Plant Reproduction Flashcards
1
Q
Adaptations of seed plants to life on land
A
- reduced gametophytes
- heterospory
- ovules & production of eggs
- pollen & production of sperm
- seeds
2
Q
Reduced gametophyte
A
- microscopic
- develops from spores within sporangia of parental sporophyte
- totally dependent on sporophyte–>2n generation
- gametophytes are protected
3
Q
Heterospory
A
2 types of spores are produced:
1. megaspore
- -> female gametophyte
2. microspore
- -> male gametophyte
4
Q
ovule
A
megasporangium + megaspore+ integuments
5
Q
integument
A
- a layer of sporophyte tissue
- surrounds, envelops, & protects megasporangium
6
Q
female gametophyte
A
- develops from megaspore
- produces 1 or more eggs
7
Q
gymnosperms
A
megasporangium surrounded by 1 integuments
8
Q
angiosperms
A
2 integuments
9
Q
pollen grain
A
- develops from the microspore
- consists of male gametophyte enclosed within a pollen wall
10
Q
male gametophyte
A
-consists of 2 cells:
1. tube cell
produces–> pollen tube
2. generative cell
produces–> sperm
11
Q
sporopollenin
A
- in pollen grain wall
- protects the grain from environmental conditions
12
Q
pollination
A
- ->the transfer of pollen to the part of the plant that contains ovules
e. g. via air, animals etc. - NOT the same as FERTILIZATION
13
Q
Significance of pollen grain
A
- sperm is not dependent on water for dispersal
- In most gymnosperms and all angiosperms
- ->their sperm do not have flagella
- because they are being transferred by air, animals, etc
- ->therefore, these plants can now pollinize dry habitats
- they are not restricted to moist environment
- ->their sperm do not have flagella
14
Q
seeds (2 kinds)
A
- seedless plants
- seed plants
15
Q
Seedless plants
A
- Spore = only protective stage (from environmental conditions)
16
Q
Seed versus Spore
A
- Seed
- multicellular embryo
- more developed, more robust, protected by seed coat - Spore
- single-celled - Seed
- dormant for long periods - Spore
- shorter life span - Seed
- supply of food - Spore
- no stored food
17
Q
Gymnosperms
A
- 1 clade of seed plants
- “naked seeds”
- seeds are exposed on sporophylls
- -> form cones (strobili)
- most–> conifers
- ex: PINES, firs, redwoods
18
Q
Gymnosperm Diversity
A
~350 million years old
-earliest fossils of extant species
19
Q
4 Phyla (Gymnosperms)
A
- Cycadophyte
- Ginkgophyta
- Gnetophyta
- Coniferophyta
20
Q
Cycadophyta
A
- large cones
- palm-like leaves
- flagellated sperm
- endangered **
21
Q
Ginkgophyta
A
Ginko biloba
- flagellated sperm
- deciduous leaves
- fan-like
- popular ornamental trees
- cities–> tolerate air pollution very well
22
Q
Gnetophyta
A
a. Welwitschia
- W. mirabilis
- SW africa
- strap-like leaves
- large
b.Ephedra
~40 species
- arid regions
- ephedrine
-decongestant
c. Gnetum
- ~35 species
- tropical trees, shrubs, vines
- Africa & Asia
23
Q
Coniferophyta
A
- LARGEST gymnosperm phyla
- woody cones
- evergreens
- retain their leaves year round
24
Q
Angiosperms
A
-Phylum Anthophyta
-seed plants with FLOWERS & FRUITS
~250,000 species
- most DIVERSE
25
Flowers
- structures specialized for sexual reproduction
- specialized shoots
- have up to 4 types of sporophylls (modified leaves)
26
Floral organs
1. sepals
2. petals
3. stamen
4. carpel
27
Sepals
- found at base of flower
- usually GREEN
- enclose the flower before it opens up
- STERILE flower organ
- does not participate directly in reproduction
- do not produce egg or sperm
28
Petals
-BRIGHTLY colored (in most)
-function --> aid in attracting pollinators
(ex: insect, animal --> bee lol)
-wind pollinated flowers
-flowers lack color
STERILE flower organs
29
Stamen
- produces MICROSPORES
- -> pollen grain
- --> male gametophyte
30
Carpel
```
produces --> MEGASPORE
--> female gametophyte
"container"
-seeds are going to be enclosed
-key structure that differentiates gymnosperms and angiosperms
-amongst angiosperms,
-some have a single carpel
-others have multiple carpels
```
31
Carpel consists of 3 parts
1. stigma
2. style
3. ovary
32
Stigma
- sticky tip of carpel
| - receives pollen
33
Style
leads from stigma to ovary
34
Ovary
contains 1 or more ovules
| if ovule is fertilized --> seed
35
Complete flower
All 4 floral organs
| : sepals, petals, carpel, stamen
36
Incomplete flower
lacks 1 or more of organs
37
Diversity in flower
- structure, color, odor
- adaptations to specific pollinators
- in many angiosperm species,
- insects or other animals are responsible for transporting pollen from one flower to another
- -> pollination
- wind pollinated plants
- --> dense populations
- ex: grasses
- most GYMNOSPERMS = wind pollinated
38
FRUITS
1. as seeds develop from ovules
- -> ovary wall thickens
- when it becomes mature --> FRUIT
2. Fleshy & dry
a. Fleshy
i. ovary wall (pericarp)
- -> softens during ripening
ex: grapes, tomatoes
b. Dry
i. softening of ovary wall DOES NOT happen
- -> ex: beans, nuts, grains
3. PROTECTS SEEDS
4. Various Adaptations
- -> aid in dispersal
1. WIND DISPERSAL
ex: maple seds
- have fruits that are --> propellers
- when wind blows, propellers help seeds disperse away
2. WATER DISPERSAL
ex: coconuts
3. ANIMAL DISPERSAL
examples:
a. burr
- -> modified to cling to fur
b. edible fruits
- -> fleshy part = gets digested
- -> seeds = tough; pass through gut (digestive tract) of animal & are defecated (pooped)
39
Angiosperm Diversity (3 divisions)
~140 million years ago
1. Basal angiosperms
2. Magnoliids
3. Monocots & Eudiocots
40
Basal angiosperms
~100 species
1. Amborella trichopoda
- at base of angiosperm tree
- small shrub--> island on south pacific
2. Water lilies
- aquatic habitats worldwide
3. Star anise
41
Magnoliids
~8000 species
1. ex: magnolia, black pepper plants
2. wood & herbaceous
42
Monocots & Eudicots
- FIGURE 30.16
- various characteristics differentiate these 2 groups
ex: 1. cotyledous
2. flower & leaf structures
3. DNA
