Animals can be traced to a common ancestor a flagellated protist like a choanoflagellate (700 MYA)

Animals can be traced to a common ancestor a flagellated protist like a choanoflagellate (700 MYA)

The ancestor of animals was probably a colonial, flagellated protist Cells in these protists Gradually became more specialized and layered Somatic cells Digestive cavity Reproductive cells 1 Colonial protist, an aggregate of identical cells 2 Hollow sphere of unspecialized cells (shown in cross section) 3 Beginning of cell specialization (cross section) 4 Infolding (cross section) 5 Gastrula-like proto-animal (cross section) Figure 18.2A

Sponges Invertebrate: Porifera no distinct tissues or organs do have specialized cells no symmetry sessile (as adults) food taken into each cell by endocytosis

INVERTEBRATES Sponges have a relatively simple, porous body Sponges, phylum Porifera Are the simplest animals and have no true tissues

Flagellated choanocytes Filter food from the water passing through the porous body Pores Amoebocyte Choanocyte Skeletal fiber Water flow Central cavity Flagella Choanocyte in contact with an amoebocyte

Invertebrate: Cnidaria Jellyfish, hydra, sea anemone, coral tissues, but no organs two cell layers radial symmetry predators tentacles surround gut opening extracellular digestion release enzymes into gut cavity

Stinging cells of mouth Cnidarians tentacles sensory cell stinging cell discharged nematocyst hydra trigger undischarged nematocyst stinging cell with nematocyst

Cnidarians are radial animals with tentacles and stinging cells Cnidarians, phylum Cnidaria Have true tissues and radial symmetry

Their two body forms are Polyps, such as hydra Medusae, the jellies Figure 18.6A C

They have a gastrovascular cavity And cnidocytes on tentacles that sting prey Tentacle Coiled thread Capsule (nematocyst) Trigger Discharge of thread Prey Cnidocyte

Sea Nettle Portuguese man o war Sea wasp (box jelly)

Safe Comb Jellies

Invertebrate: Platyhelminthes Flatworms tapeworm, planaria mostly parasitic bilaterally symmetrical allows high level of specialization within parts of the body now have a mouth at one end & an anus at the other! ectoderm mesoderm endoderm

Colorized SEM 80 Units with reproductive structures Hooks Sucker Scolex (anterior end)

Invertebrate: Nematoda Roundworms bilaterally symmetrical have both mouth & anus well-developed digestive system many are parasitic hookworm C. elegans

Ascaris

Invertebrate: Mollusca Mollusks clams, snails, squid bilaterally symmetrical (with exceptions) soft bodies, mostly protected by hard shells true coelem

Gastropods Gastropods are the largest group of molluscs And include the snails and slugs

Bivalves The bivalves have shells divided into two halves And include clams, oysters, mussels, and scallops

Cephalopods Cephalopods are adapted to be agile predators And include squids and octopuses

Wiwaxia between mollusca and annelida

Open Versus Closed circulatory System Open circulatory system A heart pumps hemolymph through a hollow cavity to circulate O 2 and nutrients. Arthropods and some molluscs Closed Circulatory System a Heart pumps blood through closed blood vessels and lymph is kept separate. Chordates, cephalopods and annelids

Invertebrate: Annelida Segmented worms earthworms, leeches segments are not specialized bilaterally symmetrical true coelem fan worm leech

Invertebrate: Arthropoda Spiders, insects, crustaceans most successful animal phylum bilaterally symmetrical segmented allows jointed appendages exoskeleton chitin + protein

Arthropod groups arachnids 8 legs, 2 body parts spiders, ticks, scorpions crustaceans gills, 2 pairs antennae crab, lobster, barnacles, shrmp insects 6 legs, 3 body parts

Colorized SEM 900 Chelicerates Chelicerates include Horseshoe crabs Arachnids, such as spiders, scorpions, mites, and ticks A black widow spider (about 1 cm wide) A scorpion (about 8 cm long) A dust mite (about 420 µm long) Figure 18.11B, C

