Phylogeny of land plants Flashcards
1
Q
Describe seed dispersal mechanisms
A
- oceanic drift
- wind
- lizards
- birds (secondary dispersal)
- dung
2
Q
Describe the Embyrophytes
A
multicellular haplodiplontic zygotes
3
Q
Describe a haplontic life cycle
A
- zygote is diploid (2n)
- zygote undergoes meiosis
- forms uni- or multicellular haploid (n) organism
- produces haploid gametes
- haploid gametes undergo fertilisation
4
Q
Describe a haplodiplontic life cycle
A
- sporophyte is diploid (2n) and multicellular
- (mega and micro-)sporangia undergo meiosis to produce haploid (n) (mega and micro-)spores
- spores form haploid multicellular gametophytic organisms (of different sexes)
- produce haploid gametes for fertilisation
5
Q
Spores do not undergo
A
fertilisation
6
Q
Describe the Bryophytes morphologically and ecologically
A
- small plants (20cm max.)
- dominant haploid phase
- leptoids, no tracheids
- rhizoids, no roots
- phyllids, thalloid, no leaves
- sporophyte usually a stalk (seta) and sporangium
- water necessary for fertilisation
7
Q
Describe the Bryophytes taxonomical
A
- mosses (12,000 sp)
- hornworts (215 sp)
- liverworts (7271 sp)
8
Q
Describe moss morphology
A
- pseudoelater
- stoma
- capsule
- calyptra
- meristem
- foot
- seta
- leafy gametophyte
- thallus
- rhizoids
9
Q
protonema
A
- thread-like chain of cells
- forms the earliest stage of development of the gametophyte in the life cycle of mosses
10
Q
Describe a moss life cycle
A
- within the sporophyte, meiosis produces 1n spores
- each spore grows into a 1n gametophyte
- sperm swim into archegonium from other antheridium and fertilise egg
- produces 2n sporophyte embryo
11
Q
Give an example of a moss
A
Phaeomegacerossquamuliger
12
Q
Describe Sphagnum moss
A
hyaline cells take up 20 times weight in water
13
Q
hyaline cells
A
- dead, polysaccharides
- absorbative, antiseptic
14
Q
When were stomata innovated?
A
after liverworts before mosses
15
Q
What separates the Charophytes from the Bryophytes?
A
- cuticle
- sporopollenin spores
16
Q
Describe the Bryophyte Monophyly hypothesis
A
two lineages of land plants
17
Q
Describe the Bryophyte Paraphylyl hypothesis
A
- hornwort sister to all land plants
- mosses sister to liverworts
- both sister to tracheophytes, step-wise
OR - hornwort sister to tracheophytes
- mosses sister to liverworts
- both sister to all other land plants, step-wise
18
Q
Soft polytomy
A
simultaneous divergence
19
Q
What taxa do Embryophytes include?
A
LMHLMS
20
Q
Characteristics of the Bryophytes
A
- sporopollenin
- spores
- cuticle
- stomates
- haploid (1n) dominance
21
Q
Describe the LMH-LMS transition
A
- vascular tissue
- rise of the diploid (2n) phase
22
Q
What is phase dominance?
A
what does the most photosynthesis
23
Q
Monilophytes
A
- Ferns
- Calamites
- Water Ferns
24
Q
Tracheophytes
A
- vascular plants
- ## have tracheids
25
tracheids
- water conducting cell
- vessel member dead at maturity
- perforations or one large hole at each end
- generally elongate with a lignified secondary wall
- c. 1-7mm in vascular plants
- 1-2mm in angiosperms
26
vessel
several to many vessel members
27
Who are the Tracheophytes?
LMS
28
Describe the Monilophytes
- gametophyte (1n) prothallus
- fronds
- circinate vernation
- 30% epiphytic
29
Describe fern fronds
- simple
- deeply pinnatifid
- once pinnate
30
sporangium
enclosure in which spores are formed
31
sori
clusters of sporangia
32
indusium
a thin membranous covering shielding a sorus on a fern frond.
33
vernation
arrangement of leaves in a bud
34
circinate
rolled up with the tip in the centre
35
Give examples of circinate vernation
- Crozier
- Fiddleheads
36
Describe epiphytic ferns
rhizome & vegetative reproduction
37
Describe the Monilophyte life cycle
- sorus (containing indium and sporangia) releases spore
- spore germinates
- forms gametophytic prothallus
- prothallus produces egg (in archegonium) and sperm
- fertilisation
- sporophyte develops into fronds
38
Describe the water ferns
- heterosporous
- Salvinia’s and Marsilea’s
39
Anabaena azollae
- nitrogen fixing cyanobacterium
- lives in the cavities of Azolla
40
List some water ferns
- Salvinia
- Marsilea
- Azolla
41
Lycophytes contain
Clubmosses, Spikemosses and Quillworts
42
List some Lycophyte genera
- Lycopodium (genus of clubmosses)
- Selaginella (spike moss)
- Isoetes (quillworts)
43
Describe lycophytes
- microphyllous leaves
44
Who has megaphyllous leaves?
- Pteropsids
- Spermatophytes
- reduced in Sphenopsids
45
Pteropsids
true ferns
46
Describe Lepidodendron
- Carboniferous clubmoss
- found in fossil grove, Victoria park, Glasgow
- leaf scars with single trace
47
Describe the polyphyletic origin of heterospory
- Selaginella
- Isoetes
- - water ferns
- many extinct lineages
- evolved at least 10 times independently
48
Describe Carboniferous Coal Swamps
an age of free sporing plants
49
Calamites
horsetails
50
Where did megaphylls evolve?
after lycophytes and before monilophytes
51
Where did microphylls evolve?
on lycophyte branch
52
Describe seed production
- a particular version of heterospory
- two types of sporangia
- microsporangia produce microspores (pollen grains) which are dispersed by wind (anemophily) or insects (entomophily)
- megasporangia and megaspores
- reduced number of megaspores provides space for nourishing tissue
- does not rely on free water.
53
Describe the megasporangium
- integument
- funicle
- ovary wall
- chalaza
- micropyle
- functional megaspore
- nucellus (ovule)
- polar nuclei
- synergies
- antipodal cells
54
What is the megagametophyte?
embryo sac
55
Seeds
fertilised ovules
