Important Biology Vocabulary

ortMedical Magnet Biology Summer Assignment Using half of a 3 x 5 index card, place the vocabulary word on the front (no lines) and the definition on the back (lines). Write legibly. Next, draw a picture on the FRONT of the card that helps you remember the DEFINITION. For example, for Biology you would write BIOLOGY on the front (no lines) and draw a picture of a plant, person, and an animal or two. All of these things represent LIFE which helps you with the definition. Then write the study of life and living things on the back (lined side). The pictures must be colored and relevant. Another example: for chlorophyll (a green pigment) you could draw a green pig! BE CREATIVE! HAVE FUN! Be prepared for a quiz on the first 10 words on the first week of school. These cards are due on the first day of classes. Knowing these terms will greatly increase your success in Biology Honors. 1. Biology-—The study of life and living things 2. Scientific method—Steps scientists use to answer questions 3. Qualitative data—information collected in the form of descriptions. 4. Quantitative data—information collected in the form of numbers 5. Hypothesis—a statement that is going to be tested 6. Controlled experiment—a test of a hypothesis under carefully managed conditions. 7. Control—the group in an experiment used as a standard of comparison. 8. Independent variable—The factor that is changed in an experiment 9. Dependent variable—the factor that is measured in an experiment. 10. Scientific model—a conceptual representation whose purpose is to explain and predict observed phenomena. 11. Metric system—a decimal system of weights and measures used in science. 12. Theory--A set of statements written to explain a group of facts or phenomena. 13. Law—a statement that everyone knows to be true. 14. Matter—something that has mass and takes up space. 15. Element—something that cannot be broken down into simpler substances 16. Compound—two or more elements combined 17. Trace elements—any element that is required in minute quantities for physiological functioning. 18. Atom—the smallest unit of an element. 19. Neutron—a particle found in the nucleus of an atom that has no charge with a mass of 1 Atomic Mass Unit (AMU) 20. Proton—a particle found in the nucleus of an atom that has a positive charge with a mass of 1 AMU. 21. Electron—a particle found in a cloud around the nucleus that has negative charge with no significant mass. 22. Atomic nucleus—the center of an atom. 23. Atomic number—the number found in the periodic table for an element. Equals the number of protons for that element. 24. Atomic mass—the average mass of an element. 25. Mass number—the sum of protons and neutrons in each atom of an element. 26. Isotopes—atoms of elements with a different number of neutrons. 27. Radioisotope—a version of an element that has an unstable nucleus so it will decay over time. 28. Energy—the ability to do work. 29. Energy levels—different areas in an atom where certain electrons will be found. 30. Electron shells—the place in an atom where electrons are most likely found.

Medical Magnet Biology Summer Assignment 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. Valence electron—electron found in the outermost shell Valence shell—the outermost shell of an atom Chemical bond-- a mutual attraction between two atoms resulting from a redistribution of their outer electrons Covalent bond—chemical bond in which atoms share electrons Molecule—a chemical compound composed of covalent bonds between atoms Non-polar covalent—a molecule in which electrons are evenly distributed Polar covalent—a molecule in which the electrons are unevenly distributed Ion—a charged atom Cation—a positively charged atom Anion—a negatively charged atom Ionic bond—bond formed when electrons are transferred between atoms. Hydrogen bond— weak attraction between a hydrogen atom and another atom Van der Waals forces— slight attraction that develops between oppositely charged regions of nearby molecules Chemical reaction-- process that changes, or transforms, one set of chemicals into another set of chemicals Reactant—elements or compounds that enter into a chemical reaction Product— elements or compounds synthesized by a chemical reaction Equilibrium-- a state in which a process and its reverse are occurring at equal rates Polar molecule-- a molecule with a slight positive charge on one side and a slight negative charge on the other. Cohesion-- attraction between molecules of the same substance. Adhesion-- force of attraction between different kinds of molecules. Solvent-- dissolving substance in a solution Solute-- substance that is dissolved in a solution Solution-- type of mixture in which all the components are evenly distributed Hydrophilic—water loving; a substance that is soluble in water; having an affinity for water Hydrophobic—water fearing; a substance that is not soluble in water; having an aversion to water Acid-- a compound that forms hydrogen ions (H+) in solution; a solution with a pH of less than 7 Base-- a compound that produces hydroxide ions (OH-) in solution; a solution with a pH of more than 7 Protein—an organic compound that contains carbon, hydrogen, oxygen, and nitrogen; needed by the body for growth and repair Carbohydrate—an organic compound made up of carbon, hydrogen, and oxygen atoms that is the major source of energy for the body Lipid—an organic compound made mostly from carbon and hydrogen atoms, which includes fats, oils and waxes. Nucleic acid—an organic compound that contains Hydrogen, Carbon, Oxygen, Nitrogen, and Phosphorus. Adenosine Triphosphate—a nucleic acid that living things use to store and release energy. Macromolecule-- a molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer. Polymer—large molecule built by combining many monomers. Monomer—small unit that can join together with other small units to form polymers.

