UNDERSTANDING GYMNOSPERMS - PowerPoint PPT Presentation

About This Presentation
Title:

UNDERSTANDING GYMNOSPERMS

Description:

... Welwitschia two huge leathery leaves Ephedra Mormon tree Gnetum leaves angiosperm-like vessels in the xylem considered an angiosperm characteristic have ... – PowerPoint PPT presentation

Number of Views:960
Avg rating:3.0/5.0
Slides: 29
Provided by: jrmg
Category:

less

Transcript and Presenter's Notes

Title: UNDERSTANDING GYMNOSPERMS


1
UNDERSTANDINGGYMNOSPERMS
  • JRMG
  • 2009-2010

2
What are GYMNOSPERMS?
  • gymnos - naked spermae - seed
  • have seeds (not fruits or flowers)
  • developed (Paleozoic Era)
  • dominant Mesozoic Era (early )
  • heterosporous seed ferns
  • Cone bearing plants

3
(No Transcript)
4
GYMNOSPERMS
  • 700 living species
  • conifers (such as pines and spruce)
  • cycads (such as the sago palm, Cycas revoluta)
  • ginkgos (the maidenhair tree, Ginkgo biloba)
  • gnetophytes (such as Mormon tea, Ephedra)

5
DIVISION GNETOPHYTA
  • 70 species (3 genera)
  • Welwitschia
  • two huge leathery leaves
  • Ephedra
  • Mormon tree
  • Gnetum
  • leaves angiosperm-like
  • vessels in the xylem
  • considered an angiosperm characteristic

6
DIVISION GNETOPHYTA
  • have some angiosperm-like features
  • Cladistic analyses support placement of the
    gnetales (or some portion of them) as outgroups
    for the flowering plants

7
Welwitschia mirabilis
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11
DIVISION CYCADOPHYTA
  • pinnate leaves and circinate vernation
  • heterosporous
  • cones are unisexual
  • dioecious
  • free-swimming sperm

12
(No Transcript)
13
DIVISION GINKGOPHYTA
  • Ginkgo biloba
  • the maidenhair tree
  • dioecious
  • males are more commonly planted
  • females produce seeds that have a nasty odor
  • pollination is by wind
  • swimming sperm

14
(No Transcript)
15
DIVISION CONIFEROPHYTA
  • Most common gymnosperms
  • Pines, spruces, firs, cedars, sequoias, redwood
    and yews
  • Can live more than 4000 y.o.

16
DIVISION CONIFEROPHYTA
  • evergreen
  • needle-like leaves
  • Needles have a thick cuticle
  • sunken stomates
  • reduced surface area

17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24

25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28
(No Transcript)
Write a Comment
User Comments (0)
About PowerShow.com