flowering plants vascular plants - uvm.edu
Post on 23-Nov-2021
7 Views
Preview:
TRANSCRIPT
4/15/21
1
Flowering Plants • Characteristics of
Angiosperms – Flowers – Ovaries and Fruits
• Parts of a flower • Life cycle
– Male and female gametophytes
– Double fertilization • Why so many species
of Flowering Plants?
• Start fungi? April 16, 2021
Vascular Plants
(bryophytes) plants N
onvascular
Plants
Liverworts
Mosses
Hornworts
plants vascular Seedless
Vascular plants
Lycophytes
Vascular Independent Sporophyte Roots
Ferns, etc
Gymnosperms
Seeds Angiosperms 500
Seed plants
450 400 350 300 50 0 Millions of years ago (mya)
1
2
3 Megaphylls
Microphylls
Gametophyte dominant
Flowering plants diversified recently
ßTertiary
ß Origin of flowering plants
Some derived features of Angiosperms
• Flowers • Ovule enclosed in an ovary • Fruits • Double fertilization
Angiosperms – the flowering plants
Stamen Carpel or pistil
Petal Sepal
Ovule inside the ovary Male and female gametes in same structure – the flower
(a) Archaefructus sinensis, a 125- million-year-old fossil
(b) Artist’s reconstruction of Archaefructus sinensis
Carpel
Stamen
5 cm
Figure 30.11
4/15/21
2
Carpels and Stamens Evolved from Leaflike Structures Angiosperms – female parts Stigma
Carpel or pistil Style
Ovary
Ovule
Female gametophyte is inside the ovule Ovule is inside the ovary
Angiosperms – male parts
Stamen Anther
The male gametophyte is inside the pollen grain
Anther
Mature flower on sporophyte plant (2n) Ovary
Embryo (2n) Endosperm (3n)
Seed coat (2n)
Female Gametophyte (in ovule)
Egg cell (n)
Style
Sperm Pollen tube Stigma
Microspore (n)
Male gametophyte (in pollen grain)
Ovule (2n)
MEIOSIS
MEIOSIS
FERTILIZATION
Key Haploid (n) Diploid (2n)
Angiosperm gametophytes are microscopic
Female gametophyte in ovule-- only 7 cells
Male gametophyte in pollen— only 3 cells!
Angiosperms fertilization Many pollen tubes growing in the style
Female Gametophye (in ovule)
4/15/21
3
Double Fertilization
Embryo
Endosperm
Major groups of angiosperms Living gymnosperms Bennettitales
Amborella
Water lilies
Star anise and relatives
Magnoliids
Monocots
Eudicots
300 250 200 150 100 Millions of years ago
50 0
>250,000 species of angiosperms!
>250,000 species of angiosperms! Why so many angiosperms? • Hypothesis – coevolution with pollinators
4/15/21
4
Flowers can have specialized pollinators
Stamens
plant-pollinator coevolution
Seeds retained in modified ovary à fruit
Mechanisms that disperse seeds by explosive action
Wings
Seeds within berries and other edible fruits
Barbs
Fruits
top related