Ebio Exam 2 Study Guide
Ebio Exam 2 Study Guide EBIO 1010 - 02
University of Louisiana at Lafayette
Popular in Evolutionary Biology
Popular in Science
Joseph Merritt Ramsey
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This 34 page Study Guide was uploaded by Lauren Notetaker on Friday March 11, 2016. The Study Guide belongs to EBIO 1010 - 02 at Tulane University taught by Bruce Fleury in Spring 2016. Since its upload, it has received 156 views. For similar materials see Evolutionary Biology in Science at Tulane University.
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Date Created: 03/11/16
EBIO Study Guide 3/10/16 - Speciﬁc items that Dr. Fleury told me were important; pay attention to bolded words! - No orders just phylum subphylum (like one question), class, and the "unranked clades" listed under kingdom animalia in the term list (spiralia, trochozoa etc) ◦ Pt 1 matching - taxonomic names (class or phylum) with terms - ex body parts, life cycle stages etc (ex: planula, larva, mastax) • Particular characteristics ◦ Pt 2 ﬁll ins more gen terms 24 ◦ Pt 3 classiﬁcation and characteristics • 2 phyla list classes with ex, common name ox 14 • Characteristics of animals (match class or phylum) 12 ▪ Lives, feeds, mates ◦ Pt 4 economic, ecological, evolutionary, importance of organisms 8 • Parasitic worms and diseases they cause ◦ Pt 5 intro to animals lecture - body plans, symmetry, protome/deut etc (see "how to be an organism" ﬁrst chapter in the study guide) Pt 1 matching - taxonomic names (class or phylum) with terms - ex body parts, life cycle stages etc (ex: planula, larva, mastax) Acoelomate - flatworms Pseudocoelomate - nematodes (roundworms), rotifers Coelomate - all other higher animals most successful organisms, the arthropods and chordates Phylum Choanoflagellata – choanoflagellates • These curious organisms are usually placed in the Kingdom Protista • They are identical to the feeding cells of the common sponge (more later) Subkingdom Parazoa , Placozoa - Sponges Subkingdom Eumetazoa -All other animals Have cells organized into tissues, organs Share a common pattern of development Have some type of symmetry Radial symmetry (Radiata) - Cnidaria, Ctenophora Bilateral symmetry (Bilateria) - everything else Protostomia – most invertebrates (may be a paraphyletic group) Spiralia – flatworms, rotifers, molluscs, annelids Platyzoa – flatworms, rotifers etc. Trochozoa – annelids, molluscs etc. Ecdysozoa – animals that molt (nematodes, arthropods) Deuterostomia – echinoderms, chordates Subkingdom Parazoa - Phylum Porifera (Sponges) • lack symmetry • lack tissues and organs - 2 layers of epithelial cells enclosing a gelatinous matrix • sessile; motile larva • colonial • specialized cell types: - amoebocytes - wandering amoeboid cells, unspecialized, totipotent, secrete spicules = skeleton, used by taxonomists to classify sponges, help sponge keep shape - choanocytes - feeding cells (collar cells), delivers food, oxygen, gametes, carries off wastes (ammonia) • ostia - choanocytes - spongocoel - osculum • asexual reproduction by fragmentation; hermaphrodite with clouds of sperm • fertilizaiton zygote becomes motile larvae - larvae are balls of collar cells, turn inside out, mature to sponge • asconoid (v small), syconoid (small), leuconoid (large) Phylum Cnidaria - Subkingdom Eumetazoa • Radially symmetric animals – Radiata • Phylum Cnidaria - hydrozoans, coral, anemones • Phylum Ctenophora – comb jellies • Bilaterally symmetric animals - Bilateria • mostly marine, some freshwater • radially symmetric • carnivorous • sessile polyp and motile medusa (sexual stage); (dimorphic like humans) • first to develop a gut cavity (GVC) • digestion is extracellular • gland cells break down food in the GVC • can eat things larger than their cells • first to develop differentiated tissues • first truly mobile • circular and longitudinal muscles • controlled by first true nerve cells • no CNS, just nerve net bc it’s not really in a hurry to go anywhere • only has two of the three eumetazoan tissue layers - ectoderm and endoderm but no mesoderm so no “body plan” • space filled with mesoglea • primitive senses - eyespots, statocysts, mechanical and chemical receptors • mostly small, can rely on diffusion for gas exchange and excretion • stringing cells called cnidocytes contain coiled nematocysts • sexual reproduction • external fertilization - zygote - planula larva - larvae mature to new poly Colonial Forms • Class Hydrozoa – Hydra, Obelia, Physalia - Hydra is immortal! - Actually only one species thought to be immortal, Turritopsis dohrnii - Medusa stage reverts to polyp when damages, restarts life cycle - Can still die from injuries, predation etc. - Sessile and motile forms - Polyp is the dominant stage in the life cycle - Polyp tentacles lined with cnidocytes • Class Scyphozoa – true jellyfish, Aurelia - True jellyfish - Aurelia - 200 species, from Latin scyphus = drinking cup - Medusa is the dominant stage - Polyp occurs only as small post-larval stage - Medusae release gametes - Zygote forms a planula larva - Planula develops into small polyp, which buds off tiny medusae - Tentacles hang from edge of bell or from around the mouth - Tentacles are studded with nematocysts - Prey is stung, tentacles pass it to mouth - Digested in complex GVC - Prey consists of crustaceans, fish - Bell can be contracted to swim through water • ClassAnthozoa – coral, sea anemones - Corals, sea fans, sea anemones - 6,200 species, from Latin anthos = flower - Occur only as polyps - Most advanced cnidarians, complex body - Symbiotic photosynthetic dinoflagellates (partner), so limited to shallow water - helps coral bc it makes it more productive bc you can get sugar from phot. partner so can’t do well bc they rely on it- shallow water need the sun - Anemones are large solitary polyps - Anemones feed on invertebrates and small fish • Class Cubozoa – sea wasps • Sea wasps – 20 species • Among the deadliest animals on Earth!! • Over 50 fatalities recorded fromAustralia, death occurs in 3-20 minutes!! Phylum Ctenophora - Subkingdom Eumetazoa • Comb jellies – once classed with cnidarians in the Phylum Coelentrata • Similar to jellyfish, but: • Simpler life cycle Lack nematocysts, capture prey with sticky cells on two long tentacles • • Combs of cilia beat in sequence to move the jelly around Subkingdom Eumetazoa - Protostomia - Spiralia - Platyzoa - Phylum Platyhelminthes (ﬂatworms) • Platyzoans are animals that • Are usually acoelomate • Are usually flat • Use cilia to help move around • Often have very complex mouth parts (“jaws”) • Cephalized - flatworms are looking back! - first creature that can see us • Acoelomate - solid body, except for GVC (gasceo vascular cavity) • Most primitive animal with all three germ tissue layers (ectoderm, mesoderm, endoderm) • Such animals are called triploblastic • Dorsoventrally flattened (advantage?) • Rely on diffusion - no respiratory or circulatory systems • First animals with true organs - ovaries, testes etc. • First animals with true