Chapter 29: Plant diversity (colonization) (3)

Question 1

Seedless vascular plants have _______ sperm and are usually restricted to ______environments

Answer 1

Seedless vascular plants have flagellated sperm and are usually restricted to moist environments

Question 2

What are the characteristic traits of vascular plants?

Answer 2

Living vascular plants are characterized by

– life cycles with dominant sporophytes
– vascular tissues called xylem and phloem
– well-developed roots and leaves

Question 3

What is the dominant life stage in seedless vascular plants?

Answer 3

In contrast with bryophytes, sporophytes of seedless vascular plants are the larger generation, as in familiar ferns

Question 4

What are the 2 types of vascular tissue?

Answer 4

xylem and phloem

Question 5

What is the function of xylem and what cells are included in them?

Answer 5

Xylem conducts most of the water and minerals and includes dead tube-shaped cells called tracheids

Question 6

Water-conducting cells are strengthened by ____ and provide structural support

Answer 6

lignin

Question 7

Roots may have evolved from
_________

Answer 7

Roots may have evolved from subterranean stems

Question 8

How are leaves characterized?

Answer 8

Leaves are categorized by two types

– Microphylls, leaves with a single vein
– Megaphylls, leaves with a highly branched vascular
system

Question 9

What are sporophylls?

Answer 9

Sporophylls are modified leaves with
sporangia

Question 10

__________ are clusters of sporangia on the
undersides of sporophylls

_________ are cone-like structures formed
from groups of sporophylls

Answer 10

Sori are clusters of sporangia on the
undersides of sporophylls

• Strobili are cone-like structures formed
  from groups of sporophylls

Question 11

What are heterosporous plants?

Answer 11

Heterosporous species
produce:

• megaspores, which give rise to female gametophytes
• microspores, which give rise to male gametophytes

Question 12

What are homosporous plants?

Answer 12

Most seedless vascular plants are homosporous, producing one type of spore
that develops into a bisexual gametophyte

Question 13

What are the characteristics of lycophytes?

Answer 13

Giant lycophytes trees thrived for millions of years in moist swamps

• Surviving species are small herbaceous plants
• Club mosses and spike mosses have vascular tissues and are not true mosses

Question 14

What are the characteristics of monilophytes?

Answer 14

Ferns are the most diverse seedless vascular plants, with more than 12,000 species

• They are most diverse in the tropics but also thrive in temperate forests
• Horsetails diverged during Carboniferous period, but now restricted to genus Equisetum
• Whisk ferns resemble ancestral vascular plants but closely related to modern ferns

Question 15

What is the significance of seedless vascular plants?

Answer 15

• The ancestors of modern lycophytes, horsetails, and ferns grew to great heights during the Devonian and Carboniferous, forming the first forests
• Increased growth and photosynthesis removed CO2 from the atmosphere and may have contributed to global cooling at the end of the Carboniferous period
• Decaying plants of Carboniferous forests
  eventually became coal