4.9: Key Terms

allele

an alternative form of a gene that arises by mutation and is found in the same place on a chromosome, directly impacting the expression of a genetic trait or phenotype.

allopatric speciation

speciation that occurs when two populations of the same species become isolated from each other due to a change in the environment, such as geographic isolation.

analogous structures

anatomical similarities between two species that suggest not a common ancestor but rather similar environmental adaptations.

ancestral characteristics

homologous structures or traits that may also be found in the common ancestor of the species being classified.

angiosperm theory

a hypothesis that suggests that primate origins and typical primate characteristics developed in response to the emergence of flowering plants.

arboreal theory

a hypothesis that proposes that primates evolved the traits they did as an adaptation to life in the trees.

artificial selection

the process of deliberately breeding certain specimens of plants or animals to encourage desired traits.

binomial nomenclature

the scientific naming system developed by Carolus Linnaeus that represents two parts of a taxonomic name. The name is italicized, the genus is always capitalized, and the species is always lowercased. For example: Homo sapiens.

bioarchaeology

the study of bones and other biological materials found in archaeological remains.

biological species definition

a definition of species as members of populations that actually or potentially interbreed in nature.

Catarrhini

a subcategory of the primate infraorder Simiiformes that includes any primate considered an Old World monkey, an ape, or in the lineage of humans. This classification features downward-facing nostrils and a 2.1.2.3 dental formula.

catastrophism

the theory that changes in Earth’s fauna and flora were caused by supernatural catastrophic forces rather than evolution.

Cercopithecoidea

a superfamily of the primate infraorder Simiiformes, subcategory Catarrhini, that consists of Old World monkeys.

cladistics

the classification of organisms based on branchings of descendent lineages from a common ancestor

derived characteristics

physical traits that are present in related organisms but absent from their last common ancestor. They are often associated with a speciation event.

diastema

a space or gap between the canines and the other teeth that allows for the upper and lower teeth to bite together.

ecological species definition

a definition of species that explains differences in form and behavior as the result of adaptations to the environment and natural selection.

ethnotaxonomy

the study of organism classifications and taxonomies developed and used largely by Indigenous peoples and other cultural groups.

evolution

changes that appear in a species over time. Evolution is dependent on genetic variation and natural selection to pass on beneficial traits that will increase survival of the species.

foramen magnum

the opening at the base of the skull where the spinal column and nerves enter to reach the brain. The position of the foramen magnum can be used to determine if a species was bipedal.

forensic anthropology

a branch of biological anthropology in which scientific techniques are used to determine the sex, age, genetic population, or other relevant characteristics of skeletal or biological materials related to matters of civil or criminal law.

fossils

any remains, impression, or traces of living things from a former geologic age.

gene flow

alteration of the frequencies of alleles in a population that results from interbreeding with organisms from another population.

genetic anthropology

a branch of biological anthropology that uses molecular science to explore questions concerning human origins, early human migrations, and the appearance of disease across time.

genetic drift

random changes in the frequencies of alleles in a gene pool.

genotype

a complete set of genetic material found in an organism.

gradualism

the idea that species evolve slowly and continuously over long periods of time.

great chain of being

a concept detailing a hierarchical structure of all matter and life.

Haplorrhini

a suborder of primates that contains tarsiers, New World monkeys, Old World monkeys, apes, and humans.

hominid

the group representing all modern and extinct great apes, including humans, chimpanzees, gorillas, orangutans, and all their immediate ancestors.

hominin

the group representing modern humans, extinct human species, and all of humanity’s immediate ancestors, including the genera Homo, Australopithecus, Paranthropus, and Ardipithecus.

Hominoidea

a superfamily of the primate infraorder Simiiformes, subcategory Catarrhini, that consists of gibbons, great apes, and humanlike primates, including Homo and related fossil forms.

homologous structures

similar anatomical structures that appear in different species and suggest a common ancestor.

hybrid zones

areas where two distinct species mate and produce offspring

industrial melanism

the prevalence of dark-colored varieties of animals (for example, peppered moths) in industrial areas where they are better camouflaged against predators than paler forms.

inheritance of acquired characteristics

the disproved idea that an organism can pass on to its offspring physical characteristics that it has acquired during its lifetime.

interspecific variation

the genetic variation seen between two species.

intraspecific variation

the genetic variation seen within a species.

law of independent assortment

a law of inheritance stating that different genes and their alleles are inherited independently.

law of segregation

a law of inheritance stating that when two alleles for a trait separate during the formation of new zygotes, these alleles will combine at random with other alleles.

morphology

the physical shape and structural form of an organism or species.

mutation

a change in the structure of a gene that results in a variant form that may be transmitted to subsequent generations.

natural selection

the process by which a species that is able to adapt and to pass on beneficial traits to its offspring ensures survival of the species; first formally introduced by Charles Darwin.

paleoanthropology

the study of the origins and predecessors of the present human species based fossils and other remains.

Parapithecoidea

a superfamily of primates from the early Oligocene that is believed to represent the earliest New World monkeys, though they first evolved in Africa.

phenotype

the set of observable characteristics or traits of an organism, such as color and structural morphology.

phylogenetic species definition

a definition of species based on individuals all possessing specific derived traits.

Platyrrhini

a subcategory of the primate infraorder Simiiformes that comprises New World monkeys

polygenic traits

traits that are controlled by multiple genes instead of just one.

primatology

the branch of biological anthropology dealing with the primates.

Proconsul

a genus of ape from the early Miocene.

prognathism

projection of the face, as seen in many nonhuman primates and early hominins.

Propliopithecoidea

a superfamily of primates from the early Oligocene that is related to Old World monkeys and is believed to represent the earliest catarrhine primate.

punctuated equilibrium

a hypothesis holding that the evolution of species proceeds in a characteristic pattern of relative stability for long periods of time interspersed with much shorter periods during which many species become extinct and new species emerge.

Purgatorius

genus of the earliest primate or proto-primate.

reproductive isolation

conditions that prevent potentially interbreeding populations from breeding.

socioecological system

the interrelationship between the diversity of plants and animals, humans’ environments, and the diversity of human culture and language.

species

a class of individuals that have some common characteristics or qualities.

stratigraphy

a branch of geology dealing with the classification, nomenclature, correlation, and interpretation of stratified rocks.

Strepsirrhini

a suborder of primates that includes lemurs, lorises, and galagos (bush babies).

survival of the fittest

the theory that the most evolutionarily fit members of a species will pass on their traits to later generations.

sympatric speciation

speciation without a geographic barrier.

taxa

the plural form of taxon, used to signify all taxonomic groups.

taxon

a specific group or subgroup of organisms.

taxonomy

the science or technique of naming and classifying life.

uniformitarianism

the concept that Earth’s surface was shaped in the past by slow-moving geological processes.

visual predation hypothesis

a hypothesis that explains the origins of unique primate traits as adaptations for preying on insects and small animals.