Millipedes and Centipedes Millipedes and centipedes Are identified by the number of jointed legs per body segment

Crustaceans The crustaceans Are nearly all aquatic Include crabs, shrimps, and barnacles

Insects are the most diverse group of organisms Insects have a three-par t body consisting of Head, thorax, and abdomen Three sets of legs Wings (most, but not all insects)

Many insects undergo Incomplete or complete metamorphosis

A. Order Or thoptera The order orthoptera includes Grasshoppers, crickets, katydids, and locusts Head Thorax Abdomen Antenna Forewing Eye Figure 18.12A Mouthparts Hindwing

B. Order Odonata The order odonata includes Dragonflies and damselflies Figure 18.12B

C. Order Hemiptera The order hemiptera includes Bedbugs, plant bugs, stinkbugs, and water striders Figure 18.12C

D. Order Coleoptera The order coleoptera includes Beetles Figure 18.12D

E. Order Lepidoptera The order lepidoptera includes Moths and butter flies Figure 18.12E

F. Order Diptera The order Diptera includes Flies, fruit flies, houseflies, gnats, and mosquitoes Haltere Figure 18.12F

G. Order Hymenoptera The order hymenoptera includes Ants, bees, and wasps Figure 18.12G

Domain Eukarya Kingdom Animal Chapters 32-34 The Animal Kingdom Clade Deuterostome Phylum Echinodermata Phylum - Chordata

Echinoderms have spiny skin, an endoskeleton, and a water vascular system for movement Echinoderms, phylum Echinodermata Includes organisms such as sea stars and sea urchins Are radially symmetrical as adults Tube foot Tube foot Spine Figure 18.13B, C

The water vascular system Has suction cup like tube feet used for respiration and locomotion Anus Spines Stomach Canals Tube feet Figure 18.13A

Starfish, Invertebrate: sea urchins, sea Echinodermata cucumber radially symmetrical spiny exoskeleton

Sponges Cnidarians Echinoderms Chordates Flatworms Molluscs Annelids Arthropods Nematodes The body plans of animals can be used to build phylogenetic trees One hypothesis of animal phylogeny Is based on morphological comparisons Deuterostomes Protostomes Radial symmetry Bilaterians Bilateral symmetry No true tissues Eumetazoans True tissues Ancestral colonial protist

Deuterostome Clade Echinoderms (seastars and sea urchins) and Chordates (Us) are monophyletic. Protostomes make up two clades: Lophotrochozoa and Ecdysozoa. Lophotrochozoa are split into 2 groups: Trochopore larva (annelida and mollusca) and Lophophore bearing (flatworms, rotifers). Ecdysozoans shed an old exoskeletons (Nematodes and Arthropods).

Our own phylum, Chordata, is distinguished by four features Chordates, phylum Chordata have A dorsal hollow ner ve cord A stiff notochord Pharyngeal slits A muscular post-anal tail

Vertebrate Evolution and Diversity Campbell s Chapter 34

Vertebrates belong to Phylum Chordata Chordata also includes: Urochordates - Tunicates Cephalochordates - Lancelets

Vertebrates fish, amphibians, reptiles, birds, mammals internal bony skeleton backbone encasing spinal column skull-encased brain Chordata hollow dorsal nerve cord becomes brain & spinal cord Oh, look your first baby picture! becomes gills or Eustachian tube becomes tail or tailbone pharyngeal pouches postanal tail becomes vertebrae notochord

All Chordates possess 1. Notochord - A rigid but flexible rod between the digestive tube and the dorsal nerve cord. 2. Dorsal hollow Nerve cord 3. Pharyngeal Slits 4. Muscular, Post-anal Tail

Chordate Characteristics

Subphylum Urochordates tunicates - seasquirts

Cephaloch ordate - Lancelets

Transitional Species 530 mya Haikouichthys A true vertebrate Myllokunmingia - early vertebrate

Neural crest Forms from closing neural tube and will form parts of the bones and cartilage of the cranium.

