Only the Critter Paper and Lab Paper may be ***REVISED*** for a better grade (the Plagiarism Paper and Bibliography are not revisable). Your paper revision will NOT be accepted without the graded original. If you want maximum credit on the revision, you must make all corrections! (whether points were taken off for them the first time or not!) It should be noted that **REVISE** means correct marked mistakes, NOT rewrite the paper! 1 Source: Basic Formatting!

Evolution of Angiosperms 2

“The rapid development as far as we can judge of all the higher plants within recent geological times is an abominable mystery.” -- letter from C. Darwin to J. Hooker “The rapid development as far as we can judge of all the higher plants within recent geological times is an abominable mystery.” -- letter from C. Darwin to J. Hooker 2 July

Putative Angiosperm Ancestors Bennettiales? Bennettiales? Flowerlike, bisexual strobili Flowerlike, bisexual strobili  Separate ovulate and pollen-bearing sporophylls 4

Putative Angiosperm Ancestors Conflicting hypotheses Conflicting hypotheses Remains an “abominable mystery” Remains an “abominable mystery” 5

Unique characteristics of Angiosperms Flowers Flowers Seeds enclosed in carpel Seeds enclosed in carpel Double fertilization  endosperm Double fertilization  endosperm Much reduced microgametophyte Much reduced microgametophyte Reduced megagametophyte (7 cells; 8 nuclei) Reduced megagametophyte (7 cells; 8 nuclei) Stamens with paired pollen sacs Stamens with paired pollen sacs Sieve-tube elements & companion cells Sieve-tube elements & companion cells 6

Earliest Angiosperm Fossils Pollen grains from 135 mya Pollen grains from 135 mya Whole plant – Archaefructus Whole plant – Archaefructus  ~ 125 mya  Semi-aquatic Middle Cretaceous – many lineages present Middle Cretaceous – many lineages present End Cretaceous – angiosperms dominant End Cretaceous – angiosperms dominant 7

Phylogenetic Relationships Monocots and Eudicots – 97% of angiosperms Monocots and Eudicots – 97% of angiosperms  Monocots -- monophyletic o Synapomorphy – single cotyledon  Eudicots – monophyletic o Synapomorphy – triaperturate pollen Remainder – multiple different evolutionary lines Remainder – multiple different evolutionary lines  Some arose before monocot/dicot split o Monoaperturate pollen  Magnoliids 8

Major Angiosperm Groups Basal Angiosperms Basal Angiosperms Mesangiosperms Mesangiosperms  Magnoliids  Monocots  Basal Eudicots  Eudicots o Rosids o Asterids 9

Groups of Angiosperms 10

Basal Angiosperms ANITA grade ANITA grade  Amborella (shrub from New Caledonia) Amborella  Nymphaeales (water lilies and some other aquatic plants) Nymphaeales  Austrobaileyales (woody aromatic plants including star anise). Austrobaileyales ANITA stands for the genera Amborella, Nymphaea, Illicium, Trimenia and Austrobaileya. ANITA stands for the genera Amborella, Nymphaea, Illicium, Trimenia and Austrobaileya. Sister to all other angiosperms Sister to all other angiosperms 11

Amborella trichopoda Dioecious Dioecious Undifferentiated stamens Undifferentiated stamens Drupes Drupes No vessels No vessels Embryo sac – 8 celled and 9 nucleate Embryo sac – 8 celled and 9 nucleate 12

The Rest of ANITA Nymphales – water lilies Nymphales – water lilies Austrobaileya scandens Austrobaileya scandens 13 Plantsystematics.org

Magnoliids Numerous, spirally arranged floral parts Numerous, spirally arranged floral parts Magnoliales (Magnolia), Laurales (Calycanthus), Piperales (Piper and Aristolochia), Canellales Magnoliales (Magnolia), Laurales (Calycanthus), Piperales (Piper and Aristolochia), Canellales Many Australasian Many Australasian Essential Oils – nutmeg, pepper & bay leaves Essential Oils – nutmeg, pepper & bay leaves 14

Monocots Monoaperturate pollen Monoaperturate pollen 3-merous floral parts 3-merous floral parts 15

Eudicots Tricolpate pollen Tricolpate pollen 4- and 5-merous floral parts 4- and 5-merous floral parts 16

Highly Simplified Angiosperm Phylogeny 17

Major Groups of Angiosperms Rosids Rosids  2 integuments  Nucellus with  2 layers of cells Asterids Asterids  Single ingegument  Nucellus with 1 layer of cells 18

Earliest Angiosperms Flowers lacking a perianth Flowers lacking a perianth 125 mya 125 mya Leefructus Leefructus Archarfructus Archarfructus Resemble Resemble Amborella not Magnolia 19

Evolution of the Flower Perianth – no distinct sepals and petals Perianth – no distinct sepals and petals  Some petals derived from sepals  Sepals derived from leaves Other petals apparently derives from stamens Other petals apparently derives from stamens Sepals – same number vascular strands as leaves Sepals – same number vascular strands as leaves Stamens – 1 vascular strand Stamens – 1 vascular strand Petals – 1 vascular strand Petals – 1 vascular strand 20

Evolution of the Flower Stamens – diverse structure and function Stamens – diverse structure and function  Woody magnoliids – broad, colored and scented  High degree of differentiation 21

Evolution of the Flower Unspecialized carpels Unspecialized carpels  Extinct angiosperms – leaflike carpels Most extant angiosperms – differentiated carpels Most extant angiosperms – differentiated carpels Variation in placentation Variation in placentation 22

