1 / 27

Plants

Plants. Chapters 23, 24, and 25. Chapter 23: Plant Diversity and Life Cycles. General Characteristics of Plants: Eukaryotic Multicellular Autotrophic Convert light energy into chemical energy by photosynthesis Takes place in the plant cell’s chloroplasts Range in Size. Origins of Plants.

etan
Download Presentation

Plants

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Plants Chapters 23, 24, and 25

  2. Chapter 23: Plant Diversity and Life Cycles • General Characteristics of Plants: • Eukaryotic • Multicellular • Autotrophic • Convert light energy into chemical energy by photosynthesis • Takes place in the plant cell’s chloroplasts • Range in Size

  3. Origins of Plants • Plants probably evolved from multicellular aquatic green algae that could not survive on land

  4. Before plants could thrive on land, they had to accomplish three things: • Absorb nutrients from their surroundings • Roots were developed • Today, about 80% of all plants species rely on symbiotic relationships with fungi called mycorrhizae

  5. Prevent drying out of their bodies • Plants have a waxy layer called a cuticle that covers the non-woody parts of the plant • Keeps water from flooding the plant tissue and keeps water from evaporating out of the plant • Reproduce without water to transmit sperm • Sperm are enclosed in pollen, a structure that keeps them from drying out • Pollen has the ability to by transported by wind or animals

  6. Plant Reproduction • A life cycle in which a haploid gametophyte alternates with a diploid sporophyte is called alternation of generations. • Gametophyte (haploid, n) stage --- gamete producing stage, sperm and egg • Sporophyte (diploid, 2n) --- spore producing stage, new plant forms by mitosis

  7. Nonvascular Plants • Reproduce by means of spores • Lack true roots, stems, and leaves • Lack vascular tissue • Use osmosis and diffusion to conduct water and nutrients through plant • Ex. Mosses • Usually found in gametophyte form which is the dominant form

  8. Seedless Vascular Plants • Do not produce seeds, reproduce with spores instead • Do contain vascular tissue and have true roots, stems, and leaves • Ex. Ferns • Dominant form is the sporophyte in vascular plants • Fern leaves are called fronds • Clusters of fern spores called sori can be found under the frond

  9. Gymnosperms—seed plants whose seeds do not develop within a fruit; “naked seed” • Ex. Conifers, evergreen • Produce cones to disperse sperm and seeds

  10. Angiosperms—seed plants whose seeds develop enclosed within a fruit; “case seed” • Fruits develop from part of a flower • Ex. Flowering plants

  11. Two types of angiosperms • Monocots—flowering plants whose seeds have one seed leaf or cotyledon • Dicots—flowering plants whose seeds have two seed leaves

  12. Gymnosperm and Angiosperm Reproduction • Sporophyte is the dominant form and the spores develop into female and male gametophytes • Female gametophyte produces eggs (ovule) , male gametophytes produce sperm (pollen) • Pollination occurs when pollen grains from the male reproductive structures of a plant transfers to the female reproductive structures of a plant

  13. Pollen can be dispersed through wind or animals • Pollen grains will develop a pollen tube to transfer sperm into the ovule where the egg is located, this is fertilization • After fertilization, the ovule develops into a seed which contains the embryo, a tough seed coat, and nutritive tissue called endosperm • Seeds may be dispersed by wind, water, animal consumption, etc…

  14. Chapter 25: Plant Processes • Plants require carbon dioxide, sunlight, and water for photosynthesis; oxygen for cellular respiration; and other minerals elements for cell organelles and enzymes • Transpiration drives water from the roots upwards to the rest of the plant • Water is pulled up the plant through cohesion of water molecules • The amount of water that evaporates off of a plant is controlled by the stomata

  15. Plant hormones stimulate or inhibit growth in a plant • A hormone is a chemical that is produced in one part of an organism and transported to another part, where it causes a response • Auxin—causes plants to bend • Gibberellins—stimulate stem elongation, fruit development, and seed germination • Cytokinins—stimulate cell division and slow the aging of plants • Ethylene—promote ripening and loosen fruits for easier harvesting • Abscisic Acid—slows the growth in plants

  16. Tropisms • Hormones can also trigger plants to respond differently called tropisms • A tropism is a response in which a plant grows toward or away from a stimulus • Phototropism—are directional movements in response to light • Thigmotropism—growth that responds to touch • Gravitropism—growth in response to gravity • Photoperiodism­—response to the length of days and nights

More Related