Plant Diversity 1: How Plant Colonized Land

5.0(1)
studied byStudied by 5 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/33

flashcard set

Earn XP

Description and Tags

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

34 Terms

1
New cards
The evolutionary history of plants begins as the story of adaption to land life.
What we can plants, truly land-adapted multicellular photoautotrophs , are descended from a lineage of one of the “green Algae” and thus are in the clade Archaeplastida.
2
New cards
(1) Evidence supporting that photo-autotrophs plants, are descended from “green Algae”
Chlorophytes, Charophytes & Plantae share:

* multicellularity
* cell walls with cellulose
* chloroplasts with same pigment (chlorophyll. a & b). Storage molecule is starch.
3
New cards
(2) Evidence supporting that photo-autotrophs plants, are descended from “green Algae”
Charophytes also share with Plantae:

* Similar flagellated sperm
* Cellulose synthesis proteins (rings)
* Cytokinesis process (cell plate formation)
4
New cards
(3) Evidence supporting that photo-autotrophs plants, are descended from “green Algae”
Sporo-pollenin - a durable polymer that protects:

* zygotes in charophytes
* spores in seedless plants
* pollen grains in seed plants
5
New cards
How did selection for land life start?
By 470 mya, multicellular green algae expanded from shallow seas into river & lakes. Green algae along lake shores meant more resources; less competition (=drying), subjected to periodic dehydration, and population with land adaptations thrive.
6
New cards
Advantages of land:
* \[CO2\] higher
* light intensity higher
* more minerals
* no “herbivores”
* no competition
7
New cards
Disadvantages of Land:
* Risk of desiccation (both adult & gametes)
* Divided resources (air vs. land)
* No “support” in air
8
New cards
8 Mechanisms explain how plants derived their characteristics:

1. Alternation of generations
2. Walled haploid spores
3. Multicellular gametangia
4. Sporophyte embryos grow protected with female gametophyte
5. Apical Meristems
6. Waxy cuticle
7. Secondary Compounds
8. Mycorrhizae
9
New cards
Mechanism #1: Alternation of generations
Plant sporophyte (2n) makes huge # unique diverse offspring per fertilization.
10
New cards
Mechanism #2: Walled haploid spores
Dispersal thru air: sporo-pollenin protects. Made within multicellular sporangium.
11
New cards
Mechanism #3: Apical Meristems (SCs)
Continuously dividing cells. Roots & shoots grow toward resources.
12
New cards
Mechanism #4: Multicellular gametangia
Protecting sperm within antheridium. Egg protected with archegonium.
13
New cards
Mechanism #5: Sporophyte embryos grow protected within female gametophyte.
Nourished via placental transfer cells.
14
New cards
Mechanism #6: Waxy cuticle
Waxy coats stop desiccation (=drying). Pore needed to allow CO2/O2 exchange - controlled by stoma in most plants.
15
New cards
Mechanism #7: Secondary Compounds
Chemicals that deter, repel or poison competitors, herbivores, & parasites. First products such as fruits.
16
New cards
Mechanism #8: Mycorrhizae
Mutualism with fungi; helps water & mineral absorption. Dates back to first land plants (before true roots).
17
New cards
Major Plant Groups
* Non-vascular Plants
* Vascular (seedless) Plants
* Vascular (seed) Plants
* Gymnosperms
* Angiosperms
18
New cards
What is the ecological important of Bryophytes?
“Pioneer” species in poor soils. Moss are major 1° producers in cold or high regions. Sphagnum “peat moss” bogs: important wetlands. Also harvested for fuel & gardening.
19
New cards
What are Bryophytes?
Lack vascular & supportive tissue. Very thin body: depends on diffusion. With rhizoids for attachment (not true roots).
20
New cards
Bryophyte Characteristics:
Haploid gametophyte is dominant form:

* Dominant = longest lasting or largest
* Make eggs & flagellated sperm
* Most are small, low growing moist areas
21
New cards
Diploid sporophyte depends on --- for food and water.
gametophyte
22
New cards
Phloem
Move sugar & organic products.
23
New cards
Xylem
Carries water & materials - most vascular plants have tracheids with walls strengthened by tough polymer: lignin.
24
New cards
Evolution of Vascular Plants
Unbranched sporophyte → branched sporophyte → supportive vascular tissue → Sporophyte photosynthesis increases (no longer need food from gametophyte)
25
New cards
Roots evolve from --- ---.
underground stems
26
New cards
Leaves evolved from --- ---.
branched stems
27
New cards
Megaphylls
Branched veins
28
New cards
Sporophylls
Sporangia shift to leaves
29
New cards
How did the success of seedless vascular plants change the Paleozoic world?
Covered the earth, increasing organic C on land (for food); further increases in O2 levels; reduced CO2 levels; all favoring success of land animals.
30
New cards
Lycophytes: Relict Group
Closest group to ancestral vascular plants. All now very small. Include club moss & spike moss. Little economic/ecological importance today.
31
New cards
Lycophytes: Whisk ferns (Psilotum)
Dichotomous branching. No true leaves or roots (lost secondarily).
32
New cards
Lycophytes: Horsetails (Equisetum)
Jointed hollow stem with tiny leaves. Strobili.
33
New cards
Lycophytes: Ferns
Most widespread & diverse magnoliophytes. Large megaphylls
34
New cards
Fern Life Cycle
The life cycle of fern is different from other land plants as both the gametophyte and the sporophyte phases are free living.