Angiosperms

Question 1

Phylum Magnioliophyta

Answer 1

• heterosporous
• female gametophytes tiny, within sporophyte
• few transitional fossils
• most primitive flower
• early cretaceous

Question 1

angiosperm phylums

Answer 1

• magnoliophyta / anthophyta

Question 2

primitive flower strucutre

Answer 2

• alternating arranged parts
• tepals
• many flattened stamens
• separate carpels

Question 3

two classes of magnoliophyta

Answer 3

• dicots: class magnoliopsida
• monocots: Class liliopsida

Question 4

how are dicots and monocots diff?

Answer 4

dicots: two cotyledons, vascular network, ring of vascular bundles, taproot, flower fours or fives

monocots: one cotyledon, vascular bundles, parallel leaf veins, fibrous root, flower three

Question 5

Sexual life cycle of flowering plant

Answer 5

main plant is sporophyte
- heterosporous (spores not released)
- megasporocyte undergo meiosis to produce four megaspores, three of them die
- microsprorcytes undergo meiosis to produce two microspores

Question 6

megagametophyte development

Answer 6

• remaining megaspore divides three times to produce 8 nuclei
• arrange to becme megagametophyte

Question 7

megagametophyte structure

Answer 7

• three antipodals on one side of the embryo sac (will die later)
• 2 central cell nuclei
• one egg surrounded by synergids (will die later)
• micropyle under egg (opening to ovule)

Question 8

microgametophyte development

Answer 8

• the four microspores form pollen grains with a generative nucleus and tube nucleus
• 3 apertures with tough wall outside
• cytoplasm contains vitamins and nutrients
• dicots have three apertures
• monocots have two apertures

Question 9

pollination

Answer 9

pollen must be transferred from anther to the stigma of the flower through different mechansisms.
- insects pollinate
- opening to flower forces insect to pass by stigma
- pollinium that attached to head or tongue
- faking a female insect
- buckets

Question 10

Fertilization

Answer 10

• sperms cells travel down polled tube from pollen grain aperature
• grows downward the style of the stigma towards ovary
• enters micropyle, one fertilizes the egg and the other fertilizes the 2 central nuclei

Question 11

seed development

Answer 11

• zygotes grows to develop a structure within the endosperm, with two cotyledons, shoot apex, root apex and suspensor.
• the cotyledons absorb the endosperm in the process.

Question 12

variations

Answer 12

• variation in the number of embryo sac nuclei, although there are typically 8
• ploidy of endosperm
• apomixis (some ovules have diploids)
• parthenocarpy (some original ovule cells just start growing seeds and skip fertilization)