BISC 104—Inquiry of Life: The Environment

Biology: The EssentialMidterm Exam Chapters 12, 22

Vocabulary by Chapter

Chapter 22

Abscisic Acid: plant hormone that inhibits seed germination and plant growth.

Alternation of Generations: the sexual life cycle of plants and many green algae, which alternates between a diploid sporophyte stage and a haploid gametophyte stage

Anthers: pollen-producing structure at tip of stamen

Apical Dominance: the suppression of the growth of lateral buds by the intact terminal bud of a plant

Asexual Reproduction: form of reproduction in which offspring arise from only one parent.

Auxins: plant hormones that promotes cell elongation in stems and fruits.

Calyx: collective term for the sepals of a flower.

Carpels: leaflike structure enclosing an angiosperm’s ovule(s)

Coevolution: genetic change in one species selects for subsequent change in another species.

Corolla: collective term for the petals of a flower.

Cotyledons: seed leaf in angiosperms

Cytokinins: plant hormone that stimulates cell division

Double Fertilization: in angiosperms, one sperm nucleus fertilizes the egg and another fertilizes the polar nuclei

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Embryo Sac: mature female gametophyte in angiosperms

Endosperm: triploid tissue that stores food for the embryo in an angiosperm seed.

Ethylene: volatile plant hormone that ripens fruit.

Fertilization: the union of two gametes.

Flowers: reproductive structure in angiosperms; produce pollen and eggs

Fruit: seed-containing structure in angiosperms

Gametes: a sex cell; sperm or egg cell

Gametophyte: haploid, gamete-producing stage of the plant life cycle

Germination: resumption of growth after seed dormancy is broken

Gibberellins: plant hormone that promotes shoot elongation

Gravitropism: directional growth response to gravity.

Hormones: biochemical synthesized in small quantities in one place and transported to another

Megaspores: in seed plants, spore that gives rise to female gametophyte

Microspores: in seed plants, a spore that gives rise to a male gametophyte

Ovary: the base of a flower’s carpel, which encloses one or more ovules; in animals, the female gonad

Ovules: egg-bearing structure that develops into a seed in gymnosperms and angiosperms

Petals: flower part interior to sepals

Photoperiod: day length

Photoreceptor: molecule or cell that detects quality and quantity of light.

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Phototropism: directional growth response to unidirectional light

Polar Nuclei: one of two nuclei fertilized to yield endosperm in angiosperms

Pollen: immature male gametophyte in seed plants (gymnosperms and angiosperms)

Pollination: physical, chemical or biological change in the environment that harms organisms

Receptacle: attachment point for flower parts

Seed Coat: protective outer layer of seed.

Seed: in gymnosperms and angiosperms, a plant embryo packaged with a food supply inside a tough outer coat.

Sepals: part of the outermost whorl of a flower

Sexual Reproduction: the combination of genetic material from two individuals to create a third individual.

Spores: reproductive cell of a plant or fungus

Sporophyte: diploid, spore-producing stage of the plant life cycle.

Stamens: male flower part interior to petals

Statoliths: starch-containing plastid in root cap cell that functions as a gravity detector

Stigma: in angiosperms, pollen-receiving tip of style

Style: in angiosperms, the stalklike-upper part of a carpel

Thigmotropism: directional growth response to touch

Tropism: orientation toward or away from a stimulus.

Zygote: the fused egg and sperm that develops into a diploid individual.

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Chapter 12

Adaptations: inherited trait that permits an organism to survive and reproduce.

Allele Frequencies: number of copies of one allele, divided by the number of alleles in a population.

Artificial Selection: selective breeding strategy in which a human allows only organisms with desired traits to reproduce.

Bottleneck: sudden reduction in the size of a population.

Descent with Modification: over many generations, natural selection can change the characteristics of populations, even giving rise to new species.

Directional Selection: form of natural selection in which one extreme phenotypes is fittest, and the environment selects against the others.

Disruptive Selection: form of natural selection in which the two extreme phenotypes are fittest

Evolution: descent with modification; change in allele frequencies in a population over time.

Fitness: an organism’s contribution to the next generation’s gene pool.

Founder Effect: genetic drift that occurs when a small, nonrepresentative group of individuals leaves their ancestral population and begins a new settlement.

