Plant Evolution 1 Flashcards
(98 cards)
1
Q
Green algae are called
A
Charophytes
2
Q
Plants evolved from
A
Green algae
3
Q
What do plants supply for other organisms?
A
- Oxygen in the atmosphere
- Food
- Shelter
4
Q
Characteristics of green algae
A
- Closest relatives to plants
- Primarily aquatic
5
Q
What type of organism are green algae
A
Photosynthetic Eukaryotes
6
Q
Why did plants move to land?
A
- Less competition and more niches than aquatic environments
- Fewer herbivores
7
Q
What adaptations do green algae and land plants share?
A
- Can photosynthesise
- Have chlorophyll a and b (photosynthetic pigments)
- Can store starch
8
Q
What is the function of Sporopollenin?
A
Prevents zygotes from drying out (desiccating)
– i.e. ensures reproduction!
9
Q
What were the challenges plants faced when moving to land?
A
Desiccation (Removal of water)
10
Q
What traits do land plants have that charophytes do not?
A
- Alternation of generations and multicellular, dependent embryos
- Walled spores produced in multicellular organs
- Multicellular gametangia produce gametes
- Apical meristems
11
Q
Describe the steps in the alternation of generations in plants
A
- Gametophyte produces haploid gametes by mitosis
- Gametes fuse
- Zygote develops into diploid sporophyte
- Sporophyte produces haploid spores by meiosis
- Spores germinate and divide to form haploid gametophyte
12
Q
What accomodation do plants have for multicellular, dependent embryos?
A
Parental tissue provides protection and nutrients for the developing embryo
13
Q
What are Sporangia?
A
Walled spores produced in multicellular organs
14
Q
What do spore walls contain?
A
Sporopollenin
15
Q
What does sporopollenin do?
A
Makes them resistant to harsh environments
16
Q
What is a sporophyte?
A
The diploid, asexual phase in the life cycle of plants
17
Q
What is a gametophyte?
A
The gamete-producing, haploid phase in the life cycle of plants
18
Q
Where are gametes produced in plants
A
Organs called gametangia
19
Q
What are female gametangia called in plants?
A
Archegonia
20
Q
What are male gametangia called in plants?
A
Antheridia
21
Q
Archegonia
A
- Female gametangia
- Produce eggs and are the site of fertilisation
22
Q
Antheridia
A
- Male gametangia
- Produce and release sperm
23
Q
What do gametangia produce?
A
Gametes
24
Q
Apical meristems
A
Area of rapidly dividing cells
25
What do plants use apical meristems for?
To sustain continual growth
26
Cuticle
Waxy covering of the epidermis
27
Stomata
Tiny pores typically found on the surface of leaves and stems that facilitate gas exchange between a plant and its environment
28
Mycorrhizae
A symbiotic association between fungi and land plants that may have helped plants without true roots to obtain nutrients
29
What is the role of secondary compounds in some plants?
To deter herbivores and parasites
30
When did land plants evolve from green algae?
450 – 500 million years ago
31
What are charophytes?
A group of green algae and closest living relatives to plants
32
What are gametangia?
Multicellular reproductive structures
33
What is the dominant life cycle stage of non-vascular plants (Bryophytes)?
Gametophyte, the haploid (n) generation is the larger, longer-lived and primary photosynthetic phase
34
What is the reduced life cycle stage of byrophytes?
Sporophyte, the diploid (2n) generation is smaller, shorter-lived and nutritionally dependent on the gametophyte
35
What are Bryophytes?
The first land plants that LACK vascular tissue
36
Non vascular
Plants without vascular tissues xylem and phloem
37
What are the three phyla of byrophytes?
1. Liverworts
2. Mosses
3. Hornworts
38
Herbaceous
Non woody
39
What constrains the height of bryophyte gametophytes?
Lack of vascular tissues
40
What is the appearance of byrophyte gametophytes?
Ground-hugging carpets that are at most only a few cells thick
41
What are byrophyte gametophytes anchored by?
Delicate rhizoids which are tubular cells or filaments of cells
42
What do byrophyte sporophytes grow out of?
Archegonia
43
What do byrophyte sporophytes consist of?
A foot, a seta, and a sporangia
44
How many spores can a single moss capsule produce?
Up to 50 million
45
Which structure regulates spore dispersal in byrophytes?
The peristome (resembles teeth)
46
Which byrophyte sporophytes have stomata?
Hornwort and moss sporophytes
47
What is important for the reproduction of byrophytes?
Water
48
Why is water important for the reproduction of byrophytes?
Sperm must *swim* to reach the egg
49
How did hornworts get their name?
Sporophyte growths resemble small “horns”
50
Characteristics of hornworts
- Have stomata
- Cells with single large chloroplast
- Often form symbiotic relationships with cyanobacteria for nitrogen fixation
51
Characteristics of liverworts
- Grow flat along the ground
- Only some have stomata
- Gametes swim in a film of water along the surface of the cells for fertilisation to occur.
- Microscopic sporophytes
52
How do liverworts that do not have stomata exchange gas?