Medical Magnet Biology Summer Assignment 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82. 83. 84. 85. 86. 87. 88. 89. 90. 91. Condensation reaction—a chemical reaction in which water is released and a macromolecule is built. Hydrolysis—A chemical reaction in which water is added and macromolecules are broken down. Monosaccharide— any of the class of sugars that cannot be hydrolyzed to give a simpler sugar. Disaccharide-- any of a class of sugars whose molecules contain two simple sugars. Glycosidic bond-- A covalent bond formed between two monosaccharides by a condensation reaction. Polysaccharide-- A polymer of up to over a thousand monosaccharides, formed by condensation reactions. Phospholipid-- A molecule that is a constituent of the inner bilayer of biological membranes, having a polar, hydrophilic head and a nonpolar, hydrophobic tail. Enzyme— A protein serving as a biological catalyst, a chemical agent that changes the rate of a reaction without being consumed by the reaction Catalyst-- A chemical agent that changes the rate of a reaction without being consumed by the reaction. Peptide bond-- The covalent bond between two amino acid units, formed by a condensation reaction. Nucleotide-- A building block of a nucleic acid, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group. Light microscope-- An optical instrument with lenses that refract (bend) visible light to magnify images of specimens. Organelle-- One of several formed bodies with specialized functions, suspended in the cytoplasm of eukaryotic cells. Electron microscope—An instrument that focuses an electron beam through a specimen, resulting in resolving power a thousandfold greater than that of a light microscope. Prokaryotic cell-- A type of cell lacking a membrane-enclosed nucleus and membraneenclosed organelles; found only in the domains Bacteria and Archaea. Eukaryotic cell-- A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles, present in protists, plants, fungi, and animals; also called eukaryote. Cytoplasm— jelly-like portion of the cell, exclusive of the nucleus, and bounded by the plasma membrane. Plasma membrane-- The fluid boundary of every cell that acts as a selective barrier, thereby regulating the cell’s chemical composition. Cell nucleus-- The chromosome-containing organelle of a eukaryotic cell. Nucleolus-- A specialized structure in the nucleus, formed from various chromosomes and active in the synthesis of ribosomes. Ribosomes— sites of protein synthesis in all types of cells. Rough Endoplasmic reticulum-- internal membrane system found in eukaryotic cells covered with ribosomes; place where proteins bound for the cell membrane are assembled Smooth endoplasmic reticulum—Site of lipid synthesis and detoxification in eukaryotic cells Golgi apparatus-- An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum. Lysosome-- A membrane-enclosed sac of digestive enzymes found in the cytoplasm of eukaryotic cells Phagocytosis— A type of endocytosis involving large, particulate substances, accomplished mainly by macrophages, neutrophils, and dendritic cells.

