Lecture 9

Question 1

Kingdom Plantae aka Embryophyta

Answer 1

290 000 extant species, most photoautotrophic, most terrestrial (some aquatic), shares a common ancestor with green algae charophytes

Question 2

first photosynthesizers on land

Answer 2

rewarded with an expanse of terrestrial habitat - space, sunlight unfiltered by water and algae, abundant CO2, mineral-rich soil, few herbivores or pathogens

Question 3

oldest terrestrial photosynthesizers

Answer 3

cyanobacteria

Question 4

oldest terrestrial plant spores

Answer 4

475 MYA, in clumps of 2 or 4

Question 5

4 main groups of plants

Answer 5

1. non-vascular plants
2. seedless vascular plants
3. gymnosperms
4. angiosperms

Question 6

3 land plant shared synapomorphies with charophytic algae

Answer 6

1. rosette-shaped cellulose-synthesizing complexes (make cellulose microfibrils of cell wall)
2. structure of sperm resembles charophyte sperm (only for plants with flagellated sperm)
3. presence of phragmoplast during cell division

Question 7

phragmoplast

Answer 7

helps construct cell plate between incipient cells, which goes on to become new cell wall

Question 8

Viridiplantae

Answer 8

some systematists put chlorophytes, charophyceans and embryophytes together

Question 9

6 synapomorphies of plantae

Answer 9

1. multicellular, dependent embryos
2. alternation of generations
3. sporopollenin
4. adaptations for water conservation
5. lignified vascular tissue for internal transport (lacking in bryophytes)
6. apical meristems

Question 10

placental cells

Answer 10

present in plant embryos so parent can provide nutrients

Question 11

alternation of generations

Answer 11

life cycle in which haploid multicellular and diploid multicellular body forms alternate

Question 12

sporopollenin

Answer 12

tough, stable polymer in walls of plant spores, including pollen

Question 13

2 adaptations for water conservation in land plants

Answer 13

1. waxy cuticle on epidermis acts as waterproofing
2. stomata pores in the epidermis of leaves and other photosynthetic organs, changes in shape of bordering cells can close pores

Question 14

lignin

Answer 14

a complex polymer of alcohols which strengthens vascular tissue

Question 15

2 types of vascular tissue

Answer 15

xylem and phloem

Question 16

apical meristem

Answer 16

undifferentiated tissue from which new cells arise, and differentiate into various tissues, including surface
epidermis and internal tissues

Question 17

compartmentalization of resources in terrestrial plants

Answer 17

structural specialization for water and minerals in ground (roots), light and gases above ground, elongation and branching to maximize exposure

Question 18

3 phyla of bryophytes

Answer 18

1. Hepatophyta (liverworts) - 9000
2. Anthocerophyta (hornworts) - 100
3. Bryophyta (mosses) - 15 000

Question 19

non-vascular plant aka bryophyte characteristics

Answer 19

not monophyletic (hornworts sister to vascular plants), lack true vascular tissue (only a few cells thick), small

Question 20

bryophyte life cycle

Answer 20

1. haploid gametophytes dominant
2. separate organs for egg and sperm
3. sperm swim through water film to fertilize egg in archegonium (need to live in moist places)
4. zygote and sporophyte retained and nourished by gametophyte, release thousands of asexually produced haploid spores

Question 21

archegonium

Answer 21

produces a single egg

Question 22

antheridium

Answer 22

produces many flagellated sperm

Question 23

sphagnum moss

Answer 23

forms extensive deposits of undecayed organic material called peat (muskeg), inhibit bacterial activity, peatlands act as carbon reservoirs stabilizing atmospheric CO2 levels, peat used as fuel, harvested for soil conditioner