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 embryoSeed 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 ResponsesVERY 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