Chapter 2 Flashcards
Habitat
The specific area of the natural environment in which an organism lives
Species
A group of related organisms that can interbreed and produce fertile, viable offspring.
Adaptations
Changes in physical structure, function, or behavior that allow an organism or species to survive and reproduce in a given environment.
Natural selection
The process by which some organisms, with features that enable them to adapt to the environment, preferentially survive and reproduce, thereby increasing the frequency of those features in the population.
Adaptive radiation
The diversification of an ancestral group of organisms into new forms that are adapted to specific environmental niches
Lamarckism
The theory of evolution through the inheritance of acquired characteristics in which an organism can pass on features acquired during it’s lifetime.
Gemmules
As proposed by Darwin, the units of inheritance, supposedly accumulated in the gametes so they could be passed on to offspring
Blending inheritance
An outdated, did reputed theory that the phenotype of an offspring was a uniform blend of the parents’ phenotypes.
Gene
The basic unit of inheritance; a sequence of DNA on a chromosome, coded to produce a specific protein
Allele
One or more alternative forms of gene
Dominant
An allele that Is expressed in an organism’s phenotype and that simultaneously masks the effects of another allele, if another one is present
Recessive
An allele that is expressed in an organism’s phenotype if two copies are present, but is masked if the dominant allele is present
Mendelian inheritance
The basic principles associated with the transmission of genetic material, forming the basis of genetics, including the law of segregation and the law of independent assortment.
Genotype
The genetic makeup of an organism; the combination of alleles for a given gene
Phenotype
The physical expression of the genotype; it may be influenced by the environment.
Chromosomes
Strand of DNA found in the nucleus of eukaryotes that contains hundreds or thousands of genes.
Evolutionary synthesis
A unified theory of evolution that combines genetics with natural selection
Four causes of evolution
Natural selection
Mutation
Gene flow
Genetic drift
Mutation
Random change in agents or chromosome, creating a new trait that may be advantageous, deleterious, or neutral in it’s effects on the organism
Gene flow
Admixture, or the exchange of alleles between two populations
Genetic drift
The random change in allele frequency from one generation to the next, with greater effect in small populations