systems - digestive system, excretory system • Sticks out a tubular pharynx to feed • Digests food in a complex GVC • Complex excretory system • Excrete ammonia by diffusion • Water and other wastes pass through simple tubes called protonephridia • Specialized cells called flame cells drive fluid through the protonephridia • Complex nervous system • Two lateral nerve cords • Rudimentary “brain” (cerebral ganglion) • Primitive sense organs • Auricles - ear-like projections, sensitive to chemicals and touch • Statocysts - cup shaped pit lined with sensitive hairs, bent by tiny weights • Eye spots - shallow pits lined with light-sensitive cells • Move by means of circular and longitudinal muscles • Thick carpet of cilia pulls the worm along • Secretes layer of mucus for smooth gliding • Asexual reproduction by transverse fission - body splits crosswise into “buds” which regenerate the missing parts of the worm • Remarkable ability to regenerate, lost in higher vertebrates • Sexual reproduction • Some species have separate sexes • Most are hermaphroditic Many copulate by hypodermic injection ; sexual • • Use sharpened penis to deposit sperm directly into the tissues of another worm • Sperm cells migrate through solid tissues to reach the egg cells • Flatworm phylogeny is a real mess… • Traditional Platyhelminthes now known to be paraphyletic or polyphyletic • Only clear division is between parasitic and non-parasitic forms • Some flatworms lack any GVC, bodies are completely solid (Acoela) • Lumped with other flatworms, they pulled entire group to the bottom of the tree of life • Now knowAcoela are not really flatworms • Leaves a big hole in lower “branches”… • Parasitic forms (flukes and tapeworms) are now considered a monophyletic clade called Neodermata (new skin) • Named from the tough outer layer that resists attack from host’s enzymes For convenience, we will follow the traditional scheme (4 classes) • • Free-living flatworms eat bacteria, insects, other worms, protists, and crustaceans • Flukes and tapeworms are parasites Class Turbellaria - flatworms Class Monogenea - flukes Class Trematoda - flukes Class Cestoda – tapeworms • Phylum Platyhelminthes - Class Turbellaria - Class Turbellaria - flatworms - 3,000 species, Planaria - Named after the turbulence produced by their carpet of cilia - Free-living - Carnivorous - Some capture prey with a sharpened penis - Most are aquatic, marine - Some marine species eat cnidarians, incorporate the cnidocytes in their own epidermis • Phylum Platyhelminthes - Class Monogenea - Class Monogenea – flukes, 1,000 sp. - Ectoparasites of fish - Simple life cycles (no intermediate host) - Attaches with hooks, suckers, spines, or clamps at anterior end • Phylum Platyhelminthes - Class Trematoda - Class Trematoda – flukes, 11,000 sp. -Clonorchis, Schistosoma - Endoparasites (inside of) of many vertebrates - Complex life cycles with intermediate hosts - Highly modified parasitic flatworms - One or two large suckers to attach to host - Extra tough epithelium to resist digestion by their host’s enzymes - Intricate life cycles with multiple hosts - Clonorchis sinensis - Chinese liver fluke - Infects 20 million EastAsians - Spread through using human feces to fertilize irrigated fields (spread via fish & snails) - Causes severe jaundice, liver cancer - Schistosoma - Schistosomiasis - Infects 200 million people in the tropics - Causes anemia, diarrhea, brain damage • Phylum Platyhelminthes - Class Cestoda - Class Cestoda - tapeworms - Tapeworms, Taenia - 5,000 species, from Greek kestos = belt - Highly modified head (scolex) with small barbs to hang on to intestinal walls of host - Body consists of a series of segments called proglottids (up to 2,000 or more!!) - Primitive excretory and nervous system (flame cells, scolex has ganglia) - Shows ultimate parasite strategy - if you don’t need it, get rid of it - No mouth, no anus, no GVC - No respiratory system - Tapeworms are hermaphroditic - Each proglottid has a complete set of male and female reproductive organs - Tapeworms absorb food directly from the intestinal fluid of the host - Rely on diffusion for respiration and excretion - Each proglottid can make 100,000 eggs - One tapeworm makes 600 million eggs/yr ! - Mature proglottids break off (sesame seeds) - Up to 30 feet long - proglottids shed in feces - Dried cow pies scatter proglottids over grass - Cows get infected by eating grass - Tapeworms form cysts in beef muscles - Can infect humans who eat rare beef Subkingdom Eumetazoa - Protostomia - Spiralia - Platyzoa - Phylum Rotifera (rotifers) • 2,000 species - from L. rota = wheel, ferre = to bear (wheel animals) - Philodina • Abundant in freshwater habitats (~1,000/liter of water!!), ~50 sp. marine • Very small (0.04 - 2.0 mm) • Pseudocoelomate - complete digestive tract • Bodies contain only about 1,000 cells • Use crown of cilia (corona) to feed, draws particles into the mouth • Muscular pharynx (mastax) grinds food • Sessile filter feeders, or raptorial (pursue prey), or both! • Cephalized, with brain, one or more pairs of eye spots, sensory bristles • Sexually dimorphic (males are smaller) • Most are parthenogenetic, unfertilized eggs develop directly into adult females (asexual) Copulate by means of hypodermic injection • • Probably evolved from primitive flatworms • Both have similar pharynx structure, numerous cilia, and flame cells Subkingdom Eumetazoa - Protostomia - Spiralia - Trochozoa - Phylum Mollusca (clams, snails, octopi) • Trochozoans are united by their shared larval form, the trochophore larva • Both groups probably evolved from flatworms • Largest and most diverse phylum (next to the arthropods), maybe 200,000 or more species! • Coelomate protostomes - first group of coelomates • Mostly aquatic, fresh and salt water • Terrestrial forms (~ 35,000 species) are mostly snails • Includes largest invertebrate (giant squid) and most intelligent invertebrate (octopus) • Internal organs embedded in solid tissue called a visceral mass • Large muscular foot extends from the visceral mass, can glide or burrow Mollusks • Scraping tongue called a radula - Use radula to scrape algae and small animals from rocks etc… • Eucoelomate, but the coelom is reduced to a small space around the heart (hemocoel) - reduced bc it’s the first coelomation; Typical of animals with rigid shell or exoskeleton - no longer need coelom for hydrostatic support; Hemocoel takes over role of support and circulation • Soft bodies encased in a hard shell of calcium carbonate - Shell secreted by soft outer fold of tissue called the mantle - Mantle enfolds a space = mantle cavity - Two pairs of gills suspended in mantle cavity • Open circulatory system, blood only partly enclosed in vessels, bathes tissues directly - Blood squeezed through 3-chambered heart - Two chambers collect aerated blood from the gills, third chamber forces it out into tissues - Blood pools in small cavities called sinuses **** • Excretion by tubular nephridia, which drains wastes collecting in the coelom - Nephridia deliver