1. 19
KEY CONCEPT Plant life began in the water and became adapted to land. (Charophytes are the ancestors of plants)

2. 19 Kingdom Plantae Characteristics of all plants Multicellular
Autotrophic
Eukaryotic

3. 19 Plants faced difficulties to maintain life on land
Obtaining resources- from air and soil- special organs
Staying upright- support tissues-lignin-c. wall
Maintaining moisture-waxy cuticle, stoma-pores on leaf
Reproducing- protective jacket for gametes, eggs remain
in female parent where they are fertilized

4. 19 Important plant characteristics likely originated in charophytes.
multicellular body allowing for specialization of cells and tissues
cell division that allows for chemical communication between cells
reproduction involving sperm swimming to egg

5. 19 True plants evolved through natural selection.
Ancestral charophytes lived in areas of shallow water.
Those that could survive longer dry periods were favored.
First true plants probably
grew at edges of water.
True plants have embryos
that develop while attached
to female parent.

6. Evidence: Charophytes are ancestors of green plants
Cell walls % cellulose
Similar chloroplasts
Similar mitosis and cytokinesis
Similar genes and rRNA sequences

7. 19
True plants evolved through natural selection.

8. Plants have adaptations that allow them to live on land.19
Plants have adaptations that allow them to live on land.
Challenges of living on land have selected for certain plant adaptations.
Maintaining moisture
A cuticle allows plants to retain moisture.
waxy, waterproof layer
holds moisture in

9. 19 Stomata are tiny holes in the cuticle. can open and close
allow air to move in and out (CO2 and O2)
Closing holds in moisture

10. 19
A vascular system allows resources to move to different parts of the plant.
collection of specialized tissues
brings water and mineral nutrients up from roots
disperses sugars from the leaves
allows plants to grow higher off the ground (lignin)
sugars
water and mineral nutrients
xylem
phloem

11. 19 Lignin allows plants to grow upright.
plant cells
lignin
hardens cell walls of some vascular tissues
provides stiffness to stems

12. 19 Pollen grains allow for reproduction without free-standing water.
pollen grains contain a cell that divides to form sperm
pollen can be carried by wind or animals to female structures

13. 19 A seed is a storage device for a plant embryo.
seed coats protect embryos from drying wind and sunlight
embryo develops inside the ovary of a female plant

14. Alternations of Generations- Taking turns19
Alternations of Generations- Taking turns
A plant's life cycle alternates between the gametophyte and sporophyte generations.
Gametophytes produce gametes
Sporophytes produce spores
Four major Groups of plants: bryophytes, pteridophytes, gymnosperms, and angiosperms.

15. Spores differ from gametes
Spores can develop into a new organism with fusing or mating.
Gametes must fuse- zygote
Spores have tough, protective coats to resist harsh conditions
Gametes are affected by harsh conditions-cold, heat, drying.

16. Bryophytes- mosses- oldest
4 Main plant Groups
Bryophytes- mosses- oldest
No seeds, no lignin-hardened vascular tissue
Pteridophytes- ferns
No seeds, have lignin-hardened vascular tissue
Gymnosperms- cone-bearing plants
First to have seeds-”naked seeds”- no chamber
Specialized leaves
Seeds- embryo with a food store
Plants can spread via seeds without drying out.
Flowering plants- angiosperms
- Seeds in ovaries- protection, dispersal

17. 19 Plants have adaptations that prevent animals from eating them.
spines and thorns
defensive chemicals