Introduction to the History of Life

         Life on Earth originated between 3.5 and 4.0 billion years ago
         Major episodes in the history of life: a preview

    Prebiotic Chemical Evolution and the Origin of Life

         The first cells may have originated by chemical evolution on a young Earth:
         an overview
         Abiotic synthesis of organic monomers is a testable hypothesis: science as
         a process
         Laboratory simulations of early Earth conditions have produced organic
         polymers
         Protobionts can form by self-assembly
         RNA was probably the first genetic material
         The origin of hereditary information made Darwinian evolution possible
         Debate about the origin of life abounds

    The Major Lineages of Life

         Arranging the diversity of life into the highest taxa is a work in progress

Chapter  26
stromatolites Rock made of banded domes of sediment in which are found the most ancient forms of life: prokaryotes dating back as far as 3.5 billion years.
*protobionts
ribozymes An enzymatic RNA molecule that catalyzes reactions during RNA splicing.
 
 

    The World of Prokaryotes

         They're (almost) everywhere! an overview of prokaryotic life
         Bacteria and archaea are the two main branches of prokaryote evolution

    Structure, Function, and Reproduction of Prokaryotes

         Nearly all prokaryotes have cell walls external to their plasma membranes
         Many prokaryotes are motile
         The cellular and genomic organization of prokaryotes is fundamentally
         different from that of eukaryotes
         Populations of prokaryotes grow and adapt rapidly

    Nutritional and Metabolic Diversity

         Prokaryotes can be grouped into four categories according to how they
         obtain energy and carbon
         The evolution of prokaryotic metabolism was both cause and effect of
         changing environments on Earth

    Phylogeny of Prokaryotes

         Molecular systematics is leading to a phylogenetic classification of
         prokaryotes

    Ecological Impact of Prokaryotes

         Prokaryotes are indispensable links in the recycling of chemical elements in
         ecosystems
         Many prokaryotes are symbiotic
         Humans use prokaryotes in research and technology

Chapter  27
domains A taxonomic category above the kingdom level; the three domains are archaebacteria, eubacteria, and eukaryotes.
peptidoglycan (PEP-tid-oh-GLY-kan) A type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides.
gram stain A staining method that distinguishes between two different kinds of bacterial cell walls.
*gram-positive
*gram-negative
*capsule
pilus (PILL-us) (plural, pili) A surface appendage in certain bacteria that functions in adherence and the transfer of DNA during conjugation.
taxis (TAKS-iss) A movement toward or away from a stimulus.
nucleoid region The region in a prokaryotic cell consisting of a concentrated mass of DNA.
binary fission The type of cell division by which prokaryotes reproduce; each dividing daughter cell receives a copy of the single parental  chromosome.
transformation (1) The conversion of a normal animal cell to a cancerous cell. (2) A phenomenon in which external genetic material is assimilated  by a cell.
conjugation (KON-joo-GAY-shun) A recombination mechanism that results in the transfer of genetic material between two bacterial cells that  are temporarily joined.
*transduction
*endospores
antibiotics A chemical that kills or inhibits the growth of bacteria, often via transcriptional or translational regulation.
photoautotrophs (FOH-toh-AW-toh-trohf) An organism that harnesses light energy to drive the synthesis of organic compounds from carbon dioxide.
chemoautotrophs (KEE-moh-AW-toh-trohf) An organism that needs only carbon dioxide as a carbon source but that obtains energy by oxidizing inorganic substances.
photoheterotrophs (FOH-toh-HET-ur-oh-trohf) An organism that uses light to generate ATP but that must obtain carbon in organic form.
chemoheterotrophs (KEE-moh-HET-er-oh-trohf) An organism that must consume organic molecules for both energy and carbon.
saprobes An organism that acts as a decomposer by absorbing nutrients from dead organic matter.
parasites (PAR-uh-site) An organism that absorbs nutrients from the body fluids of living hosts.
nitrogen fixation The assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that an be directly used by plants.
obligate aerobes aerobe (OB-lig-it AIR-obe) An organism that requires oxygen for cellular respiration and cannot live without it.
facultative anaerobes (FAK-ul-tay-tiv AN-uh-robe) An organism that makes ATP by aerobic respiration if oxygen is present but that switches to fermentation under anaerobic conditions.
obligate anaeobes (AN-ur-obe) An organism that cannot use oxygen and is poisoned by it.
*anaerobic respiration
*bacteriorhodopsin
cyanobacteria Photosynthetic, oxygen-producing bacteria (formerly known as blue-green algae).
signal sequences A stretch of amino acids on polypeptides that targets proteins to specific destinations in eukaryotic cells.
*methanogens
*extreme halophiles
*extreme thermophiles
decomposers Saprotrophic fungi and bacteria that absorb nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms, and convert them into inorganic forms.
symbiosis An ecological relationship between organisms of two different species that live together in direct contact.
symbionts (SIM-by-ont) The smaller participant in a symbiotic relationship, living in or on the host.
*host
mutualism (MYOO-choo-ul-iz-um) A symbiotic relationship in which both the host and the symbiont benefit.
commensalism (kuh-MEN-sul-iz-um) A symbiotic relationship in which the symbiont benefits but the host is neither helped nor harmed.
parasitism A symbiotic relationship in which the symbiont (parasite) benefits at the expense of the host by living either within the host  (endoparasite) or outside the host (ectoparasite).
parasite (PAR-uh-site) An organism that absorbs nutrients from the body fluids of living hosts.
*opportunistic
Koch's postulates A set of four criteria for determining whether a specific pathogen is the cause of a disease.
exotoxins (EKS-oh-TOKS-in) A toxic protein secreted by a bacterial cell that produces specific symptoms even in the absence of the bacterium.
endotoxins (EN-doh-TOKS-in) A component of the outer membranes of certain gram-negative bacteria responsible for generalized symptoms of  fever and ache.
 