wastes to mantle cavity to be pumped out • Most species have separate sexes - External fertilization in water • Afew are hermaphroditic (bivalves, land snails, sea slugs) • All mollusks share a common larval form, the trochophore larva • Primitive annelids also have trochophores Economic Importance: • Mollusks are delicious!! Escargot, scallops, oysters, calamari etc... • Multibillion dollar seafood industry, oysters cultivated since 1 B.C. • Pearls found in both fresh and saltwater forms • Bivalves filter tremendous amounts of water, help remove pollutants, cleanse aquatic ecosystems • Dye “Tyrian purple” was one of the most important trade goods in the ancient world Phoenicians harvested Tyrian purple from the mollusk Murex • • Used from about 1600 B.C to about 1500A.D., when it was replaced by cheaper pigments Class Polyplacophora - chitons Class Bivalvia - bivalves (clams) Class Gastropoda - snails Class Cephalopoda - octopus and squids • Class Polyplacophora - 800 species, chitons - Soft body protected by 8 overlapping plates (poly = many, placophora = plates) - Plates suggest segmented ancestor (annelid worms?) - Most primitive group of mollusks - Highly adapted for adhering to rocks and other hard surfaces, create partial vacuum by using mantle cavity - Dorsoventrally flattened (like flatworms) - Typical eucoelomate body, tube-in-a-tube - Other mollusks are highly modified versions of the primitive chiton body plan • Class Bivalvia - Laterally flattened - Great adaptation for burrowing in sand - 20,000 species - clams, oysters, scallops - Two shells (“valves”) hinged together, closed by powerful adductor muscles - Shell can be slammed shut, protect against predators - Pair of siphons (tubes or openings) moves water in and out - Incurrent siphon brings in oxygen, food - Excurrent siphon carries off wastes, gametes (bivalves are hermaphrodites) - Bury in sand, breathe & eat through siphons - Cilia on gills moves water through the mantle cavity - Sedentary filter feeders (lacks a radula) - Mucus on gills trap particles of food - Cilia move food to labial palps - Labial palps move food to mouth - Gills used in both feeding and respiration • Class Gastropoda - 62,000 living species - snails, slugs, limpets, whelks, conch, abalone - Maybe as many as 150,000 species! - Single shell - Highly mobile, waves of muscular contractions in the foot moves snail along - Motion helped by mucus trail - 80% of molluscan diversity - Widest range of ecological niches among the mollusks - Can be grazers, browsers, filter feeders, scavengers, detritivores, and even carnivores! - Basic chiton plan twisted into a spiral (one side grows faster in development) - Torsion results in visceral mass being rotated 180 degrees - Torsion advantage - Gills located toward front, best for forward moving animal - Unlike chiton, can withdraw into shell, only a single opening to protect from predators - Opening sealed by a shelly plate called an operculum - Feed with radula, scrape algae or animals from rocks and other surfaces - Radula modified into a drill in the whelks, can bore through shells of other mollusks - Some are filter feeders - Some are parasites, one family sucks blood from mollusks and worms - Mobile, so highly cephalized - Pair of sensory tentacles - Chemoreceptors for taste - Statocysts for balance - Some with eyes on tentacle tips - Eyes are primitive cups with photoreceptors - Higher gastropods have sealed eye with lens - Pulmonate snails - adapted for life on land - Mantle cavity lined with blood vessels, acts like a primitive lung - Can still submerge in water, must return to surface to breathe - Slugs - seem to lack shells, but the shells are reduced to small plates under the skin - Marine slugs (nudibranchs) are vividly colored and patterned - Nudibranchs can eat cnidarians, arm themselves with stinging cells (just like the flatworms) - Blue sea slug Glaucus atlanticus is one of the most spectacular and dangerous creatures in the ocean - Eats Man of War, goes for the most potent cnidocytes and concentrates them in its “fingertips” – so even more dangerous than the Man of War it consumes • Class Cephalopoda - 700 species - octopus, squid, ammonites - Active marine predators - Feed on fish, crustaceans, other mollusks - Formed from ancestral mollusk by extending dorsal surface to become the head, ventral foot becomes posterior foot - Muscular foot becomes divided into tentacles, 8 in octopus, ten in squid - Only mollusks with a closed circulatory system (active predators) - Nautilus has shell, squid has reduced shell (internal plates), octopi lack shells - Modified tentacle used to carry sperm to female, octopus has internal fertilization - Male performs courtship display - Tentacles lined with large suckers for locomotion, capture of prey - Mouth equipped with poison glands - Prey stunned or killed by poisoned saliva - Prey torn apart by strong beak, shredded by radula - Squid can move up to 40 km/hr (25 mph) - Mantle modified for swimming and as an escape mechanism - Quickly squeeze mantle shut for rapid escape from danger! - Squirt dark ink to cover their escape - Ammonites are very primitive cephalopods - Enlarges their shells as they grow - Lives in the outermost chambers - Uses other chambers for storing air, can rise or descend through the water - Logarithmic spiral of the Nautilus shell is one of the most beautiful objects in nature - Squid are the largest invertebrates, 40-50 feet long; biggest, fastest, smartest - Size estimated from squid sucker scars on sperm whales (their chief predator) - Giant octopi seen in the Sea of Japan with tentacles 45 feet long - Giant Squid (Architeuthis) and Colossal squid (Mesonychoteuthis) are the most mysterious - 40 foot specimen of Colossal Squid recently caught in theAntarctic Ocean - Giant cephalopods live in deep water, rarely seen, source of many myths - Cephalopods have large, complex brains, excellent senses (typical of predators) - Cephalopod eye is extremely sophisticated, looks and works like the vertebrate eye, (cornea, lens, iris, and retina); can see better than we can - Statocysts, many tactile and chemoreceptor cells on arms - Giant nerve cell in squid was used for early work in neurophysiology - Octopi are the most intelligent invertebrates, can solve simple puzzles Subkingdom Eumetazoa - Protostomia - Spiralia - Trochozoa - Phylum Annelida (polychaetes, earthworms, leeches) Abilateral body in motion, with a distinct head and tail end, opens a new pathway in evolution • • The parts of the body between the head and tail are now free to specialize to perform different functions • Among the annelid worms, and the arthropods, the body becomes organized into a linear series of identical compartments called segments • Each segment (or metamere) is separated by cross walls called septae • This process is called segmentation (or metamerism) • Segmentation probably evolved as an adaptation for burrowing through soft sediments • It gives annelid worms a remarkable ability to push their way through soil • Segmentation