Lecture 18

Question 1

why are seeds advantageous

Answer 1

protect embryo, stored food

Question 2

all seed plants are what

Answer 2

heterosporous

Question 3

spores are no longer released, they are stored in what

Answer 3

the megasporangium

Question 4

in ovule evolution, how many megaspores survive

Answer 4

one of four

Question 5

what envelops the megasporangium

Answer 5

the integument

Question 6

where does the embryo develop

Answer 6

inside the megagametophyte

Question 7

what is the one important trend that was seen during the evolution of the seed

Answer 7

gradually integuments fused until only opening left at apex (micropyle)

Question 8

what are the five phyla of seed plants with living representatives

Answer 8

cyadophyta, ginkgophyta, coniferophyta, gnetophyta, anthophyta

Question 9

what is polyembryony

Answer 9

all eggs are fertilized by only one embryo develops fully

Question 10

how does fertilization occur in gymnosperms

Answer 10

male pollen grain transferred to female gametophyte usually by wind, water not required

Question 11

what do gymnosperms lack

Answer 11

no antheridia in seed plants

Question 12

how do sperm differ among the different gymnosperm groups

Answer 12

nonmotile in conifers and gnetophytes, motile in cycads and ginko

Question 13

what are some characteristics of coniferophyta

Answer 13

most numerous, widespread, ecologically important gymnosperm, leaves have many drought resistant characteristics

Question 14

what are pine needles like

Answer 14

adapted for low soil moisture, thick cuticle, hypodermis, sunken stomata

Question 15

what is the pine life cycle

Answer 15

two years to complete, microsporangia and megasporangia born on separate cones on same tree, usually male on lower branches and females up higher

Question 16

what are characteristics of pine microsporangiate cones

Answer 16

small, microsporocytes, meiosis in early spring, immature male gametophyte

Question 17

what are characteristics of pine megasporangiate cones

Answer 17

larger, seed scale complex, scales in spiral, ovule, after meiosis only one megaspore is functional

Question 18

when does pine pollination occur

Answer 18

in the spring

Question 19

when does pine fertilization occur

Answer 19

about 12 months after pollination, all eggs are fertilized but only one is functional

Question 20

what is the seed life cycle for pines

Answer 20

two diploid sporophytic generations, one haploid generation, seeds usually shed in fall of second year

Question 21

what two trees are in the family cupressaceae

Answer 21

bald cypress and redwood

Question 22

which family has the tallest living plant

Answer 22

family cupressaceae

Question 23

what are some characteristics of cycads

Answer 23

11 genera, palm like plants, fairly large, distinct trunk covered with bases of shed leaves, true secondary growth, highly toxic, reproductive units (conelike structures and unisexual)

Question 24

how do cycads pollinate

Answer 24

insects

Question 25

what is the one living member of the phylum ginkophyta

Answer 25

ginko biloba

Question 26

which phylum resembles angiosperms

Answer 26

gnetophyta

Question 27

what are the three families of gnetophyta

Answer 27

gnetum, ephedra, welwitschia

Question 28

how do gnetophytes share angiosperm like features

Answer 28

strobili flower clusters, similar xylem vessels, lack of archegonia, double fertilization, insect pollination