| A | B |
|---|
| evolution | process by which species arise and change over time |
| paleontology | the study of fossils |
| strata | layers of sediment |
| extant | organisms still in existance |
| inheritance of acquired characteristics | the environment can produce physical changes in an organism during its lifetime that are inheritable (giraffe stretching its neck) |
| uniformatarianism | natural processes witnessed today are the same processes that occurred in the past (geology) |
| biogeography | the study of the geographical distribution of organisms throughout the world |
| natural selection | a process where inherited variation in organisms gives individuals a higher fitness (survival and reproductive advantage) in a particular environment and will increase in the population over time. |
| fitness | the reproductive success of an individual relative to other members of the population |
| adaptation | any evolved trait that helps an organism to be more suited to its environment |
| artificial selection | human-controlled breeding to select for particular traits (in dogs, or plants, etc) |
| transitional fossils | bear a resemblance to two groups that in the present day are classified separately |
| homologous | anatomically similar structures derived from a common ancestor (forelimb bones) |
| analogous | anatomical structures with similar function but different evolutionary paths (wings in birds and bats) |
| homeobox (Hox) genes | orchestrate the development of the body plan in all animals |
| population | a group of organisms of a single species living together in the same geographic area |
| microevolution | evolutionary change within populations |
| population genetics | study of the diversity of populations at the level of the gene (how genetic diversity changes over time) |
| gene pool | alleles of all genes in all the individuals in a population |
| allele frequency | percentage of each allele in a population's gene pool |
| Hardy-Weinberg equilibrium | A stable non-evolving state caused by no mutation, no migration, large population size (no genetic drift), random mating, and no natural selection. |
| Hardy-Weinberg principle | Allele frequencies can be expressed as p + q =1 and genotype frequencies by p^2 + 2pq+q^2 = 1 |
| mutation | a change in the DNA sequence (a source of new genetic variation). Errors made during DNA replication or as a result of mutagens. |
| Gene flow | the movement of alleles between populations (migration of gametes between populations) |
| Genetic drift | refers to changes in allele frequencies of a gene pool due to chance events. |
| Bottleneck effect | A type of genetic drift in which the lost of genetic diversity is due to natural disasters, disease, overhunting, or habitat loss. |
| Founder effect | A type of genetic drift in which variation is lost when a few individuals break away from a large population to found a new population. |
| inbreeding | mating between relatives (side-effect of small population size--genetic drift) |
| non-random or assortative mating | occurs when individuals choose a mate with a preferred trait |
| polygenic trait | natural selection in a genetic context, results in a bell curve that can shift |
| stabilizing selection | occurs when an intermediate phenotype is the most adaptive for the given environmental conditions. |
| directional selection | occurs when an extreme phenotype is favored, and the curve shifts towards one of the extremes |
| disruptive selection | occurs when two or more extreme phenotypes are favored over the intermediate phenotype |
| sexual selection | adaptive changes in males and females that lead to an increased ability to secure a mate |
| Female choice | includes good genes hypothesis--traits that improve chance of survival- and runaway hypothesis-traits that improve male appearance |
| sexual dimorphism | males and females differ in size and other traits |
| male competition | includes cost-benefit analysis--access to mating vs. cost of competition |
| territoriality | type of defensive behavior needed to defend a territory from competing males |
| heterozygote advantage | heterozygote is favored over the two homozygotes (sickle cell) |
| macroevolution | evolution on a large scale, above the species level |
| speciation | splitting of one species into two or more species |
| taxonomist | a scientist who classifies organisms into groups |
| morphology | physical appearance |
| morphological species concept | species are distinguished from each other by one or more diagnostic traits |
| diagnostic traits | distinct physical characteristics |
| cryptic species | species that look almost identical but are very different in other traits, such as habitat or courtship behaviors |
| evolutionary species concept | identification of certain morphological traits (diagnostic) in fossils, requires that members of a species share a distinct evolutionary pathway |
| phylogenetic species concept | an evolutionary family tree is used to identify species based upon a common ancestor |
| monophyletic | a branch that contains all the descendants for a common ancestor |
| biological species concept | relies primarily on reproductive isolation to identify different species |
| zygote | first cell that results when a sperm fertilizes an egg |
| prezygotic isolating mechanisms | prevent reproductive attempts or make it unlikely that fertilization will be successful |
| hybridization | mating between two species |
| habitat isolation | when two species occupy different habitats within the same geographic range |