 

    Introduction to the Protists

         Protists are the most diverse of all eukaryotes
         Symbiosis was involved in the genesis of eukaryotes from prokaryotes

    Protist Systematics and Phylogeny

         Monophyletic taxa are emerging from modern research in protist
         systematics
         Members of candidate kingdom Archaezoa lack mitochondria and may
         represent early eukaryotic lineages
         Candidate kingdom Euglenozoa includes both autotrophic and heterotrophic
         flagellates
         Subsurface cavities (alveoli) are diagnostic of candidate kingdom Alveolata
         A diverse assemblage of unicellular eukaryotes move by means of
         pseudopodia
         Slime molds have structural adaptations and life cycles that enhance their
         ecological role as decomposers
         Diatoms, golden algae, brown algae, and water molds are members of
         candidate kingdom Stramenopila
         Structural and biochemical adaptations help seaweeds survive and
         reproduce at the ocean's margins
         Some algae have life cycles with alternating multicellular haploid and diploid
         generations
         Red algae (candidate kingdom Rhodophyta) lack flagella
         Green algae and plants probably had a common photoautotrophic ancestor
         Multicellularity originated independently many times
 

Chapter  28
*acritarchs
protozoa (plural, protozoa) A protist that lives primarily by ingesting food, an animal-like mode of nutrition.
algae (plural, algae) A photosynthetic, plantlike protist.
syngamy (SIN-gam-ee) The process of cellular union during fertilization.
plankton Mostly microscopic organisms that drift passively or swim weakly near the surface of oceans, ponds, and lakes.
*serial endosymbiosis
flagellates (fluh-JEL-um) (plural, flagella) A long cellular appendage specialized for locomotion, formed from a core of nine outer doublet  microtubules and two inner single microtubules, ensheathed in an extension of plasma membrane.
*euglenozoa
*euglenoids
*kinetoplastids
*alveolata
*dinoflagellates
*apicomplexans
*sporozoites
ciliates (SILL-ee-um) (plural, cilia) A short cellular appendage specialized for locomotion, formed from a core of nine outer doublet microtubules  and two inner single microtubules ensheathed in an extension of plasma membrane.
conjugation (KON-joo-GAY-shun) A recombination mechanism that results in the transfer of genetic material between two bacterial cells that  are temporarily joined.
pseudopodia (SOO-doh-POH-dee-um) (plural, pseudopodia) A cellular extension of amoeboid cells used in moving and feeding.
*detritus
*amoebas
*heliozoans
*radiolarian
*forams
*plasmodial slime molds
plasmodium (PLAZ-moh-DEZ-muh) (plural, plasmodesmata) An open channel in the cell wall of plants through which strands of cytoplasm  connect from adjacent cells.
*cellular slime molds
*strmenopila
*diatoms
*golden algae
*water molds
*white rusts
*downy mildews
*brown algae
*thallus
*holdfast
*stripe
*blades
alternation of generations A life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the  gametophyte; characteristic of plants.
sporophyte The multicellular diploid form in organisms undergoing alternation of generations that results from a union of gametes and that  meiotically produces haploid spores that grow into the gametophyte generation.
gametophyte (guh-MEE-toh-fite) The multicellular haploid form in organisms undergoing alternation of generations, which mitotically produces  haploid gametes that unite and grow into the sporophyte generation.
heteromorphic (HET-ur-oh-MOR-fik) A condition in the life cycle of all modern plants in which the sporophyte and gametophyte generations  differ in morphology.
isomorphic Alternating generations in which the sporophytes and gametophytes look alike, although they differ in chromosome  number.
*red algae
*green algae
isogamy (eye-SOG-uh-mee) A condition in which male and female gametes are morphologically indistinguishable.
anisogamy
