Lecture 3+4 Flashcards
How do we define a “plant”
kingdom plantae
have chloroplasts, use photosynthesis
What are the apomorphies that define the group “Viridiplantae?
CSCSC
* Cellulosic cell wall
* Specialized chloroplasts
* Chlorophyll b
* Stacked thylakoids
(grana)
* Starch
What are the apomorphies that define the group “Embryophyta”?
PAACH
Haplodiplontic life cycle (alternation of generations)
Cuticle – polymer of fatty acids
Parenchyma tissue
Antheridium & Archegonium
The apomorphies described in #3 (see embryophyes) are though to be in response to a major
evolutionary event. What was that event?
Land colonization (Silurian period ~400 mya)
What are “non-vascular plants”? Which groups are contained within
Collectively called “Bryophytes”
* Liverworts
* Mosses
* Hornworts
- What is the characteristic aspect of the life cycle of all bryophyte
Dominant Gametophyte stage
During this stage, the plant is haploid and the sex organs that produce the gametes are developed
What are the apomorphies of the group “Tracheophyta”?
SERV
* vascular tissue
* Endodermis
* Roots
Increasing importance
of the diploid phase
(Sporophyte)
What does it mean for a plant to have a “dominant sporophyte phase”? In which plants do we
observe this?
Shoots (v important) and sporangia
* Stems elevate reproductive
organs and leaves, conduce
water, minerals and sugars
* Multiple-branches, multiple
sporangia
* gametophyte is smaller and
much shorter lived
* observed in tracheophytes
- What are the characteristics of tracheophyte sporophyte
Lignified walls and sclerenchyma
* Lignin – complex polymer of phenolic
chains
* Incorporated into a secondary wall,
secreted between the plasma
membrane and the primary cell wall
* Sclerenchyma – nonconductive cells
with thick lignified walls (e.g., fibers)
- Define and briefly describe the vascular tissue of plants
- Highly specialized cells
- Tracheary elements +
parenchyma & sclerenchyma
= XYLEM - Dead at maturity
- Lignified secondary walls
- Water and mineral
conduction - Sieve elements +
parenchyma & sclerenchyma
= PHLOEM - No lignified secondary
wall - Lose nucleus and other
organelles, but retain
others - Consistent and
characteristic spatial
arrangement of xylem and
phloem (stele)
- Name the characteristics that define a root. Why is this an important organ in the context of land
colonization?
My CARR
* Apical meristem (as in stems)
* Root cap (calyptra)
* Root hairs
* Central vascular cylinder
* Mycorrhizae
* Major evolutionary novelty bc of specialized organs for anchorage and absorption
- What the major groups of vascular plans (three)
SLF
* Lycophytes
* Ferns
* Seed plants
- What characterizes a Lycophyte?
Leaves (Sporophytic leaves)
* Dorsiventral organs
* Greatly increased light capture
* Further modified into other structures
small, herbaceous plants
- Contrast a Lycophyll vs a Euphyll.
- Euphylls have a Leaf gap – nonvascular parenchymatic tissue, lycophylls have no gap and a single vascular vein
- Single vein in lycophyll vs multiple strands in euphyll
- In ferns we first observe a characteristic shift in the haplodiplontic cycle. What is that shift?
In a fern’s life cycle, the dominant phase is the sporophyte in the diploid phase, wherein the sporophyte plant goes through meiosis to produce haploid spores
What are the evolutionary steps that led to the development of seeds?
spores –> IM
1. heterospory
2. endospory
3. reduction to 1 megaspore
4. retention of megaspore
5. evolution of integument + micropyle
- How are gymnosperms different than angiosperms?
Gymnosperms
- ovules are not enclosed by carpel
- non-flowering seed plants
Angiosperms
- Highly diverse - >230,000 sps
- Enclosed seeds
- Coevolution with animals
- What is the important evolutionary advantage of the angiosperm flower?
Fruit production