| temporal isolation | several related species can live in the same habitat but could reproduce at different times of the year |
| behavioral isolation | many species have courtship rituals that allow males and females to recognize one another |
| mechanical isolation | when animal genitalia or plant floral structures are incompatible |
| gamete isolation | even if gametes meet, they may not be able to fuse to form a zygote |
| hybrid inviability (zygote mortality) | a zygote may die because it has the wrong number of chromosomes or receives incompatible instructions from the maternal and paternal genes |
| hybrid sterility | the hybrid zygote may develop into a sterile adult |
| allopatric speciation | the eventual result of populations that have become separated by a geographical or other form of physical barrier |
| reinforcement | the process of natural selection that reinforces reproductive isolation |
| sympatric speciation | speciation in the same geographical location due to changes in behavior, diet, microhabitat |
| polyploidy | a chromosome number beyond diploid (2n) |
| autoploidy | occurs when a diploid species produces diploid gametes due to nondisjunction during meiosis (can form triploid or tetraploid plants) |
| alloploidy | occurs when two different but related species of plants hybridize, followed by a doubling of the chromosomes |
| adaptive radiation | a type of speciation that occurs when a single ancestral species rapidly gives rise to a variety of new species as each adapts to a specific environment |
| convergent evolution | occurs when a biological trait evolves in two unrelated species as a result of exposure to similar environments |
| Pax 6 | is required for eye formation in all animals |
| Hox | determine the location of repeated structures in all vertebrates |
| Tbx5 | transcription factor that turns on the genes needed to make a limb during development |
| Pitx1 | development of the pelvic fin bud |
| LUCA (last universal common ancestor) | common to all organisms that live or have lived on planet Earth |
| biomolecules | organic molecules (containing C) |
| primordial soup hypothesis | early Earth had very little oxygen but instead was made of water vapor, hydrogen gas, methane, and ammonia |
| abiotic synthesis | process of chemical evolution, forming organic molecules from inorganic materials |
| iron-sulfur hypothesis | dissolved gases emitted from thermal vents, such as CO and hydrogen sulfide, would pass over iron and nickel sulfide catalysts |
| proteinoids | small polypeptides that have some catalytic properties |
| microspheres | proteinoids in water form these structures |
| protein-first hypothesis | assumes that protein enzymes arose prior to the first DNA molecule |
| RNA-first hypothesis | only RNA was needed to progress toward the formation of the first cell (can make DNA and proteins) |
| protocell (protobiont) | a structure characterized by having an outer membrane |
| index fossils | fossils that are widely distributed for a limited time period (relative dating) |
| geologic timescale | divides the history of the Earth into eras and then periods and epochs |
| Precambrian | life began (simple prokaryotes)-stromatolites and then evolved into eukaryotic multicellular organisms (3.8 BYA to 545 MYA) |
| Paleozoic | 1st Era (includes Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian periods), has 3 mass extinctions |
| Mesozoic | 2nd Era (age of the dinosaurs--Triassic, Jurassic, and Cretaceous), 2 mass extinctions--Pangaea |
| Cenozoic | 3rd Era (includes Paleogene, Neogene, and Quaternary periods) |
| Holocene | current Epoch, after mammalian extinction |
| mass extinctions | disappearance of a large number of species or higher taxonomic groups within an interval of a few million years |
| taxon | is the general name for a group containing an organism or organisms that exhibit a set of shared traits |
| Taxonomy | a branch of systematic biology that identifies, names, and organizes biodiversity into related categories |
| phylogeny | evolutionary "family tree" that represents the evolutionary history of taxa |
| binomial nomenclature | each species receives a unique two part Latin name |
| classification hierarchy | kingdom, phyum, class, order, family, genus, and species (most recently domain was added as the broadest category) |
| domains | Bacteria, Archaea, and Eukarya |
| Bacteria | prokaryotes, single-celled, phospholipid membrane, cell wall with peptidoglycan |
| Archaea | prokaryotes, single-celled, various branched lipids in their membrane and cell wall without peptidoglycan |
| Eukarya | single or multicellular, phospholipid membrane, membrane-bound organelles, introns--inlcude Animalia, Plantae, Fungi, and Protista |
| common ancestor | at the base of each branch of the phylogenetic tree |
| ancestral traits | traits found in a common ancestor |
| derived traits | those not found in a common ancestor, important for clarifying evolutionary relationships |
| cladistics | method that uses shared, derived traits to develop a hypothesis of evolutionary history |
| cladogram | a phylogeny constructed with cladistic methods |
| clade | a common ancestor and all of its descendant lineages |
| parsimony | considers the simplest solution to be the most optimal |
| outgroup | taxon that is used to determine the ancestral and derived traits of characters in the ingroup |
| ingroup | the taxa for which the evolutionary relationships are being determined |
| chordates | dorsal spinal or nerve cord |
| molecular clock | neutral mutations can be used to construct a timeline of evolutionary history |
