductive organs that are composed of 4 kinds of specialized leaves

Sepals Enclose the bud before it opens, leaf-like

Petals Brightly colored, attract insects to flower

Stamen Male reproductive structure of flower, made of 2 parts Anther Filament – long, thin, stalk that supports the anther Anther – makes pollen grains Anther Filament Anther + Filament = Stamen

Pistil Female reproductive structure, made of 3 parts

Stigma where pollen grains land, sticky

Style Connects stigma to ovary Style

Ovary swollen base of the pistil where ovules are formed

Flowers contain ovaries, which surround and protect the seeds After pollination, the ovary develops into a fruit, which protects the seed and aids in its dispersal.

Fruit Ripened ovary, thick wall of tissue that surrounds the seed

Pollen Pollen Grain Contains the male gamete

Pollination The transfer of pollen from the male gametophyte to the female gametophyte

Seeds An embryo of a plant that is encased in a protective covering and surrounded by a food supply

Embryo Early development stage of a sporophyte plant The seed’s food supply provides nutrients to the embryo as it grows

Seed Coat Surrounds and protects the embryo and keeps the contents of the seed from drying out Can be specialized for dispersal

Pollination Most gymnosperms (some angiosperms) are wind pollinated Most angiosperms are pollinated by animals Insect pollination beneficial to insects and other animals: provides them with food Plants also benefit: this method of pollination is more efficient Q: What kind of symbiotic relationship is this? A: Mutualism

Seed Dispersal Animals Wind and water