oogamy (oh-OG-um-ee) A condition in which male and female gametes differ, such that a small, flagellated sperm fertilizes a large, nonmotile egg.
 
 

    An Overview of Plant Evolution

         Structural, chemical, and reproductive adaptations enabled plants to
         colonize land
         The history of terrestrial adaptation is the key to modern plant diversity

    The Origin of Plants

         Plants probably evolved from green algae called charophytes
         Alternation of generations in plants may have originated by delayed meiosis
         Adaptations to shallow water preadapted plants for living on land

    Bryophytes

         The embryophyte adaptation evolved in bryophytes
         The gametophyte is the dominant generation in the life cycles of bryophytes
         The three divisions of bryophytes are mosses, liverworts, and hornworts

    The Origin of Vascular Plants

         Additional terrestrial adaptations evolved as vascular plants descended from
         bryophyte-like ancestors
         The branched sporophytes of vascular plants amplified the production of
         spores and made more complex bodies possible

    Seedless Vascular Plants

         A sporophyte-dominant life cycle evolved in seedless vascular plants
         The three divisions of seedless vascular plants are lycophytes, horsetails,
         and ferns
         Seedless vascular plants formed vast "coal forests" during the Carboniferous
         period

Chapter  29
stomata (plural, stomata) A microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant.
*secondary products
lignin (LIG-nin) A hard material embedded in the cellulose matrix of vascular plant cell walls that functions as an important adaptation for  support in terrestrial species.
*sporopollenin
gametangia (GAM-eh-TANJ-ee-um) (plural, gametangia) The reproductive organ of bryophytes, consisting of the male antheridium and  female archegonium; a multichambered jacket of sterile cells in which gametes are formed.
gametophyte (guh-MEE-toh-fite) The multicellular haploid form in organisms undergoing alternation of generations, which mitotically produces haploid gametes that unite and grow into the sporophyte generation.
sporophyte The multicellular diploid form in organisms undergoing alternation of generations that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generation.
vascular tissue Plant tissue consisting of cells joined into tubes that transport water and nutrients throughout the plant body.
gymnosperms (JIM-noh-spurm) A vascular plant that bears naked seeds not enclosed in any specialized chambers.
angiosperms (AN-jee-oh-spurm) A flowering plant, which forms seeds inside a protective chamber called an ovary.
*division
*charophytes
antheridium (an-theh-RID-ee-um) In plants, the male gametangium, a moist chamber in which gametes develop.
archegonium (ar-kih-GO-nee-um) In plants, the female gametangium, a moist chamber in which gametes develop.
sporangium (plural, sporangia) A capsule in fungi and plants in which meiosis occurs and haploid spores develop.
*mosses
*liverworts
*hornworts
xylem (ZY-lum) The tube-shaped, nonliving portion of the vascular system in plants that carries water and minerals from the roots to the rest of  the plant.
phloem (FLOH-um) The portion of the vascular system in plants consisting of living cells arranged into elongated tubes that transport sugar  and other organic nutrients throughout the plant.
homosporous (home-OS-pur-us) Referring to plants in which a single type of spore develops into a bisexual gametophyte having both male and  female sex organs.
heterosporous (HET-ur-OS-pur-us) Referring to plants in which the sporophyte produces two kinds of spores that develop into unisexual  gametophytes, either female or male.
*megaspores
*microspores
*lycophytes
epiphytes (EP-eh-fite) A plant that nourishes itself but grows on the surface of another plant for support, usually on the branches or trunks of  tropical trees.
*sporophyls
*horsetails
*ferns
 
