Honors BiologyChapter 22- Plants

I. Characteristics

A. Kingdom Plantae1. Eukaryotes2. Cell wall contains cellulose3. Carry out photosynthesis using chlorophyll a &

b4. Most are autotrophic, few are parasites

B. Requirements1. Sunlight2. Gas exchange: O2 & CO2

3. Water4. Minerals

C. Evolution of Plants1. Started in the water2. Ancestors of today’s plants were water dwellers

very similar to today’s green algae3. Proof in fossil record4. Plants moved to land & had many challenges

a. Did not have roots or leavesb. Had trouble getting water

5. Moving to land allowed new ecosystems to form6. Green algaemossesfernsseed plants

D. Plant life Cycle1. Land plants have 2 distinct sexual life cycles-

Alternation of generationsa. 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 Algae1. 1st plant2. Mostly aquatic3. Single celled or branching filaments4. Absorb nutrients directly from their surroundings5. Does not contain specialized tissue

B. Mosses & Bryophytes1. 1st plants to become established on land2. Secured to the ground with rhizoids that absorb

water from the soil3. Have specialized reproductive organs4. Does not have vascular tissue to transport water

so they have to be very small5. Have a thin waxy coat to prevent drying out6. Bryophyte groups: mosses, liverworts, hornworts

C. Vascular Plants 1. Also called tracheophytes2. Contains vascular tissue

a. Xylem: transports water up from rootsb. Phloem: transports nutrients produced during

photosynthesisc. 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 seeds1. Seed is a plant embryo2. Provides food supply and a protective covering

seed coat3. The seed is diploid4. Seeds allow the plants to reproduce without open

water

5. Pollen= male gametophyte6. Seeds= female gametophyte7. Pollination: the transfer of pollen from male to

female structure

B. Gymnosperms – (gymno = naked; sperma = seed)

1. Females cones bear seeds directly on the inside surfaces of scales

2. Winds carries pollen to seed cones3. Ex. Pines & firs (conifers), cycads, ginkgoes

IV. Flowering PlantsA. Angiosperms

1. Most flowers produce both gametes in each flower

2. Wind or animals distributes pollen3. bear their seed in flowers4. Very diverse: Monocots, Dicots, Woody,

Herbaceous

5. Monocotsa. 1 seed leaf or cotyledonb. parallel veins on leafc. floral parts in multiples of 3d. vascular bundles scattered in stemse. fibrous root system f. ex. Corn, wheat lilies, orchids, rice, palms

6. Dicotsa. 2 cotyledonsb. Branched veins in leavesc. Floral parts in multiples of 4 or 5d. Vascular bundles in stems are arranged in a ringe. Taproot systemf. Ex. Roses, clover, tomatoes, oaks, daisies

7. Advantages of Flowersa. Draws in pollinators to make pollination

more efficient

8. Advantages of Fruita. Fruit is a matured ovariesb. Helps to disperse the seeds inside of itc. Spread when animals eat the fruit and later

pass the seeds

9. Plant life spana. 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