Introduction to Plants And why we love them!

Plants provide: The base for food chains Shade Shelter Oxygen

Characteristics of Plants: Multicellular eukaryotes Have cell walls made of cellulose Develop from multicellular embryos Carry out photosynthesis Most are autotrophs A few are parasites or saprophytes They are sessile

Plant Life Cycle: Consist of two alternating cycles: Diploid (2N) is the sporophyte which produces spores Haploid (N) is the gametophyte which produces gametes (eggs and sperm) Called alternation of generation Mosses and ferns require water to reproduce Seed plants do not require water to reproduce

Plant Survival Kit: Sunlight for photosynthesis Leaves are adapted to maximize exposure Water and minerals for photosynthesis and growth Plants have structures to reduce water loss

Plant Survival Kit continued… Gas exchange Plants need both O2 and CO2 Gases must be exchanged between the plant and the atmosphere Movement of water and nutrients Simpler plants by diffusion Higher plants by specialized structures

Four Main Groups Mosses Ferns Cone bearing plants Seed bearing plants These are the most abundant of all plants (almost 90%)