 

    Overview of Reproductive Adaptations of Seed Plants

         The gametophytes of seed plants became even more reduced than the
         gametophytes of seedless vascular plants
         In seed plants, the seed replaced the spore as the main means of
         dispersing offspring
         Pollen became the vehicles for sperm cells in seed plants

    Gymnosperms

         The Mesozoic era was the age of gymnosperms
         The four divisions of extant gymnosperms are the cycads, the ginkgo, the
         gnetophytes, and the conifers
         The life cycle of a pine demonstrates the key reproductive adaptations of
         seed plants

    Angiosperms (Flowering Plants)

         Terrestrial adaptation continued with the refinement of vascular tissue in
         angiosperms
         The flower is the defining reproductive adaptation of angiosperms
         Fruits help disperse the seeds of angiosperms
         The life cycle of an angiosperm is a highly refined version of the alternation
         of generations common to all plants
         The radiation of angiosperms marks the transition from the Mesozoic era to
         the Cenozoic era
         Angiosperms and animals have shaped one another's evolution
         Agriculture is based almost entirely on angiosperms

    The Global Impact of Plants

         Plants transformed the atmosphere and the climate Plant diversity is a
         nonrenewable resource
 

Chapter  30
seed An adaptation for terrestrial plants consisting of an embryo packaged along with a store of food within a resistant coat.
*nucellus
*integuments
ovule (OV-yool) A structure that develops in the plant ovary and contains the female gametophyte.
conifer A gymnosperm whose reproductive structure is the cone. Conifers include pines, firs, redwoods, and other large trees.
tracheids (TRAY-kee-id) A water-conducting and supportive element of xylem composed of long, thin cells with tapered ends and walls  hardened with lignin.
vessel elements A specialized short, wide cell in angiosperms; arranged end to end, they form continuous tubes for water transport.
fiber A lignified cell type that reinforces the xylem of angiosperms and functions in mechanical support; a slender, tapered sclerenchyma cell  that usually occurs in bundles.
*flower
sepals (SEE-pul) A whorl of modified leaves in angiosperms that encloses and protects the flower bud before it opens.
*petals
stamens The pollen-producing male reproductive organ of a flower, consisting of an anther and filament.
carpels (KAR-pel) The female reproductive organ of a flower, consisting of the stigma, style, and ovary.
*filament
anther (AN-thur) The terminal pollen sac of a stamen, inside which pollen grains with male gametes form in the flower of an angiosperm.
*stigma
*style
ovary (OH-vur-ee) (1) In flowers, the portion of a carpel in which the egg-containing ovules develop. (2) In animals, the structure that produces  female gametes and reproductive hormones.
fruit A mature ovary of a flower that protects dormant seeds and aids in their dispersal.
pollen grains An immature male gametophyte that develops within the anthers of stamens in a flower.
ovules (OV-yool) A structure that develops in the plant ovary and contains the female gametophyte.
embryo sac The female gametophyte of angiosperms, formed from the growth and division of the megaspore into a multicellular structure with eight haploid nuclei.
*cross-pollination
double fertilization A mechanism of fertilization in angiosperms, in which two sperm cells unite with two cells in the embryo sac to form the zygote and endosperm.
*cotyledons
endosperm (EN-doh-spurm) A nutrient-rich tissue formed by the union of a sperm cell with two polar nuclei during double fertilization, which provides nourishment to the developing embryo in angiosperm seeds.
coevolution The mutual influence on the evolution of two different species interacting with each other and reciprocally influencing each other's adaptations.
 
