chapter 33

1. adhering junction Junction where a mass of anchored proteins help adjoining cells adhere.
2. adipose tissue A connective tissue having an abundance of fat-storing cells.
3. blood Fluid connective tissue of water, solutes, and formed elements (blood cells, platelets). Transports substances to and from cells, helps maintain internal environment.
4. bone tissue Of vertebrate skeleton, a tissue of osteoblast secretions hardened with minerals.
5. cardiac muscle tissue A contractile tissue that is present only in the heart wall.
6. cartilage Connective tissue with solid, pliable intercellular material that resists compression.
7. dense, irregular connective tissue Animal tissue with fibroblasts, many asymmetrically positioned fibers in ground substance. In skin and some capsules around organs.
8. dense, regular connective tissue Animal tissue with rows of fibroblasts between parallel bundles of fibers. In tendons, elastic ligaments.
9. ectoderm The first-formed, outermost primary tissue layer of animal embryos; gives rise to nervous system tissues and integument's outer layer.
10. endocrine gland Ductless gland that secretes hormones, which the bloodstream distributes.
11. endoderm Inner primary tissue layer of animal embryos; source of inner gut lining and derived organs.
12. epithelium Animal tissue that covers external surfaces and lines internal cavities and tubes. One surface is free and the other rests on a basement membrane.
13. exocrine gland Glandular structure that secretes products, usually through ducts or tubes, to a free epithelial surface.
14. gap junction Cylindrical arrays of proteins in the plasma membrane that pair up as open channels for signals between adjoining cells.
15. gland cell A cell that secretes products unrelated to their own metabolism for use elsewhere
16. homeostasis State in which physical and chemical aspects of internal environment (blood, interstitial fluid) are being maintained within ranges suitable for cell activities.
17. internal environment Blood + interstitial fluid.
18. loose connective tissue Animal tissue with fibers, fibroblasts loosely arrayed in semifluid ground substance.
19. mesoderm Primary tissue layer of all large, complex animals; gives rise to many internal organs and part of the integument.
20. nervous tissue Connective tissue composed of neurons and often neuroglia.
21. neuroglia Collectively, cells that structurally and metabolically support neurons. They make up about half the volume of nervous tissue in vertebrates.
22. neuron Type of nerve cell; basic communication unit in most nervous systems.
23. organ Body structure with definite form and function that consists of more than one tissue.
24. organ system Organs interacting chemically, physically, or both in a common task.
25. skeletal muscle tissue Striated contractile tissue that is the functional partner of bone.
26. smooth muscle tissue Nonstriated contractile tissue found in soft internal organs.
27. tight junction Cell junction where strands of fibrous proteins oriented in parallel with a tissue's free surface collectively block leaks between the adjoining cells.
28. tissue Of multicelled organisms, a group of cells and intercellular substances that function together in one or more specialized tasks.

