4. Chapter 29: Plant Diversity

Question 1

What are the four main groups of land plants?

Answer 1

1. Bryophytes (i.e. mosses) 2. Pteridophytes (i.e. ferns) 3. Gymnosperms (i.e. conifers) 4. Angiosperms (i.e. flowering plants)

Question 2

What are some characteristics of plants?

Answer 2

1. multicellular, eukaryotic, photosynthetic autotrophs (‘seaweeds’ fit this description too) 2. have cell walls made of cellulose and chlorophyll a and b in chloroplasts (so do green algae)

Question 3

What is the name of the green algal group that is most is similar to plants (at a cellular level)?

Answer 3

Charophyceans, supported by molecular data

Question 4

What features distinguish plants from other organisms?

Answer 4

1. apical meristems 2. alternating generations 3. walled spores 4. multicellular gametangia 5. multicellular, dependent embryos

Question 5

What is the apical meristems?

Answer 5

localized regions of cell division at the tips of the shoots and roots; sustains plant growth; light and CO2 above ground; water and minerals in soil

Question 6

What is alternation of generations?

Answer 6

1. Mature sporophyte produce spores (N) via meiosis 2. Spores develop into multicellular gametophyte via mitosis 3. gametophytes produce gametes (N) via mitosis 4. fusion of two gametes to form zygote (2N) 5. Zygote develops into sporophyte via mitosis (2N)

Question 7

What is the dominant generation in bryophytes? in other groups?

Answer 7

1. Gametophyte generation 2. Sporophyte generation

Question 8

Where are spores produced? What adaption allows them to resist harsh environment?

Answer 8

Produced in the sporangia; covered sporopollenin, very durable organic materials

Question 9

What are gametangia?

Answer 9

multicellular organs that produce gametes

Question 10

What are the male and female gametangia called?

Answer 10

1. archegonium: produces single egg in vase-shaped organ 2. antheridia: produce many sperms (bryophytes, pteridiophytes and some gymnosperms have flagella and swim to eggs)

Question 11

Where does fertilization occur?

Answer 11

archegonium - zygote develops into embryo which is multicellular and dependent

Question 12

Why do land plants have terrestrial adaptations?

Answer 12

1. acquiring, transporting and conserving water 2. reducing the effect of UV radiation 3. repelling herbivores and pathogens (i.e. waxy cuticle protects microbial attack and water loss) (i.e. guard cells minimize water loss - stomata in epidermis allow exchange of CO2 and O2)

Question 13

What are the two major groups that plants are divided into?

Answer 13

1. vascular plants: transport water and nutrient throughout plant 2. non-vascular plants: bryophytes

Question 14

What is the xylem?

Answer 14

• Dead, tube-shaped cells - carries water up from roots - functions as system of microscopic water pipes

Question 15

What is the phloem?

Answer 15

• living tissue in which nutrient-conducting cells are arranged into tubes

Question 16

What are secondary compounds? Examples?

Answer 16

produced by land plants that have toxic effects to defend against herbivorous animals or microbes (i.e. alkaoids, terpenes, and tannins) (i.e. alakloid quinine helps prevent malaria)

Question 17

How else are plants grouped?

Answer 17

seed plants or seedless plants (bryophytes and pteriophytes are seedless; seed for reproduction on land)

Question 18

List the major events in the evolution of land plants.

Answer 18

1. bryophytes: from algal ancestor 2. vascular tissue: in pteridophytes 3. seeds in gymnosperms 4. flowers in angiosperms

Question 19

What are the three groups of the bryophytes?

Answer 19

1. Liverworts 2. Hornworts 3. Mosses (Liverworts and hornworts are models of what early plants were probably like)

Question 20

What is the most common bryophyte?

Answer 20

Mosses

Question 21

What is the dominant phase of bryophytes’ life cycle?

Answer 21

gametophyte (sporophytes smaller and present only part of the time)

Question 22

Describe the gametophytes of bryophytes.

Answer 22

1. multicellular by mitosis 2. only few cells thick, close to water b/c no vascular tissue 3. have stem-like structures that bear leaf-like appendages (not true, only few cm tall) 4. produce gametes in gametangia - vase-shaped archegonium produce single eggs - antheridia produce flagellated sperm (swims to and fertilize eggs by chemical attractants) - nourishes young sporophytes

Question 23

Describe the moss sporophyte of bryophytes.

Answer 23

• consist of elongated stalk (the seta) and a sporangium (the capsule: site of meiosis and spore production)

Question 24

Draw the moss life cycle.

Answer 24

Question 25

Draw the liverwort life cycle. What are gemma cups?

Answer 25

For asexual reproduction.

Question 26

What are sphagnum?

Answer 26

genus of peat moss; that can form large peat bogs (Burn’s bog), important carbon reservoirs, soil conditioner b/c incredible water storage (low pH, prevents decomposition)

Question 27

What was a major evolutionary advantage for the pteridophytes?

Answer 27

vascular tissue, allowed colonization of drier habitats

Question 28

What are the two modern phyla of the pteridophytes (seedless vascular plants)?

Answer 28

Phylum Lycophyta - lycophytes - single unbranched vein - existed as 40m trees; went extinct when climate became cooler and drier - “club moss” is a fern relative Phylum Pterophyta - ferns and their relatives - Horsetails (in carboniferous era grew to 15m, today 15 species in single equisetum; hollow stem allow movement of oxygen into roots)

Question 29

Describe some characteristics of ferns.

Answer 29

1. large leaves (12,00 species, appeared ~380 may) 2. extensively branched vascular system 3. produce clusters of sporangia, called sori 4. vascular tissue allows some species to grow to tree size 5. sporophyte dominant life cycle (larger, more complex); gametophytes are small 6.produce single type of spore (homosporous) which develops into gametophyte with archegonia (female) and antheridia (male) 7. have flagellated sperm that swims to egg (require damp habitats)

Question 30

Draw the fern life cycle

Answer 30

Question 31

What formed “coal forests”?

Answer 31

In carboniferous period, dead plants (ferns) accumulated as peat converted to coal (fossil fuel); fuelled industrial revolution; contributed to “greenhouse gases”, climate change.

Question 32

Homoporous spore of ferns

Answer 32