Gene Pool: all of the genes and their alleles in a population

Genetic Drift: change in allele frequencies that occurs purely by chance.

Genetic Variation: Within a species, no two individuals are exactly alike. Some of this variation is heritable.

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Genotype Frequencies: number of individuals of one genotype, divided by the number of individuals in the population.

Hardy-Weinberg Equilibrium: Situation in which allele frequencies do not change from one generation to the next.

Largest Harvested: Remove the largest 90% of the fish from two of the tanks, leaving the smallest 10% to reproduce. This treatment simulated fishing policies that protect all fish below a minimum size.

Limited Resources: Every habitat contains limited supplies of the resources required for survival.

Microevolution: relatively short-term changes in allele frequencies within a population or species.

Modern Evolutionary Synthesis: the idea that genetic mutations create the variation upon which natural selection acts.

Natural Selection: differential reproduction of organisms based on inherited traits.

On the Origin of Species: proposed natural selection as an evolutionary mechanism.

Overproduction of Offspring: More individuals are born than survive to reproduce.

Population: interbreeding members of the same species occupying the same region

Random Harvested (Control): Remove 90% of the fish, without size bias

Sexual Dimorphism: differences in appearance between males and females

Sexual Selection: type of natural selection resulting from variation in the ability to obtain mates.

Small Harvested: Remove the smallest 90% of the silversides.

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Stabilizing Selection: form of natural selection in which extreme phenotypes are less fir than the optimal intermediate phenotype.

Struggle for Existence: Individuals compete for the limited resources that enable them to survive.

Unequal Reproductive Success (Natural Selection): The inherited characteristics of some individuals make them more likely to obtain resources, survive, and reproduce.

Chapter 13

Absolute Dating: determining the age of a fossil in years

Analogous: similar in function but not in structure because of convergent evolution, not common ancestry

Biogeography: the study of the distribution patterns of species across the planet.

Convergent Evolution: the evolution of similar adaptations in organisms that do not share the same evolutionary lineage

Fossil: any evidence of an organism from more than 10,000 years ago

Geological Timescale: a division of Earth’s history into eons, eras, periods, and epochs defined by major geological or biological events.

Half-Life: the time it takes for half the atoms in a sample of a radioactive substance to decay

Homeotic: describes any gene that, when mutated, leads to organisms with structures in the wrong places

Homologous: similar in structure or position because of common ancestry

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Molecular Clock: application of the rate at which DNA mutates to estimate when two types of organisms diverged from a shared ancestor.

Paleontology: the study of fossil remains or other clues to past life.

Plate Tectonics: theory that Earth’s surface consists of several plates that move in response to forces acting deep within the planet.

Radiometric Dating: type of absolute dating that uses known rates or radioactive decay to date fossils

Relative Dating: placing a fossil into a sequence of events without assigning it a specific age.

Vestigial: having no apparent function in one organism, but homologous to a functional structure in another species.

Chapter 14

Allopatric Speciation: formation of new species after a physical barrier separates a population into groups that cannot interbreed

Ancestral Characters: characteristics already present in the ancestor of a group being studied.

Background Extinction Rate: steady, gradual loss of species through natural competition or loss of genetic diversity.

Biological Species Concept: a population, or group of populations, whose members can interbreed and produce fertile offspring

Clade: monophyletic group of organisms consisting of a common ancestor and all of its descendants.

Cladistics: Phylogenetic system that defines groups by distinguishing between ancestral and derived character

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Cladogram: treelike diagram built using shared derived characteristics

Derived Characters: characteristic not found in the ancestor of a group being studied.

Extinct: disappearance of a species

Gene Pool: all of the genes and their alleles in a population

Gradualism: theory that proposes that evolutionary change occurs gradually, in a series of small steps

Impact Theory: idea that mass extinctions were caused by impacts of extraterrestrial origin

Macroevolution: large-scale evolutionary change.

Mass Extinctions: the disappearance of many species over relatively short expanses of time.

Outgroup: basis for comparison in a cladistics analysis

Phylogenetic Tree: Diagram depicting hypothesized evolutionary relationships

Phylogenetic: field of study that attempts to explain the evolutionary relationships among species.

Polyploidy: cell with extra chromosome sets

Postzygotic Reproductive Barriers: separation of species due to selection against hybrid offspring.