takes place in the mesoderm, in the body wall, and in the muscles • Supply systems, like the circulatory, nervous and excretory systems, run through each segment • Segmentation evolved independently in two groups of protostomes (annelids and arthropods) and in the deuterostomes (chordates like us!) • In both cases, the ancestral species was a burrowing aquatic worm • By anchoring segments or groups of segments to the ground with special bristles called setae, annelids can push their way through the soil • Small stiff bristles are made of chitin ( = cellulose plus a nitrogen group) • Setae also help to anchor the worm in its burrow when it is attacked by a predator • Segments are free to specialize • Segments are identical - if one or more are damaged, the rest may survive • Annelids have amazing powers of regeneration • 8,600 species, fr Latin annelus = little ring • Ancient group, may date back to the Precambrian • Coelomate protostomes • Primarily aquatic, even “earth”worms, both fresh water and marine • One of Linnaeus’original taxa – Vermes (all the “wormy” animals) • Only thing they really had in common was being longer than they were wide… • Lamarck defined theAnnelida, correctly linking them to mollusks (Cuvier got it wrong, linked them to arthropods) • Most are small (~0.5 mm), butAustralian earthworms reach nine feet, record is 22 feet!! • Closed circulatory system • Respiration via diffusion, though many aquatic forms have gills • Excretion by nephridia, one pair/segment • Well-developed nervous system • Brain consists of several ganglia • Smaller ganglia, along paired ventral nerve cord, control each segment • Segments contract individually in waves • Eyes, statocysts, and chemoreceptors Class Polychaeta - paddle worms, Nereis Class Oligochaeta - earthworms Class Hirudinea - leeches • PhylumAnnelida - Class Polychaeta - 5,400 species, fr Latin poly = many, chaeta = bristle - tube worms, fan worms, paddle worms, Nereis - Most primitive annelids - Mainly marine - Common and abundant (13,425 worms/m found in Tampa Bay sediments!!) - Highly cephalized - Complex sensory organs - Eyes with lens and retina - Separate sexes - External fertilization in water - Mating swarms driven by the phases of the moon - Trochophore larvae (suggests common ancestor with mollusks) - Each segment has a pair of paddle-like appendages called parapodia - Parapodia are covered with setae (hence many bristles) - Used for swimming, crawling, burrowing - Parapodia also provide more surface area for respiration by diffusion - Most polychaetes also have gills (very active, so need more oxygen) - Paddleworms have jaws of chitin (pincers), carnivorous or omnivorous - Many polychaetes are filter feeders • PhylumAnnelida - Class Oligochaeta (earthworms) - 3,100 species, oligo = few - earthworms, Lumbricus - Live in soil and in bottom sediments of fresh water habitats - Afew species have re-invaded the ocean - Extremely abundant, one meadow yielded 8,700 worms/m 2 - Most earthworms are scavengers feeding on dead organic matter, mostly vegetation (detritus - detritivores) - Fresh water forms eat detritus and protists - Critically important in aerating the soil - 22-40 metric tons of soil per hectare pass through the guts of earthworms every year - If all the dirt ever churned up by worms were stacked up, it would cover the entire land surface of the Earth 300 miles thick, 50 times the height of Everest!! - Important in bait industry (worm ranching or vermiculture) - Lack parapodia, streamlined body - have to push through dirt - Lack cephalization - Lack eyes, but have light sensitive cells in some segments - Why?? - want to be as efficient as possible to move through dirt in a streamline nature - Complex circulatory system, row of 5 blood vessels acts as a heart - Pharynx draws in food - Soil particles in the crop grind the food - Reproduce asexually by transverse fission (like flatworms) - Clitellum - series of segments swollen by large mucus glands - Clitellum secretes mucus to hold worms together while they mate - Fertilized eggs released into mucus - Mucus dries into protective cocoon - Hermaphroditic, fertilize one another simultaneously • PhylumAnnelida - Class Hirudinea - 500 species - leeches - Most modified as parasites, some are scavengers or predators, feeding on worms, snails, insects - 75% of species suck blood from mammals or crustaceans - Common in fresh water habitats, a few species are marine or terrestrial - Can be abundant - one stream in Illinois had 10,000 leeches/m !!2 - Highly modified as parasites - Store blood meal in special pouches on the digestive tract - Leeches suck up to 5 to 10 times their own weight in blood each time they feed - Anterior and posterior sucker, attach to host - Suckers also help them crawl across the bottom - Coelom is greatly reduced, not divided into compartments like other annelids - Leeches are strong swimmers, no longer need the adaptations of a burrowing animal - Bite of the leech is antiseptic - Leeches release an anticoagulant in their saliva, keeps the blood flowing - For centuries doctors used leeches to bleed their patients (often to death) to get rid of “bad blood” (imbalance of humours) - At height of the leech craze in the 1830’s, France was importing over 50 million medicinal leeches per year - Medicinal leech is now a threatened species! - Medicinal leeches (Hiruo medicinalis) undergoing a revival - Used to drain blood clots and to drain postoperative swelling, bleeding - Unlikely to evolve resistance - secretions go after seven critical steps in the clotting process! - The traditional remedy is to pour salt on a feeding leech, or touch it with a burning cigarette - don’t pull it off! - Recent studies show that these techniques cause the leech to vomit into the wound before letting go – enhances the risk of infection – peel them off gently with fingernails or a dull butter knife! - One species of leech (Placobdelloides jaegerskioeldi) has one of the most unusual habitats of any annelid - It lives and mates only in the rectum of the hippopotamus! - Annelids share a common ancestor with mollusks - Polychaetes and earthworms probably evolved from primitive burrowing marine worms - Leeches and earthworms are sister clades, polychaetes are bit of a mystery… - Leeches probably evolved from earthworms - Lack parapodia and cephalization - Hermaphroditic, develop a clitellum to breed - Lay eggs in a cocoon Phylum Nematoda • Protostomes are divided into • Spiralia – flatworms, rotifers, molluscs, annelids • Ecdysozoa – animals that molt (nematodes, arthropods) • Ecdysozoa - ecdysis means periodically shedding an exoskeleton in order to grow • Cuticle molted • Radial cleavage • Don’t use cilia to move • Lack trochophore larva (found in molluscs and annelids) • Potentially the most diverse group next to arthropods (mostly undiscovered) • Round, bilaterally symmetric • Pseudocoelomate (most pseudocoels are ecdysozoans) • Mainly aquatic • Usually molt four times during their lives • basically filled with water • Lack circular