BILD 3 Lecture 16: BILD 3 Lecture 16
13 Jun 2018
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BILD 3 Lecture 16
5/9/2018
• More derived plants=majority of land plants
o Go through alteration of generations
o Difference between primitive plants and more derived= more of the lands, the
longest phase of the life cycle (what you see) is the diploid sporophyte, in
contrast with the transient diploid stage in primitive plants
▪ The diploid haploid gametophyte is short lived in derived plants
▪ Fertilization gives rise to a diploid embryo
▪ 2n sporophyte fives rise to 1n gametophyte (by meiosis) that makes 1n
gametes by mitosis fertilization produces the 2n embryo that makes the
next 2n sporophyte
• Plants colonized land ~450-500 MYA, but there were no flowers until ~140 MYA
(angiosperms)
o Reason: earliest plants would have first evolved in water, and pollinated by
water dispersal. Then wind dispersal was common once on land. Then, insects
came into the picture, and as animals colonized that land, they could pollinate as
ell. So, the plants don’t hae to solely rely on ind for pollination dispersal. The
plants that could pollinate in these ways had an advantage, which lead to a rise
in angiosperms and the insects that did the pollination.
• Angiosperm diversity
o Angiosperms comprise more than 250,000 living species
o Previously, angiosperms were divided into two main groups: monocots and
dicots
▪ Monocots have one embryonic leaf, and dicots have two embryonic
leaves
o
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