Prezygotic Reproductive Barriers: separation of species due to factors that prevent the formation of a zygote

Punctuated equilibrium: theory that life’s history has been characterized by bursts of rapid evolution interrupting long periods of little change

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Speciation: formation of one or more new species.

Species: a distinct type of organism

Sympatric Speciation: formation of a new species within the habitat boundaries of a parent species

Systematics: field of study that includes taxonomy and phylogenetic

Taxon: a group of organisms at any rank in the taxonomic hierarchy

Taxonomy: the science of describing, naming, and classifying organisms.

Chapter 15

Algae: aquatic, photosynthetic protist

Amoeboid Protozoa: unicellular protist that produces pseudopodia

Apicomplexans: non-motile protist with cell containing an apical complex; obligate animal parasite

Archaea: one of two domains of prokaryotes

Autotrophs: organism that produces organic molecules by acquiring carbon from inorganic sources; primary producers

Bacillus: rod-shaped prokaryotes

Bacteria: one of two domains of prokaryotes

Basidiomycetes: fungus that produces sexual spores on a basidium

Brown Algae: multicellular photosynthetic aquatic protist with swimming spores and brownish accessory pigments.

Cell Wall: a rigid boundary surrounding cells of many prokaryotes, Protists, plants, and fungi

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Cellular Slime Mold: protist in which feeding stage consists of individual cells that come together as a multicellular “slug” when food runs out.

Chemotrophs: organism that derives energy by oxidizing inorganic or organic chemicals

Chytridiomycetes: microscope fungus that produces motile zoospores

Ciliates: protist with cilia-covered cell surface

Coccus: spherical prokaryote

Diatoms: photosynthetic aquatic protist with a two-part silica wall

Dinoflagellates: unicellular aquatic protist with two flagella of unequal length; many have cellulose plates

Disrupting Cell Membranes: Polymyxin antibiotics exploit differences between bacterial and eukaryotic cell membranes

Endophytes: fungus that colonizes a plant without triggering disease symptoms.

Endospores: dormant, thick-walled structure that enables some bacteria to survive harsh conditions

Endosymbiont Theory: the idea that mitochondria and chloroplasts originated as free-living bacteria engulfed by other prokaryotic cells

Eukaryotic Cell: organism composed of one or more cells containing a nucleus and other membrane-bounded organelles

Facultative Anaerobes: organism that can live with or without O2

Flagellated Protozoa: unicellular heterotrophic protist with one of more flagella

Flagellum: a long whiplike appendage that a cell uses for motility

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Foraminiferans: amoeboid protozoan with calcium carbonate shell

Fungi: kingdom containing mostly multicellular eukaryotes that are heterotrophs by external digestion

Geological Timescale: a division of Earth’s history into eons, eras, periods, and epochs defined by major geological or biological events.

Glomeromycetes: fungus lacking sexual spores; forms mycorrhizae

Green Algae: photosynthetic protist that has pigments, starch, and cell walls similar to those of land plants/.

Heterotrophs: organism that obtains carbon and energy by eating another organism; consumer

Hyphae: a fungal filament; the basic structural unit of a multicellular fungus

Inhibiting Cell Wall Synthesis: Penicillin is an antibiotic that interferes with cell wall formation. A bacterium that cannot make a rigid cell wall will burst and die.

Inhibiting Enzymes: Theoretically, antibiotics could block any bacterial metabolic pathway that does not occur in host cells. Sulfanilamide, for example, interferes with a bacterial enzyme that participates in an essential chain of chemical reactions.

Inhibiting Protein Assembly: The antibiotics streptomycin, Chloramphenicol, and erythromycin bind to the bacterial ribosomes, killing bacteria without harming us.

Inhibiting Transcription: Rifamycin antibiotics prevent RNA synthesis in bacteria by binding to a bacterial form of RNA polymerase

Lichens: association of a fungus and a green alga or cyanobacterium

Mycelium: assemblage of hyphae that forms an individual fungus

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Mycorrihiza: mutually beneficial association of a fungus and the roots of a plant

Nitrogen Fixation: conversation of N2 to NH4+, a form of nitrogen that plants

can use.

Nucleoid: the part of a prokaryotic cell where the DNA is located.

