Chapter 29: Plant diversity (colonization)(2)

Question 1

Gametes are produced within organs called _____________

Answer 1

Gametes are produced within organs called gametangia.

Question 2

Name the male and female gametangia.

Answer 2

Archegonia – female gametangia, produce eggs and are the site of fertilization

• Antheridia – male gametangia, produce and release sperm cells

Question 3

How do apical meristems aid as a derived trait?

Answer 3

Plants sustain continual growth
in their apical meristems

• Localize the region of the cell division
• Cells from the apical meristems
  differentiate into various tissues

Question 4

Explain the life cycle of land plants.

Answer 4

1. The gametophyte produces haploid gametes by mitosis.
2. Two gametes unite (fertilization)
   and form a diploid zygote.
3. The zygote develops into a
   multicellular diploid sporophyte.
4. The sporophyte produces unicellular
   haploid spores by meiosis.
5. The spores develop into multicellular
   haploid gametophytes.

Question 5

Land plants can be informally grouped based on the presence or absence of _________

Answer 5

Land plants can be informally grouped based on the presence or absence of vascular tissue.

Question 6

What are bryophytes?

Answer 6

Bryophytes – nonvascular plants are commonly

– not a monophyletic group
– their relationships to each other and to vascular plants are unresolved

Question 7

What are the classifications of seedless vascular plants?

Answer 7

Seedless vascular plants can be divided into clades

– Lycophytes – club mosses and their relatives
– Monilophytes – ferns and their relatives

Question 8

How can seed plants be divided?

Answer 8

– Gymnosperms, the “naked seed” plants, including the conifers

– Angiosperms, the flowering plants

Question 9

How can bryophytes be classified?

Answer 9

Bryophytes are represented today by three phyla of small herbaceous (nonwoody) plants

– Liverworts – phylum Hepatophyta
– Mosses – phylum Bryophyta
– Hornworts - phylum Anthocerophyta

Question 10

Bryophyte” refers to all nonvascular plants,
whereas

– Bryophyta refers only to phylum of
_______

Answer 10

Bryophyte” refers to all nonvascular plants,
whereas
– Bryophyta refers only to phylum of
mosses

Question 11

What is the dominant life stage in bryophytes?

Answer 11

In all three bryophyte phyla, gametophytes are larger and longer-living than sporophytes

• Sporophytes are typically present only part of the time

Question 12

Explain the life cycle of bryophytes.

Answer 12

A spore germinates into a gametophyte
* Gametophyte = protonema and gamete producing gametophore

• Rhizoids anchor gametophytes to substrate
• Mature gametophytes produce
  – flagellated sperm in antheridia and
  – an egg in each archegonium
• Sperm swim through film of water to reach and fertilize egg

Bryophyte sporophytes grow out of archegonia.

Question 13

What are the smallest and simplest sporophytes of all extant plant
groups?

Answer 13

Bryophyte sporophytes.

Question 14

What does the structure of a sporophyte consist of in bryophytes?

Answer 14

A sporophyte consists of a
– Foot – absorbs nutrient and water from the gametophyte
– seta (stalk) – conducts nutrients to the sporangium
– sporangium (capsule) – discharges spores through a
peristome

Question 15

Liverworts, hornworts, and moss all have sporophyte stomata for gas exchange. True or false?

Answer 15

False. Hornwort and moss sporophytes have stomata for gas
exchange
– liverworts do not

Question 16

List the features and structures of Liverworts

Answer 16

Gametophytes
* flattened liver-shaped
* described as thalloid
* gametangia are on elevated gametophore

Sporophytes – miniature structures

Question 17

List the features of hornwarts.

Answer 17

Sporophyte
* can grow up to 5 cm tall.
* lacks seta and consists of only a sporangium
* Sporangia releases mature spores by splitting open from the tip of the horn.

Gametophyte
* Flat, 1 – 2 cm in diameter
* Grows horizontally
* Often has multiple sporophytes attached

Question 18

Which bryophyte was the first symbiont to colonize land?

Answer 18

hornworts

Question 19

List the features of mosses.

Answer 19

Gametophyte
* Heights of <1 mm – 2 m
* Blades of their leaves are
usually one cell thick

Sporophyte
* Typically tall with heights
up to 20 cm
* Green and photosynthetic
when young.

Question 20

What is the ecological and economic importance of mosses?

Answer 20

• Mosses are capable of inhabiting diverse and sometimes extreme environments
• They are especially common in moist forests and wetlands
• Some mosses might help retain nitrogen in the soil

Question 21

What is sphagnum? How is useful?

Answer 21

Sphagnum, or “peat moss,” forms extensive deposits of partially decayed organic material known as peat

• Peat can be used as a source of fuel
• Sphagnum is an important global reservoir of organic carbon

Question 22

Why is it bad to overhearvest peat?

Answer 22

Overharvesting of Sphagnum and/or a drop in water level in peatlands could release stored CO2 to the atmosphere