Lecture Outline - Chapter 30

30.1. Evolution and Classification of Animals (p. 584)

1. Animals are multicellular eukaryotes that are heterotrophic by ingesting food. (Fig. 30.1) (Table 30.1)
2. Animals produce heterogametes (eggs and sperm) and follow diplontic life cycle in which adults are always diploid and only gametes are haploid.
3. General Classification
   • a. All animals likely evolved from protozoan ancestor. (Fig. 30.2)
   • b. About 34 animal phyla but nine phyla contain major animal groups.
   • c. Invertebrates without backbones comprise all but last phylum Chordata that contains mostly vertebrates.
4. Symmetry is one basis for classification.
   • a. May have asymmetry or no basic symmetry.
   • b. Radial symmetry has animals organized circularly; animals such as cnidaria and echinoderms are relatively inactive or may be sessile, stuck to substrate.
   • c. Bilateral symmetry forms right and left halves; animals may be more active and move toward head end.
5. Body Plans
   • a. May be a sac plan with one opening to an incomplete digestive system.
   • b. Tube-within-a-tube plan has two openings and complete digestive system route with specialized parts along tube.
6. Number of Germ Layers
   • a. Sponges have cellular level of organization without specialized tissues.
   • b. Cnidaria have tissue level of organization with two germ layers, ectoderm and endoderm.
   • c. Other animals have three germ layers--ectoderm, mesoderm, and endoderm--and have organ level of organization.
7. Presence or Absence of a True Coelom
   • a. A true coelom is an internal body cavity lined with mesoderm.
   • b. Flatworms are solid or acoelomate, "no coelom."
   • c. Roundworms are pseudocoelomate with partial mesoderm next to body wall.
   • d. Beyond roundworms, these more derived animals are coelomate.
8. Coelomates Divided Into Two Branches
   • a. Protostomes are animals that develop mouth at blastopore, invagination of endoderm during embryonic development.
   • b. Deuterostomes are animals that develop anus at blastopore.
9. Segmentation
   • a. Segmentation results from repetition of body parts, allowing further specialization and differentiation.
   • b. Mollusks are nonsegmented; annelids, arthropods, and chordates are segmented.

1. Sponges Have Pores
   • a. In phylum Porifera with 5,000 species.
   • b. Some freshwater but mostly sessile marine filter feeders.
   • c. Multicellular but without specialization; thought to be separate evolutionary line from other animals.
   • d. Structures
     • i. Most shaped like a vase; wall is flattened epidermal cells.
     • ii. Middle wall layer is semi-fluid matrix, amoeboid cells transport nutrients, produce spicules, and sex cells.
     • iii. Central cavity has opening called an osculum; body wall is perforated by many pores.
     • iv. Collar cells found on inner wall have flagella to cause water to pass in through pores and out osculum; collar cells also engulf food particles and pass them to amoeboid cells.
   • e. Reproduce
     • i. Asexually by budding.
     • ii. Sexually by releasing sperm and eggs into central cavity; zygote forms ciliated larvae that swims to new location.
   • f. Regeneration: because of lack of specialization, sponges easily regenerate from broken segments.
   • g. "Skeletal" Structure
     • i. Classified on basis of internal skeleton of spicules, needle-shaped protective crystals.
     • ii. Calcium sponges use calcium carbonate; glass sponges use silica.
     • iii. Spongin fibers are modified collagen network that gives sponges a spongy texture.
2. Cnidaria Have Radial Symmetry (p. 588)
   • a. In phylum Cnidaria with 9,000 species.
   • b. Tubular and bell-shaped animals mostly of coastal reefs, some in oceanic waters.
   • c. Only two germ layers, endoderm and ectoderm.
   • d. Radially symmetrical; any longitudinal cut produces identical halves.
   • e. Cnidocytes are stinging cells that release nematocysts, long coiled hollow threads that may contain poison; triggered when touched.
   • f. Two basic body forms:
     • i. Polyps, as in hydra and hydranths, are usually sessile with mouth directed upward.
     • ii. Medusae, as in jellyfish, are free floating; mouth directed downward.
     • iii. Probably ancestral cnidaria had both forms; some still alternate generations today. (Fig. 30.4a)
   • g. Sexual reproduction results in zygote that forms ciliated planula larvae.
   • h. Diversity:
     • i. Sea anemones are solid polyps resembling brightly colored flowers.
