Plant organs and tissues Kingdom Plantae: more than 400,000 different kinds of plants

Classification Cotyledons- seed leaves in their embryos monocots- single seed leaf, one group of plants dicots- two seed leaves, another group of plants that are divided further An easier way to classify is by the: 1. number of seed leaves, 2. the strength and composition of their stems, and 3. the number of growing seasons they live.

Plant Life Cycle A sporophyte produces haploid spores through meiosis. These spores grow into multi-cellular structures called gametophytes Each gametophyte produces reproductive cells called gametes-sperm and egg cells During fertilization, a sperm and egg fuse with each other, producing a diploid zygote. The Zygote develop into a new sporophyte, and the cycle begins again. Alternation of generation between haploid and diploid phases. Diploid (2N) phase is known as the sporophyte (spore-producing plant). Haploid (N) phase is known as the gametophyte (gamete-producing plant)

Mosses, liverworts, and hornworts Bryophytes Mosses, liverworts, and hornworts Lack specialized tissues for the transport of water “nonvascular plants” mosses hornworts liverworts

*Vascular Tissue: tissue that transports water and nutrients in some plants Tracheophytes Seedless Vascular Vascular plants Seedless plants such as ferns and both flowering and nonflowering seed plants Contain specialized tissues that transport water and nutrients =tracheids Allows growth to large sizes Ferns horsetails Club mosses

Vascular Tissue Two main types of vascular tissue: forms the transport system among the roots, stems, and leaves of vascular plants. Two main types of vascular tissue: Xylem- moves water and nutrients from the ground upward in the plant. Phloem- carries food made in a plant’s leaves down to other plant parts. Roots, stems, and leaves are plant organs Bryophytes do not have roots, stems, or leaves. They absorb substances directly from their surroundings.

Roots anchor and support the plant, absorb water and dissolved nutrients from the soil, and store food and water. TAPROOTS FIBROUS ROOTS Single large root that grows deep into the soil. As the root grows deeper, other smaller roots branch from the main root dandelion, carrots, and beets DICOTS Does NOT have a single main root many small, shallow roots branch out from the base of the plant grass MONOCOTS

Stems hard, rigid stems woody stem of a tree is its trunk transport materials between a plant’s roots and its leaves and flowers support the leaves and flowers some plants the stems store food and water (potato). WOODY PLANTS HERBACEOUS PLANTS plants that develop into trees and shrubs hard, rigid stems woody stem of a tree is its trunk live for many years grasses and many garden plants green, flexible stems smaller have shorter life spans

Leaves main organs that carry out photosynthesis in most vascular plants Stomata (stoma: singular)- small openings on their undersides carbon dioxide and oxygen are exchanged between the plant and the air through the stomata water may also enter and exit a leaf through the stomata Guard Cells- tiny structures, control the size of the stomata help control the movement of materials into and out of the plant.

Petiole- tubelike structure that attaches a leaf to its stem Similar structures that all leaves share: Blade- is the broad, flat part of the leaf. Absorbs sunlight needed for photosynthesis. Veins- running throughout the blade, tubelike structures that transport water in the leaf Petiole- tubelike structure that attaches a leaf to its stem

Organs of Seed Plants Anchor and support the plant, Roots Stems Anchor and support the plant, absorb water and dissolved nutrients from the soil, and store food and water Tap roots and fibrous roots Transport materials between a plant’s roots and its leaves and flowers. Support the leaves and flowers In some plants, it stores food and water Woody plants and herbaceous plants Leaves Main organ that carry out photosynthesis Petiole, blade, veins are similar structures in all leaves Monocots and dicots

Seeds Plant embryo and a food supply, encased in a protective covering. Unlike mosses and ferns, gametes of seed plants do not need standing water for fertilization. Adaptations that allow for reproduction without standing water: Reproductive process that takes place in cones or flowers. Transfer sperm by pollination Protection of embryos in seeds Cones Vs. Flowers

Gymnosperms Conifers- plants that form seeds in cones pines, cedar, firs, and juniper trees thin, needle-shaped leaves that help prevent water loss this adaptation allows conifers to live in places that are dry or cold for part of the year Venus flytrap is a plant with a leaf adaptation that when a insect touches a receptor, the leaf shuts and the insect becomes trapped.

Cones Reproduction in conifers takes place in cones, which are produced by a mature sporophyte plant. produce two types of cones: pollen (male) and seed (females) cones Seed cones are much larger and contain ovules near the base of each scale.

Flowers are leaves that have been modified for sexual reproduction. angiosperms Flowers are leaves that have been modified for sexual reproduction. a seed plant that produces seeds enclosed in fruits the fruit develops inside the flowers Flower- reproductive structure of an angiosperm attract birds and insects that help the plant reproduce petals surround its reproductive parts Stamen- male reproductive part Pistil- female reproductive part pistil contains the ovary, which produces the female sex cells and then protects the seed as they develop

Pathway to making a baby flower: Pollen (male sex cell) must be transferred from the stamen of a flower to the stigma on the pistil Transferred by the wind, or by animals Animals that transfer pollen are called pollinators The transfer of pollen from the stamen to a pistil is called pollination. If pollen lands on the tip of the pistil of a similar flower, the pollen can fertilize that flower Sperm in the pollen travels through a tube to reach the eggs in the ovary Fertilization occurs when the sperm and egg cells unite After fertilization, one or more seeds develop in the ovary Finally, the ovary develops into a protective fruit

Flowers and fruits Attract animals such as bees, moths, or hummingbirds Drawn by color, scent, or even shape of the flower—carry pollen with them as they leave They go from flower to flower, carrying pollen as they go, which is much more efficient than the wind pollination of most gymnosperms. After pollination, ovaries develop into a fruit fruit- structure containing one or more matured ovaries the wall of the fruit help disperse the seeds inside it animals eat the fruit, and as the seeds travel through the digestive system, it develops and by the time it exits the animal may be miles away.