Medical Magnet Biology Summer Assignment 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 104. 105. 106. 107. 108. 109. 110. 111. 112. 113. 114. 115. 116. 117. 118. 119. Pinocytosis-- A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes. Vacuole-- cell organelle that stores materials such as water, salts, proteins, and carbohydrates Mitochondria-- cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use Chloroplast-- organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy Cytoskeleton-- network of protein filaments in a eukaryotic cell that gives the cell its shape and internal organization and is involved in movement Centrioles-- structure in an animal cell that helps to organize cell division Flagella-- structure used by protists for movement; produces movement in a wavelike motion Cilia-- short hairlike projection that produces movement Cell wall-- strong, supporting layer around the cell membrane in some cells Selectively permeable-- A property of biological membranes that allows some substances to cross more easily than others. Integral proteins-- a transmembrane protein with hydrophobic regions that completely spans the hydrophobic interior of the membrane. Peripheral proteins-- A protein appendage loosely bound to the surface of a membrane and not embedded in the lipid bilayer. Transport proteins-- A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane. Diffusion-- The spontaneous tendency of a substance to move down its concentration gradient from a more concentrated to a less concentrated area. Passive transport-- The diffusion of a substance across a biological membrane. Osmosis-- The diffusion of water across a selectively permeable membrane. Hypertonic solution-- the solution with a greater solute concentration. Hypotonic solution-- the solution with a lower solute concentration. Isotonic solution-- the same solute concentration as another solution. Active transport-- The movement of a substance across a biological membrane against its concentration or electrochemical gradient with the help of energy input and specific transport proteins. Exocytosis-- The cellular secretion of macromolecules by the fusion of vesicles with the plasma membrane. Endocytosis-- The cellular uptake of macromolecules and particulate substances by localized regions of the plasma membrane that surround the substance and pinch off to form an intracellular vesicle. Exergonic reaction-- A spontaneous chemical reaction, in which there is a net release of free energy. Endergonic reaction-- A non-spontaneous chemical reaction, in which free energy is absorbed from the surroundings. Phosphorylation—the addition of a phosphate group to a molecule. Activation energy-- The amount of energy that reactants must absorb before a chemical reaction will start; also called free energy of activiation. Substrate-- The reactant on which an enzyme works. Active site-- The specific portion of an enzyme that attaches to the substrate by means of weak chemical bonds.

Medical Magnet Biology Summer Assignment 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. 130. 131. 132. 133. 134. 135. 136. 137. 138. 139. 140. 141. 142. 143. Fermentation-- A catabolic process that makes a limited amount of ATP from glucose without an electron transport chain and that produces a characteristic end product, such as ethyl alcohol or lactic acid. Cellular respiration-- The most prevalent and efficient catabolic pathway for the production of ATP, in which oxygen is consumed as a reactant along with the organic fuel. Cristae-- An infolding of the inner membrane of a mitochondrion that houses the electron transport chain and the enzyme catalyzing the synthesis of ATP. Mitochondrial matrix-- The compartment of the mitochondrion enclosed by the inner membrane and containing enzymes and substrates for the Krebs cycle. Redox reaction-- A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction. Electron transport chain-- A sequence of electron carrier molecules (membrane proteins) that shuttle electrons during the redox reactions that release energy used to make ATP. Glycolysis-- The splitting of glucose into pyruvate. The one metabolic pathway that occurs in all living cells, serving as the starting point for fermentation or aerobic respiration. Citric acid cycle-- A chemical cycle involving eight steps that completes the metabolic breakdown of glucose molecules to carbon dioxide; occurs within the mitochondrion; the second major stage in cellular respiration. Aerobic-- Containing oxygen; referring to an organism, environment, or cellular process that requires oxygen. Anaerobic-- Lacking oxygen; referring to an organism, environment, or cellular process that lacks oxygen and may be poisoned by it. Alcohol fermentation-- The conversion of pyruvate to carbon dioxide and ethyl alcohol. Lactic acid fermentation-- The conversion of pyruvate to lactate with no release of carbon dioxide. Pyruvate-- the end product of glycolysis and may be metabolized to lactate or to acetyl CoA. Photosynthesis-- The conversion of light energy to chemical energy that is stored in glucose or other organic compounds; occurs in plants, algae, and certain prokaryotes. Chlorophyll-- A green pigment located within the chloroplasts of plants. Chlorophyll a can participate directly in the light reactions, which convert solar energy to chemical energy. Stomata-- small openings in the epidermis of a plant that allows carbon dioxide, water, and oxygen to diffuse into and out of the leaf Stroma-- The fluid of the chloroplast surrounding the thylakoid membrane; involved in the synthesis of organic molecules from carbon dioxide and water. Thylakoids-- The flattened membrane sacs inside the chloroplast, used to convert light energy to chemical energy. Calvin cycle-- The second of two major stages in photosynthesis (following the light reactions), involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate. Mitosis-- A process of nuclear division in eukaryotic cells. Cell cycle-- An ordered sequence of events in the life of a eukaryotic cell, from its origin in the division of a parent cell until its own division into two; composed of the M, G1, S, and G2 phases. Genome-- The complete complement of an organism’s genes; an organism’s genetic material. Chromosomes-- Threadlike, gene-carrying structures found in the nucleus. Each one consists of one very long DNA molecule and associated proteins.. Somatic cells—All cells in a multicellular organism except a sperm or egg cell.

