Transcript Seed Plants
Warm Up Although ferns have vascular tissue, they still must live in moist, shady environments. Explain why. Plants The Characteristics of Seed Plants Chapter 8 Section 3 Discover Activity • Which plant part is it? Page 262 Objectives: • To identify the characteristics that seed plants share. • To explain how seeds become new plants. • To describe the functions of roots, stems, and leaves. Seed Plants • Seed plants share 2 main characteristics: – Have vascular tissue – Use pollen and seeds to reproduce Characteristics • Seed plants are vascular plants that produce seeds. • Vascular tissue is a system of tiny tubes that transport food, water, and other materials. • Xylem carries water and minerals up from the roots through out the plant. • Phloem carries food throughout the plant, both upward and downward. • Seed plants have true roots, stems and leaves. http://sps.k12.ar.us/massengale/plant_taxonomy_bi.htm Conductive Vessel Element in Mountain Mahogany Wood (SEM x750). This image is copyright Dennis Kunkel at www.DennisKunkel.com, used with permission. Phloem http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPLAN TANAT.html Seeds • Seed plants do not require water to reproduce. • The reproductive structures of seed plants are known as cones and flowers. • Seed plants produce pollen which are tiny structure that contain the cells that will later become sperm cells. http://www.cssd11.k12.co.us/dohnts/images/bio/pollen1.gif http://www.cssd11.k12.co.us/dohnts/images/bio/bat028.gif • A seed consists of a seed coat, a young plant, and stored food. • The young plant is called an embryo. • Germination is the early growth of an embryo plant (the one inside the seed). • Cotyledons are the seed leaves on the embryo. • In some seeds, food is stored in the cotyledons. • The seed coat protects the embryo so that the seed can inactive for a long period of time. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPL ANTANAT.html http://sps.k12.ar.us/massengale/plant_taxonomy_bi.htm Try This Activity • The In-Seed Story page 264 Seed Dispersal • Seed dispersal is the scattering of seeds, usually far from where they were produced. • Look at the sample seeds and discuss how they are dispersed. Germination • Germination occurs when the embryo begins to grow again and pushes out of the seed. • For this to happen the seed absorbs water from the environment and the embryo uses the stored food to begin to grow. • The roots grow downward and the leaves grow upward. Roots • Roots provide several functions for the plant. They are – Anchor plants – Absorb water and minerals from the soil – Store food. • Fibrous roots consist of several main roots that branch often. • Taproot systems consists of a long, thick main root with thin roots coming from it. Root Structure • Root hairs are many thin, hair-like extensions that greatly increase the surface area through which the plant takes in water and minerals from the soil. Root Structure • The root cap is a structure that covers and protects the tip of the root as it grows. Just behind the root cap is a region that contains growth tissue, where new cells are formed. Stems • Stems provide the means by which water, minerals and food are transported and they support the leaves and other parts of the plant. • Plants are divided into two categories based on the structure of their stems. Stem Structure • The parts of stems are bark, the outermost layer of a woody stem, cambium, a growth region where xylem and phloem are made, and pith, the center containing large, thin-walled cells that store water and food. • Woody are stems that contain wood; they are hard. http://www.geocities.com/RainForest/62 43/diversity4.html#Plant Annual Rings • The annual rings are made of xylem. During the spring the xylem grows rapidly and has a wide, light brown ring. During the summer it grows more slowly and produces a thin dark ring. http://web.utk.edu/~grissino/images/zuni%20doug-fir.jpg • Herbaceous are stems that are green and soft. Leaf Structure • The outermost layer of a leaf is called the epidermis. They are covered by a waxy, waterproof coating that prevents excess water loss. Leaf Structure • Light passes through the epidermis to the mesophyll where photosynthesis takes place. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html Leaf Structure • Stomata are the guard cells that allow gases to enter and leave a leaf. They are located on the lower layer of the mesophyll. Stomatal apparatus as seen on a leaf epidermal peel of corn. The above image is from gopher://wiscinfo.wisc.edu:2070/I9/.image/.bot/.130/Leaf/Corn_e pidermal_peel. Note the two sets of guard cells. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html Scanning electron micrograph of Equisetum (horsetail or scouring rush) epidermis. Note the oval stomatal apparatuses in the center of the stem. The above image is from http://www.mcs.csuhayward.edu/sem/images/horsel4.gif. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPLANT ANAT.html Pea Leaf Stoma, Vicea sp. (SEM x3,520). This image is copyright Dennis Kunkel at www.DennisKunkel.com, used with permission. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS .html • Photosynthesis occurs in the leaf and is the process in which food is made using light energy. It has two products glucose (food) and oxygen. Photosynthesis Raw Materials – Carbon dioxide + Water Needed but not used up Sunlight and Chlorophyll End Products – Glucose + Oxygen http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookPS.html http://sps.k12.ar.us/massengale/plant_taxonomy_bi.htm Leaf Structure • Transpiration is the process in which water is lost through a plant's leaves Observing Roots • Carefully loosen the soil from the geranium and the other plant with a tap root. Have students examine and draw the root systems. Actitivities • Teacher Demo • Try This Activity • Teacher Demo Lab • Investigating Stomata Homework