     • ii. Corals have calcium carbonate skeletons and form coral reefs in shallow waters.
     • iii. Portuguese man-of-war has gas-filled polyp with other polyps dangling to feed or reproduce.
     • iv. In jellyfishes, medusa is primary stage and polyp is inconspicuous.
   • i. Hydras Are Solitary Polyps (Fig. 30.5)
     • i. Attached to underwater rocks and plants in most lakes and ponds.
     • ii. Body is small tubular polyp less than one centimeter long.
     • iii. Body is dead-end sac; one opening is both mouth and anus.
     • iv. Outer layer of epidermis is from ectoderm; inner layer, called gastrodermis, is from endoderm and is able to contract.
     • v. Outer ectoderm separated from inner endoderm by jellylike mesoglea.
     • vi. Circular and longitudinal muscle fibers provide movement; nerve cells form nerve net.
     • vii. Gastrodermal cells secrete enzymes, absorb nutrients and gases that are distributed by diffusion from gastrovascular cavity.
     • viii. Hydras reproduce sexually or asexually.
       - no medusae, only polyp stage.
       - under favorable conditions, hydras produce outgrowths called buds.
       - can produce ovary or testis in body wall for sexual reproduction.
       - has ability to regenerate from small fragment.
3. Flatworms Are Flat (p. 590)
   • a. In phylum Platyhelminthes with 13,000 species.
   • b. Acoelomate with sac body plan.
   • c. Three germ layers present; mesoderm provides bulk and complexity.
   • d. Systems: muscles, excretory, digestive, and reproductive organs; lack respiratory and circulatory organs (diffusion is adequate at small size).
   • e. Grouped into three classes; one free living and two parasitic.
   • f. Planaria Are Free-Living (Fig. 30.6) (p. 590)
     • i. Small black, brown, or colorless flat worms.
     • ii. Live in fresh water where they feed on living or dead organisms.
     • iii. Rid body of excess water by excretory organ that contains a flame cell with cilia.
     • iv. Ladder-type nervous organ; small brain with two nerve cords joined by cross-branches.
     • v. Cephalization: planaria locate sensory "eyespots" to anterior.
     • vi. Glide by ciliated epidermis on film of mucus.
     • vii. Pharynx is mouth that sucks in food particles to gastrovascular cavity; undigested wastes also exit through pharynx.
     • viii. Planaria are hermaphroditic, possessing both male and female organs; generally cross-fertilize; eggs hatch in 2-3 weeks into tiny worms.
     • ix. Able to regenerate.
   • g. Parasitic Flatworms Have Lost Features (p. 591)
     • i. Two parasitic classes include tapeworms and flukes.
     • ii. No sensory organs concentrated at head; instead equipped with hooks and suckers to attach to host.
     • iii. Absorbs nutrients from host's digestive tract; therefore lacks own digestive system.
     • iv. Coated by protective glycocalyx, a mucopolysaccharide coating.
     • v. Energy does to extensive reproductive system.
     • vi. Some use secondary host to harbor larvae until transmitted to primary host for adult stage to infect digestive tract, bile duct, blood, or lungs.
     • vii. Schistosomiasis
       - Caused by blood flukes.
       - Found in people living in Far East and Africa.
       - Enters body by penetrating skin. (Fig. 30.7)
     • viii. Tapeworms
       - Have scolex (head) containing hooks and suckers.
       - Body segments are long series of proglottids, each containing male and female reproductive organs.
       - Eggs are released in feces; eggs are eaten by animals and larvae burrow into muscle to encyst.
       - Can be acquired by eating poorly cooked beef or pork.
       - Larval worms form cyst in meat; digested out of cyst, they attach to intestinal wall.
4. Roundworms Are Nonsegmented (p. 592)
   • a. In phylum Nematoda with 500,000 species.
   • b. Found almost anywhere (sea, fresh water, soil, etc.).
   • c. Have a tube-within-a-tube body plan; digestive system is complete.
   • d. Have a pseudocoelom (body cavity with incomplete mesodermal lining); fluid-filled and acts as a hydrostatic skeleton to counter muscle contraction. (Fig. 30.8b)
   • e. Ascaris Infects Humans
     • i. Female Ascaris roundworms are larger parasites (20-35 cm length).
     • ii. Longitudinal muscles produce whiplike motion.