muscles, use longitudinal muscles so thrash wildly about • Tough cuticle (non-living outer layer) resists abrasion, rings provide grip on surfaces to help burrow • Unlike arthropods, cuticle has no chitin, uses collagen • So nematode cuticle is porous, can still rely on diffusion • Excrete ammonia by diffusion • Exchange gases by diffusion • Primitive nervous system - nerve ring for brain, dorsal and ventral nerve cords • Bristles and other structures for primitive mechanical and chemical senses Most have separate sexes • • Sexually dimorphic, males are smaller • Males have a copulatory hook to hold open the female’s genital pore • Economic importance • Root nematodes cause over $5 billion crop damage per year • Several medically important parasites • Many harmful parasitic species: • Ascaris etc. - intestinal roundworms, common in young vertebrates - close to the soil • Infects 1 of 6 people worldwide, especially common in children in the southeastern US Female worm can hold up to 1 million eggs, and can lay up to 200,000 eggs per • day!! • Many harmful parasitic species: • 340 million Ascaris victims per year with serious side effects, 100,000 deaths per year! • Filarial worms - infect lymph system, cause grotesque swelling = elephantiasis • Many harmful parasitic species: • Trichinella - causes trichinosis in vertebrates (birds and mammals), worms form cysts in muscles of pigs etc • Up to 500 million worms tunnel through host’s body - permanent organ and muscle damage • Many harmful parasitic species: • Hookworms - common in school children • ~ 570 to 740 million people infected in the tropics alone - worms leave in feces, reenter through the soles of the feet • Symptoms are many and varied… • Victims become pale, anemic, severe digestive problems • Infection dulls mental processes, victims are easily fatigued - hence “germ of laziness” • Muscles become weak, so abdomen protrudes (potbelly) • • Victims have a gaunt appearance, protruding shoulders (angel wings) • Get unusual dietary cravings (pica) - eat chalk, dirt, paper.. • Some were so badly infected they were blind, fluid of the eyes was filled with live worms!! • Easy to cure (vermicidal purgative), very easy to become reinfected • Must wear shoes, not defecate outdoors • Widespread infection and suffering, went unrecognized until the early 20th Century • Charles Wardell Stiles, zoologist with the USDA, was responsible for uncovering the extent of the infection; hard time getting ppl to diagnose and treat; always getting into trouble and had strict parents • Got John D. Rockefeller to fund a massive study, treatment programi6.tx • Poor condition of southern soldiers may have contributed to the outcome of the Civil War • Robert Penn Warren describes rebel soldiers as “those gaunt, barefoot, whiskery scarecrows” • Rockefeller Sanitary Commission for the Eradication of Hookworm Disease (1910-1915) • vaccine: Goes after two key enzymes in hookworm metabolism, slowly kills it Ecological importance • • Aerate the soil (like earthworms) • Recycle bacteria and fungi into animal tissue • Guinea worm (Dracunculiasis medinensis) is thought to be the fiery serpent of biblical Israelites • Probably dates toAncient Egypt (Pharaoh worm) • Mentioned also in the Sanskrit Rig-Veda (14th Century BC) • Arabs, Persians, were familiar with it, called it Medina vein – described by Rhazes and Avicenna in the 9 CenturyAD • Adult nematode worm up to 1200 mm long! • Intermediate host is a type of aquatic invertebrate called a copepod • Copepod intermediate host discovered in 1870 by Alesej Pavlovich Fedchenko, a major step in early tropical medicine • Ancient remedy was to patiently wind the worm out on a stick!! • Practice was so common, physicians advertised with signs showing a worm on a stick • This remedy is depicted on the staff of the Greek physician Asclepius • Thought to have practiced around 1200 BC, immortalized in the Iliad, revered as the Greek god of medicine • This staff ofAsclepius is the true symbol of the medical profession • The caduceus (entwined snakes) is really the symbol of the herald (Mercury) !?! • Why did doctors switch to the caduceus of Mercury? • Medicine was traditionally associated with alchemy, and alchemists were associated with Mercury (the hermetic arts)! PhylumArthropoda • Nearly 1.2 million named species of arthropods, does not include extinct species • Subphylum Trilobita dominated Paleozoic marine ecology, over 10,000 species • The cockroaches of the Cambrian… • The giant sea scorpions were top dogs in the Paleozoic oceans Eurypterids were the largest arthropods that ever lived, up to nine feet long! • • Over one million named species (named), fr. Greek arthros = jointed, poda = foot • Jointed appendages • Eucoelomate protostomes • Crustaceans dominate the sea, and insects dominate the land • With few exceptions, each sticks to its own turf… • Share common ancestor with polychaete worms • Phylum Onychophora – velvet worms are sister clade, share common ancestor with arthropods; • arrow, cone jellies, velvet not on test*** • Bodies are covered with a tough cuticle (= non-living outer layer) made of chitin and protein, which acts as an exoskeleton • Problem - how can you get bigger if your skeleton is on the outside? • Solution - must molt to grow (arthropods are vulnerable while molting) • Open circulatory system • Respiration via gills in aquatic forms • Terrestrial forms rely on diffusion to exchange gases • Sexes are separate • Pronounced sexual dimorphism • Internal fertilization in terrestrial forms • Some aquatic forms have external fertilization • Arthropods do everything with legs • They creep, crawl, and swim with modified legs • They use modified legs to bite, sting, suck, and chew • They use modified legs as sensory organs (pedipalps, antennae) • Many (like the crawfish) use modified legs to mate with! • Each joint has a set of tendons, that can be pulled back and forth by tiny muscles • These flexible joints allow an infinite variety of movements • The first animals to succeed on land were arthropods • The legs of arthropods were an essential instrument in that conquest • It’s like having the ultimate Swiss army knife… • Economically important • Seafood industry, edible insects • Pollinate commercial crops (fruit) • Carry or cause many diseases, such as malaria, typhus, Lyme disease, bubonic plague • Pollinate flowering plants • Critical in most food chains • Primary converters of plant to animal tissue • Most are tiny - why?? in lab manual • • Size limited by reliance on diffusion to exchange gases • Exoskeleton would be so thick that a large insect couldn’t move about • Escape detection by predators if small • Fusion of segments into functional units (tagma - tagmosis) • 3 major body sections • head, thorax, abdomen • head + thorax = cephalothorax • One of the molecular tools behind our new map of biodiversity is comparison of hox genes • Hox genes control the development of the animal body • Hox genes in a fruit fly, for example, determine how each section of the body