Lecture 11

Question 1

seed plant dominance

Answer 1

sporophyte dominant and gametophyte dependent

Question 2

5 Innovations of Seed Plants

Answer 2

1. independent sporophyte and dependent gametophyte
2. heterospory
3. ovules
4. pollen
5. seeds

Question 3

seed plant heterospory

Answer 3

almost all seedless plants homosporous, but all seed

plants produce megaspores and microspores

Question 4

seed plant ovules

Answer 4

megaspore retained within parent sporophyte

Question 5

seed plant pollen

Answer 5

microspores develop into pollen grains

Question 6

seed plant seeds

Answer 6

fertilized ovule develops into seed containing next generation sporophyte

Question 7

female gametophyte

Answer 7

develops via mitosis from megaspore (1n) produced within sporophyte megasporangium (2n) wrapped in integuments (2n)

Question 8

ovule

Answer 8

integuments + megaspore + megasporangium

Question 9

male gametophyte

Answer 9

microspores (1n) retained in microsporangium on parent sporophyte, undergo mitosis –> tiny 1n male gametophytes

Question 10

immature pollen

Answer 10

tiny 1n male gametophytes

Question 11

pollen grain 2 cells

Answer 11

1. generative cell

2. tube cell

Question 12

sporopollenin

Answer 12

tough coating of pollen grain

Question 13

orchids and milkweeds

Answer 13

larger clumps of pollen (pollinia) rather than 4, 8, 16 clumps

Question 14

pollen allergies

Answer 14

caused by proteins in sporopollenin

Question 15

pollination

Answer 15

drastic change in tactics, entire male gametophyte (pollen) goes in search of eggs

Question 16

seed

Answer 16

sporophyte embryo in gametophyte tissues in parent sporophyte wrapping

Question 17

dispersal stage in seed plants

Answer 17

seed (as opposed to spore in seedless plants)

Question 18

2 main clades of extant seed plants

Answer 18

1. gymnosperms

2. angiosperms

Question 19

gymnosperms

Answer 19

seed “naked” - ovule and seed lie on surface of sporophyll, sporophylls normally in cones

Question 20

4 extant gymnosperm phyla (monophyletic)

Answer 20

1. gingkophyta (1)
2. gnetophyta (70)
3. cycadophyta (130)
4. coniferophyta (600)

Question 21

gingkophyta

Answer 21

1 extant species, Gingko biloba, distinctively bilobed leaves, may be 200 MYO, originally from China, none wild, sporophytes are large and woody, separate male and female sporophytes, wind-pollinated, flagellated sperm, extracts increase blood flow and thought to improve memory

Question 22

cycadophyta

Answer 22

diverse and dominant in Mesozoic, tropical areas, flagellated sperm, many pollinated by insects, separate male and female sporophytes with large cones, females produce fleshy-coated seeds

Question 23

3 genera of gnetophyta

Answer 23

1. Gnetum
2. Welwitschia
3. Ephedra

Question 24

Gnetum

Answer 24

35 species of tropical trees and vines

Question 25

Welwitschia

Answer 25

1 species, 2 leaves grow continuously, moisture from morning fog

Question 26

Ephedra

Answer 26

40 desert species, some contain ephedrine

Question 27

ephedrine

Answer 27

alkaloids found in ephedra, cause bronchi and lungs to dilate

Question 28

coniferophyta

Answer 28

most species rich, named for cones, woody shrubs or trees, many have leaves shaped as needles, others have scale-like or flat leaves, most are evergreen

Question 29

bark beetles

Answer 29

bore into conifers and lay eggs, able to survive in large numbers due to mild winters

Question 30

pitch

Answer 30

pine resin so healthy trees can pitch out beetles

Question 31

amber

Answer 31

fossilized resin

Question 32

pine life cycle

Answer 32

1. mature tree 2n sporophyte, sporangia located in sporophylls, in cones
2. megasporangia and microsporangia on same tree (pines) or separate
3. wind pollinated
4. wind dispersal of seeds