     • iii. Ingested larvae ingested in protective coating; from intestine, they go to the liver, heart, and the lungs.
     • iv. After ten days growth in lungs, larvae migrate up to throat where they are swallowed and return to parasitize intestine.
     • v. Mature worms mate and female releases larva-containing eggs in feces.
   • f. Other Roundworms
     • i. Trichinosis
       - Serious infection of humans.
       - Contracted by eating uncooked or rare pork with encysted larvae.
       - Female adult burrows into intestinal wall; produces live offspring that migrate through bloodstream and encyst in muscle. (Fig. 30.9)
       - No cure once infected.
     • ii. Elephantiasis
       - caused by filarial worm carried by mosquito serving as secondary host.
       - blocks lymph vessels causing swelling of limbs.
     • iii. Pinworm infections common among children in southern United States.
     • iv. Small hookworms cause serious anemia when attach in numbers to intestinal wall and feed on blood.
     • v. Good hygiene, proper sewage systems, and cooking meat thoroughly offer protection.

1. Coelomic animals are divided into two groups based on embryological evidence. (Figs. 30.8c, 30.10)
2. Protostomes
   • a. Called protostomes because blastopore becomes mouth.
   • b. Also called schizocoelomates because they form a coelom by splitting the mesoderm.
   • c. Includes mollusks, annelids, and arthropods.
   • d. Have a trochophore larvae that is top-shaped with band of cilia at midsection.
3. Deuterostomes
   • a. Called deuterostomes because blastopore becomes anus.
   • b. Also called enterocoelomates because coelom forms by out-pocketing of the primitive gut.
   • c. Includes echinoderms and chordates.
   • d. Have a dipleurula larvae. (bands of cilia as in Fig. 30.10)
4. Mollusks Have Soft Bodies
   • a. In phylum Mollusca with 110,000 species.
   • b. Three distinct parts of all mollusks include:
     • i. Visceral mass is soft portion that contains internal organs.
     • ii. Foot is muscle used for locomotion.
     • iii. Mantle is membranous or muscular covering; encloses viscera and may secrete shell.
   • c. Many show cephalization; have eyes and sense organs.
   • d. Highly diverse group adapted to many modes of life. (Fig. 30.11)
   • e. Gastropods
     • i. Includes snails, conches, and nudibranchs.
     • ii. Have a ventrally flattened foot, moves by contractions.
     • iii. Conches and snails have coiled shell containing visceral mass.
     • iv. Some have vessels under mantle allowing "lung" for life on land.
   • f. Cephalopods
     • i. Includes octopuses and squids.
     • ii. Foot has evolved into tentacles; shell is reduced or absent.
     • iii. Powerful beaks and a radula (toothy tongue) tear prey apart.
     • iv. Advanced eye but evolved separately from vertebrates.
     • v. Brain is fused ganglia; large nerves control contraction of mantle for "jet propulsion."
   • g. Bivalves Have a Double Shell
     • i. Bivalves include clams, oysters, and scallops.
     • ii. "Bivalve" refers to "two shells."
     • iii. Comparison of clam to active squid is presented in Table 30.2.
     • iv. Freshwater clam represents some bivalves.
     • v. Shell composed of protein and calcium carbonate is secreted by mantle.
     • vi. Pearl is formed when irritating particle is placed between mantle and mother-of-pearl.
     • vii. Gills function in gas exchange.
     • viii. Heart lies in reduced pericardial cavity; is remains of coelom.
     • ix. Blood flows through sinuses of open circulatory system.
     • x. Clams lack cephalization; nervous system composed of three pairs of ganglia.
     • xi. Clam is filter feeder; food and water enter incurrent siphon, mucous secretions adhere food to gills and mouth, anus empties into excurrent siphon.
     • xii. Two excretory kidneys lie below heart; remove waste from pericardial cavity.
     • xiii. Sexes are separate; marine clams produce trochophore larvae showing relationship to annelids.
5. Annelids Are Segmented Worms (p. 597)
   • a. Phylum Annelida has about 12,000 species.
   • b. Segmentation results from partitions called septa that divide body internally; segmented coelom acts as hydrostatic skeleton.
   • c. Digestive system is specialized with: pharynx, stomach, accessory glands.
   • d. Closed circulatory system delivers blood to every segment.
   • e. Brain connects to solid ventral nerve cord with ganglia in each segment.
   • f. Nephridia are paired tubules that collect wastes in each segment.
