1. Evolution of Plants

2. A. Characteristics of Plants
1) Eukaryotes
with a nucleus
2) Multicellular with tissues
specialized cells that work together
3) Cell wall made of
cellulose
4) Autotrophs/photosynthetic
5) Have 2 different body forms
(alternation of generations)

3. B) 1n vs 2n
1) 1n = haploid (half #chromosomes)
a) gametes are 1n (egg & sperm)
b) gametes are made by meiosis
2) 2n=diploid (full set of chromosomes)
a) zygotes are 2n
b) sperm fertilizes egg to make zygote
c) 1n egg + 1n sperm = 2n zygote

4. C. Meiosis vs Mitosis
1) meiosis: cell division to make gametes
a) only done for sexual reproduction
b) one cell divides into 4 cells
c) each cell has ½ the DNA of the parent cell
2) mitosis: cell division to grow
a) each cell has the same amount of DNA as the parent cell
b) one cell divides into 2 cells

6. D. Body forms in the two Generations
1. gametophyte=plant body,makes gametes
A. gametes are reproductive cells
B. egg and sperm
C. each has ½ the DNA needed to make an embryo
2. Sporophyte = plant body makes spores
A. Spore =
reproductive structure
protected by hard wall.
B. germination = plant breaks wall of spore and begins to grow.

7. Plant Evolution

9. E. Vocab
1.Spores (1n) germinate and grow into
gametophytes (1n)
2. Gametes(1n) fuse and grow into
sporophytes(2n)
3.Sporophytes(2n) make spores(1n) by
Meiosis (2n n)
4.Gametophytes(1n)make gametes (1n)
Mitosis (1n n)

11. F. Charophytes: Link plants & algae
1.no alternation of generation
a. so not plant
b. live in water but can dry out
2.similar to plants
a. cell walls made of…
cellulose
b. Chloroplasts

12. G. First True plants (w/ alt. gen.) evolved 50 mya
1.Primitive plants have:
a) swimming sperm
b) main generation = gametophyte
c) sporophyte ON gametophyte
d) no veins (non-vascular)
e) no seeds
f) these traits are like algae

13. 2. 50 mya =Ordovician Period
a. Ozone layer had finally formed
b. ozone protects from U-V radiation
c. allowed life to move onto land
3. Advantages to life on land
a. Higher CO2 concentration
b. More direct sunlight
c. Soil nutrients
d. No herbivores

14. 4. Challenges to Life on Land a. Desiccation (drying out)
i. got a wax coating = cuticle
b. Gravity
i. water holds up aquatic plants
ii. Air offers no support
iii. Early plants lay on ground
5. Earliest plants = Bryophytes
a. Hornworts
b. Liverworts
c. Mosses

15. period3. Called Bryophytes

16. H. First Vascular plants
1.have veins to transport H2O & sugars
2. called Rhyniophytes
3. only stems
a. no roots
b. no leaves
4. no seeds
5. only fossils
(paleobotany)
6. evolved into 2 modern groups of plants

18. I. Extant (living) vascular plants
1.Seedless: Lycophytes, horsetails & ferns
a.New traits
i. stronger cell walls
-. grow up off the ground
(upright growth)
-. Reach light
ii. rhizomes = underground stems
iii. First dominant sporophyte
(sporophyte larger than gametophyte)

19. b.primitive traits
i. swimming sperm
(so need damp habitat)
ii. no seeds

20. Lycophyte sporophytes
Ground pines
Club moss

21. Horse tails sporophytes
Equisetum Scouring Rushes

22. Ferns
sporophytes
sori full of spores
Gametophytes microscopic

24. C. Carboniferous Period:
i. coal deposits
ii. Seedless vascular plants tall as trees
iii. Δ sea levels dry & flood swamps
iv. Layers of dead plants build up faster than they
decompose

25. 2. First Seed Plants = gymnosperms
a. Gymnosperm = naked seed(no fruit)
b. Conifers = seeds in cones
c. appear in Carboniferous period

26. d. seeds = adaptation to dry
e. seeds made by ovules (eggs)
fertilized by sperm carried by pollen
(not swimming sperm)
f. Pollen = freedom from water, it is carried by wind so can disperse on land

28. G . Advantages of Seeds
i. Multicellular vs spores unicellular
ii. Have stored energy
(starch/oil)
* allows delayed germination
*enhanced early growth
iii. Protective coating over embryo
iv. May have dispersal aids

29. 3. More modern seed plants =Angiosperms
a. Angiosperms = flowering plants
b. Seeds form in Ovary of flower
c. Ovary may grow into a fruit
d. now 90% of all plant species
e. Co-evolved with pollinators

31. 4. Flowers
a. Sex
i. Male flowers only make pollen
ii. Female flowers only make ovules
iii. Perfect flowers have both
(hermaphrodites)
b. Complete flowers
i. Must have all flower parts (none missing)
ii. Must be perfect (both male and female)
ii. Imperfect flowers are missing parts

34. Male flower parts

35. Female flower parts