Obligate Aerobes: organism that requires O2 for generating ATP

Obligate Anaerobes: organism that must live in the absence of O2

Peptidoglycan: material in bacterial cell wall

Phototrophs: organism that derives energy from sunlight

Pili: short projection made of protein on a prokaryotic cell.

Plasmids: small circle of double-stranded DNA separate from a cell’s chromosome

Plasmodia Slime Mold: protist in which feeding stage consists of a plasmodium containing many nuclei

Prokaryote: a cell that lacks a nucleus and other membrane-bounded organelles; bacteria and archaea.

Protist: eukaryotic organism that is not a plant, fungus, or animal

Protozoan: unicellular protist that is heterotrophic and (usually) motile

Red Algae: multicellular, photosynthetic, marine protist with red or blue accessory pigments.

Ribosomes: a structure built of RNA and protein where mRNA anchors during protein synthesis

RNA World: the idea that the first independently replicating life form was RNA

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Spirillum: spiral-shaped prokaryote

Spores: reproductive cell of a plant or fungus

Water molds: filamentous, heterotrophic protist; called an oomycete

Zygomycetes: fungus that produces zygospores

Chapter 17

Amniotes: a vertebrate in which protective membranes surround the embryo (amnion, chorion, and allantois); reptiles and mammals

Amniotic Egg: reptile or Monotremes egg containing fluid and nutrients within membranes that protect the embryo

Amphibian: tetrapod vertebrate that can live on land but requires water to reproduce.

Annelids: segmented worm; phylum Annelida

Arachnids: type of chelicerate arthropod; spider, ticks, mites, and scorpions

Arthropods: segmented animal with an exoskeleton and jointed appendages; phylum Arthropod.

Bilateral Symmetry: body form in which only one plane divides the animal into mirror image halves.

Birds: tetrapod vertebrates with feathers, wings, and an amniotic egg

Bivalves: type of mollusk

Blastula: stage of early animal embryonic development; a sphere of cells surrounding a fluid-filled cavity

Bony Fishes: jawed fish with a skeleton made of bone; ray-finned fishes and lobe-finned fishes.

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Caecilians: type of amphibian

Cartilaginous Fishes: jawed fish with a skeleton made of cartilage; sharks, skates, and rays

Centipedes: type of Mandibulates arthropod

Cephalization: development of sensory structures and a brain at the head end of an animal

Cephalopods: type of mollusk

Chelicerates: arthropod with clawlike mouthparts (chelicerae); horseshoe crabs and arachnids

Chitons: type of mollusk

Chordates: animal that at some time during its development has a notochord, hollow nerve cord, pharyngeal pouches or slits, and a Postanal tail; phylum Chordata

Cnidarians: animal with radial symmetry, two germ layers, a jellylike interior, and Cnidocytes; phylum Cnidarian

Cnidocytes: cell in cnidarians that can fire a toxic barb in predation or defense

Coelacanths: type of lobe-finned fish

Coelom: fluid-filled animal body cavity that forms completely within mesoderm

Completer Digestive Tract: digestive tract through which food passes in one direction from mouth to anus.

Cranium: part of the skull that encloses the brain

Crocodilians: type of reptile

Crustaceans: type of Mandibulates arthropod

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Culture: the knowledge, beliefs, and behaviors that humans transmit from generation to generation

Deuterostomes: clade of bilaterally symmetrical animals in which the first opening in the gastrula develops into the anus

Dorsal, Hollow Nerve Chord: tubular nerve cord that forms dorsal to the notochord; one of the four characteristics of chordates

Echinoderms: unsegmented Deuterostomes with a five-part body plan, radial symmetry in adults, and a spiny outer covering; phylum Echinodermata.

Ectoderm: outermost germ layer in an animal embryo

Ectotherm: animal that lacks an internal mechanism that keeps its temperature within a narrow range; invertebrates, fishes, amphibians, and nonavian reptiles

Endoderm: innermost germ layer in an animal embryo

Endotherms: animal that maintains its body temperature by using heat generated from its own metabolism; birds and mammals

Exoskeleton: skeleton on the outside of an animal

Feathers: in birds, an epidermal outgrowth composed of keratin

Fishes: vertebrate animal with fins and external gills

Flatworms: unsegmented worm lacking a coelom; phylum Platyhelminthes

Flukes: type of parasitic flatworm

Foot: ventral muscular structure that provides movement in mollusks

Free-Living Flatworms: planarian or marine flatworm

Frogs: type of amphibian

Gastropods: type of mollusk

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Gastrovascular Cavity: digestive chamber with a single opening

Gastrula: stage of early animal embryonic development during which three tissue layers form

Hagfish: jawless animal with a cranium but not vertebrae

Hominids: any of the “great apes” (orangutans, gorillas, chimpanzees, and humans)

Hominines: extinct or modern human

Hominoids: any ape, including humans.