Medical Magnet Biology Summer Assignment 144. 145. 146. 147. 148. 149. 150. 151. 152. 153. 154. 155. 156. 157. 158. 159. 160. 161. 162. 163. 164. 165. 166. 167. 168. 169. 170. Gametes-- Haploid cells, such as an egg or sperm. They unite during sexual reproduction to produce a diploid zygote. Chromatin-- The complex of DNA and proteins that makes up a eukaryotic chromosome. Sister chromatids--Replicated forms of a chromosome joined together by the centromere and eventually separated during mitosis or meiosis II. Centromere-- The centralized region joining two sister chromatids. Cytokinesis-- The division of the cytoplasm to form two separate daughter cells immediately after mitosis. G1 phase-- The first growth phase of the cell cycle, consisting of the portion of interphase before DNA synthesis begins. S-Phase-- The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated. G2 phase--The phase of the cell cycle consisting of the portion of interphase after DNA synthesis occurs. Prophase--The stage of mitosis in which the chromatin is condensing and the mitotic spindle begins to form, but the nucleolus and nucleus are still intact. Metaphase--The stage of mitosis in which the spindle is complete and the chromosomes, attached to microtubules at their kinetochores, are all aligned at the metaphase plate. Anaphase--The stage of mitosis in which the chromatids of each chromosome have separated and the daughter chromosomes are moving to the poles of the cell. Telophase--The stage of mitosis in which daughter nuclei are forming and cytokinesis has typically begun. Metaphase plate--An imaginary plane during metaphase in which the centromeres of all the duplicated chromosomes are located midway between the two poles. Cleavage furrow--The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate. Cell plate--A double membrane across the midline of a dividing plant cell, between which the new cell wall forms during cytokinesis. Binary Fission--The separation of a parent into two or more individuals of approximately equal size. Origin of replication--Site where the replication of a DNA molecule begins. Cancer--a large group of different diseases, all involving unregulated cell growth. Metastasis--The spread of cancer cells to locations distant from their original site. Meiosis--A two-stage type of cell division in sexually reproducing organisms that results in cells with half the chromosome number of the original cell. Diploid--A cell containing two sets of chromosomes (2n), one set inherited from each parent. Haploid--A cell containing only one set of chromosomes (n). Zygote--The diploid product of the union of haploid gametes in conception; a fertilized egg. Fertilization--The union of haploid gametes to produce a diploid zygote. Tetrad--A paired set of homologous chromosomes, each composed of two sister chromatids. Tetrads form during prophase I of meiosis. Chiasma--The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis. Homologous chromosomes--Chromosome pairs of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism’s father, the other from the mother.