   • g. Marine Worms Have Parapodia
     • i. Class Polychaeta refers to many setae on marine worms.
     • ii. Setae are bristles that anchor worm as it moves.
     • iii. Polychaetes have fleshy lobes called parapodia on each segment for swimming and gas exchange.
     • iv. Nereis is genus of common marine clam worm. (Fig. 30.13)
     • v. Nereis has chitinous jaws on head to capture and eat small animals and crustacea.
     • vi. Nereis also shows cephalization, head region with eyes and other sense organs.
     • vii. Other polychaetes include sessile tube worms that filter feed on particles.
     • viii. Reproduction may involve shedding portion of body with sperm or eggs for fertilization; trochophore larvae show relationship with mollusks.
   • h. Earthworms Live Underground
     • i. In class Oligochaeta meaning "very small setae."
     • ii. Earthworms lack well-developed head (no need for cephalization since not predatory) or parapodia (reduces water loss and eases movement in soil). (Fig. 30.14)
     • iii. Setae protrude in small clusters from body surface to grip soil when segments bulge; withdraw when segment contracts.
     • iv. Terrestrial but must be kept moist for gas exchange.
     • v. Food drawn into mouth by pharynx, stored in crop, ground up in gizzard, digested and absorbed along intestine.
     • vi. Ventral solid nerve cord with lateral nerves each segment.
     • vii. Paired nephridia for excretion in each segment.
     • viii. Closed circulatory system uses five pairs of hearts to move blood anteriorly in dorsal vessel, posteriorly in ventral vessel.
     • ix. Earthworms are hermaphroditic; clitellum is a girdle about each worm that secretes mucus to shelter sperm passage an cocoon the eggs; no larval stage.
   • i. Leeches Are Parasites
     • i. Mostly fresh water, but some terrestrial or marine.
     • ii. Similar to other annelids but lack setae.
     • iii. Modified with two suckers, small oral sucker and large posterior sucker.
     • iv. Most attach to open wounds; few cut through tissues.
     • v. Hirudin is a powerful anticoagulant that prevents clotting during feeding.
6. Arthropods Have Jointed Appendages (p. 600)
   • a. Phylum Arthropoda contains over six million species, more than any other group.
   • b. Exoskeleton
     • i. Composed primarily of chitin.
     • ii. Serves to protect, anchor muscles, prevent drying out.
     • iii. Because it is hard and unexpandable, must be shed (molted) if animal is to enlarge.
   • c. Some jointed segments are fused into regions: head, thorax and abdomen.
   • d. Ancient trilobites had appendages on each segment; modern arthropods have fused segments for walking, swimming, eating etc.
   • e. Insects, arachnids, centipedes, and millipedes contain species adapted to terrestrial life. (Fig. 30.15)
   • f. Well-developed nervous systems are common.
     • i. Brain and solid ventral nerve cord.
     • ii. Compound eye forms many complete visual units; detects movement.
     • iii. Simple eyes have single lens dispersing image to many receptors.
7. Crustacea Have a Calcified Exoskeleton
   • a. Largely marine group includes: lobsters, shrimps, barnacles, and crabs.
   • b. Exoskeleton is calcified; body forms are very diverse.
   • c. Head has pair of compound eyes, two pair of antennae, three pair of mouthparts.
   • d. In crayfish, head and thorax (bearing pair of claws and four pairs of walking legs) are fused into cephalothorax covered by a carapace that covers gills.
   • e. Abdominal segments are equipped with swimmerets; first pair is enlarged in male for passing sperm to female.
   • f. Fan-shaped tail ends in uropods and telson.
   • g. Crayfish feeds food to stomach through gastric mill that grinds food, and filters it before absorption takes place.
   • h. A pair of green glands excrete wastes at base of antennae.
   • i. Coelom is reduced to cavity around reproductive system; hemolymph washes respiratory pigment (hemocyanin) through hemocoel sinuses, an open circulatory system.
   • j. Ventral nerve cord and ganglia system similar to earthworm.
   • k. Sexes are separate; gonads are ventral to pericardial cavity an sperm exit at base of fifth leg, ovaries open at base of third walking leg; eggs are attached to swimmerets of female.
8. Most Insects Have Wings
   • a. Over one million described; totals more than all other species combined.
   • b. Huge variety includes: dragonflies, grasshoppers and crickets, beetles, moths and butterflies, flies, bees and wasps, etc.