Horseshoe Crabs: type of chelicerate arthropod

Hydrostatic Skelton: skeleton consisting of constrained fluid in a closed body compartment.

Incomplete Digestive Tract: digestive tract with one opening that takes in food and ejects waste.

Insects: type of Mandibulates arthropod

Invertebrates: animal without a backbone

Jaws: bones that frame the entrance to the mouth.

Lampreys: type of jawless fish

Lancelets: type of invertebrate chordate

Lateral Line: network of canals that extends along the sides of fished and houses receptors organs that detect vibrations.

Leeches: type of annelid

Lizards: type of reptile

Lobe-Finned Fishes: type of bony fish; coelacanths and lungfishes.

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Lungfishes: type of lobe-finned fish

Lungs: sac-like structure where gas exchange occurs in air-breathing vertebrates

Mammals: amniotes with hair and mammary glands

Mammary Glands: milk-producing gland in mammals

Mandibulates: arthropod with jawlike mouthparts (mandibles); crustaceans, insects, centipedes, and millipedes.

Mantle: dorsal fold of tissue that secretes a shell in most mollusks.

Marsupials: mammal that bears live young after a short gestation.

Medusa: free-swimming form of a cnidarian

Mesoderm: embryonic germ layer between ectoderm and endoderm in an animal embryo

Metamorphosis: developmental process in which an animal changes drastically in body from during the transition between juvenile and adult.

Millipedes: type of Mandibulates arthropod

Mollusks: unsegmented animal with a soft body, mantle, muscular foot, and visceral mass; phylum Mollusca

Monotremes: egg-laying mammal

Notochord: flexible rod that forms the framework of the vertebral column and induces formation of the neural tube; one of the four characteristics of chordates

Oligochaetes: type of annelid

Pharyngeal Pouches or Slits: opening in the pharynx of a chordate embryo; one of the four characteristics or chordates.

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Placenta: structure that connects the developing fetus to the maternal circulation in placental mammals

Placental Mammals: mammal in which the developing fetus is nourished by a placenta

Polychaetes: type of annelid

Polyp: sessile form of a cnidarian

Postanal Tail: muscular tail that extend past the anus; one of the four characteristics of chordates.

Primates: mammal with opposable thumbs, eyes in front of the skull, a relatively large brain, and flat nails instead of claws; includes prosimians, simians, and hominids

Prosimioan: type of primate; a lemur, aye-aye, Loris, tarsier, or bush baby

Protostomes: clade of bilaterally symmetrical animals in which the first opening in the gastrula develops into the mouth.

Pseudocoelom: fluid-filled animal body cavity lined by endoderm and mesoderm

Radial Symmetry: body form in which any plane passing through the body from the mouth to the opposite end divides the body into mirror images.

Radula: a chitin-rich, toungelike strap in many mollusks

Ray-finned Fishes: type of bony fish

Reptiles: tetrapod vertebrate with an amniotes egg and a dry scaly body covering

Roundworms: unsegmented worm with a Pseudocoelom; phylum Nematoda

Salamanders: type of amphibian

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Segmentation: division of an animal body into repeated subunits.

Simian: type of primate; a monkey

Snakes: type of reptile

Sponges: simple animal lacking true tissues and gastrulation; phylum Porifera.

Tapeworms: type of parasitic flatworm

Tetrapods: vertebrate with four limbs

Trilobites: extinct type of arthropod

Tunicates: type of invertebrate chordate

Vertebrae: one unit of the vertebral column; composed of bone or cartilage that supports and protects the spinal cord.

Vertebrates: animal with a backbone.

Visceral Mass: part of a mollusk that contains the digestive and reproductive systems

Water Vascular System: system of canals in echinoderms; provides locomotion and osmotic balance.

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