Key Concepts in Evolutionary Biology and Genetics
Key Evolutionary and Genetic Concepts
Fixism
Belief that all species were created as we see them today. Species are therefore immutable.
Lamarckism
Evolutionary theory proposed by Lamarck. It considers that living beings change throughout their lives as a result of the use or disuse of organs. Body modifications acquired are transmitted to the offspring. Also called evolutionism.
Genotype
The combination of specific alleles of a cell of an individual for the full genome, or more often, a particular gene.
Phenotype
The apparent or visible characters of an organism, resulting from the combined action of genotype and the influence of environmental factors.
Mutation
The process that gives rise to the emergence of a new alternative to a gene. The gene resulting from this process.
Selection Processes
- Sexual Selection: Effects of “the struggle between individuals of one sex, usually males, for possession of the other sex.”
- Artificial Selection: A technique of reproductive control through which humans alter the genes of domesticated or cultivated organisms. This technique operates on heritable characteristics of species, increasing the frequency with which certain variations appear in the following generations. It produces a directed evolution, in which human preferences determine the traits that allow survival.
Genealogy
It is a graphic representation outlining the genealogical data of an individual in an organized and systematic way, whether as a tree or table.
Catastrophism
Theory that explains that the geological and biological changes produced on our planet were not due to gradual change, but to sudden and violent events, disasters, which give the theory its name.
Chromosome
Structure of circular or rod shape that comes from nuclear chromatin during its division. It is a linear grouping of genes.
Natural Selection
The process where populations or individuals with advantageous traits produce more offspring, replacing those that will not have them.
Speciation
An evolutionary process where one species forms two or more new species.
Synthetic Theory (Modern Synthesis)
The theory of evolution accepted today. It gets its name, first, because it is a theory that collaborates across three main disciplines: genetics, systematics, and paleontology; and secondly, because it recognizes various causes of evolution: natural selection, genetic mutations, recombination of genes, and geographical isolation.
Theory of Punctuated Equilibrium
States that for most of the time of a species’ existence, it remains stable or with minor changes. Accumulated evolutionary change occurs during speciation (formation of a new species), which would be a kind of genetic revolution, rapid in geological terms. It does not dispute the gradual character of evolutionary change but refuses the uniformity of its rhythm.
Inheritance
It is the transmission, through the genetic material contained in the cell nucleus, of the anatomical, physiological, or other characteristics of a living being to its descendants. The result will be features (genes) from both parents, depending on the mode of reproduction.
Evolution
Continuum of changes in living things, through gradual modifications, in which the enormous variety of current and extinct plant or animal forms and species has been produced over geologic history.
Encephalization Quotient
Brain weight of an individual in relation to their body weight.
Genetic Drift
It is an evolutionary force acting together with natural selection by changing the characteristics of the species over time.