Agnathans Jawless Ostracoderms 450-375 million years ago

Hagfish slime-eels Has a cranium but no jaws, teeth or backbone. Still has Notochord

Sea Lampreys Have a cranium and a cartilaginous partial wrapping around notochord. No jaws or teeth.

Jaws evolved from Pharyngeal slits supports.

450 mya salmon, trout, sharks Characteristics body structure Vertebrates: Fish bony & cartilaginous skeleton jaws & paired appendages (fins) scales body function gills for gas exchange two-chambered heart; single loop blood circulation ectotherms reproduction external fertilization external development in aquatic egg gills body

Chondrichthyes includes Sharks and rays Jawed fish with Catilaginous skeletons

Have teeth and a lateral line Sharks have been around for more than 400 million years. Sharks existed about 200 million years before dinosaurs. There are more than 375 species of sharks living today.

Megalodon Fake

Whale Shark Largest extant fish 30 40 feet

Osteichthyes Bony fish have Calcified endoskeleton Operculum gill covering 30,000 species Water comes in mouth through pharynx and out through the gills Swim bladder is used for buoyancy and came from lungs

Osteichthyes Bony fish Three Extant groups (classes) Actinopterygii ray finned fish Actinista Lobed finned fish Dipnoi - Lungfish

Actinopterygii ray finned fish Include commonly known fish like trout, perch and flounder. 1. Skin secrete mucus that reduces drag 2. Have keratin scales 3. Most reproduce externally 4. Two Chambered heart 5. Ectothermic

Anatomy of typical Ray finned fish

Actinista Lobed finned fish Walk on bottom with muscular fins Coelacanth

Dipnoi - Lungfish All living lungfish live in the remnants of Gondwana; Australia, Africa and South America Have an amphibian-like lung

Tetrapod evolution from fish The split between fish and amphibians is very blurry. Lungfish and frogs breath the same way

Fossil record

From fish to Amphibians

Tiktaalik Fish with a neck

Femur Pelvis Tibia Humerus Ulna Shoulder Fibula Lobe-finned fish Radius Pelvis Femur Humerus Shoulder Fibula Tibia Early amphibian Ulna Radius

Acanthostega tetrapod FISH

Ichthyostega

Class - Amphibians Amphi (two) bios (lives) spend part of the time in water and part on land 1. Breath through lungs and moist skin 2. Eggs are laid in water and larva (tadpoles) lose lateral line. 3. Ectothermic 4. Three Chambered heart

350 mya Vertebrates: Amphibian Amphi (two) bios (lives) spend part of the time in water and part on land frogs salamanders toads Characteristics body structure legs (tetrapods) moist skin body function lung lungs (positive pressure) & diffusion through skin for gas exchange three-chambered heart; veins from lungs back to heart ectotherms reproduction external fertilization external development in aquatic egg metamorphosis (tadpole to adult) glottis closed buccal cavity

Orders Order Urodela (tailed ones) Salamanders Order Anura No tails frogs and toads Order Apoda no legs legless

Urodela 500 species Lungless

4,200 species Anurans

Lungless frog

150 species Apodans

The Amniotes Class Mammals - you Class Testudines - turtles Class Sphenodontia - tuataras Class Squamata snakes and lizards Class Crocodilia- crocodiles and alligators Class Aves - birds

Amniotic Egg The egg has a shell that allows the animal to live on land exclusively (although many have returned to the water). Extraembryonic membranes Allantois disposal of waste Amnion protects embryo and prevents dehydration Chorion Exhange gases for the embryo Yolk Sac contains nutrients in yolk

Skull features separated the Earliest Amniotes Synapsids - (One opening behind temple)lead to therapsids and mammals Anapsids - (No openings on the temple of the skull)lead to An extinct group of reptiles (and maybe turtles) Diapsids (two arches opening) Lead to the dinosaurs, modern reptile, archesaurs and birds

