Flashcards in Midterm 1: ch 1-4 Deck (34):
A feature of an organism created by the process of natural selection.
The process that produces adaptation. Natural selection is based on three postulates: (1) the availability of resources is limited; (2) organisms vary in the ability to survive and reproduce; and (3) traits that influence survival and reproduction are transmitted from parents to offspring.
The form and structure of an organism
The biological capacity to reproduce.
Variation in genotypes for the same phenotypes
Random change in gene frequencies due to sampling variation that occurs in any finite population. Genetic drift is more rapid in small populations than in large populations.
The movement of genes from one population to another, or from one part of a population to another, as the result of interbreeding
A state that occurs when all of the individuals in a population are homozygous for the same allele at a particular locus.
Occurs when one gene influences two or more seemingly unrelated phenotypic traits
One whose phenotype is influenced by more than one gene
One whose phenotype is influenced by one gene
The unchanging frequency of genotypes that results from sexual reproduction and occurs in the absence of other evolutionary forces such as natural selection, mutation, or genetic drift.
Phenotypic differences between individuals that exist because those individuals developed in different environments.
Describing traits that are very insensitive to environmental conditions during development, resulting in similar phenotypes in a wide range of environments
Describing traits that are very sensitive to environmental conditions during development, resulting in different phenotypes in different environments
Evolution of populations within a species.
Evolution of new species, families, and higher taxa.
biological species concept
The concept that species are defined as a group of organisms that cannot interbreed in nature.
ecological species concept
The concept that natural selection plays an important role in maintaining the differences between species, and that the absence of interbreeding between two populations is not a necessary condition for defining them as separate species
Speciation that occurs when two or more populations of a single species are geographically isolated from each other and then diverge to form two or more new species.
A hypothesis that speciation can result from selective pressures favoring different phenotypes within a population, without positing geographic isolation as a factor
The process in which a single lineage diversifies into a number of species, each characterized by distinctive adaptations.
The evolutionary relationships among a group of species, usually diagrammed as a “family tree.”
A branch of biology that is concerned with the use of phylogenies for naming and classifying organisms.
Similarity between traits that is due to convergent evolution, not common descent.
Similarity between traits that is due to common ancestry, not convergence.
A trait that appears earlier in the evolution of a lineage or clade. Ancestral traits are contrasted with derived traits, which appear later in the evolution of a lineage or clade.
A trait that appears later in the evolution of a lineage or clade. Derived traits are contrasted with ancestral traits, which appear earlier in the evolution of a lineage or clade.
A theory postulating that genetic change is caused only by mutation and drift.
A taxonomic category below family and above species. There may be several species in a genus, and several genera in a family.
A taxonomic level above genus but below order. A family may contain several genera, and an order may contain several families.
The taxonomic level that lies between infraorder and family. An infraorder may contain several superfamilies, and a superfamily may contain several families
A system for classifying organisms in which patterns of descent are the only criteria used.