Angiosperms

Introduction to Botany. Lecture 33

Alexey Shipunov

Minot State University

November 23th, 2010

Shipunov BIOL 154.33

Angiosperms

Outline

1 AngiospermsGeneral featuresClassification of angiosperms

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Angiosperms

Exam 4

Exams 1−4

Points

Fre

quen

cy

0 50 100 150

05

1015

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Angiosperms

Exam 4 statistics

E_1 E_2 E_3 E_4Min. : 3.00 Min. : 29.00 Min. : 29.00 Min. : 20.001st Qu.:38.00 1st Qu.: 55.50 1st Qu.: 57.00 1st Qu.: 35.00Median :53.00 Median : 74.00 Median : 76.00 Median : 54.00Mean :52.08 Mean : 70.74 Mean : 73.68 Mean : 55.683rd Qu.:65.00 3rd Qu.: 86.00 3rd Qu.: 87.75 3rd Qu.: 66.75Max. :90.00 Max. :100.00 Max. :139.00 Max. :124.00NA’s : 6.00 NA’s : 3.00 NA’s : 7.00 NA’s : 7.00

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AngiospermsGeneral featuresClassification of angiosperms

Angiosperms in general

Names: Angiospermae (“angion” is a “bottle”),Magnoliopsida, angiosperms, flowering plants250,000 species, more than 90% of all plants diversity, thediversity is comparable with mollusks (200,000) andarthropods (≈ 1,000,000) and much more than fungi(75,000) and vertebrates (30,000)≈ 300 families and ≈ 40 ordersGrow everywhere except open ocean and central Antarctic

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AngiospermsGeneral featuresClassification of angiosperms

Diagnostic characters of angiosperms

FlowerAngiospermyStigmaDouble fertilizationFruitParcellationIn all, any of these characters taken alone is not unique,but together they delimit the group

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AngiospermsGeneral featuresClassification of angiosperms

Origin of angiosperms

Morphologically, angiosperms are similar to Gnetopsidabut molecular data deny this similarity and placeangiosperms as outstanding branch of all seed plantsTransitional forms are still not discovered; candidates areeither too close to angiosperms or too far from themTrue angiosperm-like structures appear from late Jurassic,shortly (10–20 mya) after they become dominantSeveral theories are trying to explain the origin ofangiosperms and (separately) origin of flower andangiospermy:

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AngiospermsGeneral featuresClassification of angiosperms

Origin of angiosperms: hypotheses

Pseudanthial theories state that flowers are result ofintegration of unisexual structures similar to EphedraEuanthial theory insists on flower origin from morecomplicated bisexual generative shootsHerbaceous theory explains the rapid evolution ofangiosperms and main factors of their transition fromgymnospermsAngiospermisation theory states that many characters ofangiosperms appeared independently in multiple lineagesof gymnosperms, but only one group was successful

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AngiospermsGeneral featuresClassification of angiosperms

Geological time scale

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AngiospermsGeneral featuresClassification of angiosperms

Milestones of angiosperm classification

Carolus Linnaeus (XVIII century) gathered all availableinformation, established species and generaMichel Adanson and Antoine Jussieau (end of XVIII)established plant familiesJohn Lindley (middle of XIX) invented plant ordersAlfred Engler and Charles Bessey (XIX-XX) startedevolutionary classificationsArthur Cronquist, Rolf Dahlgren, Armen Takhtajan andRobert Thorne (XX-XXI) developed different well-arguedcontemporary classifications based on morphologyFrom 1993, Angiosperm Phylogeny Group (APG) as wellas several individuals started to employ molecularcharacters. Luckily, one of the most accessible chloroplastDNA genes, rbcL, appeared to be extremely useful fortracing changes on family and order levels

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AngiospermsGeneral featuresClassification of angiosperms

Taxonomic map of angiosperms: subclasses

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AngiospermsGeneral featuresClassification of angiosperms

Taxonomic map: orders

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AngiospermsGeneral featuresClassification of angiosperms

Dendrogram of subclasses

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AngiospermsGeneral featuresClassification of angiosperms

Cladogram of subclasses

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AngiospermsGeneral featuresClassification of angiosperms

Paraphyly

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AngiospermsGeneral featuresClassification of angiosperms

Magnoliidae portrait

Nymphaea sp. (water-lily)

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AngiospermsGeneral featuresClassification of angiosperms

Liliidae portrait

Acorus calamus (calamus, or sweet flag)

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AngiospermsGeneral featuresClassification of angiosperms

Rosidae portrait

Geranium sp. (wild geranium)

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AngiospermsGeneral featuresClassification of angiosperms

Asteridae portrait

Penstemon sp. (beard-tongue)

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AngiospermsGeneral featuresClassification of angiosperms

Evolutionary history of subclasses

Magnoliidae are historically most ancient, first fossilsappear in Late Jurassic. They dominate fresh waters andmaybe, filled lower floors of forests in CretaceousLiliidae appeared in Lower Cretaceous, they started todominate grasslands in NeogeneRosidae appeared in Lower Cretaceous, they madebroad-leaf forests in Late Cretaceous and onwardsAsteridae originated in Middle Cretaceous, they started arapid divergence in Paleogene

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AngiospermsGeneral featuresClassification of angiosperms

Summary

Angiosperm characters are not unique but taken togetherthey able to distinguish the groupFrom four subclasses of angiosperms, two (Magnoliidaeand Rosidae) are paraphyletic

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Appendix For Further Reading

For Further Reading

Th. L. Rost, M. G. Barbour, C. R. Stocking, T. M. Murphy.Plant Biology. 2nd edition.Thomson Brooks/Cole, 2006.Chapter 25.

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