   • c. Insect Features
     • i. Three body regions: head, thorax, and abdomen.
     • ii. Head has sensory antennae, eyes, and mouthparts.
     • iii. Thorax has three pair of legs, adults may have one or two pair of wings that help them evade enemies, find food, disperse, etc.
     • iv. Abdomen contains most internal organs.
     • v. Exoskeleton is lighter with less chitin than other arthropods.
   • d. Grasshopper As Example
     • i. Front wings are leathery, protect broad flying hind wings.
     • ii. Third pair of legs is suited to jumping.
     • iii. Tympanum on side of first abdominal segment for sound reception.
     • iv. Chewing mouthparts harvest food; stored in crop; gastric mill grinds food before stomach digests it.
     • v. Malpighian tubules extend into hemocoel, absorb nitrogenous wastes and excrete into digestive system.
     • vi. Spiracle openings lead to tubules called tracheae that diffuse gases for respiration.
     • vii. Circulation involves tubular heart that pumps clear hemolymph through open hemocoel.
     • viii. Insects reproduce by copulation; female stores sperm in seminal receptacle; female grasshopper deposits fertilized eggs in ground by ovipositor to overwinter.
   • e. Metamorphosis is Change in Form
     • i. Grasshoppers undergo gradual metamorphosis from larva to winged adult.
     • ii. Butterflies and other insects undergo complete metamorphosis from larva to pupa to reorganized adult.
   • f. Major differences exist between crayfish and grasshopper exemplary of two major arthropod groups:
     • i. Gills versus trachea.
     • ii. Ammonia versus uric acid excretions.
     • iii. Respiratory pigments versus simple diffusion.
     • iv. Contrasting locomotor and nervous systems.
9. Echinoderms Have a Spiny Skin (p. 604)
   • a. In phylum Echinodermata with 6,000 species.
   • b. Include only marine sea stars, sea urchins, sea cucumbers, feather stars, sea lilies, and sand dollars. (Fig. 30.19)
   • c. Calcium rich endoskeleton forms spines and plates.
   • d. Appear radially symmetrical as adults but larva is bilateral. (Fig. 30.10)
   • e. Water vascular system is unique to this phylum.
10. Starfish Have Arms
    • a. In ocean along coastlines; feed on clams, oysters, etc.
    • b. Oral (mouth) side is underside; aboral (anus) side on top.
    • c. Pincerlike pedicellariae keep surface free of particles.
    • d. Tiny skin gills respire.
    • e. Each of five arms has groove lined by tube feet that help open up a clam.
    • f. Central ventral stomach is everted into bivalve; begins external digestion.
    • g. Nervous system has central ring with radial nerves in each arm.
    • h. Water enters water vascular system through sieve plate, passes to radial canal in each arm and to ampulla above each tube foot, providing slow hydraulic system of movement.
    • i. Lack respiratory, excretory, or circulatory systems.
    • j. Reproduction involves asexual fragmentation-regeneration and sexual release of eggs or sperm to produce bilateral larvae that metamorphose into adults.
11. Chordates Have Three Basic Characteristics (p. 605)
    • a. Phylum Chordata has 45,000 species.
    • b. All chordates at some time in their life history must have:
      • i. Dorsal notochord just below nerve cord; replaced by vertebral column in adult vertebrates.
      • ii. Dorsal hollow nerve cord that lies above the notochord.
      • iii. Pharyngeal pouches that become gills in fishes and amphibian larvae but are seen only during embryonic development in other vertebrates; in humans these become eustachian tubes, tonsils, thymus, and parathyroids.
12. Invertebrate Chordates (p. 606)
    • a. Tunicates or sea squirts (Fig. 30.20)
      • i. Are ocean floor dwellers.
      • ii. Have a thick-walled squat sac with incurrent and excurrent siphons.
      • iii. Numerous gill slits are retained in adult for filter feeding.
      • iv. Larvae have the three chordate traits; ancestors may have matured in larval form to become primitive fish.
    • b. Lancelet
      • i. In genus Branchiostoma, formerly Amphioxus. (Fig. 30.21)
      • ii. Bury themselves in coastal waters and filter feed with anterior mouth and gills exposed.
      • iii. Retain all three chordate characteristics as an adult; muscles show segmentation and dorsal hollow nerve cord is branched.

