week 7b

Question 1

what major event allowed gymnosperms to dominante

Answer 1

the carbonfierous period saw lycophytes and pteridophytes reduce atmosphereic CO2, causing climate cooling and drying, leading to their decline and favouring gymnosperms

Question 2

when did gymnosperms dominate Earth’s vegetation

Answer 2

during the mesozoic era (248-65 million years ago)

Question 3

what reproductive structures do gymnosperms use

Answer 3

spores and seeds

Question 4

what does “gymnosperm” mean

Answer 4

“naked seeds” - seeds are not enclosed in fruit

Question 5

what advantage do seeds offer gymnosperms

Answer 5

protections and energy supply for young sporophytes

Question 6

which groups are considered gymnosperms

Answer 6

cycads, ginkgos, conifers, and gnetophytes

Question 6

what are examples of conifers

Answer 6

pines, spruces, and firs

Question 7

what reproductive structure do conifers have

Answer 7

woody cones

Question 8

are most conifers evergreen

Answer 8

yes, they shed some but not all leaves each year

Question 9

what type of leaves do conifers have

Answer 9

needle-like leaves

Question 10

what substance do many conifers produce

Answer 10

resin

Question 11

what do cycads look like

Answer 11

shrubby or treelike with palmlike leaves

Question 12

what type of cones do cycads have

Answer 12

large, cone-shaped strobili

Question 13

where are cycads typically found

Answer 13

warm climates

Question 14

how many species of ginkgoes exist today

Answer 14

only one - ginkgo biloba

Question 15

what is the leaf shape of ginkgo biloba

Answer 15

fan-shaped leaves

Question 16

what type of spores do most seedless vascular plants produce

Answer 16

homosporous - one type pf spore

Question 17

what is heterospory

Answer 17

producing microspotes (male) and megaspores (female)

Question 18

what is endosporous development

Answer 18

gametophytes develop inside the spore wall, offering protection

Question 19

what advantage does heterospory offer

Answer 19

increases cross-fertilization and protection of gametes/embryos

Question 20

what do gymnosperms retain in their reproductive structures

Answer 20

haploid spores produced by the 2n sporophyte

Question 21

what is pollination in gymnosperms

Answer 21

transfer of pollen to female parts; no water required

Question 22

what is an ovule in gymnosperms

Answer 22

an egg inside a gametophyte, retained inside tegument and megasporangial tissue

Question 23

what is the gymnosperm male gametophyte

Answer 23

the pollen grain, which undergoes gametogensis to form sperm

Question 24

what does a fertilized ovule become

Answer 24

a seed with an embryo, nutritive tissue and a seed coat

Question 25

what are the advantages of seeds

Answer 25

- dormancy until favourable conditions - long-distance dispersal - stored food for the embryo - no need for water for fertilization

Question 26

how are pollination and fertilization different

Answer 26

pollination = pollen reaches female parts fertilization = sperm unites with egg to form zygotew

Question 27

what structure protects ovulues and seeds in angiosperms

Answer 27

carpels - specialized protective leaves in flowers

Question 28

what is the role of fruit in angiosperms

Answer 28

nourishes and disperses seeds

Question 29

what are the 2 major groups of angiosperms

Answer 29

monocots and eudicots

Question 30

how many angiosperm species are known

Answer 30

at least 260k

Question 31

what distinguishes monocots from eudicots

Answer 31

monocots = 1 cotyledon, parrallel-veined leavesm scattered vascular bundles eudicots = 2 cotyledons, net-veined leaves, central vascular in stem

Question 32

what is a cotyledon

Answer 32

an embryonic leaf in seed-bearing plants; often the first leaves to emerge during germination

Question 33

what unique reproductive structures do angiosperms have

Answer 33

flowers and fruits (which develop from flowers and help disperse seeds)

Question 34

what is endosperm

Answer 34

nutritive seed tissue formed via double fertilization, supports embryo growth

Question 35

what is double fertilization in angiosperms

Answer 35

1 sperm fertilizes egg = embryo 1 sperm fuses with gametphyte tissue = endosperm

Question 36

what doe sthe ovule's integument become

Answer 36

the seed coat

Question 37

what vascular adaptation makes angiosperms efficient

Answer 37

vessel elements more efficient than tracheids) advanches phloem structure

Question 38

what reproductive advantages do angiosperms have

Answer 38

- double fertilization - endosperm formation - ovary that becomes fruit for protection and dispersal

Question 39

how do angiosperms interact with pollinators

Answer 39

many have specific animal pollinators and undergo co-evolution (changes in 1 affect the other)

Question 40

what's the benefit of animal pollination over wind pollination

Answer 40

increases pollination efficiency and specificity

Question 41

what are 3 features of land plant embryos

Answer 41

1. multicellular and diploid 2. retained in maternal tissue 3. receive nutrients via placental transfer tissues

Question 42

why are embryos considered a critical land plant innovation

Answer 42

they allow protected development of sporophytes within the parent plant

Question 43

how have land plants transformed Earth

Answer 43

- helped form soils - increased atmospheric oxygen - supported evolution of modern ecosystems - enabled animal colonization of land