develops, front to back • Amazingly enough, the genes are arrayed in the same relative order as the parts of the body they govern • All higher animals turn out to have this same developmental toolkit • It must have evolved very early in the history of higher animals • Studies on arthropods have demonstrated that mutations in these genes are behind the incredible diversity of arthropod bodies • Further mutations in Hox genes would have had a big effect on subsequent development • Highly cephalized, very active • Intricate mouthparts • Highly developed CNS, 3 pair of ganglia fused into a brain • Elaborate sensory organs • Elaborate sensory organs • Antennae • Simple eyes • Compound eyes • Subphylum Chelicerata - arachnids • Subphylum Crustacea – crustaceans • Subphylum Myriapoda – centipedes, millipedes • Subphylum Hexapoda - insects • one question on subphylum that’ll be easy • Chelicerae are modified for manipulating food - usually fangs or pincers • ClassArachnida - 93,000 sp. - spiders, scorpions, ticks, mites - Body = cephalothorax (fusion of head and thorax) + abdomen - - 4 pair of walking legs (=8 legs) - First pair of appendages are chelicerae - Second pair are pedipalps, modified for sensory functions and manipulating prey - - Mostly carnivorous (mites are herbivores) - Secrete powerful digestive enzymes to dissolve prey, sip them like a root beer float All crustaceans share a common larval form, the nauplius larva, • PhylumArthropoda - Subphylum Myriapoda • centipedes, millipedes • Centipedes and millipedes form the subphylum Myriapoda (lots and lots of legs) • Class Chilopoda - centipedes (more dangerous) • Class Diplopoda – millipedes (fatter) • Subphylum Myriapoda - Class Chilopoda – centipedes - 2,800 species, centi = 100, but they don’t really have 100 legs - One pair of legs per segment - Uniramous appendages - Carnivorous, eat mostly insects - Poison fangs, very painful bite, a dangerous creature!! • Subphylum Myriapoda -Class Diplopoda - millipedes - 11,000 species, milli = 1,000, but they don’t really have 1,000 legs - Mostly herbivorous, feed on decaying vegetation (detritivore = feed on detritus) - Two pair of legs per segment (fusion) - Curl up in a spiral to protect themselves, secrete a defensive fluid (cyanide gas) • PhylumArthropoda - Subphylum Hexapoda - Class Insecta – insects - Over 925,000 named species, maybe up to 30 million species undiscovered - Insects evolved about 200 mya, cockroaches and dragonflies were the first to appear - We live in the Age of Insects - Body consists of head, thorax, abdomen - Uniramous appendages - 3 pair of walking legs (= 6 legs) - Communicate by scent and sound (pheromones) - Compound eyes - Terrestrial forms breathe via openings along the abdomen called spiracles - Spiracles open into a network of tiny tubes called trachea - Lose water vapor through trachea, many insects have valves to close spiracles - Excrete by means of malphigian tubules, projections of the digestive tract - Only invertebrates that fly - One or two pair of wings (usually two) - Extremely elaborate mouthparts, highly modified for chewing, sucking, or piercing - Insects undergo metamorphosis – simple or complete - Simple metamorphosis (hemimetabolous) - about 10% - No resting stage, juvenile looks like tiny adult (ex. grasshopper), no pupa - Complete metamorphosis (holometabolous) - about 90% - Resting stage (pupa), adults look different, live in different places, eat different things (ex. butterfly) Phylum Echinodermata (sea lilies, starfish, sea urchins, sea cucumbers) KingdomAnimalia Parazoa Eumetazoa Protostomia Deuterostomia Echinodermata Chordata • 6,000 species, fr. Greek ekhinos = spine, derma = skin Eucoelomate deuterostomes • • common ancestor • Sedentary, slow moving, marine animals • Five-part radial symmetry (pentamerous) • Lack cephalization • Echinoderms have no brain or CNS…Why? • radial - sedentary/sessile; not going anywhere in a hurry • Their nervous system reflects their return to a sedentary lifestyle, radial symmetry • Five-part radial symmetry is superficial – ancestor was bilateral • Asexual reproduction by splitting or fragmentation - great regenerative power Sexual reproduction by external fertilization • • Larvae are bilaterally symmetric, cephalized, reflect ancestral echinoderms • Endoskeleton of calcium carbonate • Endoskeleton consists of numerous small plates, covered by a thin skin (epidermis) • Many small spines extend from the body • Open circulatory system • Large coelom functions in both respiration and circulation • Locomotion and feeding by means of tube feet; propelled by hydraulic system • Here’s how it works… • Water flows through the madreporite (like a filter, slightly off center; technically bilaterally symmetric) • Water passes into a ring canal • Water passes into the radial canals (arms) • Water passes into tube feet • Longitudinal muscles contract to move the tube feet back and forth • Water flows through small filter (madreporite) • Water passes from the madreporite into the ring canal • Water passes into the radial canals (arms) • Water passes into tube feet • Each tube foot resembles a miniature eye dropper • The bulb or ampullae squeezes water into the tube foot • One-way valve keeps water from flowing back out until the bulb relaxes Longitudinal muscles, attached to either side of the tube feet, contract to pull the • stiffened foot back and forth • The coordinated action of thousands of tiny tube feet pulls the animal along • Nervous system consists of a simple nerve ring • Five branches from nerve ring enervate the five arms • Echinoderms have an odd type of connective tissue called catch or mutable (change) connective tissue • Catch connective tissue can change from solid to near liquid at will • Can shed arms to escape predators Class Crinoidea - sea lilies ClassAsteroidea - star fish Class Echinoidea - sea urchins, sand dollars Class Ophiuroidea - brittle stars Class Holothuridea - sea cucumbers • Class Crinoidea - 630 species, fr. Greek krinon = lily - sea lilies, feather stars - Living fossils, sessile forms are ancient species – modern forms are mainly motile - Mouth and anus atop disk, disk may be attached to a stalk (primitive) - Tube feet modified for filter feeding • ClassAsteroidea - 1,500 species, fr. Greek aster = star, starfish - Important marine predators - wolves in slow motion - one of most common fossils - Most have five arms (some have up to 20!) - Superficial radial symmetry (madreporite is off center) - Some starfish feed on bivalves - Clamp onto shell with tube feet and pull... - Can extrude their cardiac stomach - adductor muscle has to take a breath so at that moment it shoves stomach inside it and floods with digestive enzymes - Slide stomach through tiny gaps in shell (0.10 mm gaps within normal shell tolerance) - Digest bivalve alive in its own shell!! - Small projections of skin stick out near the base of the spines - These finger-like projections are called dermal gills - Dermal gills aid in respiration and excretion (accomplished by