Medical Magnet Biology Summer Assignment 171. 172. 173. 174. 175. 176. 177. 178. 179. 180. 181. 182. 183. 184. 185. 186. 187. 188. 189. 190. 191. 192. 193. 194. 195. 196. 197. 198. Sex cell-- A spermatozoon or an ovum; a cell responsible for transmitting DNA to the next generation Karyotype--A display of the chromosome pairs of a cell arranged by size and shape. Variation--Differences between members of the same species. Genetics--The scientific study of heredity and hereditary variation. Gene--A discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA Locus--A specific place along the length of a chromosome where a given gene is located. Asexual reproduction--A type of reproduction involving only one parent that produces genetically identical offspring by budding or by the division of a single cell or the entire organism into two or more parts. Trait--Any detectable variation in a genetic character. Homozygous--Having two identical alleles for a given gene. Heterozygous--Having two different alleles for a given gene. Allele--Alternative versions of a gene that produce distinguishable phenotypic effects Dominant--An allele that is fully expressed in the phenotype of a heterozygote. Recessive--An allele whose phenotypic effect is not observed in a heterozygote. Punnett square--A diagram used in the study of inheritance to show the results of random fertilization in genetic crosses. Genotype--The genetic makeup, or set of alleles, of an organism. Phenotype--The physical and physiological traits of an organism, that are determined by its genetic makeup. Monohybrids--An organism that is heterozygous with respect to a single gene of interest. All the offspring from a cross between parents homozygous for different alleles are monohybrids. For example, parents of genotypes AA and aa produce a monohybrid of genotype Aa. Dihybrids--An organism that is heterozygous with respect to two genes of interest. All the offspring from a cross between parents doubly homozygous for different alleles are dihybrids. For example, parents of genotypes AABB and aabb produce a dihybrid of genotype AaBb. Codominance--The situation in which the phenotypes of both alleles are exhibited in the heterozygote. Incomplete dominance--The situation in which the phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele. Epistasis--A type of gene interaction in which one gene alters the phenotypic effects of another gene that is independently inherited. Polygenic--An additive effect of two or more gene loci on a single phenotypic character. Carriers--In genetics, an individual who is heterozygous at a given genetic locus, with one normal allele and one potentially harmful recessive allele. The heterozygote is phenotypically normal for the character determined by the gene but can pass on the harmful allele to offspring. Deletion--1) A deficiency in a chromosome resulting from the loss of a fragment through breakage. (2) A mutational loss of one or more nucleotide pairs from a gene. Duplication--An aberration in chromosome structure due to fusion with a fragment from a homologous chromosome, such that a portion of a chromosome is duplicated. Inversion--An aberration in chromosome structure resulting from reattachment in a reverse orientation of a chromosomal fragment to the chromosome from which the fragment originated. Translocation--An aberration in chromosome structure resulting from attachment of a chromosomal fragment to a nonhomologous chromosome. Bacteriophage--A virus that infects bacteria; also called a phage.

Medical Magnet Biology Summer Assignment 199. 200. 201. 202. 203. 204. 205. 206. 207. 208. 209. 210. 211. 212. 213. 214. 215. 216. 217. 218. 219. 220. 221. 222. 223. 224. Semiconservative model--Type of DNA replication in which the replicated double helix consists of one old strand, derived from the old molecule, and one newly made strand. Lagging strand--A discontinuously synthesized DNA strand that elongates in a direction away from the replication fork. Okazaki fragment--A short segment of DNA synthesized on a template strand during DNA replication. Many Okazaki fragments make up the lagging strand of newly synthesized DNA DNA ligase--A linking enzyme essential for DNA replication; catalyzes the covalent bonding of the 3’ end of a new DNA fragment to the 5’ end of a growing chain. Primer--A polynucleotide with a free 3´ end, bound by complementary base pairing to the template strand that is elongated during DNA replication. Primase--An enzyme that joins RNA nucleotides to make the primer. Helicase--An enzyme that untwists the double helix of DNA at the replication forks. Transcription--The synthesis of RNA on a DNA template. Translation-- The synthesis of a polypeptide using the genetic information encoded in an mRNA molecule. There is a change of languagefrom nucleotides to amino acids. Codon--A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code. Anticodon--A specialized base triplet at one end of a tRNA molecule