It was used to refer to saltatory changes producing new forms in an abrupt, non-gradual manner. sedimentary /sed-ə-MENT-er-ee, British: sed-ə-MEN-tree/ adj. sequencing Determination of the order of nucleotides (base sequences) in a DNA or RNA molecule or the order of amino acids in a protein. A fluid, resembling blood serum, secreted into the cavities of the body by the serous membranes, which line them. See also: mutation, polymorphism, single-gene disorder. single variations An obsolete term much in use in evolutionary discussion during the 19th century, for example in Darwin's writings. When this occurs, each forms a duplicate of itself and the resulting two structures, called sister chromatids, are joined at the centromere. An instrument used to accurately administer small amounts of fluid; when a needle is attached to a syringe it can be used to make injections. systematist One who engages in the practice of systematics. On the Origins of New Forms of Life Mammalian Hybrids Cat-rabbit Hybrids: Fact or fiction? The liquid present in the mouth and secreted by the salivary glands. The DNA in such bands is either denser (GC-rich) or less dense (AT-rich) than the DNA in the main band. The second is the secondary spermatocyte, which is produced from the primary spermatocyte by division. A mature male haploid gamete capable of active movement by means of a undulipodium. The genus of birds comprised of the banded penguins. The column of nervous tissue that in vertebrates runs along the back, and that in bony animals is enclosed within the vertebral column. splice sites Locations where RNA splices exons together to form a continuous gene transcript. spore (1) in a plant or fungus, an asexual reproductive cell that does not participate in fertilization; (2) in prokaryotes, a dormant, relatively impervious cell that is resistant to destruction by heating. A new type of organism arising in a single generation. saliva (common names: spit, spittle) /sə-LIE-və/ n. Its capacity for contraction is the essential trait that makes muscles work. Any fraction of DNA that forms a separate band from the main body of DNA during isopycnic Cs CL gradient centrifugation ("satellite" refers to the subordinate or minor status of such bands). Certain aspects of their worldview, based on religious dogmas, have carried over into modern biological thought, for example, their ideas concerning continuity, gradualism, and ideal forms. The outermost coat of the eyeball, extending from the optic nerve to the edges of the cornea. The first of these two types is the primary spermatocyte, which is a mature sex cell that develops from the spermatogonium without division. During spermatogenesis, one of the primordial, undifferentiated sex cells that give rise, via maturation and growth, first to a primary spermatocyte, then via division, to two secondary spermatocytes that in turn divide to form four spermatids, which then mature without further division into four fully functional spermatozoa — spermatogonial /sperm-awd-ə-GŌ-nee-əl/ spermatozoon (pl spermatozoa) /sper-mat-ə-ZŌ-ən; pl: -ZŌ-ə/ n. An angular bend in the large intestine between the transverse and descending colons.
Standard 4 Genetics and Biotechnology The student will investigate the concepts of genetics and heredity, different methods of reproduction, patterns of inheritance, and genetic disorders; as well as, explore and evaluate DNA technologies from both a scientific and ethical perspective.
Relative dating does not provide actual numerical dates for the rocks.
Fossils are important for working out the relative ages of sedimentary rocks.
sexual reproduction Reproduction that involves the fusion of gametes. It fused with another, smaller paleocontinent, Kazakhstania, in the Carboniferous. Abnormal erythrocytes containing iron granules in the mitochondria. OVERVIEW OF SIGNAL TRANSDUCTION PATHWAYS Silurian Period (S) /sə-LURE-ee-ən/ n.
In humans the sex chromosomes comprise the 23rd chromosome pair. In certain crosses sex-linked traits manifest themselves only in the heterogametic sex. The paleocontinent Siberia came into existence as a separate entity in the Cambrian. Most signal transduction processes are ordered sequences of intracellular reactions ("signal transduction pathways") mediated by enzymes and activated by second messengers.
Open tropical or semitropical grassland, usually with a scattering of small trees and bushes; a biome found in regions where heavy rain seasons alternate with lengthy dry seasons. Scala Naturae (also Great Chain of Being) /SKAL-ə nat-T(Y)OOR-eye/ n. sodium carbonate (Na₂CO₃) /SŌD-ee-əm KAR-bə-nate/ n. A sodium salt of carbonic acid; used in making detergents, paper, and glass. The most common form of salt, also known as table salt or common salt; in its mineral form it is called halite. A graphic of all an organism's chromosomes, each labeled with a different color. Under the microscope it can be seen that staphylococci are round in shape (i.e. PICTURE structural gene A gene that encodes a product (e.g., a polypeptide, t RNA, or r RNA). The determination, by means of both experimental techniques and computer simulation, of the three-dimensional structures of proteins. Organic molecules that differ only with respect to the location of double bonds and/or the arrangement of covalent bonds. A protein that contributes to cell or tissue structure. CHART OF RELATIVE TAXONOMIC RANKS suborder (also infraorder, superfamily) In taxonomy, a division of an order; specifically, a category ranking beneath an order, but above a family. The first antibiotics discovered were sulfonamides. MOLECULAR STRUCTURE sulfur Chemical element; atomic weight 32.064; atomic number 16.