Lecture 8- Plant Diversity I

Question 1

Veridiplantae Members and Shared Derived Trait

Answer 1

All green plants: Chlorophytes, charophytes, land plants
Derived trait: Cellulose cell walls

Question 2

Streptophyta Members and adaptations

Answer 2

Charophytes and land plants
Adaptations for land- Many charophytes live at edges of ponds
Sometimes dries out -> selection favors survival on dry land

Question 3

Streptophyta Shared Derived Traits

Answer 3

1. Streptopollenin
   Polymer, surrounds zygote
   Prevents desiccation
2. Structure of flagellated sperm
3. Cell plate

Question 4

Derived Traits Land Plants

Answer 4

1. Alternation of Generations
   -> 2 multicellular life stages
   Haploid gametophyte- produces gametes by mitosis
   Diploid sporophyte- produces spores by meiosis
2. Multicellular, Dependent Embryo
   2n embryo retained within tissue of female gametophyte. Nutrients transferred from parent.
3. Walled Spores Produced in Sporangia
   Sporangia: Multicellular organs that produce spores
   Sporocytes: Diploid cells, undergo meiosis-> haploid spores
   Spores: Haploid reproductive cells
   Spore wall contains sporopollenin
   Resistant to harsh conditions
4. Multicellular Gametangia
   Gametangia: Multicellular gamete-producing organs- 2 types
   Archegonia: Produce eggs, site of fertilization
   Antheridia: Produce and release sperm
5. Apical Meristems
   Plants don’t move, do elongate
   Apical meristems: Localized regions of cell division at tips of roots and shoots
   Cells differentiate from apical meristems
6. Cuticle
   Waxy covering over all above-ground parts
   Prevents desiccation
   Provides some protection from microbes
   Does not allow for gas exchange
7. Stomata (singular= stoma)
   Tiny openings on surface
   Can open and close
   Allow gas exchange
   Allow water evaporation

Question 5

1. Alternation of Generations

Answer 5

-> 2 multicellular life stages
Haploid gametophyte- produces gametes by mitosis
Diploid sporophyte- produces spores by meiosis

Question 6

2. Multicellular, Dependent Embryo

Answer 6

2n embryo retained within tissue of female gametophyte. Nutrients transferred from parent.

Question 7

3. Walled Spores

Answer 7

Produced in Sporangia
Sporangia: Multicellular organs that produce spores
Sporocytes: Diploid cells, undergo meiosis-> haploid spores
Spores: Haploid reproductive cells
Spore wall contains sporopollenin
Resistant to harsh conditions

Question 8

4. Multicellular Gametangia

Answer 8

Gametangia: Multicellular gamete-producing organs- 2 types
Archegonia: Produce eggs, site of fertilization
Antheridia: Produce and release sperm

Question 9

5. Apical Meristems

Answer 9

Plants don’t move, do elongate
Apical meristems: Localized regions of cell division at tips of roots and shoots
Cells differentiate from apical meristems

Question 10

6. Cuticle

Answer 10

Waxy covering over all above-ground parts
Prevents desiccation
Provides some protection from microbes
Does not allow for gas exchange

Question 11

7. Stomata (singular= stoma)

Answer 11

Tiny openings on surface
Can open and close
Allow gas exchange
Allow water evaporation

Question 12

Nonvascular Plants

Answer 12

Basal plants
Bryophytes- mosses and relatives
Lack specialized vascular systems
Paraphyletic

Question 13

Vascular Plants

Answer 13

Includes both seedless and seed plants
Basal lineage: Seedless vascular plants
-Ferns and related plants
Paraphyletic

Question 14

Seed Plants

Answer 14

Seed: Embryo with supply of nutrients within protective coat
Majority of extant plant species, best adapted for life on land.

Two types: Gymnosperms and angiosperms

Question 15

Gymnosperms

Answer 15

“Naked seed”
Seeds not enclosed in a chamber
Example: Conifers

Question 16

Angiosperms

Answer 16

“Container seed”
Flowering plants
Seeds enclosed in fruit
Most dominant type of plant

Question 17

Nonvascular plants characteristics

Answer 17

Basal land plants
Small, herbaceous (non-woody)
Mosses (Bryophyta)
(And related plants)

No specialized transport tissue
Rely on diffusion, osmosis
-> typically small

Require moist environment for water and reproduction

Question 18

Bryophyte Life Cycle
Define:
Gametophyte
Antheridium
Archegonium
Sporophyte
Sporangium

Answer 18

Gametophyte: Gamete-forming plant (haploid)
Antheridium: Sperm-producing structure
Archegonium: Egg-producing structure
Sporophyte: Spore-forming plant (diploid)
Sporangium: Spore-producing structure

Question 19

Moss Life Cycle

Answer 19

Spores are dispersed due to meiosis by sporangium.
Spores are either male or female gametophyte (n).
If male, becomes antheridia. If female, becomes archegonia.
Release sperm and egg.
Fertilization occurs within archegonium.
Forms diploid zygote.
Divisions and becomes embryo.
Growth and becomes young sporophyte.
Matures into mature sporophytes.
Goes through meiosis and forms haploid spores.

Question 20

Importance of Mosses

Answer 20

Extremely common
Can colonize bare, sandy soil
-> help retain N in soil
Sometimes harbor N-fixing bacteria

Peat: Partially decayed organic matter
Moss is important component
Important fuel source
Important C reservoir

Question 21

Derived Traits of Vascular Plants

Answer 21

1. Sporophyte dominant- lager, independent
2. Transport in vascular tissue- have lignin
   Lignin: Polymer in cell walls of water-conducting cells
   Enables tall growth
   -> Outcompete shorter plants for light, better spore dispersal
3. Roots: Organs that absorb water and nutrients from soil, anchor plants. -> allow for taller growth
4. Leaves: Primary photosynthetic organs, increase surface area
5. Sporophylls: Modified leaves with sporangia
   Very diverse

Question 22

Classification of “Seedless Vascular Plants”

Answer 22

Paraphyletic
Ferns (monilophytes) and related plants