de6502fd0716cfb47b896a66b212c2e6.ppt
- Количество слайдов: 65
Origin & Evolution Orders of the day Rheiformes Struthioniformes Casuariiformes Velociraptor mongolensis
RATITES (from Latin Ratitus = flat) • • Primative (paleognathus palate) Flightless birds lacking a keel on the sternum Keel
RATITES Rheas, ostriches, cassowaries, kiwis and the recently extinct Moas of New Zealand Elephant Birds of Madagascar
Large Flightless Birds • Elephant Bird • New Zealand Moas • Ostrich, Emu, etc.
Rheiformes Two species Greater Rhea Darwin’s (or Lesser) Rhea Greater Rhea Head height 1. 7 m, mass 25 kg 3 toes Grass & leaf eaters South American steppes to high Andes
Struthioniformes Max of 2. 15 m (7’) tall and 150 kg (330 lbs) Only bird species with two toes
Casuariiformes Family Casuariidae Australia & New Guinea 3 species Back height 1 m, mass 85 kg Dangerous! 10 -cm nail on inner toe Solitary except when breeding Papuans are said to buy 8 large pigs or 1 wife with a cassowary
Casuariiformes Family Dromiceidae Emu 1 species Australian Back height 1 m, mass 55 kg 1964 W. Australia paid bounties on 14, 000 Emu. Hardy & easy to breed in captivity
Are birds living dinosaurs? Thomas Huxley thought so in 1867 Sauropsida (birds + reptiles) Velociraptor mongolensis
Shared skeletal traits – birds & modern reptiles • Single occipital condyle • Lower mandible composed of several elements • Single inner ear bone • Uncinate processes on the ribs
Shared traits – birds & modern reptiles • Single occipital condyle (mammals have two). • Lower mandible composed of several elements (mammals have only one, the dentary). • Single, inner ear bone (the columella); mammals have three. • Uncinate processes on the ribs (lacking in mammals).
Single occipital condyle
Shared traits – birds & modern reptiles • Single occipital condyle (mammals have two). • Lower mandible composed of several elements (mammals have only one, the dentary). • Single, inner ear bone (the columella); mammals have three. • Uncinate processes on the ribs (lacking in mammals).
(a) Barn Owl (b) Alligator
Shared traits – birds & modern reptiles • Single occipital condyle (mammals have two). • Lower mandible composed of several elements (mammals have only one, the dentary). • Single inner ear bone (the columella); mammals have three. • Uncinate processes on the ribs (lacking in mammals).
Shared traits – birds & modern reptiles • Single occipital condyle (mammals have two). • Lower mandible composed of several elements (mammals have only one, the dentary). • Single, inner ear bone (the columella); mammals have three. • Uncinate processes on the ribs (lacking in mammals).
Nonskeletal similarities • nucleated RBCs • similar eggs and reproductive pattern • egg tooth • female birds and some female reptiles are the heterogametic sex–with the ZW combination of sex chromosomes
Birds & mammals had different reptilian ancestors
Origin of birds Mesozoic – The age of reptiles
Archaeopteryx lithographica Oldest fossil bird, 150 million years old Feather found in 1860 Total of 7 fossils Berlin Fossil found in 1876
Archaeopteryx & reptiles • • SMALL BRAIN CASE TEETH HAND WITH 3 FINGERS SMALL FLAT STERNUM SOLID BONES MANY TAIL BONES ABDOMINAL RIBS Modern birds • • LARGE BRAIN CASE NO TEETH NO HAND LARGE KEELED STERNUM HOLLOW BONES FUSED INTO PYGOSTYLE NONE
furcula
Was Archaeopteryx a bird or a feathered dinosaur?
Fossil feathers found on >12 theropod dinosaurs and dromaeosaurs not closely related to Archaeopteryx
Microraptor zhaoianus 130 million years old
Microraptor gui 4 -winged dinosaur (Dromaeosaur)
Two possible ancestors Thecodonts or theropods
Euparkia Bipedal 5 th metatarsal & toe reduced Paired row of epidermal scales along back Archaeopteryx Pigeon
Closest Dinosaur Relatives lightly built, big-brained, feathered dromaeosaurs Velociraptor mongolensis Sinornithosaurus
Post Archaeopteryx
Two Major Bird Lineages • Enantiornithes – Fusion of tarsometatarsus in opposite order – Most diverse avian group in Cretaceous • Neornithes Sinornis Iberomesornis Nanantius Enantiornis
Enantiornithes “Opposite birds, ” so named because of a reversed pattern of fusion of tarsal elements relative to modern birds. Show adaptive radiation in Cretaceous Have well developed flight apparatus, skull with teeth and a primitive pelvic region Formerly thought to represent early forms of many modern lineages; actually are a side branch, extinct by end of Cretaceous
Tertiary Modern Birds 65 MYA Enantiornithes Toothed Divers Ichthyornis Cretaceous Enantiornithes Neornithes 135 MYA Jurassic Confusiousornis Archaeopteryx “Opposite” birds Liaoningornis
Sinornis
Sinornis santensis
Forelimbs of (A) Ornitholestes, a theropod dinosaur (B) Archaeopteryx (C) Sinornis, an archaic bird from the lower Cretaceous, and (D) the wing of a modern chicken
Confuciusornis
Two Major Bird Lineages • Enantiornithes • Neornithes – Predecessors to modern birds – Toothed divers – Hesperornis – Tern-like – Ichthyornis
Ichthyornis Hesperornis
Upper Cretaceous
K-T IMPACT The Cretaceous-Tertiary meteor impact was the end of many species on Earth, including the dinosaurs and toothed birds.
MYA Eocene Shorebirds Moas Ducks 38 Flamingoes Oligocene Pseudodontorns MYA Miocene Remiorniths 26 Most Non-Passerine Orders MYA Piciformes 7 Owls Pliocene Coraciiformes MYA Pleistocene Terror Birds 2 Elephant Birds Passerines Gastornis 54 Presbyornis MYA Paleocene Non-passerine Radiation 65 MYA Enantiornithes Modern Birds
Eocene 54 -37 million years BP Major period of evolution at least 20 modern orders arise
Large Carnivorous Birds • Gastornis / Diatryma – Europe / NA • Australian Dromonithids ‘Giant Demon Duck of Doom’ • Terror Birds – South America • Far from sympatric http: //www. bbc. co. uk/beasts/factfiles/videofactfile. shtml? phorusrhacos_v http: //www. pts. org. tw/~web 02/beasts/factfiles/videofactfile. shtml. 734. html
Pliocene 11 -2 million years BP • • ¾ of fossil birds in modern genera Climate mild, dry & stable Extensive mountain building Bird species reach max of ca. 11, 000
Pleistocene 2 million – 11, 000 years BP • • • Dramatic climate change About 1/5 th of all bird species went extinct Modern species arise Rapid evolution of passerines Expansion of large flightless birds
La Brea Tar Pits 14, 500 years BP
Teratorns
La Brea Tar Pits 14, 500 years old
CA Pleistocene 180 fossil bird species known 31 (17%) extinct
How many bird species? Brodkorb (1971) estimates 150, 000 species have existed during the past 150 million years. If so, on average 1 new species arises every 1, 000 years. How species arise is the next topic.
Sinornis