that recognizes a particular complementary codon on an mRNA molecule. Mutation--A rare change in the DNA of a gene, ultimately creating genetic diversity. Point mutation--A change in a gene at a single nucleotide pair. Frameshift mutation--A mutation occurring when the number of nucleotides inserted or deleted is not a multiple of three, resulting in the improper grouping of the following nucleotides into codons. Insertion--A mutation involving the addition of one or more nucleotide pairs to a gene. Substitution—A mutation involving the replacement of one or more nucleotides with an equal amount. Endangered species--A species that is in danger of extinction throughout all or a significant portion of its range. Natural selection--Differential success in the reproduction of different phenotypes resulting from the interaction of organisms with their environment. Evolution--All the changes that have transformed life on Earth from its earliest beginnings to the diversity that characterizes it today. Adaptation--heritable characteristic that increases an organism's ability to survive and reproduce in an environment Fossil--A preserved remnant or impression of an organism that lived in the past. Taxonomy--A set of characteristics used to assess the similarities and differences between various species, leading to a classification scheme; the branch of biology concerned with naming and classifying the diverse forms of life. Gradualism--A view of Earth’s history that attributes profound change to the cumulative product of slow but continuous processes. Catastrophism--The hypothesis by Georges Cuvier that each boundary between strata corresponded in time to a catastrophe, such as a flood or drought that had destroyed many of the species living there at that time. Uniformitarianism--Charles Lyell’s idea that geologic processes have not changed throughout Earth’s history. Vestigial organ--A structure of marginal, if any, importance to an organism.

Medical Magnet Biology Summer Assignment 225. 226. 227. 228. 229. 230. 231. 232. 233. 234. 235. 236. 237. 238. 239. 240. 241. 242. 243. 244. 245. 246. 247. 248. 249. 250. 251. 252. 253. Biogeography--The study of the past and present distribution of species. Gene pool--The total aggregate of genes in a population at any one time. Hardy-Weinberg equilibrium--The condition describing a non-evolving population (one that is in genetic equilibrium). Genetic drift--Unpredictable fluctuations in allele frequencies from one generation to the next because of a population’s finite size. Bottleneck effect--Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population. Founder effect--Genetic drift that occurs when a few individuals become isolated from a larger population, with the result that the new population’s gene pool is not reflective of the original population. Gene flow--Genetic additions to or substractions from a population resulting from the movement of fertile individuals or gametes. Fitness--The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals. Directional selection--Natural selection that favors individuals at one end of the phenotypic range. Disruptive selection--Natural selection that favors individuals on both extremes of a phenotypic range over intermediate phenotypes. Stabilizing selection--Natural selection that favors intermediate variants by acting against extreme phenotypes. Speciation--The origin of new species in evolution. Species--A group whose members possess similar anatomical characteristics and have the ability to interbreed. Binomial nomenclature--classification system in which each species is assigned a two-part scientific name Phylogeny--The evolutionary history of a species or group of related species. Cladogram--A diagram depicting patterns of shared characteristics among taxa. Ecology--The study of how organisms interact with their environment. Abiotic—Nonliving things that are part of an environment. Biotic--Referring to all the organisms that are part of the environment. Population--A localized group of individuals that belong to the same biological species. Community--All the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction. Ecosystem--All the organisms in a given area as well as the abiotic factors with which they interact; a community and its physical environment. Biosphere--The entire portion of Earth inhabited by life; the sum of all the planet’s ecosystems. Climate--The prevailing weather conditions at a locality. Biome--Any of the world’s major ecosystems, classified according to the predominant vegetation and characterized by adaptations of organisms to that particular environment. Photic zone--The narrow top slice of the ocean, where light permeates sufficiently for photosynthesis to occur. Canopy--The uppermost layer of vegetation in a terrestrial biome. Understory--layer in a rain forest found underneath the canopy formed by shorter trees and vines Permafrost--A permanently frozen stratum below the arctic tundra.

