AP Biology Big Idea #1
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| 6469554201 | Fitness | The contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals. |  | 0 |
| 6469554202 | Directional Selection | Most common when a population's environment changes or when members of a population migrate to a new habitat with different environmental conditions than their former one. |  | 1 |
| 6469554203 | Disruptive Selection | Occurs when conditions favor individuals on both extremes of a phenotypic range over individuals with intermediate phenotypes. | | 2 |
| 6469554204 | Stabilizing Selection | Acts against extreme phenotypes and favors intermediate variants. | | 3 |
| 6469554205 | Heterozygote Advantage | Greater reproductive success of heterozygous individuals compared to homozygotes; tends to preserve variation in gene pools. Ex. Individuals that are heterozygous for the sickle cell allele are also immune from getting malaria. | 4 | |
| 6469554206 | Sexual Selection | Natural selection for mating success | 5 | |
| 6469554207 | Hardy-Weinberg Theorem | The principle that frequencies of alleles and genotypes in a population remain constant from generation to generation. | 6 | |
| 6469554208 | Mutation | Introduces new alleles that may provide a selective advantage or disadvantage to a population. | 7 | |
| 6469554209 | Gene Pool | The aggregate of genes in a population at any one time; consists of all alleles at all gene loci in all individuals of the population. | 8 | |
| 6469554210 | Hardy-Weinberg Equilibrium | The condition describing a non-evolving population (one that is in genetic equilibrium)., 1). No mutations. 2). Random mating. 3). No natural selection. 4). The population size must be extremely large, no genetic drift. 5). No gene flow. i.e. transfer of pollen. | 9 | |
| 6469554211 | Gene Flow | Describes the movement of individuals between populations resulting in the removal of alleles from a population when they leave (emigration) or the introduction of alleles when they enter (immigration). |  | 10 |
| 6469554212 | Genetic Drift | Random increase and decrease of alleles. | | 11 |
| 6469554213 | Allopatric speciation | Begins when a population is divided by a geographic barrier so that interbreeding between the two resulting populations is prevented. Therefore, differential evolution creates reproductive barriers that prevent interbreeding and thus create new species. |  | 12 |
| 6469554214 | Adaptive radiation | Relatively rapid evolution, occurs when the ancestral species is introduced to an area where diverse geographic or ecological conditions are available for colonization |  | 13 |
| 6469554215 | Bottleneck | Occurs when a population undergoes a drastic decrease in size; severely vulnerable to genetic drift. |  | 14 |
| 6469554216 | Divergent Evolution | Describes two or more species that originate from a common ancestor and become increasingly different over time | 15 | |
| 6469554217 | Sympatric speciation | Formation of a new species without the presence of a geographic barrier. |  | 16 |
| 6469554218 | Cladogram | A.k.a. phylogenetic tree; a "tree-like" graphical representation of the relatedness of species. Each branch represents the divergence of a species from a common ancestor. |  | 17 |
| 6469554219 | Ecological stress | Physical, chemical, and biological constraints on the productivity of species and on the development of ecosystems. | 18 | |
| 6469554220 | Paleontology | Provides fossils that reveal the prehistoric existence of extinct species. As a result, changes in species and the formation of new species can be studied. | 19 | |
| 6469554221 | Biogeography | Uses geography to describe the distribution of species. | 20 | |
| 6469554222 | Embryology | Reveals similar stages in development (ontogeny) among related species. The similarities help establish evolutionary relationships (phylogeny). |  | 21 |
| 6469554223 | Comparative anatomy | Describes two kinds of structures that contribute to the identification of evolutionary relationships among species. Homologous structures and Analagous structures. |  | 22 |
| 6469554224 | Molecular biology | Examines the nucleotide and amino acid sequences of DNA and proteins from different species | 23 | |
| 6469554240 | Founder Effect | Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population. | 24 | |
| 6469554241 | Fossils | Preserved remains of once-living organisms | 25 | |
| 6469554242 | Gradualism | A proposed explanation in evolutionary biology stating that new species arise from the result of slight modifications (mutations and resulting phenotypic changes) over many generations. | 26 | |
| 6469554243 | Artificial Selection | Breeding organisms with specific traits in order to produce offspring with identical traits. | 27 | |
| 6469554244 | Homology | Similarity in characteristics resulting from a shared ancestry. | 28 | |
| 6469554245 | Taxonomy | SCIENCE OF CLASSIFICATION; IN BIOLOGY, THE PROCESS OF CLASSIFYING ORGANISMS IN CATEGORIES | 29 | |
| 6469554246 | Phenotype | An organism's physical appearance, or visible traits. | 30 | |
| 6469554247 | Genotype | An organism's genetic makeup | 31 | |
| 6469554248 | Homologous Structures | Body parts that resemble one another in different species because they have evolved from a common ancestor |  | 32 |
| 6469554249 | Analogous Structures | Body parts that resemble one another in different species, not because they evolved from a common ancestor, but because they evolved independently as adaptations | 33 | |
| 6469554250 | Vestigial Structures | Homologous structures that no longer serve any functions | 34 | |
| 6469554251 | Endosymbiotic theory | Describes how eukaryotic cells originated from a mutually beneficial association among various kinds of prokaryotes | 35 | |
| 6469554252 | Autotrophs | Manufacture their own organic compounds using light energy of that from inorganic substances | 36 | |
| 6469554253 | Heterotrophs | Living organisms that obtain energy by consuming organic substances |  | 37 |
| 6469554254 | Extinct | No longer existing or living. | 38 | |
| 6469554255 | Sickle Cell Anemia | Sickle Cell disease is a serious disorder in which the body makes sickle-shaped red blood cells. They tend to block blood flow in the blood vessels of the limbs and organs. Blocked blood flow can cause pain and organ damage. | 39 | |
| 6469554256 | Phylogeny | The evolutionary history of a species or group of related species. | 40 | |
| 6469554257 | Systematics | The analytical study of the diversity and relationships of organisms, both present-day and extinct. | 41 | |
| 6469554258 | Molecular Systematics | The comparison of nucleic acids or other molecules in different species to infer relatedness. | 42 | |
| 6469554259 | Fossil Record | The chronicle of evolution over millions of years of geologic time engraved in the order in which fossils appear in rock strata. | 43 | |
| 6469554260 | Phylogenetic Tree | A branching diagram that represents a hypothesis about evolutionary relationships. | 44 | |
| 6469554261 | Monophyletic | Pertaining to a grouping of species consisting of an ancestral species and all its descendants; a clade. Made up of an ancestral species and all of its descendant species. | 45 | |
| 6469554262 | Genetic Code | The sequence of nucleotides in DNA or RNA that determines the specific amino acid sequence in the synthesis of proteins. It is the biochemical basis of heredity and nearly universal in all organisms. | 46 | |
| 6469554263 | Species | A group of individuals capable of interbreeding. | 47 | |
| 6469554264 | Speciation | The formation of a new species. | 48 | |
| 6469554265 | Polyploidy | The possession of more than the normal two sets of chromosomes found in diploid. | 49 | |
| 6469554266 | Hybridization | Occurs when two distinctly different forms of a species mate and produce progeny along a geographic boundary called a hybrid zone. | 50 | |
| 6469554267 | Prezygotic Isolating Mechanisms | Consists of mechanisms that prevent fertilization. | 51 | |
| 6469554268 | Postzygotic Isolating Mechanisms | Consists of mechanisms that prevent the formation of fertile progeny. | 52 |