 

    Overview of Reproductive Adaptations of Seed Plants

         The gametophytes of seed plants became even more reduced than the
         gametophytes of seedless vascular plants
         In seed plants, the seed replaced the spore as the main means of
         dispersing offspring
         Pollen became the vehicles for sperm cells in seed plants

    Gymnosperms

         The Mesozoic era was the age of gymnosperms
         The four divisions of extant gymnosperms are the cycads, the ginkgo, the
         gnetophytes, and the conifers
         The life cycle of a pine demonstrates the key reproductive adaptations of
         seed plants

    Angiosperms (Flowering Plants)

         Terrestrial adaptation continued with the refinement of vascular tissue in
         angiosperms
         The flower is the defining reproductive adaptation of angiosperms
         Fruits help disperse the seeds of angiosperms
         The life cycle of an angiosperm is a highly refined version of the alternation
         of generations common to all plants
         The radiation of angiosperms marks the transition from the Mesozoic era to
         the Cenozoic era
         Angiosperms and animals have shaped one another's evolution
         Agriculture is based almost entirely on angiosperms

    The Global Impact of Plants

         Plants transformed the atmosphere and the climate Plant diversity is a
         nonrenewable resource
 
 

    What Is an Animal?
    An Overview of Animal Phylogeny and Diversity

         Parazoans lack true tissues
         Radiata and bilateria are the major branches of eumetazoans
         Evolution of body cavities led to more complex animals
         Coelomates branched into protostomes and deuterostomes

    The Origins of Animal Diversity

         Most animal phyla originated in a relatively brief span of geological time
         Developmental genetics may clarify our understanding of the Cambrian
         diversification
 
 

    The Parazoa

         Phylum Porifera: Sponges are sessile with porous bodies and choanocytes

    The Radiata

         Phylum Cnidaria: Cnidarians have radial symmetry, a gastrovascular cavity,
         and cnidocytes
         Phylum Ctenophora: Comb jellies possess rows of ciliary plates and
         adhesive colloblasts

    The Acoelomates

         Phylum Platyhelminthes: Flatworms are dorsoventrally flattened
         acoelomates

    The Pseudocoelomates

         Phylum Rotifera: Rotifers have jaws and a crown of cilia
         Phylum Nematoda: Roundworms are unsegmented and cylindrical with
         tapered ends

    The Coelomates: Protostomes

         Phylum Nemertea: The phylogenetic position of proboscis worms is
         uncertain
         The lophophorate phyla: Bryozoans, phoronids, and brachiopods have
         ciliated tentacles around their mouths
         Phylum Mollusca: Mollusks have a muscular foot, a visceral mass, and a
         mantle
         Phylum Annelida: Annelids are segmented worms
         Phylum Arthropoda: Arthropods have regional segmentation, jointed
         appendages, and an exoskeleton

    The Coelomates: Deuterostomes

         Phylum Echinodermata: Echinoderms have a water vascular system and
         secondary radial symmetry
         Phylum Chordata: The chordates include two invertebrate subphyla and all
         vertebrates
 

