Some Highlights • First Life on Land Probably Ordovician (Or Maybe Even Earlier), but Not Abundant Until Silurian • History of Land (I

Life on land in the Paleozoic

Paleozoic Terrestrial Life: Some highlights • First life on land probably Ordovician (or maybe even earlier), but not abundant until Silurian • History of land (i. e., vascular) plants. • Plants, coal, glaciation, and atmosphere • History of insects • History of terrestrial vertebrates (tetrapods)

1 Challenges of living on land (for both plants and animals) • Dessication • Feeding • Locomotion • Respiration • Reproduction

2 Highlights of vascular plant evolution • Oldest definite vascular plant: Late Silurian • Oldest seed: Middle Devonian • Changing dominance of different groups • Coal swamps dominated by lycopods, ferns, and sphenopsids: Carboniferous • Dominance of conifers and cycads: Triassic-Jurassic • First flowers: Early Cretaceous

3 The Rhynie Chert (Scotland)

Rhynia

4 Cooksonia fossil specimen (L) and Specimen of Cooksonia pertoni with sporangia, from the Silurian of Shrewsbury, England. Image reconstruction (R). from http://www.xs4all.org/~steurh/eng/cook.html. Both Images from

http://www.ucmp.berkeley.edu.

Early Devonian landscape, painting by Zdenek Burian

5 www.copyrightexpired.com/earlyimage/prehistoriclifebeforekt/n2m_devonianscene.jpg

The Gilboa Forest, Gilboa, Schoharie Co., NY -- Eospermatopteris, a seedfern and one of the earliest trees

6 The origin of seeds

7 Archeopteris, an early seed fern (progymnosperm)

8 -- LYCOPOD SPHENOPSID --

TREE FERNS ------

Lycopods

Lepidodendron Stigmaria

Living lycopods

9 Sphenopsids

Calamites

Modern horsetails

10 11 12 13 Carboniferous coals in cyclothems

14 15 16 Paleozoic Terrestrial Life: Some highlights • First life on land probably Ordovician (or maybe even earlier), but not abundant until Silurian • History of land (i. e., vascular) plants. • Plants, coal, glaciation, and atmosphere • History of insects • History of terrestrial vertebrates (tetrapods)

17 The oldest known insect

Rhyniognatha hirsti Rhynie Chert Early Devonian, Scotland Engel & Grimaldi, Nature, 427, Feb. 2004

Carboniferous Insects

Meganeura

Cockroach

18 19 Paleozoic Terrestrial Life: Some highlights • First life on land probably Ordovician (or maybe even earlier), but not abundant until Silurian • History of land (i. e., vascular) plants. • Plants, coal, glaciation, and atmosphere • History of insects • History of terrestrial vertebrates (tetrapods)

20 A, Acanthostega; - Late Devonian B, Ichthyostega; - Late Devonian C, Tulerpeton; - Late Devonian D, Loxommatidae; - Carboniferous E. Crassigyrinus; - Carboniferous F, Anthracosauroidea; - Carbaniferous to Triassic G. Amniota (including Seymouriamorpha); - Carb-Recent H, Aistopoda; - Carboniferous I, Nectridea; - Carboniferous to Permian J, Colosteidae; - Carboniferous K, Capitosauroidea; - Carboniferous to ?Cretaceous L, Lissamphibia. - Triassic to Recent

Nested taxa and selected synapomorphies (unique characteristics):

1, Tetrapoda (limbs with digits, sacrum, fenestra ovalis, hyomandibula modified

into a stapes); 2, reduced gill apparatus; 3, cleithrum free from scapulocoraroid, five digits in hind limb; 4, Neotetrapoda (five digits or less in both fore and hind limbs);

5, Reptiliomorpha (retractor pit for eye muscles); 6, loss of post-temporal fosas; 7, incipient pterygoid flange, phalangeal (finger/toe) formala of pes is 2, 3, 4, 5, 5, diplospondylous vertebrae, stapes sound-conducting; 8, Amphibia (four-digit manus); 9,

large interpterygoidian vacuities; 10. Temnospondyli

('waisted' humerus, strap-like occipital condyle

21 22 Two reconstructions of Acanthostega

23 Primitive Amniotes (Reptiles)

Seymouria, Late Permian Hylonomus, Early Pennsylvanian (the earliest known reptile)

The amniotic egg

24 Terrestrial Tetrapod Diversity (after Benton, 1985)