Honors Biology Chapter 22- Plants

I. Characteristics A. Kingdom Plantae 1. Eukaryotes 2. Cell wall contains cellulose 3. Carry out photosynthesis using chlorophyll a & b 4. Most are autotrophic, few are parasites

B. Requirements 1. Sunlight 2. Gas exchange: O2 & CO2 3. Water 4. Minerals

C. Evolution of Plants 1. Started in the water 2. Ancestors of today’s plants were water dwellers very similar to today’s green algae 3. Proof in fossil record 4. Plants moved to land & had many challenges a. Did not have roots or leaves b. Had trouble getting water 5. Moving to land allowed new ecosystems to form 6. Green algaemossesfernsseed plants

D. Plant life Cycle 1. Land plants have 2 distinct sexual life cycles- Alternation of generations a. Diploid phase (2N) Called the sporophyte Produces haploid spores during meiosis The spores grow into gametophytes b. Haploid phase (N) Called the gametophyte Produces reproductive gametes (egg & sperm cells)

II. Seedless Plants A. Green Algae 1. 1st plant 2. Mostly aquatic 3. Single celled or branching filaments 4. Absorb nutrients directly from their surroundings 5. Does not contain specialized tissue

B. Mosses & Bryophytes 1. 1st plants to become established on land 2. Secured to the ground with rhizoids that absorb water from the soil 3. Have specialized reproductive organs 4. Does not have vascular tissue to transport water so they have to be very small 5. Have a thin waxy coat to prevent drying out 6. Bryophyte groups: mosses, liverworts, hornworts

C. Vascular Plants 1. Also called tracheophytes 2. Contains vascular tissue a. Xylem: transports water up from roots b. Phloem: transports nutrients produced during photosynthesis c. Tracheids: hollow tube like cells in the xylem that allow the movement of water big evolutionary innovation 3. Seedless vascular plants: ferns, club mosses, horsetails a. Requires open water for fertilization of gametes

III. Seed plants- Gymnosperms & Angiosperms A. Importance of seeds 1. Seed is a plant embryo 2. Provides food supply and a protective covering seed coat 3. The seed is diploid 4. Seeds allow the plants to reproduce without open water

5. Pollen= male gametophyte 6. Seeds= female gametophyte 7. Pollination: the transfer of pollen from male to female structure

(gymno = naked; sperma = seed) Gymnosperms – (gymno = naked; sperma = seed) 1. Females cones bear seeds directly on the inside surfaces of scales 2. Winds carries pollen to seed cones 3. Ex. Pines & firs (conifers), cycads, ginkgoes

IV. Flowering Plants A. Angiosperms 1. Most flowers produce both gametes in each flower 2. Wind or animals distributes pollen 3. bear their seed in flowers 4. Very diverse: Monocots, Dicots, Woody, Herbaceous

5. Monocots a. 1 seed leaf or cotyledon b. parallel veins on leaf c. floral parts in multiples of 3 d. vascular bundles scattered in stems e. fibrous root system f. ex. Corn, wheat lilies, orchids, rice, palms

6. Dicots a. 2 cotyledons b. Branched veins in leaves c. Floral parts in multiples of 4 or 5 d. Vascular bundles in stems are arranged in a ring e. Taproot system f. Ex. Roses, clover, tomatoes, oaks, daisies

7. Advantages of Flowers a. Draws in pollinators to make pollination more efficient

8. Advantages of Fruit a. Fruit is a matured ovaries b. Helps to disperse the seeds inside of it c. Spread when animals eat the fruit and later pass the seeds

9. Plant life span a. Annuals: must re-plant every year Example: tomatoes, cucumbers, wheat b. Biennials: re-plant every other year Example: celery c. Perennials: come back every year Example: grass, maple trees, asparagus