Chapter 1

• A species is an evolutionarily independent population or group of populations. Generally distinct from other species in appearance, behavior, habitat, ecology, genetic characteristics, and so on.
• Fitness is the ability of an individual to produce viable offspring relative to others of the same species.
• A chromosome is a gene-carrying structure consisting of a single long molecule of double-stranded DNA and associated proteins (e.g., histones). Most prokaryotic cells contain a single circular chromosome; eukaryotic cells contain multiple noncircular (linear) chromosomes located in the nucleus.
• A phylum, in Linnaeus’ system, is a taxonomic category above the class level and below the kingdom level. In plants, sometimes called a division.
• Control, in a scientific experiment, is a group of organisms or samples that do not receive the experimental treatment but are otherwise identical to the group that does.
• A protein is a macromolecule consisting of one or more polypeptide chains. Each polypeptide has a unique sequence of amino acids and each protein generally possesses a characteristic three-dimensional shape.
• Phylogeny is the evolutionary history of a group of organisms
• The double helix is the secondary structure of DNA, consisting of two antiparallel DNA strands wound around each other. Some RNAs may also form a double helix in stem-and-loop secondary structures.
• Ribonucleic acid (RNA) is a usually single-stranded nucleic acid composed of ribonucleotides. Functions include catalytic components of ribosomes (rRNA), transporters of amino acids (tRNA), and messages of the DNA code required for protein synthesis (mRNA), among others.
• The chromosome theory of inheritance is the principle that genes are located on chromosomes and that patterns of inheritance are determined by the behavior of chromosomes during meiosis.
• Heritable refers to traits that can be transmitted from one generation to the next.
• A phylogenetic tree is a branching diagram that depicts the evolutionary relationships among species or other taxa.
• An organism is any living entity that contains one or more cells.
• The tree of life is the phylogenetic tree that includes all organisms
• A theory is an explanation for a broad class of phenomena that is supported by a wide body of evidence. A theory serves as a framework for the development of new hypotheses.
• Adaptation is any heritable trait that increases the fitness of an individual with that trait, compared with individuals without that trait, in a particular environment.
• A genus, in Linnaeus’ system, is a taxonomic category of closely related species. Always italicized and capitalized to indicate that it is a recognized scientific genus.
• Chemical evolution is the theory that simple chemical compounds in the early atmosphere and ocean combined via chemical reactions to form larger, more complex substances, eventually leading to the origin of life and the start of biological evolution.
• A prokaryote is a member of the domain Bacteria or Archaea; a unicellular organism lacking a nucleus and containing relatively few organelles or cytoskeletal components. Compare with eukaryote.
• A domain is a taxonomic category, based on similarities in basic cellular biochemistry, above the kingdom level. The three recognized domains are Bacteria, Archaea, and Eukarya.
• LUCA is the last universal common ancestor of cells. This theoretical entity is proposed to be the product of chemical evolution and provided characteristics of life that are shared by all living organisms on Earth today.
• Evolution is the theory that all organisms on Earth are related by common ancestry and that they have changed over time, and continue to change, via natural selection, genetic drift, gene flow, and mutation. (2) Any change in the genetic characteristics of a population over time, especially a change in allele frequencies.
• A eukaryotes is a member of the domain Eukarya; an organism whose cells contain a nucleus, numerous membrane-bound organelles, and an extensive cytoskeleton. May be unicellular or multicellular. Compare with prokaryote.
• Natural selection is the process by which individuals with certain heritable traits tend to produce more surviving offspring than do individuals without those traits, often leading to a change in the genetic makeup of the population. A major mechanism of evolution. The only evolutionary process that produces adaptation.
• Speciation is the evolution of two or more distinct species from a single ancestral species.
• A taxon is any named group of organisms at any level of a classification system
• A scientific name is the unique, two-part name given to each species, with a genus name followed by a species name—as in Homo sapiens. Scientific names are always italicized. Also known as Latin names.
• Taxonomy is the branch of biology concerned with describing, naming, and classifying goups of organisms.
• Cell theory is the theory that all organisms are made of cells and that all cells come from preexisting cells.
• Deoxyribonucleic acid (DNA) is a nucleic acid composed of deoxyribonucleotides that carries the genetic information. Generally occurs as a double helix with two intertwined strands held together by noncovalent bonds.
• Cells are highly organized compartment bounded by a thin, flexible structure (plasma membrane) and containing concentrated chemicals in an aqueous (watery) solution. The basic structural and functional unit of all organisms.
• ATP (or adenosine triphosphate) is a molecule consisting of an adenine base, a sugar, and three phosphate groups that are linked together with covalent bonds that have high potential energy. Universally used by cells as a monomer for RNA synthesis and to store and transfer chemical energy.
• A population is a group of individuals of the same species living in the same geographic area at the same time.
• Genes, in a molecular context, are a section of DNA (or RNA, for some viruses) that contains the regulatory sequences and coding information for the transcription of one or more related functional RNA molecules, some of which encode polypeptides. (2) In Mendelian genetics, the hereditary determinant of a trait, such as flower color or seed shape in pea plants.
• Central dogma the scheme for information flow in the cell: DNA → RNA → protein.
• A null hypothesis is a hypothesis that specifies what the results of an experiment will be if the main hypothesis being tested is wrong. Often states that there will be no difference between experimental groups.
• A hypothesis is a testable statement that explains a phenomenon or a set of observations.
• An experiment is a powerful scientific tool in which researchers test the effect of a single, well-defined factor on a particular phenomenon.
• A prediction is a measurable or observable result of an experiment based on a particular hypothesis. A correct prediction provides support for the hypothesis being tested.
• A molecule is a substance made up of two or more atoms held together by covalent bonds.