26.1 Evolution of seed plants

Question 1

Evolution

Answer 1

• bryophytes followed by liverworts followed by pterophytes
• alternation of generations needed water, now not needed anymore
• Heterosporous seedless are the evolutionary precursor to seed plants

Question 2

Seed plants diplontic

Answer 2

• Dominant sporophyte
• gametophyte is small cluster of cells enclosed in the sporophyte tissue
• all heterosporous
• megasopres are the eggs
• microspores are the sperm
• the mature gametophytes are inside the spore, so they aren’t free living

Question 3

Seeds & Pollen

Answer 3

• adaptation to drought

Question 4

Evolution with periods

Answer 4

Progymnosperms => Gymnosperms => Angiosperms
Pennsylvanian => Triassic/Jurassic => Cretaceous

Question 5

Pollen grains (n)

Answer 5

male gametophyte with protective coat

Question 6

Seed

Answer 6

-protects embryo
- offers nutrition to ensure optimal germination conditions
- disperses generations trhough times.

Elkinsia polymorpha has the first seed fern where the cuple protects the ovule.

Question 7

Gymnosperm adaptations

Answer 7

Dominate taiga and apline forests due to dry and cold growth condition adaptations
seeds have a 2n embryo that is the sporophyte

Question 8

Seeds (gymnosperms)

Answer 8

diploid embryo
- protective & growth storage tissue
- hardened tissue to prevent desiccation
- dormancy by dessication and asbcisic acid
- scattered lots and avoids competition with parent

Question 9

Pollen grains (gymnosperms)

Answer 9

• reaches without water to destination
• prevents desiccation
• pollen forms pollen tubes (where some gymnosperms still have flagella to swim down the tube which are also encased in the pollen grain)

Question 10

Angiospem evolution

Answer 10

• same time as pollinator insects
• paleobotanists study ancient plants
• are a sister clade with gymnosperms so not derived
• make a fruit with a flower which protects the emryb oand increases variability and range of seed dispersal
• Woody magnolid hypothesis (states that the early anscestors were shrubs)

Question 11

Amborella trichopoda

Answer 11

First angiospermA

Question 12

Angiosperm types

Answer 12

Basal angiosperms (primitive) such as water lillies that share the same morpholocial traits with both monocots and eudicots
- Monocot or eudicot (based on leaf structure and embryo)

Question 13

Flowers

Answer 13

Responsible for gamete production
- fertilization
- embryo development
- stable from enviornmental fluctuateions
- most diverse phylum after insects
- mutualistic pollinator (coevolution)

Question 14

Fruit

Answer 14

• the thickened ovary after fertilization
• disperal and protection of seed
• it inspired velcro due to the hooked spiney seeds.