1. In subphylum Vertebrata with 43,700 species.
2. Have all chordate features but embryonic notochord replaced in adult by vertebral column.
3. Jointed Endoskeleton
   • a. Is internal.
   • b. Shows segmentation.
   • c. Actively grows.
   • d. Protects internal organs.
   • e. Serves as place of muscle attachment, allowing rapid complex movements.
4. General Features
   • a. Two pairs of appendages date from pectoral and pelvic fins of fish.
   • b. High degree of cephalization and complex sense organs: eyes, balance organs, sound receptors all common.
   • c. Complete digestive tract and large coelom.
   • d. Closed circulatory system.
   • e. Excretory system with kidneys.
   • f. Reproduction usually sexual and by separate sexes.
5. Fishes Live in Water (p. 608)
   • a. Three living classes: jawless, cartilaginous, and bony fishes.
   • b. Jawless Fishes
     • i. In class Agnatha with 63 species.
     • ii. Lack jaws and have no fins or scales.
     • iii. Hagfish is scavenger feeding on dead fish.
     • iv. Lamprey is parasitic; uses round mouth as sucker to tap into fish circulatory system.
   • c. Cartilaginous Fishes
     • i. In class Chondrichthyes with 850 species.
     • ii. Have internal skeleton composed of cartilage.
     • iii. Includes sharks, which vary from dangerous hammerheads to whale sharks that filter zooplankton.
     • iv. Rays and skates are flat; usually partly buried in sand and feed on clams.
   • d. Bony Fishes
     • i. In class Osteichthyes with 20,000 species.
     • ii. Swim bladder found in most. (Fig. 30.23)
       - secrete or absorb gasses from air bladder.
       - permits fish to adjust buoyancy.
     • iii. Ray-finned Fishes
       - include perch, salmon, trout, etc.
       - have fins supported by bony rays.
     • iv. Reproduce by spawning where sperm and eggs are shed into water at same time; zygote develops into larvae.
   • e. Lobe-finned Fishes
     • i. Include ancestors that evolved into amphibians.
     • ii. Had fleshy appendages that could be adapted to land locomotion; ancestors to amphibians also had lung.
     • iii. Example of a "living fossil" is coelacanth; however is lung-less and not direct ancestor to amphibians.
6. Amphibians Live a Double Life (p. 609)
   • a. In class Amphibia with about 3,900 species.
   • b. Were dominant and diverse group in Carboniferous period.
   • c. Includes frogs, toads, newts, salamanders.
   • d. Distinct walking legs for land locomotion; have five or fewer toes.
   • e. Respiration usually by inefficient lungs and gas exchange through skin.
   • f. Breathe by forcing air in mouth into lungs.
   • g. Divided atria but a single ventricle in heart; partial mixing of oxygenated and deoxygenated blood.
   • h. Most amphibious with larval stage (tadpole for frogs and toads) that lives in water but changes into adult that lives on land. (Fig. 30.24)
   • i. Fertilization occurs externally in water.
7. Reptiles Reproduce on Land
   • a. In class Reptilia with 6,000 species.
   • b. Includes turtles, alligators, snakes, and lizards.
   • c. Were dominant during the Mesozoic era (Age of Reptiles).
   • d. Large dinosaurs are most memorable of group.
     • i. Brachiosaurus was huge herbivore 17 meters tall.
     • ii. Tyrannosaurus rex was huge carnivore 5 meters tall.
     • iii. Birds are descended from dinosaur ancestors.
   • e. Reptilian Characteristics
     • i. Body covered with hard, horny scales that protect animal from desiccation and predators.
     • ii. Well-developed lungs protected by rib cage.
     • iii. Heart has two atria but separation of ventricles by interventricular septum is incomplete.
     • iv. Internal fertilization eliminates need of water for fertilization because penis passes sperm directly to female.
     • v. Leathery shelled egg eliminates need for swimming larval stage; has extraembryonic membranes to feed and protect embryo, eliminate wastes.
     • vi. Are "cold-blooded" in sense that they do not maintain warm temperature by high cellular metabolism; however they do regulate body temperature by exposure to sun, etc.
8. Birds Can Usually Fly (p. 611)
   • a. In class Aves with 9,000 species.
   • b. Feathers are unique to birds; are modified reptilian scales.
   • c. Many orders of birds: flightless ostriches, divers, penguins, ducks, etc.
