Why are there so many angiosperms? Flashcards
Describe angiosperm description rate
2000 species per year being described for about the last 40-50 years
Angiosperm species estimate
231,413 - 369,4334
What percentage of Embryophytes are the angiosperms?
89.4%
Describe Eucalyptus regnans
- swamp gum / Mountain Ash
- tallest flowering plant
- > 100m
- 17m girth
- Tasmania and S Australia
Cymbalaria muralis
Ivy leaved toadflax
Wolffia
Duckweed
List the three angiosperm habits
trees, shrubs and herbs (herbaceous)
Describe trees and shrubs
- woody
- secondary thickening (herbs do not)
Eucalyptus regnans
100m
Describe the diversity of angiosperm fruits
- dry: poppy
- fleshy: tomato
- dehiscent: Indian balsam
- indehiscent: sycamore
- apocarpy: beans & buttercups
- syncarpy: oranges, apples, tomatoes
false fruits: strawberry
Describe the habit and life history diversity of angiosperms
Epiphytes
Climbers/Lianas
Switch plants
Succulents
Terrestrial
Aquatic
Ephemerals
Annuals
Biennials
Perennials
Bulbs
Corms
Rhizomes
Describe plant construction
roots, leaves, stems and flowers
The world is dependent on angiosperms for
food, clothing, medicine and energy
Angiosperms co-exist in
high-diversity assemblages relative to other plant groups
Describe biotic pollination
- entomophily
- ornithophily
- chiropterophily
List three co-inciding biological phenomena
- floral innovation
- insect diversification
- angiosperm diversification
Describe wind-pollination
- anemophily
- evolved repeatedly from insect pollinated ancestors
- Graminioid monocots (grasses, sedges & rushes) & Fagaceae
- conifers (gymnosperms)
Entomophily has been argued to decrease extinction rates by
maintaining gene flow in small, sparse populations and so ensuring their survival.
Entomophily can act as a driver of speciation based on
- selection for pollinator specialisation
- e.g. orchids
Describe Gymnosperms
- Conifers, Gnetales, Cycads, Ginkgo
- exclusively woody, no herbs or annuals
Describe cycads
- gymnosperms
- obligate entomophiles
- not especially species-rich group
Describe Gnetales
- gymnosperms
- degree of adaptation to entomophily
Describe Bennettitales
- fossil gymnosperms
- evidence of beetle pollination
Describe Hymenoptera
- most important group of insect pollinators
- first appear in the early Triassic
Angiosperms arose after
the origin of entomophily in one or more Gymnosperms
Early entomophilous plants generalists and specialized plant pollinator relationships appeared
relatively late within the angiosperms.
Describe the carpel
synapomorphy
Carpel evolution prompted
- pollen tube competition
- incompatibility systems
- many fruit types
Paedomorphosis
precocious reproductive maturation
Is lignification a synapomorphy
- no
- many basal angiosperms are woody
Describe angiosperms relative to Gymnosperms
- paedomorphic trends
- faster life cycles (Arabidopsis)
- increased rate of speciation and/or reduced extinction
Diversification relies up
- unique key character innovations
- ecological opportunity (extrinsic environmental factors)
Two sister lineages differences may be
stochastic
Describe SR
- species My-1
= [ln n1 – ln n0] / t
SR
speciation rate
Describe TFS
My species-1 = t / ln n1
TFS
time for speciation
n1 =
number of species in a monophyletic clade
Describe time calibrated phylogeny
- uses known fossil records
- background rate of diversification used to calculate expected number of species in each clade over the time since the clade’s origin
High diversification rates in various independent clades
- Cyperales
- Poales
- Fabales
- Rosaceae
- Apiales
- Asterales
- Boraginales
- Solanales
- Gentianales
- Lamiales
Describe the Succulent Karoo
- arid region of the Cape
- onset of recent aridity: c. 5Mya
- adjacent areas experiencing aridity on and off since Cretaceous
- 5000 species, 40% endemism
Describe the Aizoaceae
– South African desert ice plants
- monophyletic Core Ruschioideae with 1,563 species
- Age of clade = 3.8-8.7Myr
- SR = 0.84-1.93 species Myr-1
Describe the putative innovations of the Aizoaceae
- wide band tracheids
- cylindrical or trigonous shaped leaves
- hygrochastic capsules
Describe wide band tracheids
- prevent collapse of primary wall and associated with adaptions to prevent water stress
- adaptations to withstand water stress
Describe cylindrical or trigonous shaped leaves
- reduced leaf surface area
- reducing water loss under dry conditions
Describe hygrochastic capsules
fruits open only when moistened to release a portion of their seeds in rain
Describe Andean Páramo
- High elevation grasslands: 3200-5000m
- 3,400 species
- 60% endemism
- most species-rich flora of any tropical mountain massif
Describe Andean Lupinus
- clade of 81 species
- age = 1.47 +/- 0.29 Myr
- coincides with first appearance of cold upland habitats in last 2-4 Myr following final uplift of the Andes 3-5 Mya
- SR = 2.49 – 3.72 species Myr-1
synnovation
synergistic interactions among traits
confluence
multiple interacting causal agents assembled step-wise through a tree.