Through a thin cuticle
53
Characteristics of mosses
- Most diverse group
- Have stomata and some have cuticle
- Some have a vascular system for water transport similar to vascular plants that is one cell thick
- Can survive in harsh environments by being able to dry out and then revive
54
Why are mosses are ecologically important?
- 10,000 species of mosses
- Play an important role in carbon and nutrient cycling
55
What are peat mosses important for?
They play a critical role in the carbon cycle
56
What is the evolutionary significance of byrophytes? (3)
- They represent an intermediate stage between aquatic algae and vascular land plants
- Demonstrate successful early adaptations to terrestrial life
- Exemplify the early evolution of specialised reproductive structure
57
Which were the first plants to grow tall?
Ferns and other seedless vascular plants
58
Traceophytes are a broad group known as the ___ plants
VASCULAR
59
Vascular plants have true….
roots and leaves
60
What are the roles of roots in vascular plants? (2)
1. To anchor plants
2. Enable absorption of water and nutrients from soil
61
What may the roots of vascular plants have evolved from?
Subterranean stems
62
What are the roles of leaves in vascular plants? (2)
1. Increase surface area – allowing
increased light capture
2. Provide protection for developing
fruits or shoots
63
What are the 4 main groups of VASCULAR plants? (traceophytes)(LAGF)
1. Lycophytes
2. Ferns
3. Gymnosperms
4. Angiosperms
64
What is the dominant life cycle stage of vascular plants?
Sporophytes
65
Compare sporophytes and gametophytes in seedless vascular plants
Sporophytes are the larger generation
66
What is the role of the xylem?
Movement of water UPWARDS from the soil to the atmosphere
67
What is the role of the phloem?
Photosynthetically produced sugars and molecules are distributed through the phloem
68
What are Sporophylls?
Modified **leaf** structures that house collections of sporangia, which produce spores
69
Most seedless vascular plants
(e.g., ferns) are ___sporous
Homosporous
70
What does it mean for a plant to be **homosporous?**
It produces only one type of spore that develops into a *bisexual gametophyte*
71
All seed plants and some
seedless vascular plants are ___sporous
Heterosporous
72
What does it mean for a plant to be **heterosporous?**
It produces two types of spores
that give rise to *male and female* gametophytes
73
Which *vascular* plants produce "sori?"
Ferns
74
What are sori?
Clusters of sporangia produced by sporophylls of ferns
75
What is the name for the group of seedless vascular plants?
Lycophytes
76
What is the distinguishing characteristic of Lycophytes?
Each leaf is usually narrow and has an unbranched mid-vein
i.e. a singular vascular bundle
77
What are the 3 main groups of lycophytes?
1. Club mosses
2. Spike mosses
3. Quillworts
78
From which plant group are club mosses?
The Lycophytes; seedless vascular plants
79
From which plant group are spike mosses?
The Lycophytes; seedless vascular plants
80
From which plant group are quillworts?
The Lycophytes; seedless vascular plants
81
From which plant group are ferns?
Monilophytes; Seedless vascular plants
82
From which plant group are liverworts?
83
From which plant group are hornworts?
84
From which plant group are mosses?
85
What are the 2 groups of SEEDLESS VASCULAR plants?
1. Lycophytes
2. Monilophytes
86
What do monilophytes and lycophytes have in common?
They are both seedless vascular plants
87
What are strobilus?
Clusters of sporophylls
88
What is the distinguishing characteristic of Monilophytes?
Leaves (fronds) usually have a branched venation
89
Which plants are monilophytes?
Ferns, horsetails, tree ferns, whisk ferns and relatives
90
What is the veterinary significance of monilophytes?
- Contain two types of toxins that poison livestock
- Young fronds can cause cancer
in humans of digestive tract –
may be caused by drinking
untreated milk from cows that
have grazed on bracken
91
How does poisoning by monilophytes present?
- May cause internal bleeding, bladder cancer, loss of coordination, appetite, horses hold head low
92
During which evolutionary period were monilophytes diverse and dominant?
The Carboniferous period
93
What are the life cycle characteristics of seedless vascular plants?
- Dominant sporophyte (2n)
- Reduced gametophyte (n)
- Water requirement present
- Spore variations
94
What are the spore variations of seedless vascular plants?
- Most ferns are homosporous (one type of spore)
- Some seedless vascular plants are heterosporous (separate male and female spores)
95
What are the Ecological impacts of seedless vascular plants? (4)
- First plants to form forests
- Reduced atmospheric CO2 and increased O2, significantly alter Earth’s atmosphere and climate
- Created new habitats for animal diversification
- Contributed to coal formation (fossilised remains from Carboniferous period)
96
What is the Evolutionary significance of seedless vascular plants?
- Represents a key transition from small ground-hugging plants to tall vertical growth
- Demonstrate the evolutionary advantage of vascular tissue
- Illustrate the trend toward sporophyte dominance in land plant evolution
- Precursor to evolution of seed plants
97
Which were the first plants to form forests?
Ferns and other seedless vascular plants
98
Which plants contributed to coal formation?
Ferns and other seedless vascular plants