Chapter  33
invertebrates An animal without a backbone; invertebrates make up 95% of animal species.
*spongocoel
*osculum
*mesohyl
*amoebocytes
*hermaphrodites
gastrovascular cavity The central digestive compartment, usually with a single opening that functions as both mouth and anus.
polyps (POL-ip) The sessile variant of the cniderian body plan. The alternate form is the medusa.
medusa (meh-DOO-suh) The floating, flattened, mouth-down version of the cnidarian body plan. The alternate form is the polyp.
*cnidocytes
*cnidae
*nematocysts
*colloblasts
*Planarians
*digestive tract
*parathenogenesis
*closed circulatory system
*lophophorate animals
*lophore
*Bryozoans
*Phoronids
*Brachiopods
*foot
*viceral mass
mantle A heavy fold of tissue in mollusks that drapes over the visceral mass and may secrete a shell.
*mantle cavity
*radula
*trochophore
*torsion
*ammonites
metanephridia (MET-uh-neh-FRID-ee-um) (plural, metanephridia) In annelid worms, a type of excretory tubule with internal openings called
nephrostomes that collect body fluids and external openings called nephridiopores.
cuticle (KYOO-teh-kul) (1) A waxy covering on the surface of stems and leaves that acts as an adaptation to prevent desiccation in terrestrial
plants. (2) The exoskeleton of an arthropod, consisting of layers of protein and chitin that are variously modified for different functions.
exoskeleton A hard encasement on the surface of an animal, such as the shells of mollusks or the cuticles of arthropods, that provides
protection and points of attachment for muscles.
molting A process in arthropods in which the exoskeleton is shed at intervals to allow growth by the secretion of a larger exoskeleton.
open circulatory systems An arrangement of internal transport in which blood bathes the organs directly and there is no distinction between
blood and interstitial fluid.
*trilobites
*chelicerates
*uniramians
*crustaceans
*chelicerae
*mandibles
*antennae
compound eyes A type of multifaceted eye in insects and crustaceans consisting of up to several thousand light-detecting, focusing ommatidia;
especially good at detecting movement.
*trilobites
*eurypterids
*Class Arachnida
book lungs Organs of gas exchange in spiders, consisting of stacked plates contained in an internal chamber.
*Class Diploda
*Class Chilopoda
*Class Insecta
*entomology
Malpighian tubules (mal-PIG-ee-un) A unique excretory organ of insects that empties into the digestive tract, removes nitrogenous wastes from
the blood, and functions in osmoregulation.
tracheal system A gas exchange system of branched, chitin-lined tubes that infiltrate the body and carry oxygen directly to cells in insects.
incomplete metamorphosis (MET-uh-MOR-foh-sis) A type of development in certain insects, such as grasshoppers, in which the larvae
resemble adults but are smaller and have different body proportions. The animal goes through a series of molts, each time looking more like an
adult, until it reaches full size.
*complete metamorphosis
*isopods
*decapods
*echinoderms
*water vascular system
*tube feet
 
 

    Invertebrate Chordates and the Origin of Vertebrates

         Four anatomical features characterize Phylum Chordata
         Invertebrate chordates provide clues to the origin of vertebrates

    Introduction to the Vertebrates

         Neural crest, pronounced cephalization, a vertebral column, and a closed
         circulatory system characterize Subphylum Vertebrata
         Overview of vertebrate diversity

    Superclass Agnatha: Jawless Vertebrates

         Lampreys and hagfishes are the only extant agnathans

    Superclass Gnathostomata I: The Fishes

         Vertebrate jaws evolved from skeletal supports of the pharyngeal slits
         A cartilaginous endoskeleton reinforced by calcified granules is diagnostic
         of Class Chondrichthyes
         A bony endoskeleton, operculum, and swim bladder are hallmarks of Class
         Osteichthyes

    Superclass Gnathostomata II: The Tetrapods

         Amphibians are the oldest class of tetrapods
         Evolution of the amniotic egg expanded the success of vertebrates on land
         A reptilian heritage is evident in all amniotes Birds began as flying reptiles
         Mammals diversified extensively in the wake of the Cretaceous extinctions

    Primates and the Phylogeny of Homo sapiens

         Primate evolution provides a context for understanding human origins
         Humanity is one very young twig on the vertebrate tree

