Unit 4 Summary 7 Flashcards
DNA sequencing
DNA sequencing: The determination of the base (nucleotide) sequence of a gene. In one common method, the DNA is cleaved using a restriction enzyme, and the cleaved fragments are subjected to various reactions before being separated by gel electrophoresis. DNA sequencing can be used to determine relationships between individuals of a species, and for determining whole genomes of populations or species.
DNA hybridisation
DNA hybridisation: Formation of a hybrid molecule when single-stranded DNA of two different organisms is brought together and their complementary bases bond together.
Thermal stability
Thermal stability: (Of DNA) Temperature needed to dissociate half of the hybrid molecules formed after bonding the DNA of two different organisms (DNA hybridisation)
Amino acid sequencing
Amino acid sequencing: Method of determining the order of amino acids in a protein
Mitochondrial DNA
Mitochondrial DNA: Circular DNA molecule found in the mitochondria
Molecular clock
Molecular clock: Estimated rate of nucleotide substitution (number of bases per year) for a particular region of DNA; used to estimate number of evolutionary changes.
Phylogeny
Phylogeny: The evolutionary relationships of organisms, usually depicted by a branching tree
Phylogenetic tree
Phylogenetic tree: A phylogenetic tree or evolutionary tree is a branching diagram or “tree” showing the inferred evolutionary relationships among various biological species or other entities—their phylogeny—based upon similarities and differences in their physical or genetic characteristics.
Cladogram
Cladogram: a branching diagram showing the cladistic relationship between a number of species.
Cladistics: Method of building phylogenetic trees based on homologous features that indicate that organisms are related
Speciation
Speciation: The evolution of a new species; for example, as a result of the splitting of an ancestral species by a geographic barrier and subsequent natural selection and/or genetic drift in the separated populations
Allopatric speciation
Allopatric speciation: The physical isolation of populations that begins the process of speciation due to geographic isolation
Geographical isolation
Geographical isolation: Populations of species that are isolated by geographic barriers or distance so that they cannot interbreed; begins the process of allopatric speciation
Selective pressures:
Selective pressures: Limiting factors in the environment of an organism that affects its survival and reproduction
Subspecies
Subspecies: Populations within a species that show genetic differences across a geographic range; also called races
Reproductive isolation
Reproductive isolation: Organisms of different species are not able to interbreed due to behavioural, mechanical or geographic isolations.
Species
Species: The fundamental unit of biological classification recognised by one or more unique characteristics; organisms of the same species (a gene pool) are generally reproductively isolated from other species (other gene pools)
Divergent evoltion
Divergent evolution: The evolution of different species from a single ancestor species, especially as a result of reproductive isolation
Homologous structures
Homologous structures: Similar features in organisms that have a common evolutionary origin, regardless of their function.
Adaptive radiation
Adaptive radiation: Rapid divergence of an evolutionary lineage from a recent common ancestor
Convergent evolution
Convergent evolution: The independent evolution of structures with similar form and function in unrelated organisms, resulting from the influence of similar environmental factors.
Analogous structures
Analogous structures: Features (such as organs) in different species that serves the same functions
Extinction
Extinction: In evolution, the dying out of a species or group of species
Background extinction
Background extinction: Average rate of natural loss (extinction) over time
Mass extinction
Mass extinction: Rapid loss of many species or groups of organisms due to an event, for example the end of the Cretaceous period with the death of dinosaurs and many animal groups