chapter20

angiosperm Flowering plant.
2. archaebacterium Member of the prokaryotic domain Archaebacteria
3. Archean eon Eon in which life arose (3.8-2.5 bya).
4. big bang Model for origin of universe.
5. Cenozoic era The present era (65 mya to present).
6. crust, of Earth Outer zone of low-density rocks resting on the Earth's mantle.
7. dinosaur One of a fabulous group of reptiles that originated in the Triassic and became the dominant land vertebrates for 125 million years.
8. Ediacaran One of the species with a highly flattened body that arose in the precambrian.
9. endosymbiosis theory Continuing physical contact between two species, one of which lives and reproduces inside the other's body.
10. eubacterium Prokaryotic cell; has a nucleoid, but no nucleus, cytoplasm, or cell membrane; most have a cell wall, some encapsulated.
11. eukaryotic cell Cell having a nucleus and other membrane-bound organelles.
12. global broiling hypothesis Theory that an asteroid impact caused the K-T mass extinction by creating a colossal fireball, the debris from which raised global air temperature by thousands of degrees.
13. gymnosperm Type of vascular plant in which seeds form on exposed surfaces of reproductive structures (e.g., on cone scales).
14. K-T asteroid impact theory A huge asteroid hit Earth at the K-T boundary; last dinosaurs perished during the mass extinction.
15. mantle Of mollusks, a tissue draped over the visceral mass. Of Earth, a zone of intermediatedensity rocks beneath the crust.
16. Mesozoic era An era (240-65 mya) of spectacular expansion in the range of global diversity.
17. Paleozoic era Era from Cambrian, Ordovician, Silurian, Devonian, Carboniferous, through the Permian (544 to 248 mya).
18. prokaryotic cell Archaebacterium or eubacterium; single-celled organism, most often walled; lacks the profusion of membranebound organelles observed in eukaryotic cells.
19. Proterozoic eon Period from 2.5 billion to 570 million years ago; period during which eukaryotic cells arose.
20. protistan Photoautotroph or heterotroph (or both) unlike bacteria; some like earliest eukaryotic cells. Has a nucleus, larger ribosomes, mitochondria, ER, Golgi bodies, chromosomes with numerous proteins, and cytoskeletal microtubules. Range in size from microscopic algae to giant kelps.
21. proto-cell Hypothetic cell-like stage between chemical evolution and the first living cell.
22. RNA world One model for prebiotic evolution in which RNA was the template for protein synthesis before the evolution of DNA.
23. stromatolite Fossilized mats of shallow-water microbial communities, mainly cyanobacteria, from Archean to precambrian. Cell secretions blocked UV radiation but trapped sediments, and new mats grew on old ones; some are half a mile thick and hundreds of miles across.

1. analogous structure Body parts that once differed in evolutionarily distant lineages but converged in structure and function as responses to similar environmental pressures.
2. asteroid Rocky, metallic body, a few to 1,000 kilometers across, hurtling through space.
3. comparative morphology Scientific study of comparable body parts of adults or embryonic stages of major lineages.
4. derived trait A novel feature that evolved but once and is shared only by the descendants of the ancestral species in which it evolved.
5. fossil Recognizable, physical evidence of an organism that lived in the distant past.
6. fossilization How fossils form. An organism or evidence of it gets buried in sediments or volcanic ash; water and dissolved inorganic compounds infiltrate it; then chemical changes and pressure from accumulating sediments above transform it to stony hardness.
7. geologic time scale Time scale for the Earth's history with major subdivisions corresponding to mass extinctions. Now radiometrically dated.
8. Gondwana Paleozoic supercontinent; with other land masses, it formed Pangea.
9. half-life The time it takes for half of a given quantity of any radioisotope to decay into a different, and less unstable, daughter isotope.
10. homologous structure Of separate lineages, comparable body parts that show underlying similarity even when they may differ in size, shape, or function; outcome of morphological divergence from a shared ancestor.
11. lineage Line of descent.
12. morphological convergence Macroevolutionary pattern. In response to similar environmental pressures over time, evolutionarily distant lineages evolve in similar ways and end up being alike in appearance, functions, or both.
13. morphological divergence Macroevolutionary pattern; genetically diverging lineages undergo change from body form of a common ancestor.
14. Pangea Paleozoic supercontinent upon which the first terrestrial plants and animals evolved.
15. plate tectonics theory Theory that great slabs (plates) of the Earth's outer layer float on a hot, plastic mantle. All plates are slowly moving and have rafted continents to new positions over time.
16. stratification Stacked layers of sedimentary rock, built up by gradual deposition of volcanic ash, silt, and other materials over time.
17. theory of uniformity Early theory that the earth's surface changes in gradual, uniformly repetitive ways (major floods, earthquakes, and other infrequent catastrophes also occur every year and were not considered unusual). Has since been replaced by plate tectonics theory.
18. adaptive radiation Macroevolutionary pattern; burst of genetic divergences from a lineage that gives rise to many species, each using a novel resource or a new (or newly vacated) habitat.
19. adaptive zone Minimum amount of energy required to get a specific reaction going, with or without the help of an enzyme. Reactions differ in the amount required.
20. allopatric speciation Speciation model. A physical barrier arises, separates populations or subpopulations of a species, ends gene flow, and favors divergences that end in speciation.
21. anagenesis Speciation pattern; changes in allele frequencies and morphology accumulate within an unbranched line of descent.
22. archipelago Island chain some distance away from a continent.
23. biological species concept Defines a species as one or more populations of individuals that are interbreeding under natural conditions, producing fertile offspring, and are isolated reproductively from other such populations. Applies to sexually reproducing species only.
24. cladogenesis Speciation pattern in which a lineage splits and isolated populations undergo genetic divergence.
25. dosage compensation Any mechanism that balances gene expression between the sexes during critical early stages of development.
26. evolutionary tree Treelike diagram; a branch point means divergence from a shared ancestor and branches signify separate lines of descent.
27. extinction Irrevocable loss of a species.
28. gene flow Microevolutionary process; alleles enter and leave a population as an outcome of immigration and emigration, respectively.
29. genetic divergence Gradual accumulation of differences in gene pools of populations or subpopulations of a species after a geographic barrier arises and separates them; thereafter, microevolution occurs independently in each.
30. gradual model of speciation Idea that species arise by many small morphological changes that accumulate over great spans of time.
31. hybrid zone Where adjoining populations are interbreeding and producing hybrid offspring.
32. mass extinction Catastrophic event or phase in geologic time when entire families or other major groups are irrevocably lost.
33. parapatric speciation Idea that neighboring populations can become distinct species while maintaining contact along a common border.
34. punctuation model of speciation Idea that most morphological changes occur in a brief span when populations start to diverge; speciation is rapid, and the daughter species change little for the next 2-6 million years or so.
35. reproductive isolating mechanism Heritable feature of body form, functioning, or behavior that prevents interbreeding between two or more genetically divergent populations.
36. speciation The formation of a daughter species from a population or subpopulation of a parent species by way of microevolutionary processes. Routes vary in their details and duration.
37. species One kind of organism. Of sexually reproducing organisms, one or more natural populations in which individuals are interbreeding and are reproductively isolated from other such groups.
38. sympatric speciation A speciation event within the home range of an existing species, in the absence of a physical barrier. Such species may form instantaneously, as by polyploidy.