   • d. Anatomy is adapted for flight.
   • e. Front legs form wings for thrust and lift.
   • f. Hind legs specialized for perching, killing and tearing prey, swimming, etc.
   • g. Large breastbone has keel for attachment of flight muscles.
   • h. Lobular air sacs are throughout the body including the lightweight bones; air circulates efficiently through special lungs so no air is stagnant.
   • i. Four-chambered heart efficiently separates oxygenated from deoxygenated blood.
   • j. Birds conserve water by excreting semi-dry uric acid.
   • k. Well developed brains allow excellent control in flight; instinctual behaviors permit patterns of migration and nesting.
   • l. Are warm blooded from metabolic heat; feathers are efficient insulation.
9. Mammals Have Hair and Mammary Glands (p. 612)
   • a. In class Mammalia with about 4,500 species.
   • b. Evolved during Mesozoic era but suppressed during era of dinosaurs.
   • c. Hair insulates against heat loss and allows expansion into cold climates.
   • d. Mammals are "warm-blooded" or homeothermic.
   • e. Requires efficient respiratory system to provide oxygen for higher metabolism.
   • f. Four-chambered heart, as in birds, provides double-loop circulation.
   • g. Mammary glands produce milk to nourish the helpless young.
   • h. Most mammal mothers develop young in uterus.
10. Mammals That Lay Eggs
    • a. Monotremes are egg-laying mammals.
    • b. Duck-billed platypus of Australia.
      • i. Female incubates eggs in burrow in ground.
      • ii. When eggs hatch, young lap milk that seeps from glands on abdomen of males and females.
    • c. Spiny anteater of Australia.
      • i. Egg moves from cloaca to pouch formed by swollen mammary glands.
      • ii. After 53 days, young left in burrow but visited by mother.
11. Mammals That Have Pouches
    • a. Marsupial young begin development in female's body but born premature.
    • b. Young, when born, leave uterus, crawl to pouch, and attach to nipple to continue development.
    • c. Includes kangaroo, opossum, and koala bear. (Fig. 30.27b)
    • d. Dominate Australia where marsupials underwent adaptive radiation without placental mammals.
12. Mammals That Have Placentas
    • a. Represent vast majority of mammals. (Fig. 30.27c)
    • b. Extraembryonic membranes modified for internal development in uterus.
    • c. Chorion is fetal portion of placenta; uterine wall grows maternal portion.
    • d. Exchanges nutrients, oxygen, and wastes between fetal and maternal blood.
    • e. Adapted to life on land, limbs provide rapid movement.
    • f. Well-developed brain.
    • g. Four-chambered heart.
    • h. Diaphragm helps breathing.
    • i. Constant internal temperature; hair usually provides insulation.
    • j. Main expansion of brain is from cerebral hemispheres; long period of dependency and brain development allows greater time for learning.
    • k. Classification based on mode of locomotion and methods of obtaining food, includes among others:
      • i. bats (order Chiroptera).
      • ii. horses (order Perissodactyla).
      • iii. whales (order Cetacea).
      • iv. mice (order Rodentia).
      • v. dogs, etc. (order Carnivora).

1. Primates Live in Trees
   • a. Order Primates has 180 species.
   • b. Adapted to living in trees:
     • i. Mobile limbs.
     • ii. Opposable thumb and fingers for grasping food, limbs of trees.
     • iii. Nails have replaced claws.
     • iv. Eyes moved to front of head for stereoscopic vision; selection against sense of smell.
     • v. Long gestation allows time for forebrain development.
     • vi. Single birth; difficult to care for many young in trees.
     • vii. Longer juvenile period gives emphasis to learned behavior.
     • viii. Extended period of parental care increases complex social interaction.
2. Prosimians are first of two suborders
   • a. Lemurs have squirrel-like appearance. (Fig. 30.28)
   • b. Tarsiers are small, have enormous eyes for nocturnal life.
3. Anthropoids
   • a. Include new world monkeys (spider monkey, capuchin) with long prehensile tails and flat noses.
   • b. Old world monkeys (baboon, rhesus) lack long tails and have protruding noses. (Fig. 30.28)
   • c. Hominoids include only apes and humans in superfamily Hominoidea.
   • d. Four types of apes:
     • i. Gibbon is smallest; specialized for swinging in trees. (Fig. 30.28)
     • ii. Orangutan is larger and still usually lives in trees.
