12 - Plant diversity The focus of the next few lectures is...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Plant diversity
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The focus of the next few lectures is on plants.   We begin with an overview of their diversity, emphasizing a few  selected groups of plants, then move to a discussion of their form and  function.
Background image of page 2
Plants are multicellular, autotrophic organisms that have: -  cell walls containing cellulose, -  chlorophylls a and b as their main photosynthetic pigments, and  -  starch as their photosynthetic storage product. 
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
In addition, the zygote is retained within the female gametangium,  where it develops into an  embryo .  (The female gametangium is the  structure within which the egg is produced.) Thus, the developing embryo is  protected  by the tissues of the  parent plant. This trait distinguishes plants from other groups of photosynthetic  eukaryotes, such as the various lineages of “green algae”, and is  considered to be a key evolutionary innovation enabling plants to  colonize land.
Background image of page 4
Plants form a  monophyletic  lineage (i.e., they are all  descendants of a common ancestor that made the transition from an  aquatic to a terrestrial environment). There is fossil evidence of plant life on land at least 430 million years  ago. There is strong evidence that the ancestors of plants belong to a  lineage of “green algae”, specifically the charophyte lineage.
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
*Charophytes and plants: Have the same main photosynthetic pigments (chlorophylls  a and b) and photosynthetic storage product (starch) and, Exhibit cell-plate formation during mitosis In addition, recent DNA sequence data supports the close  relationship between charophytes and plants. 
Background image of page 6
The diversification of plants on land has been characterized by three  additional key evolutionary innovations, including: 1. the evolution of specialized conducting cells called  tracheids which enabled long-distance transport of water and solutes.
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
*Tracheids are characteristic of the lycophytes, pteridophytes (I.e.  ferns and their relatives), gymnosperms, and angiosperms, which  collectively are known as the  vascular plants Tracheids do not occur in the mosses, hornworts or liverworts. 
Background image of page 8
2. the evolution of 
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/03/2008 for the course BIO 182 taught by Professor Chaux during the Spring '08 term at University of Arizona- Tucson.

Page1 / 41

12 - Plant diversity The focus of the next few lectures is...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online