chapter 17

allele One of two or more molecular forms of a gene that arise by mutation and code for different versions of the same trait.
allele frequency For a given gene locus, the relative abundances of each kind of allele among all the individuals of a population.
antibiotic Metabolic product of soil microbes that kills bacterial competitors for nutrients.
balanced polymorphism Form of selection in which two or more alleles for a trait are being maintained in a population over time.
biogeography Scientific study of the world distribution of species.
bottleneck Severe reduction in the size of a population, brought about by intense selection pressure or a natural calamity.
catastrophism Idea that abrupt changes in the geologic or fossil record were divinely invoked.

comparative morphology Scientific study of comparable body parts of adults or embryonic stages of major lineages.
directional selection Mode of natural selection by which allele frequencies underlying a range of phenotypic variation shift in a consistent direction, in response to directional change or to new conditions in the environment.
disruptive selection Mode of natural selection by which the different forms of a trait at both ends of the range of variation are favored and intermediate forms are selected against.
evolution Genetic change in a line of descent. Outcome of microevolutionary events: gene mutation, natural selection, genetic drift, and gene flow.
fitness Increase in adaptation to environment, as brought about by genetic change.

fixation Loss of all but one kind of allele at a gene locus for all individuals in a population.
fossil Recognizable, physical evidence of an organism that lived in the distant past.
founder effect A form of bottlenecking. By chance alone, a few individuals that establish a new population have allele frequencies that differ from those of the original population.