Major Evolutionary Trends Different pollination vectors Different pollination vectors Bisexual/ unisexual flowers Bisexual/ unisexual flowers Differentiated perianth Differentiated perianth Specialized pollinators develop Specialized pollinators develop Fruit dispersal vectors Fruit dispersal vectors 23

Generalized Evolutionary Trends 1.Flowers with indefinite merosity  definite merosity 2.Floral axis shortened; floral parts often fused 3.Ovary inferior; differentiated perianth 4.Actinomorphic symmetry  zygomorphic 24

Floral Diversity 25

Specialized Families Asteraceae and Orchidaceae – 2 largest families Asteraceae and Orchidaceae – 2 largest families Among the most specialized Among the most specialized One monocot – one eudicot One monocot – one eudicot 26

Asteraceae Disk Flowers & Ray Flowers Disk Flowers & Ray Flowers Any combination thereof! Any combination thereof! 27

Orchidaceae Highly specialized flowers Highly specialized flowers Often intricate pollinator relationships Often intricate pollinator relationships 28

Pollinators Primative -- Wind Primative -- Wind  Indistinct & ineffective  Flowers much reduced  Copious amounts of pollen 29

Animals Agents of Floral Evolution Plants can’t move around (DuH!) – depend on “animals” Plants can’t move around (DuH!) – depend on “animals”  Co-evolution  Perfect flowers – each visit more efficient! 30

Beetle Pollinated Flowers open Flowers open Dull colored Dull colored Strong (usually) fruity odor Strong (usually) fruity odor Floral parts thick Floral parts thick 31

Fly pollinated Carrion (or fruity) smell Carrion (or fruity) smell Reddish to purple-brown Reddish to purple-brown No nectar guides No nectar guides 32

Bee pollinated Flowers open Flowers open Colored but not red Colored but not red Sweet odor Sweet odor Nectar guides Nectar guides 33

Bee Pollination: milkweed leg trap Pollen sacs [pollinium]

Butterfly Pollinated Flowers produce nectar Flowers produce nectar Various colors – reds Various colors – reds Sweet odor Sweet odor Nectar guides Nectar guides Often landing platforms Often landing platforms 35

Nocturnal Moth Pollination Open at night Open at night Usually white (or light) Usually white (or light) Strong/ sweet odor Strong/ sweet odor Lots of nectar Lots of nectar 37

Deception Pollination False food reward False food reward  Sweet smell  Nectar  Mimic food-rewarding flowers Sexual deception Sexual deception  Pseudo-copulation  Prominent in orchids 38

Bat pollinated Flowers open at night Flowers open at night White White Strongly scented Strongly scented Lots of pollen Lots of pollen 39

Bird Pollinated Copious, thin nectar Copious, thin nectar Little odor Little odor Colorful – often red Colorful – often red Tubular Tubular 40

Important Pigments Small number of pigments Small number of pigments  Caretonoids  Flavinoids -- Block UV o Anthocyanins o Water soluble o pH determines color o Colors can change post pollination o Flavonols o Colorless – white/ivory pigments  Betalains o Only in Caryophyllids 41

Marsh Marigold Outer yellow – UV absorbing carotenoids Outer yellow – UV absorbing carotenoids Inner yellow – UV reflective flavinoid calchone Inner yellow – UV reflective flavinoid calchone 42

Fruits Ripe ovary and associated structures Ripe ovary and associated structures Fruit dispersal fundamental aspect of radiation Fruit dispersal fundamental aspect of radiation Parthenocarpic -- without fertilization and seed development (e.g., banana, pineapple, citrus …) Parthenocarpic -- without fertilization and seed development (e.g., banana, pineapple, citrus …) 43

Fruit Types Simple Fruit Simple Fruit  One of more fused carpels from single flower Aggregate Fruit Aggregate Fruit  Individual carpels in a single flower Multiple Fruit Multiple Fruit  Derived from an inflorescence (e.g., many flowers) Accessory Fruit Accessory Fruit  Tissue not from ovary 44

Simple Fruits Fleshy or Dry at maturity Fleshy or Dry at maturity Fleshy Fleshy  Berries – 1 –many seeds; all parts fleshy  Drupes – 1 seeded; fleshy mesocarp; stony endocarp  Pomes – compound inferior ovary – accessory fruit Dry Dry  Dehiscent – multiple seeds o Legume, silique, follicle, capsule  Indehiscent – only one seed o Achene, samara, cypsels 45

Fruit Dispersal Wind Wind  Dandelions – cypselas  Maples – schizocarp Water Water  Coconut Animals Animals  Ingestion  Adhering Self-dispersal Self-dispersal 46

Biochemical Evolution Secondary Metabolites Secondary Metabolites  Alkaloids – morphine, cocaine, caffeine, nicotine  Terpenoids – taxol, rubber, cardiac glycosides, isoprene  Phenolics – flavonoids, tannins, lignins, catechols, salicylic acid  Quinones – coqnzyme Q  Raphids – Calcium oxalate 47

Secondary Metabolites Protect against herbivory Protect against herbivory  Reduce palatability  Total avoidance Mustards – cabbage, horseradish, mustard Mustards – cabbage, horseradish, mustard  Avoided by most herbivorous insects  Attractants for others (e.g., cabbage butterfly) Insects that do feed often brightly colored Insects that do feed often brightly colored  They are also protected from predation 48

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