1
Q
Viridiplantae
A
Land plants and green algae
2
Q
Green algae split into 2 major clades
A
- Chlorophytes – Never made it to land
- Charophytes – Did
3
Q
Land plants have two major features
A
- Protected embryos
2. Multicellular haploid and diploid phases
4
Q
Adaptations to terrestrial life
A
- Protection from desiccation by a waxy cuticle and stomata
- Evolution of leaves which increase photosynthetic surface area
- Shift to a dominant vertical diploid generation
5
Q
Plant life cycles
A
- Humans have a diplontic life cycle
- Plants have a haplodiplontic life cycle
- Multicellular diploid stage = Sporophyte
- Multicellular haploid stage = Gametophyte
6
Q
As more complex plants evolved:
A
- Diploid stage became the dominant portion of the life cycle
- Gametophyte became more limited in size
- Sporophyte became nutritionally independent
7
Q
Green algae have two distinct lineages
A
- Chlorophytes – Gave rise to aquatic algae
- Streptophytes – Gave rise to land plants
8
Q
Chlamydomonas
A
- Unicellular chlorophyte with two flagella
- Have eyespots to direct swimming
- Reproduces asexually as well as sexually
9
Q
Volvox
A
- Colonial chlorophyte
- Hollow sphere of a single layer of 500-60,000 cells
- A few cells are specialized for reproduction
10
Q
Ulva
A
- Multicellular chlorophyte
- Haplodiplontic life cycle
- Gametophyte and sporophyte have identical appearance
11
Q
Charophytes
A
Green algae related to land plants
12
Q
Two clades of Charophytes
A
- Charales
- Choleocaetales
13
Q
Charales
A
- Macroscopic
- Plant-like plasmodesmata
- Sister clade to land plants
14
Q
Choleocaetales
A
- Microscopic
- Plant-like mitosis
- Next closest plant relatives
15
Q
Bryophytes
A
- The closest living descendants of the first land plants
- Called nontracheophytes because they lack tracheids (specialized transport cells)
16
Q
Liverworts (bryophyte)
A
- Have flattened gametophytes with liver-like lobes
- Form gametangia in umbrella-shaped structures
- Also undergo asexual reproduction
17
Q
Hornworts (bryophyte)
A
- Sporophyte has stomata
- Sporophyte is photosynthetic
- Cells have a single large chloroplast
18
Q
Vascular tissues are two types
A
- Xylem – Conducts water and dissolved minerals upward from the roots
- Phloem – Conducts sucrose and hormones throughout the plant
- These enable enhanced height and size in the tracheophytes
19
Q
Vascular plants (Tracheophyte)
A
Have gametophytes reduced in size and complexity relative to sporophytes
20
Q
Seeds (Tracheophyte)
A
- Highly-resistant structures that protect the plant embryo
- Occur only in heterosporous plants
21
Q
Fruits (Tracheophyte)
A
- In flowering plants add a layer of protection to seeds
- Also attract animals that disperse seeds
22
Q
Vascular plants include seven extant phyla grouped in three clades:
A
- Lycophytes (club mosses)
- Pterophytes (ferns and their relatives)
- Seed plants
23
Q
Club mosses (Lycophytes)
A
- Are the earliest vascular plants
- They lack seeds
- Superficially resemble true mosses but they are not related
- Homosporous or heterosporous
24
Q
Whisk ferns (Pterophytes)
A
- Saprophyte consists of evenly forking green stems without leaves or roots
- Some gametophytes develop elements of vascular tissue
- Only one known to do so
25
Horsetails (Pterophytes)
- All 15 living species are homosporous
- Constitute a single species, Equisetum
- Consist of ribbed, jointed photosynthetic stems that arise from branching rhizomes
26
Ferns (Pterophytes)
- The most abundant group of seedless vascular plants with about 11,000 species
- The conspicuous sporophyte and much smaller gametophyte are both photosynthetic
27
Fern morphology
- Sporophytes have rhizomes
- Fronds (leaves) develop at the tip of the rhizome as tightly rolled-up coils
- They unroll and expand
28
Fern reproduction
- Most fern are homosporous
- Produce distinctive sporangia in clusters called sori on the back of the fronds
- Diploid spore mother cells in sporangia produce haploid spores by meiosis
- At maturity, the spores are catapulted by snapping action
29
Seed plants
-Evolved from spore-bearing plants known as progymnosperms
30
The seed represents an important advance
1. Protects the embryo
2. Easily dispersed
3. Introduces a dormant phase in the life cycle
31
Seed plants produce 2 kinds of gametophytes
- Male gametophytes
- Pollen grains
- Dispersed by wind or a pollinator
- Female gametophytes
- Develop within an ovule
- Enclosed within diploid sporophyte tissue
32
Gymnosperms
Plants with naked seeds
33
Conifers (gymnosperm)
The largest gymnosperm phylum
34
Pines (gymnosperm)
- Leaves have:
1. Thick cuticle and recessed stomata
2. Canals into which cells secrete resin
35
Cycads (gymnosperm)
- Slow-growing gymnosperms of tropical and subtropical regions
- Sporophytes resemble palm trees
36
Gnetophytes (gymnosperm)
-Only gymnosperms with vessels in their xylem
37
Ginkgophytes (gymnosperm)
-Only one living species remains
38
Dioecious
-Male and female reproductive structures form on different trees
39
Angiosperm
The flowering plants
40
Archaefructus
The oldest known angiosperm in the fossil record
41
Amborella
The closest living relative to the original angiosperm
42
Flower morphology
- Primordium develops into a bud at the end of a stalk called the pedicel
- Pedicel expands at the tip to form a receptacle, to which other parts attach
- Flower parts are organized in circles called whorls
43
Flower morphology continued
- Outermost whorl = Sepals
- Second whorl = Petals
- Third whorl = Stamens (androecium)
- Each stamen has a pollen-bearing anther and a filament (stalk)
- Innermost whorl = Gynoecium
- Consists of one or more carpels that house the female gametophyte
44
Carpel structure
- Three major regions
- Ovary = Swollen base containing ovules
- Later develops into a fruit
- Stigma = Tip
- Style = Neck or stalk
45
Pollination
The mechanical transfer of pollen from anther to stigma
46
Angiosperms include:
Eudicots- Use flowers to attract insect pollinators
| Monocots- Some rely on wind for pollination
biology 102
flashcards
Decks in class (12)
# Cards