gene flow Microevolutionary process; alleles enter and leave a population as an outcome of immigration and emigration, respectively.
gene pool All genotypes in a population.
genetic drift Change in allele frequencies over the generations due to chance alone. Its effect is most pronounced in very small populations.
genetic equilibrium In theory, a state in which a population is not evolving. Compare Hardy-Weinberg rule.
Hardy-Weinberg rule Allele frequencies stay the same over the generations when there is no mutation, the population is infinitely large and isolated from other populations of the species, mating is random, and all individuals are reproducing equally and randomly.
inbreeding Nonrandom mating among close relatives that share many identical alleles.
lethal mutation Mutation with drastic effects on phenotype; usually causes death.
microevolution Of a population, any change in allele frequencies resulting from mutation, genetic drift, gene flow, natural selection, or some combination of these.
mutation rate Of a gene locus, the probability that a spontaneous mutation will occur during or between DNA replication cycles.
natural selection Microevolutionary process; the outcome of differences in survival and reproduction among individuals that differ in details of heritable traits.
neutral mutation A mutation with little or no effect on phenotype, so natural selection can't change its frequency in a population.
polymorphism The persistence of two or more qualitatively different forms of a trait (morphs) in a population.
population All individuals of the same species that are occupying a specified area.
sampling error Use of a sample or subset of a population, an event, or some other aspect of nature for an experimental group that is not large enough to be representative of the whole.
sexual selection A microevolutionary process; a type of selection that favors a trait giving an individual a competitive edge in attracting or keeping a mate (favors reproductive success).
stabilizing selection Mode of natural selection by which intermediate phenotypes in the range of variation are favored and extremes at both ends are eliminated.
theory of uniformity Early theory that the earth's surface changes in gradual, uniformly repetitive ways (major floods, earthquakes, and other infrequent catastrophes also occur every year and were not considered unusual). Has since been replaced by plate tectonics theory.

vocabulary chapter 13 and 14

adenine : A purine; a nitrogen-containing base in certain nucleotides. Base pairs with thymine in DNA.

bacteriophage : Category of viruses that infect bacterial cells.

cloning: Making a genetically identical copy of DNA or of an organism.

cytosine : Pyrimidine; one of the nitrogen-containing bases in nucleotides.

deoxyribonucleic acid (DNA) : Of cells and many viruses, the molecule of inheritance. H bonds join its two helically twisted nucleotide strands, one of which has instructions (in its base sequence) for synthesizing all of the enzymes and other proteins required to build and maintain cells.

DNA ligase : Enzyme that seals new base-pairings during DNA replication.

DNA polymerase : Enzyme of replication and repair that assembles a new strand of DNA on a parent DNA template.

DNA repair : Enzyme-mediated process that fixes small-scale alterations in a DNA strand by restoring the original base sequence.

DNA replication: Any process by which a cell duplicates its DNA molecules before dividing.

guanine: Nitrogen-containing base in one of four nucleotide monomers of DNA or RNA.

nucleotide: Small organic compound with deoxyribose (a five-carbon sugar), a nitrogenous base, and a phosphate group. Monomer for adenosine phosphates, nucleotide coenzymes, and nucleic acids.

thymine: A nitrogen-containing base; one of the nucleotides in DNA (not in RNA).

x-ray diffraction:image Pattern that forms on film exposed to x-rays that have been directed at a molecule; reveals positions of atoms, not the molecular structure.

anticodon: Series of three nucleotide bases in tRNA; can base-pair with an mRNA codon.

base sequence: Sequential order of bases in a DNA or RNA strand.

base-pair substitution:One amino acid has replaced another during protein synthesis.

carcinogen: Any substance or agent that can trigger cancer.

codon :One of 64 possible base triplets in an mRNA strand. A code word for an amino acid in a polypeptide chain; a few codons also act as START or STOP signals for translation.

deletion: At cytological level, loss of a segment from a chromosome. At molecular level, loss of one to a few base pairs from a DNA molecule.

exon:One of the base sequences of an mRNA transcript that will become translated.

gene mutation:A small-scale change in the nucleotide sequence of a DNA molecule.

genetic code:The correspondence between nucleotide triplets in DNA (then mRNA) and specific sequences of amino acids in a polypeptide chain; the basic language of protein synthesis in cells.

insertion: Insertion of one to a few bases into a DNA strand. Also, a movable attachment of muscle to bone.

intron:A noncoding portion of a pre-mRNA transcript; excised before translation.


ionizing radiation: High-energy wavelengths.

mRNA (messenger RNA): A single strand of ribonucleotides transcribed from DNA, then translated into a polypeptide chain. The only RNA encoding protein-building instructions.

mutation rate:Of a gene locus, the probability that a spontaneous mutation will occur during or between DNA replication cycles.