Dimetrodon a mammal-like reptile

Titanophoneus a dominant Therapsid

Reptilian Heritage evident Terrestrial adaptations: Keratin scales protect from dessication (drying out) Must get all air from their lungs. Fertilization is internal Ectothermic absorb external heat but have behaviors that assist in temperature control. Three chambered heart The first radiation was based upon skull differences and happened about 250 MYA

250 mya Vertebrates: Reptiles Characteristics body structure dry skin, scales, armor body function lungs for gas exchange thoracic breathing; negative pressure three-chambered heart ectotherms reproduction internal fertilization external development in amniotic egg leathery shell dinosaurs, turtles lizards, snakes alligators, crocodile embryo amnion chorion allantois yolk sac

The age of Reptiles The Mesozoic Era saw a wide diversification of reptiles and their cousins the dinosaurs. From 251 to 65 MYA When the dominant amphibians and therapsids went extinct at the end of the Permian (also ending the Paleozoic Era) Dinosaurs took over.

Testudines Turtles no openings in temples but other factors do not link them to the other anapsids.

Newly discovered fossil from China has shed light on how the turtle's shell evolved. The 220 million-year-old find, described in Nature journal, shows that the turtle's breast plate developed earlier than the rest of its shell. The breast plate of this fossil was an extension of its ribs, but only hardened skin covered its back.

Diapsids split into Lepidosauria Extinct oceanic reptiles Sphenodontia Mosasaurs Plesiosaurs Ichthyosaurs Squamata snakes and reptiles Archosauria- Crocodilians Pterosaurs Ornithischia Saurischians Aves

Leptidosaurians

Class Sphenodontia - tuataras Last of a primitive reptile found only in New Zealand

Archosauria Crocodilians Pterosaurs Ornithischia Saurischians Aves

Crocodilians Alligators and Crocodiles

pterosaurs

Ornithschians Herbivorous and extinct

Saurishians Herbivorous and carnivorous

She s a he!

Archaeopteryx

150 mya Vertebrates: Birds finches, hawk ostrich, turkey Characteristics body structure feathers & wings thin, hollow bone; flight skeleton body function very efficient lungs & air sacs four-chambered heart endotherms reproduction internal fertilization external development in amniotic egg trachea anterior air sacs lung posterior air sacs

Birds are a branch of the Saurischians

Birds 8,600 species Ratite birds are flightless. Form and function Four chambered heart Endothermic Hatched from eggs

220 mya / 65 mya mice, ferret elephants, bats whales, humans Vertebrates: Mammals Characteristics body structure hair specialized teeth body function lungs, diaphragm; negative pressure four-chambered heart endotherms reproduction internal fertilization internal development in uterus nourishment through placenta birth live young mammary glands make milk (specialized sweat glands) muscles contract diaphragm contracts

Split into three groups from the therapsids during the Mesozoic The Monotremes egg layers Marsupials pouches Eutherians Placental mammals

Marsupials versus Eutherians Probably split ~125 MYA Marsupials radiated in the southern continents Eutherians radiated in the northern land masses and spread south. A great deal of Convergent Evolution

Vertebrates: Mammals Sub-groups monotremes egg-laying mammals duckbilled platypus, echidna marsupials pouched mammals short-lived placenta koala, kangaroo, opossum placental true placenta shrews, bats, whales, humans

Whale ancestor

Vertebrate quick check Which vertebrates lay eggs with shells? Which vertebrates are covered with scales? What adaptations do birds have for flying? What kind of symmetry do all vertebrates have? Which vertebrates are ectothermic and which are endothermic Why must amphibians live near water? What reproductive adaptations made mammals very successful? What characteristics distinguish the 3 sub-groups of mammals?

That s the buzz! Any Questions? 2007-2008