

leftover words from Chapter 12
nektonic
plankton
benthonic (benthic)
herbivore
carnivore
omnivore
Introduction
first tetrapods 365 mya
Permian extinction knocked off 90% of all invertebrates & 65% of vertebrates
Vertebrate Evolution
CHORDATE has a NOTOCHORD
VETEBRATES have backbones
Fig.13.1-lancelet (a model for vertebrate ancestors?)
Fish
oldest evidence of fish-scales from Upper Cambrian
OSTRACODERMS (bony skin) jawless fish
PLACODERMS had front end of fish armor-plated (had jaws)
Important evolutionary step was hinged gill arches-evolved into jaws (Fig.13.7)
DUNKLEOSTEUS-huge, armor-plated fish (see my photo) Late Devonian (37 ft. long)
CARTILAGINOUS FISH (sharks and rays) = CHRONDRICHTYANS (Early Devonian)
BONY FISH (OSTEICHTHYANS) -most fish today are this type
two groups: RAY-FINNED (ACTINOPTERYGIAN) modern fish
LOBE-FINNED (SARCOPTERYGIAN) ancestor to amphibians
a. COELACANTHS (Middle Devonian)
b. LUNGFISH (modified swim bladder for a lung)
c. CROSSOPTERYGIANS (2 pairs of muscular limbs)
ancestor to amphibians- Fig.13.10 & 13.11
TRILOBITES hit by end of Cambrian extinction and gone by end of Permian
Amphibians
first land-dwellers: insects and snails
oldest amphibians: Upper Devonian-long tails, fins along back, strong backbone,
pectoral and pelvic girdles
2006 discovery-"fishapod" from Northern Canada (broad skull and flexible neck)
large amphibians up to 2 meters- ERYOPS (Fig.13.14)
(Mississippian/Pennsylvanian)
Reptiles
AMNIOTIC EGG (could be laid out of water..protective shell) separates reptiles
from amphibians
Reptiles evolved from labyrinthodonts by Late Mississippian
PELYCOSAURS (finback reptiles) FIg.13.18, died out by Permian
THERAPSIDS (mammal-like reptiles) Permian- ENDOTHERMIC (warm-blooded)
THECODONTS-ancestors to dinosaurs Fig.13.17
Plants
Table 13.2 evolution of land plants
Most land plants are now VASCULAR (tissues can transmit water),
evolved by Middle Silurian
Late Devonian, trees up to 33 ft. tall
GYMNOSPERMS-seeds but no flowers
ANGIOSPERMS-seeds and flowers
famous plants: SIGILLARIA and LEPIDODENDRON-scars on trunk
CALAMITES (horsetail rush)
GLOSSOPTERIS (famous fossil)
Very good summary of the Paleozoic Table 13.3. p.269