Login

Join for Free!
112240 members


Ferns and their life cycle

Plants!

Moderator: BioTeam

Ferns and their life cycle

Postby MissAshley » Mon Nov 30, 2009 7:18 pm

Please Help me with these two questions.

1.Early botanists admired ferns but found their life cycle perplexing. In the 1700s, they learned to propagate them by sowing what appeared to be tiny dustlike "seeds" from the undersides of fronds. Despite many attepts, the scientists could not find the pollen source, which they assumed must stimulate the "seeds" to develop.

Imagine you could write to one of these botanists. Compose a note that would clear up their confusion.



2.Today, the tallest bryophytes reach a maximum height of 20 centimeters (8 inches) or so. So far as we know from fossils, there were no giants among their ancestors. Lignin and vascular tissue first evolved in relatives of club moss, and some extinct species stoode 40 meters (130 feet) high. Among modern seed plants, Sequoia (a gymnosperm and Eucalyptus (an angiosperm) can be more than 100 meters (330 feet) high.

Explain why evolution of vascular tissues and lignin would have allowed such a dramatic increase in plant height. How might being tall give one plant species a competitive advantage over another?
MissAshley
Garter
Garter
 
Posts: 8
Joined: Wed Nov 11, 2009 8:15 pm

Postby JackBean » Tue Dec 01, 2009 1:39 am

1) what are these seeds?
2) imagine rain forest and it's levels
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.
User avatar
JackBean
Inland Taipan
Inland Taipan
 
Posts: 5652
Joined: Mon Sep 14, 2009 7:12 pm

Postby plasmodesmata11 » Tue Dec 01, 2009 2:35 am

1) exactly as jack said...
2) also think about diffusion in bryophytes and other methods of material transportation in higher plants
plasmodesmata11
Coral
Coral
 
Posts: 198
Joined: Sun Nov 30, 2008 3:51 am
Location: University of Rhode Island


Postby flyfield » Wed Dec 09, 2009 12:10 pm

As you said, when many plants grow together ,one plant can get more light if it is enough tall.I think light will be one of the most important things which are a plant needed to survive.
flyfield
Garter
Garter
 
Posts: 3
Joined: Wed Dec 09, 2009 11:21 am

Postby JackBean » Sat Dec 12, 2009 3:28 am

Why then, can't plant survive, when kept just on e.g. plate of glass? :roll:
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.
User avatar
JackBean
Inland Taipan
Inland Taipan
 
Posts: 5652
Joined: Mon Sep 14, 2009 7:12 pm

Postby EronJonson » Fri Feb 26, 2010 2:20 am

You could find that answer if you typed life cycle of ferns in google, it'd be easier than asking some questions straight out of a book.

As for the second part though, because the lignin is what gives the cell walls of the plants their rigidity, thus causing them to be able to hold more weight on itself. And if you can't figure it out, taller plants have more access to sunlight, therefore outcompeting other plants for valuble resources.
EronJonson
Garter
Garter
 
Posts: 3
Joined: Fri Feb 26, 2010 2:02 am

Re:

Postby EronJonson » Fri Feb 26, 2010 2:22 am

JackBean wrote:Why then, can't plant survive, when kept just on e.g. plate of glass? :roll:


They need a nutrient source, they also need a media to grow in, either organic or inorganic. It would also greatly help if this didn't allow sunlight to penetrate towards the roots.
EronJonson
Garter
Garter
 
Posts: 3
Joined: Fri Feb 26, 2010 2:02 am

Postby jaycee » Mon Aug 01, 2011 1:54 pm

The life cycle of a fern is beautiful and complex, but with a little study, you can understand it. Start with number 1 below, the spore. This is like the seed of a flowering plant, in that it is the way the fern reproduces and spreads. A spore, however, is different in that it is a single cell that has only one copy of each chromosome (haploid), and a seed is multicellular and has two (diploid). The spore develops into a plant called a gametophyte that can produce both sperm and eggs. These unite in the processes called fertilization, producing a "baby" fern called a zygote, which now has two copies of each chromosome (it is diploid). By normal cell division, this grows into the fern as we know it, the green leafy plant on the forest floor. The fern produces the spore (still diploid), and the cycle continues.
Read more: http://www.davidlnelson.md/Cazadero/Fern_Life_cycle.htm
jaycee
Garter
Garter
 
Posts: 3
Joined: Mon Aug 01, 2011 12:29 pm


Return to Botany Discussion

Who is online

Users browsing this forum: No registered users and 0 guests

cron