Plants

Characteristics Multicellular Eukaryotic Cell Wall = Cellulose Cuticle – waxy, waterproof Photosynthesis Evolved from green algae

Adaptations Cuticle – to prevent water loss Leaf – plant organ that grows from a stem and usually is where photosynthesis occurs Roots – absorbs water and minerals from soil Stem – provides support for growth and transport of food, water, and materials

Reproduction Seeds – contain an embryo, seed coat, and food supply Alternation of Generations Gametophyte – haploid Sporophyte – fertilized, diploid

Seed Plants Embryo – early stage of development of an organism Include one or more cotyledons – store or absorb food for the developing embryo Seed Coat

Seed Plants Advantages of Seeds Contains a supply of food Embryo protected by seed coat Easy dispersal

Plant Tissues Dermal Tissue (epidermis) – composed of flattened cells that cover all parts of the plant Functions like the skin of animals Tightly compacted like a jigsaw Stomata (stoma) – openings in the leaf tissue that control the exchange of gases Guard Cells – control the opening and closing of stomata

Xylem –transports water and dissolved minerals from the roots to the rest of the plant Phloem – transport sugars and other organic compounds Meristems – regions of actively dividing cells

Plant Hormones Auxins – promotes cell elongation Gibberellins – promote growth Cytokinins – stimulate cell division Ethylene – promotes ripening

Plant Responses VERY IMPORTANT! Tropism – plants response to an external stimulus 1. Photo-tropism – grows toward the light 2. Gravitropism – grows in response to gravity 3. thigmotropism – grows in response to touch, Ivey up a wall Nastic Movement – venus fly trap

Two types of seed plants 1. Gymnosperms (conifers) – Cones Needle shaped leaves Scale like leaves Seeds in cones Evergreens (leaves year round) Cold or dry habitats Deciduous (lose their leaves)

Flowering Plants - Angiosperms Produce flowers Seeds enclosed in fruits Monocot & Dicots

Flower Parts Structures for sexual reproduction Stamen (male) – contains anther and filament, pollen is sperm

Pistil (female) – contains stigma, style and ovary

Structure of a Flower

A fertilized ovule is a seed Seed contains embryo and stored food A mature ovary is a fruit Seed Dispersal Wind, rain, and animals Seed germination is growth of the embryo