     • iii. Gorilla is largest and spends most of time on ground.
     • iv. Chimpanzee are most human-like in appearance; live both in trees and on ground.
   • e. Molecular data places humans as genetically very similar to chimpanzees and gorillas.
   • f. Details of locomotion and posture separate humans from apes.
     • i. Monkeys are quadrupedal, leap from branch to branch, and their vertebral column is arched.
     • ii. Apes swing from branch to branch, their vertebral column is straight, and their arms are elongated.
     • iii. Humans are bipedal, their vertebral column is S-shaped, and they have a strong short pelvis.
4. Hominids Walk Erect (p. 616)
   • a. Hominid line begins with australopithecines; includes humans and fossils in human lineage.
   • b. Fossils of first hominids found mostly in East Africa and South Africa.
     • i. Ardipitheus ramidus dates from 4.4 MYA (million years ago); discovered in 1994, teeth are larger, skull is smaller, and creature did not walk erect--represents transition between apes and humans.
     • ii. Australopithecus anamensis, dated at 4 MYA, has jaws of ape but legs of human.
     • iii. Australopithecus afarensis (Lucy) (Fig. 30.29)
       - Over 250 fossils; dated at 3.4 MYA.
       - Show ancestor that was bipedal; footprints show it walked erect.
       - Skull retained many apelike features but canine teeth, larger in males and smaller in females, were smaller than those of apes.
       - Brain size was half our size, about that of an ape.
       - No evidence of tool use.
       - After some time of little change (stasis), branched into up to ten species by 2 MYA. . .
     • iv. Australopithecus africanus was slender species found in southern Africa by Raymond Dart in 1920s.
     • v. Australopithecus robustus and Australopithecus boisei.
       - larger forms from eastern and southern Africa.
       - more robust to live in drier habitats.
       - ate meat occasionally, perhaps using tools to process animal carcasses.
     • vi. Australopithecus aethiopicus discovered in 1985 dated from 2.5 MYA and likely ancestral to A. robustus and A. boisei.
5. Homo habilis Made Tools
   • a. Homo habilis means "handy man" and refers to stone tools found with remains.
   • b. Dates 1.6 to 2 MYA but brain is 45% larger than Lucy.
   • c. Larger brain, smaller teeth, crude stone tool use all suggest it was scavenger and predator of small animals, as well as fruits, seeds, and berries.
   • d. Division of labor, speech, and culture may have hastened adaptation of H. habilis and extinction of australopithecines.
6. Homo erectus Traveled
   • a. Homo erectus fossils in Africa, Asia, and Europe between 1.9 and 0.5 MYA.
   • b. Compared to Homo habilis, H. erectus had larger brain (1,000 cc), bigger brow, flatter face, modern nose.
   • c. Fashioned advanced tools. (Fig. 30.31)
   • d. First hominid to use fire.
   • e. May have returned to home bases after hunting; facilitated social interaction, rearing of children, cultural learning.
   • f. Striding gait allowed massive migration.
7. Modern Humans Originated How? (p. 618)
   • a. About 300,000 YBP, archaic Homo sapiens evolved in Europe, Asia, and Africa.
   • b. Multiregional continuity hypothesis states each population evolved into modern humans; each population would derive from H. erectus ancestors in each location. (Fig. 30.32a)
   • c. Out-of-Africa hypothesis states advanced H. sapiens in Africa migrated to Europe and Asia about 100,000 YBP and interbred or supplanted the local populations there. (Fig. 30.32b)
8. Two Homo sapiens of Interest
   • a. Homo sapiens neanderthalensis are named from Neander Valley in Germany where one of first skeletons discovered.
     • i. Date from 200,000 years ago.
     • ii. They had larger brains (1,400 cc) than modern humans, perhaps to control larger musculature.
     • iii. Shorter body was more massive and perhaps cold-adapted.
     • iv. Excellent hunters of wide-ranging animals.
     • v. Controlled fire; buried their dead with flowers and tools, perhaps with a religion.
   • b. Homo sapiens sapiens are referred to as Cro-Magnon man after a cave site in southern France.
     • i. Resemble modern humans in facial features and brain size. (Fig. 30.34)
     • ii. Excellent hunters, demonstrated societal living and beginning of use of language, and painted drawings on cave walls.
     • iii. Produced advanced Aurignacian tools. (Fig. 30.32)