diffusion) - Numerous small stalks also project from the skin - These stalks, called pedicillaria, bear tiny pincers - Pedicillaria can be used to help capture tiny prey - also prevent other things from putting a house on it - Pedicillaria can be also be used to repel boarders • Class Echinoidea - 950 species, fr. Greek ekhinos = spine - sea urchins, sand dollars - Lack arms but you can see remnants - diadema is most common to step on - aristotle’s lantern is little mouth pinchers - Still show 5 part radial symmetry (look at the 5 rows of tube feet) - Over 5,000 fossil species of urchins - Well protected by sharp spines attached to the skeletal plates under the skin - Spines are movable, help urchins creep about - Many urchins are well defended with long sharp spines - Modified tube feet constantly sense and probe the environment as the urchin moves along - Feed by scraping algae off hard surfaces using sharp shelly “teeth” - Ecologically important, can occur in large numbers and devastate kelp beds and coral reefs - Economically important – harvested for their gonads (ewww…); popular sushi dish - Sea urchin roe is not actually roe (eggs) but gonads - Popular dish in the Orient (Japanese sushi called “uni”), Spain, Greece, Italy and Chile - Thought to be an aphrodisiac - Contains one of the cannabinoids (chemicals in marihuana) - Sand dollars are bilateral, sedentary - endo skeleton - Highly modified for burrowing in sand - Sedentary, move about 7-50 cm per day - Feed on organic matter in the sand as they burrow through it • Class Ophiuroidea - 2,000 species, fr. Greek ophis = snake, oura = tail - brittle stars, basket stars - Resemble starfish, but with long brittle arms - Brittlestars (and most starfish) lack an anus - Many are small, fast-moving - Carnivores, scavengers, and filter feeders, most diverse group of echinoderms - Brittle stars can be very abundant, carpeting the sea floor with their long and delicate filter-feeding arms Class Holothuridea - 1,500 species, fr. Greek holothurum = sedentary marine animal (!) - Sedentary marine animals - Superficial 5 part radial symmetry - Skeletal plates under the skin reduced to a few scattered plates - tube in a tube - Tube feet modified for filter feeding on plankton (algae, protozoa, larvae, gametes) for some - Mouth surrounded by tentacles - Tentacles coated with mucus (yum!) - Mucus traps tiny prey - Brings tentacles into mouth to wipe off mucus - Recoats tentacles and extends to feed again - Several species scour the ocean floor like tiny vacuum cleaners - Economic importance: - Sea cucumbers are a prized (and expensive) gourmet delicacy in the Orient - Sold as trepang or beche-de-mere - Unique defensive mechanism - they evert sticky tubules out their anus when threatened - Tubules are sticky or toxic, regenerate Phylum Chordata Animalia Parazoa Eumetazoa Protostomia Deuterostomia Echinodermata Chordata Cephalochordata Urochordata Vertebrata Phylum Chordata - lancelets, tunicates, vertebrates • 65,000 species, fr. Greek chorda = cord • Eucoelomate deuterostomes • Share common ancestor with echinoderms • All chordates share three basic traits: • Pharyngeal gill slits (pre adaptation of vertebrate jaw) • Dorsal hollow nerve cord • Notochord • Pharyngeal gill slits • Gill slits appear in the pharynx of all chordates at some stage in their development • Gill slits in pharynx evolved to aid in respiration and filter feeding • Larger more active chordates need more oxygen, so tissue between slits becomes highly folded (more surface area) for respiration • Gill arches become reinforced with cartilage to hold slits open • Gill arches become ossified (bony) • Bony gill arches migrate forward • Arches form primitive biting jaw • Vertebrates no longer limited to filter feeding • Biting jaws were a tremendously important evolutionary innovation • Dorsal hollow nerve cord • Hollow nerve cord forms early on in development along the dorsal side • Dorsal hollow nerve cord develops into the spinal cord and brain • Notochord • All chordates have a notochord at some stage in their development • Notochord consists of a flexible supporting rod made of cartilage • In most adult chordates, the notochord develps into (or is replaced by) the vertebral column Subphylum Cephalochordata - lancelets Subphylum Urochordata - tunicates Subphylum Vertebrata – vertebrates • Subphylum Cephalochordata - lancelets - - From Greek khephale = head, Latin chorda = cord – 30 sp., lancelets, Amphioxus - Very common in shallow water - Hard to see, because they’re buried in the sand, with only their heads sticking out - Filter feed by means of pharyngeal gill slits - Sedentary, cephalization greatly reduced - Segmented musculature (mesoderm) - Independent evolution of segmentation - Segmentation in chordates is probably an adaptation for burrowing (as in annelid worms) Subphylum Urochordata - tunicates • - 1,300 species, fr. Greek oura = tail, Latin chorda = cord - tunicates - looks like a sponge, works like a mollusk and not related to either - won’t ask parts - Sessile marine organisms - Covered with a cellulose cloak or tunic - Use pharyngeal gill slits to exchange gases and feed - Pharynx lined with cilia, draws water in through incurrent siphon, out through excurrent siphon - Suspended organic particles stick to layer of mucus in the pharynx - Superficial resemblance to mollusks and sponges in form and function, not related (convergent evolution) - Larvae look like tiny tadpoles - Larvae settle down, turn into sessile adults - Tunicates probably derived from bilateral, motile ancestor - Vertebrates may have arisen from tunicates through neoteny - sexually precocious - Neoteny occurs when the juvenile form becomes capable of sexual reproduction and bypasses the adult stage altogether - Asurprisingly common occurrence in evolution - One species of tunicate lacks the patience for filter feeding, and has evolved a more direct approach to catching prey… - siphon is converted into a trap Subphylum Vertebrata • fish, amphibians, reptiles, birds, mammals • Have a vertebral column • Vertebral column consists of a linear series of vertebrae (backbones) • Spinal cord runs through vertebrae • Endoskeleton of bone or cartilage • Closed circulatory system • Separate sexes • Pronounced sexual dimorphism • Highly cephalized • Very well developed sense organs • Complex nervous system • Brain enclosed in a bony skull (protection) • Vertebrate phylogeny is rapidly changing (what a surprise!) • Aconvenient way of sorting them out: • Superclass Pisces - fish • Superclass Tetrapoda - four-limbed vertebrates • Superclass Pisces • Class Myxini – hagfish • Class Cephalaspidomorphi - lampreys • Class Chondrichthyes - sharks, skates, rays • ClassActinopterygii – ray-finned bony fishes • Class Sarcopterygii – lobe-finned bony fishes • Superclass Tetrapoda • ClassAmphibia - frogs, toads, salamanders • Class Reptilia - turtles, snakes, crocodiles • ClassAves - birds • Class Mammalia - mammals • Phylum Chordata - Subphylum Vertebrata • Superclass Pisces • Class Myxini – hagfish • Class Cephalaspidomorphi – lampreys • Two clades are often grouped together as the cladeAgnatha (without jaws) • Both clades are sister to other vertebrates • Class Myxini - 58 species - hagfish - Jawless fish - Skeleton of cartilage (connective tissue intermediate between bone and muscle – strong, flexible) - Both have bony skull, but hagfish lack vertebrae - Lack paired fins - Parasites, scavengers - ancestors were probably filter feeders - Ancient relatives of hagfish were the only vertebrates on earth for 100 million years! • Class Cephalaspidomorphi - Lampreys – 35 sp., marine and fresh water - Recently recognized as a separate clade from hagfish - Have bony skull and primitive vertebrae - Lamprey larvae are so weird they were thought to be an entirely different animal - Metamorphose after 5-7 years, as big a step as going form tadpole to frog - Many lampreys are parasites on bony fishes • Class Chondrichthyes - 970 species, from Greek khondros = cartilage, ikhthus = fish - sharks, skates, rays - Jaws to chew and manipulate food - Lack bony skeleton, jaws made of cartilage - Usually consider sharks primitive, but cartilaginous condition may be derived - Lack gas bladder of bony fish - stop swimming and they sink - Lateral line - sensory system in the skin - Sensors can detect pressure waves in water, can sense approaching predators and struggling prey - Shark attacks are relatively rare, 2001-2006 only ~20 attacks, 4 deaths/yr - Skin covered with tooth-like denticles - Very large liver, rich in vitamins - Paired fins - pectoral fins, pelvic fins - Function of paired fins?? - Paired fins are horizontal stabilizers, keep sharks on a steady keel - tail provides push - Paired fins are a preadaptation for vertebrate forelimbs and hindlimbs - Apreadaptation is when evolution takes an existing structure and puts it to a new use - Evolution always has to work with what is already there (like paired fins) - Shark skin (shagreen) once sold as sandpaper, still used in boots, belts etc.. - Shark livers once used as a source of commercial vitamins, before synthetic vitamins were invented - Pretty darned tasty! - Superclass Pisces - ClassActinopterygii – ray-finned bony fishes - Class Sarcopterygii – lobe-finned bony fishes - one you eat and one you don’t - Both clades are sometimes united as the clade Osteichthyes (bony fish) - Bony fish have a swim bladder - gas bag that can be inflated or deflated at will, regulates buoyancy - Swim bladders have flexible walls that inflate or deflate according to ambient pressures • ClassActinopterygii - 23,000 species, fr. Greek aktin = ray, pterygion = fin - Bony skeleton (lightweight, thin bones) - Bony jaws - Fins are webs of skin supported by horny or bony rays or spines - Fins are moved by internal body muscles, no muscles in the fins themselves - Protective scales (not = reptile scales) • Class Sarcopterygii - 8 sp., from Greek sarkodes = fleshy, pterygion = fin - Lobe-finned fishes have fins that contain bone and muscle to move their fins - Ancient group, dating back 390 mya - Only two species of coelacanth and six species of lungfish still survive - Amphibians evolved from lobe-finned fish - Lungfish can breathe air - They can burrow into the mud during the dry season, slow their metabolism to 1/60 its th normal rate - Superclass Tetrapoda - ClassAmphibia - frogs, toads, salamanders - Class Reptilia - turtles, snakes, crocodiles - ClassAves - birds - Class Mammalia - mammals • ClassAmphibia - 5,300 species, fr. Greek amphi = both sides, bios = life - frogs, toads, salamanders - Gave rise to all higher vertebrates - First vertebrates on land, ~300 mya - Evolved from lobe-finned fish (similar to the coelacanth) - Skeletons are mostly reinforced version of lobe-finned fish skeleton, fight gravity - Terrestrial forms had tough skin to resist dessication - Reached enormous sizes… - External fertilization in water - Eggs have no shells, so must stay in water - Larvae develop in water (like the tadpole) - Primitive sprawling posture, legs held out to the side, belly drags on the ground - With one notable exception… - Lungs very primitive - Must breathe through skin to supplement - Skin must stay moist to breathe - Vulnerable to acid rain and UV radiation - Currently undergoing widespread extinction • Class Reptilia - 8,000 species, fr. Greek reptilis = creeping - turtles, snakes, crocodiles, lizards, dinosaurs - Evolved ~280 mya - First fully terrestrial animals - Improved posture, limbs held out at an angle to the side, belly above the ground - Efficient motion aided by stronger lungs - Dry skin covered with scales can withstand arid or semi-arid habitats - Expand and contract ribs to breathe, unlike “mouth pushing” amphibians - Adaptations for life on land - Covered with scales, won’t dry out - Internal fertilization - Amniotic egg - egg develops a protective membrane and shell - analogous to the seed - Dinosaurs dominated the entire planet for over 130 million years - Fully improved posture, legs held under the center of gravity, feet facing forward - Dinosaurs were endothermic (warm blooded) - Pneumatic bones (lot of air spaces) so could reach enormous size and still move quickly - Efficient respiratory system, similar to birds - Rapid growth rate – teenage T. rex would have gained five tons in only four years! - Complex social behavior - traveled in packs, took good care of young • ClassAves - 9,000 species, fr. Latin avis = bird - Bones lightweight, hollow, fused together for strength - Forearms modified for flight - Limbs covered by feathers - Feathers evolved from reptilian scales - Feathers are a preadaptation, evolved for insulation (several feathered dinosaurs recently found) - Birds are warm blooded (like mammals) - Birds evolved from theropod dinosaurs, probably during the Jurassic - Strictly speaking, birds (like dinos) are reptiles… - Birds share fully improved posture with dinosaurs and mammals - Most efficient metabolism and respiratiry system of any vertebrate • Class Mammalia - 5,000 species, fr.Latin mamma = breast - Evolved from reptiles, ~200 mya - Major radiation in the Cretaceous - Death of the dinosaurs was a great opportunity for mammals - Nourish young with milk from mammary glands - All mammals have nipples - Do all mammals have navels?? NO! - Placental mammals nourish fetus inside the body, attached by an umbilical cord to a placenta (hence the navel) - Marsupials, like koalas and kangaroos, nourish young in an external pouch - Monotremes, like the echidna and platypus, still lay eggs, like their reptilian ancestors - Mammals are endothermic (warm blooded), like birds - Bodies are covered with hair, unique mammalian invention - Hair is made of keratin, same protein makes fingernails, toenails, claws, hooves, horns! Pt 2 fill ins more gen terms (exoskeleton neoteny) 24 Pt 3 classiﬁcation and characteristics • 2 phyla list classes with ex, common name ox 14 • Characteristics of animals (match class or phylum) 12 ▪ Lives, feeds, mates ▪ Sta
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