Medical Magnet Biology Summer Assignment 254. 255. 256. 257. 258. 259. 260. 261. 262. 263. 264. 265. 266. 267. 268. 269. 270. 271. 272. 273. 274. 275. 276. 277. 278. 279. 280. 281. Arid—extremely dry. Immigration--The influx of new individuals from other areas. Emigration--The movement of individuals out of a population. Logistic growth--A model describing population growth that levels off as population size approaches carrying capacity. Exponential growth--The geometric increase of a population as it grows in an ideal, unlimited environment. Carrying capacity--The maximum population size that can be supported by the available resources, symbolized as K. Predation--An interaction between species in which one species eats the other. Niche--The sum total of a species’ use of the biotic and abiotic resources in its environment. Habitat--area where an organism lives including the biotic and abiotic factors that affect it Mimicry-- the similarity of one species to another which protects one or both Symbiosis--An ecological relationship between organisms of two different species that live together in direct contact. Parasitism--A symbiotic relationship in which the symbiont (parasite) benefits at the expense of the host by living either within the host (as an en-doparasite) or outside the host (as an ectoparasite). Mutualism--A symbiotic relationship in which both participants benefit. Commensalism--A symbiotic relationship in which the symbiont benefits but the host is neither helped nor harmed. Pathogen--A disease-causing agent. Keystone species--A species that is not necessarily abundant in a community yet exerts strong control on community structure by the nature of its ecological role or niche. Exotic species—A species that is introduced to an environment in which it has no natural predators. Trophic level--each step in a food chain or food web Food chain--The pathway along which food is transferred from trophic level to trophic level, beginning with producers. Food web--The elaborate, interconnected feeding relationships in an ecosystem. Autotroph--An organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. Autotrophs use energy from the sun or from the oxidation of inorganic substances to make organic molecules from inorganic ones. Producer—An organism that has the ability to create its own energy. Heterotroph--An organism that obtains organic food molecules by eating other organisms or their by-products. Consumer--organism that relies on other organisms for its energy and food supply. Detritivore--A consumer that derives its energy from nonliving organic material; a decomposer. Decomposer--Any of the 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. Scavenger--animal that consumes the carcasses of other animals Biomass--The dry weight of organic matter comprising a group of organisms in a particular habitat.

Medical Magnet Biology Summer Assignment 282. 283. 284. 285. 286. 287. 288. 289. 290. 291. 292. 293. 294. 295. 296. 297. 298. 299. Succession— Transition in the species composition of a biological community, often following ecological disturbance of the community; the establishment of a biological community in an area virtually barren of life. Primary succession--A type of ecological succession that occurs in a virtually lifeless area, where there were originally no organisms and where soil has not yet formed. Secondary succession--A type of succession that occurs where an existing community has been cleared by some disturbance that leaves the soil intact. Pioneer species--first species to populate an area during succession Limiting factor--factor that causes population growth to decrease Eutrophication--A process by which nutrients, particularly phosphorus and nitrogen, become highly concentrated in a body of water, leading to increased growth of organisms such as algae. Biogeochemical cycle--Any of the various nutrient circuits, which involve both biotic and abiotic components of ecosystems. Nitrogen fixation--The assimilation of atmospheric nitrogen by certain prokaryotes into nitrogenous compounds that can be directly used by plants. Biological magnification--A trophic process in which retained substances become more concentrated with each link in the food chain. Greenhouse effect--The warming of planet Earth due to the atmospheric accumulation of carbon dioxide, which absorbs infrared radiation and slows its escape from the irradiated Earth. Global warming--increase in the average temperatures on Earth Cerebrum--The dorsal portion of the vertebrate forebrain, composed of right and left hemispheres Cerebelum—Part of the vertebrate hindbrain located dorsally; functions in unconscious coordination of movement and balance. Brainstem--Collection of structures in the adult brain, including the midbrain, the pons, and the medulla oblongata; functions in homeostasis, coordination of movement, and conduction of information to higher brain centers. Pons--Portion of the brain that participates in certain automatic, homeostatic functions, such as regulating the breathing centers in the medulla. Medulla--a swelling of the hindbrain dorsal to the anterior spinal cord that controls autonomic, homeostatic functions, including breathing, heart and blood vessel activity, swallowing, digestion, and vomiting. Xylem--Vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from roots to the rest of the plant. Phloem--Vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant.