VERTEBRATE EVOLUTION & DIVERSITY 1 ANIMAL DIVERSITY No true tissues Ancestral protist True tissues Radial symmetry True Animals Bilateral symmetry Bilateral Animals Deuterostomes Lophotrochophores Ecdysozoans Sponges Cnidarians Flatworms Molluscs Annelids Nematodes Arthropods Echinoderms Chordates 2 LAYERS FORM 3 LAYERS: PIT = mouth 3 LAYERS: PIT = anus 2 1
CHORDATES Backboned animals also referred to as vertebrates Dorsal hollow nerve cord Flexible notochord Pharyngeal slits behind mouth Post anal tail Present in chordate embryos 3 HAGFISHES AND LAMPREYS Kingdom Animalia Phylum Chordata HAGFISHES (1 st Craniates) Has a head Blind; scavengers Feed from the inside out! Slime for protection Slime glands LAMPREYS (1 st Vertebrates) Head and vertebral column Larval suspension feeders in streams Adult parasites in the oceans or lakes 4 2
SHARKS AND RAYS (jawed vertebrates) Kingdom: Animalia Phylum: Chordata Class: Chondrichthyes Gill slits Skeletal rods Skull Mouth Current hypthothesis: jaws may have evolved from a modification of bones in front of the fill slits. Hinged jaw 5 SHARKS AND RAYS (1 st jawed vertebrates) Kingdom: Animalia Phylum: Chordata Class: Chondrichthyes Evolved 440 mya Cartilaginous fishes (do not fossilized well) Sharks: open water predators, ampullae of lorenzini Rays: live on the sandy seafloor Lateral line system 6 3
RAY FINNED FISHES (jawed vertebrates) Kingdom Animalia Phylum Chordata Class Actinopterygii Bony fishes Delicate ray like fins Gills Bony skeleton Flattened scales w/mucus Operculum Swim bladder evolved from primitive lung Operculum Swim bladder Many adaptations to colonize many aquatic habitats (over 27,000 spp) 7 LOBED FIN FISHES (jawed vertebrates) Kingdom Animalia Phylum Chordata Class Sarcopterygii Rod shaped bones in strong pectoral and pelvic fins for walking Lungfishes can gulp air; coelacanth is a living fosssil (video for today) Ancestors Link aquatic and land chordates 8 4
AMPHIBIANS (1 st tetrapods) Likely morphological progression from lungfish to land animals Devonian Carboniferous Permian Lungfishes Limbs with digits Time known to exist Amphibians Amniotes Key to limb bones Humerus Radius Ulna 9 AMPHIBIANS (1 st tetrapods) Kingdom Animalia Phylum Chordata Class Amphibia Salamanders, snakes, frogs Found in damp habitats; some terrestrial (toads vs frogs) Need water for reproduction (eggs dry out) Dehydration is a problem Undergo metamorphosis (tadpole frog) Global decrease in amphibians! 10 5
AMNIOTES Evolution of the amniotic egg solved problem of reproducing on land Embryo Amnion (fluid like sac) Waterproof shell for protection and moisture Allantois (waste) Chorion (gas exchange) Chorion Yolk (nutrients) Albumen / egg white (more nutrients) 11 REPTILES & BIRDS (Amniotes) Kingdom Animalia Phylum Chordata Class Reptila / Class Aves REPTILES ADAPTED FOR LAND: Thick scales Ectothermic or cold blooded Suited for low food conditions Dinosaurs, crocs, alligators, turtles, snakes, lizards BIRDS ADAPTED FOR FLIGHT: Descendants of dinosaurs Few bones in tail; great eyes Light bones; few teeth Endothermic or warm blooded Complex circulation; lungs Archaeopteryx Drawing of primitive bird based on fossil evidence 12 6
Ancestral chordate Lancelets Tunicates Chordates Head Vertebral column Jaws Lungs or lung derivatives Hagfishes Lampreys Sharks, rays Ray-finned fishes Lobe-fins Jawed vertebrates Vertebrates Craniates Lobed fins Legs Amniotic egg Milk Amphibians Reptiles Mammals Amniotes Tetrapods 13 MAMMALS (Amniotes w/ hair and mammary glands) Kingdom Animalia Phylum Chordata Class Mammalia First mammals 200 mya; much smaller than now Endothermic; complex circulation; 4 chamber heart; highly mobile Lots of adaptations: teeth, reproduction; MONOTREMES Lay eggs Platypus, anteater MARSUPIALS Short gestation Opposum, kangaroos EUTHERIANS Placental mammals Humans, zebras 14 7
EUTHERIAN CLADES 15 PRIMATES Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Lemurs, lorises, and pottos Tarsiers Anthropoids: monkeys and apes w/ opposable thumbs Monkeys: equal length fore/hind limbs Old World vs. New World monkeys New World monkeys Old World monkeys Gibbons Orangutans Monkeys Apes Anthropoids Gorillas Chimpanzees Humans 16 8
PRIMATES Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Lemurs, lorises, and pottos Tarsiers APES No tail; forelimbs longer than back Larger brain relative to body size Big toe is widely separated for grasping trees Genes of humans and chimps are 99% identical New World monkeys Old World monkeys Gibbons Orangutans Gorillas Chimpanzees Monkeys Apes Anthropoids Chimps and humans diverged from a common ancestor Humans 17 HOMININS Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Family Hominidae Millions of years ago 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 Paranthropus boisei Australopithecus africanus Australopithecus afarensis Ardipithecus ramidus Sahelanthropus tchadensis Paranthropus robustus Australopithecus sediba ergaster habilis erectus Hominins are species more closely related to humans than apes? sapiens neanderthalensis 18 9
19 HUMANS Kingdom Animalia Phylum Chordata Class Mammalia Order Primates Family Hominin Genus Large brain relative to body size Mean brain volume (cm 3 ) 1,500 1,300 1,100 900 neanderthalensis sapiens erectus ergaster 700 500 habilis Paranthropus boisei Chimpanzee Gorilla 300 Australopithecus afarensis 0 20 40 60 80 100 120 Mean body mass (kg) 20 10
ECOLOGY(CH 34.1 34.4) The study of interactions of organisms with their environment ABIOTIC FACTORS: light Temperature Water Inorganic nutrients (N,P) Oxygen for aquatic species BIOTIC FACTORS: Food Predators Competitors for food and mates Humans! 21 ECOLOGY Provides insight into environmental changes In 1950 s we wanted to control nature (livestock, agriculture, disease) Chemical pesticides invented (DDT) By the late 1950 s people became concerned with pesticide use Large impacts on birds of prey Book: Silent Spring 1962 22 11
REQUIRED VIDEO The core concepts of this material are fair game for exams! The Coelacanth: A living fossil of a fish See link on the course website: http://www.biosbcc.net/harrer 23 12