Chapter  34
Chordates (KOR-date) A member of a diverse phylum of animals that possess a notochord; a dorsal, hollow nerve cord; pharyngeal gill slits; and
a postanal tail as embryos.
notochord (NO-toh-kord) A longitudinal, flexible rod formed from dorsal mesoderm and located between the gut and the nerve cord in all
chordate embryos.
Urochordates (tunicates) A chordate without a backbone, commonly called a tunicate, a sessile marine animal.
*lancelets
cephalochordates A chordate without a backbone, represented by lancelets, tiny marine animals.
*somites
paedogenesis (pee-doh-JEN-eh-sis) The precocious development of sexual maturity in a larva.
neural crest A band of cells along the border where the neural tube pinches off from the ectoderm; the cells migrate to various parts of the
embryo and form the pigment cells in the skin, bones of the skull, the teeth, the adrenal glands, and parts of the peripheral nervous system.
amniotic egg (AM-nee-AH-tik) A shelled, water-retaining egg that enables reptiles, birds, and egg-laying mammals to complete their life cycles on dry land.
amniotes A vertebrate possessing an amnion surrounding the embryo; reptiles, birds, and mammals are amniotes.
Superclass Agnatha (AG-naa-thun) A member of a jawless class of vertebrates represented today by the lampreys and hagfishes.
ostracoderms (os-TRAK-uh-durm) An extinct agnathan; a fishlike creature encased in an armor of bony plates.
*Superclass Gnathostomata
placoderms (PLAK-oh-durm) A member of an extinct class of fishlike vertebrates that had jaws and were enclosed in a tough, outer armor.
Class Chondrichthyes The vertebrate class of cartilaginous fishes, represented by sharks and their relatives.
*spiral valve
lateral line system
oviparous (oh-VIP-ur-us) Referring to a type of development in which young hatch from eggs laid outside the mother's body.
ovoviviparous (OH-voh-vy-VIP-ur-us) Referring to a type of development in which young hatch from eggs that are retained in the mother's
uterus.
cloaca (kloh-AY-kuh) A common opening for the digestive, urinary, and reproductive tracts in all vertebrates except most mammals.
Class Osteichthyes The vertebrate class of bony fishes, characterized by a skeleton reinforced by calcium phosphate; the most abundant and diverse
vertebrates.
*operculum
swimm bladder
Superclass Actinopterygli (ray-finned fish)
Superclass Sarcopterygii (lobe-finned fishes and lungfish)
Class Amphibia The vertebrate class of amphibians, represented by frogs, salamanders, and caecilians.
*urodeles
*Anurans
Apodans
extraembryonic membranes (EKS-truh-EM-bree-AHN-ik) Four membranes (yolk sac, amnion, chorion, allantois) that support the developing
embryo in reptiles, birds, and mammals.
Class Repitlia The vertebrate class of reptiles, represented by lizards, snakes, turtles, and crocodilians.
ectotherms (EK-toh-thurm) An animal, such as a reptile, fish, or amphibian, that must use environmental energy and behavioral adaptations to
regulate its body temperature.
*synapsids
*sauropsids
*anapsids
*diapsids
*dinosaurs
*pterosaurs
*endothermic
*Cretaceous crisis
*Chelonia
*Squamata
*Crocodilia
Class Aves The vertebrate class of birds, characterized by feathers and other flight adaptations.
*ratites
*carinates
*passeriformes
Class Mammalia The vertebrate class of mammals, characterized by body hair and mammary glands that produce milk to nourish the young.
placenta (pluh-SEN-tuh) A structure in the pregnant uterus for nourishing a viviparous fetus with the mother's blood supply; formed from the
uterine lining and embryonic membranes.
*therapsids
monotremes (MON-uh-treem) An egg-laying mammal, represented by the platypus and echidna.
marsupial (mar-SOOP-ee-ul) A mammal, such as a koala, kangaroo, or opossum, whose young complete their embryonic development inside a
maternal pouch called the marsupium.
*eutherian mammals
*prosimians
*anthropoids
paleoanthropology (PAY-lee-un-TOL-uh-jee) The scientific study of fossils.
mosaic evolution The evolution of different features of an organism at different rates.