anthro test 1

Vertebrates

Animals that possess a backbone or spinal column.

Homologies

Anatomical or genetic traits shared by different species due to inheritance from a common ancestor.

Analogies

Traits with similar functions that evolved independently in different lineages through convergent evolution rather than shared ancestry.

Ancestral trait

A physical or genetic characteristic inherited from a remote ancestor that has remained largely unchanged.

Derived trait

A newly evolved feature present in a lineage that was not present in its ancestral state.

Clade

A taxonomic group consisting of a single common ancestor and all of its descendants.

Cladogram

A branching diagram used to illustrate evolutionary relationships based on shared derived characteristics.

Intraspecific vs. interspecific variation

Intraspecific variation refers to differences occurring within the same species, whereas interspecific variation refers to differences between distinct species.

Mammalian characteristics

Defining traits of mammals, including hair or fur, mammary glands for milk production, three middle ear bones, and endothermy.

Primate characteristics

Defining traits of primates, including forward-facing eyes with stereoscopic vision, prehensile hands and feet, flattened nails, and enlarged brains relative to body size.

Phylogenetic tree

An evolutionary diagram showing inferred genealogical relationships among species over evolutionary time.

Biological species concept

A species definition stating that a species is a group of naturally interbreeding populations that are reproductively isolated from other such groups.

Speciation

The evolutionary process through which new, distinct biological species arise.

Recognition species concept

A species definition based on shared mate-recognition systems and fertilization mechanisms among individual organisms.

Behavioral isolation

A reproductive barrier where unique courtship displays or mating behaviors prevent different species from interbreeding.

Ecological species concept

A species definition that classifies organisms based on the specific ecological niche and environmental resources they utilize.

Phylogenetic species concept

A species definition identifying a species as the smallest diagnosable cluster of organisms sharing a unique evolutionary lineage.

Allopatric speciation

Speciation that occurs when populations become geographically separated from one another, preventing gene flow.

Parapatric speciation

Speciation that occurs when neighboring populations diverge while maintaining continuous contact along a shared boundary.

Sympatric speciation

Speciation occurring within populations residing in the same geographic area without physical isolation.

Sexual dimorphism

Systematic differences in physical appearance or size between males and females of the same species beyond reproductive organs.

Ecological niche

The unique functional role, environmental conditions, and resource set utilized by a species within an ecosystem.

Heterodont

An organism possessing teeth differentiated into distinct shapes and specialized functions, such as incisors, canines, premolars, and molars.

Endothermic

Organisms capable of generating and regulating their own internal body heat through metabolic processes.

Punctuated equilibrium

An evolutionary model proposing long periods of evolutionary stasis interrupted by sudden bursts of rapid speciation.

Phyletic gradualism

An evolutionary model proposing that species diverge continuously and incrementally over long periods of time.

Plesiadapiformes

An extinct group of early Cenozoic mammals considered close relatives or ancestral precursors to true primates.

Primate locomotion types

The primary modes of movement in primates, including vertical clinging and leaping, quadrupedalism, brachiation, and bipedalism.

Factors affecting primate social structure

Key ecological and biological variables shaping group life, including food resource distribution, predation risk, group size, and mating systems.

Primate diet quality (leaves vs. fruit vs. meat)

The nutritional content of dietary items: leaves are low quality (high fiber, low energy), fruit is medium quality (high sugar), and meat is high quality (dense protein and fat).

Hominoid

A member of the biological superfamily Hominoidea, which includes all living and extinct apes and humans.

Hominid

A member of the family Hominidae, including modern humans, chimpanzees, gorillas, orangutans, and their extinct ancestors.

Hominin

A member of the tribe Hominini, encompassing modern humans and all extinct bipedal ancestor species following the split from the chimpanzee lineage.

Human-chimpanzee last common ancestor

The ancestral hominoid species from which the human and chimpanzee lineages diverged approximately $6\text{ to }8\text{ million years ago}$.

Ardipithecus

An early hominin genus from the early Pliocene ($\approx 4.4\text{ million years ago}$) showing facultative bipedalism along with arboreal traits like a grasping big toe.

Australopithecus

An extinct genus of early hominins characterized by obligate bipedalism, small brain size, and large postcanine teeth.

Homo habilis

An early species of the genus Homo ($\approx 2.4 - 1.4\text{ million years ago}$) associated with an expanded braincase and Oldowan stone tool technology.

Homo erectus

An extinct hominin species ($\approx 1.9\text{ million to }110,000\text{ years ago}$) characterized by modern human-like body proportions, larger brain capacity, and Acheulean tool manufacture.

Archaic Homo sapiens

Middle Pleistocene hominins displaying a mosaic of primitive ancestral features alongside derived modern human traits.

Homo neanderthalensis

An extinct hominin species in Europe and Western Asia with robust body adaptations for cold climates, large brain capacity, and complex Mousterian tools.

Major trends in hominin evolution

Key macroevolutionary changes over time, including obligate bipedalism, reduction in canine and molar size, dramatic brain enlargement, and increasing cultural/technological complexity.

Epigenetics

The study of inherited or acquired changes in gene expression that do not alter the underlying DNA sequence.

Random assortment

The random alignment and separation of homologous chromosomes during meiosis, creating genetic variation in gametes.

Recombination

The exchange of genetic material between homologous chromosomes during meiosis (crossing over), creating novel allele combinations.

Main messages of article 'The Forgotten Father of Epigenetics'

Conrad Waddington introduced epigenetics and the epigenetic landscape to explain how development mediates between genotype and phenotype.

Mutation

A permanent change in the nucleotide sequence of DNA, acting as the primary source of all new genetic variation.

Complex trait

A trait influenced by multiple genes and environmental factors, showing continuous variation rather than discrete categories.

Simple trait

A trait governed by a single gene (Mendelian inheritance) displaying distinct, discrete phenotypic categories.

ABO blood groups

A human blood typing system controlled by a single gene with three alleles ($A$, $B$, and $O$) demonstrating dominant, recessive, and codominant patterns.

Codominance

An inheritance pattern where two different alleles for a gene are fully and simultaneously expressed in a heterozygous individual.

Human genome project

An international scientific initiative completed in $2003$ that mapped and sequenced the complete set of human DNA.

Autosome

Any chromosome that is not a sex chromosome, corresponding to pairs $1$ through $22$ in humans.

Why sex is a complex trait

Biological sex involves complex interactions among genetic pathways, sex hormones, receptors, and environmental signals rather than a simple binary.

Sex steroid

Steroid hormones, such as estrogens and androgens, that regulate sexual differentiation, reproduction, and secondary sex characteristics.

DSD

Differences or Disorders of Sex Development; congenital conditions where chromosomal, gonadal, or anatomical sex development is atypical.

DNA Methylation

An epigenetic mechanism where a methyl group is added to DNA bases, typically suppressing gene transcription.

Histone modification

Chemical alterations to histone proteins that alter chromatin structure and affect accessibility for gene transcription.

Intergenerational Epigenetics

The inheritance of epigenetic changes across generations without altering the underlying DNA sequence.

Levels of regulation of gene expression

The control of gene activity occurring at chromatin remodeling, transcriptional, post-transcriptional, translational, and post-translational stages.

Epigenetic marks

Chemical modifications on DNA or histones that regulate gene expression patterns without modifying the nucleotide sequence.

Hox genes

A conserved group of homeotic genes that direct the body plan and segment identity along the head-to-tail axis during embryonic development.

Plasticity

The capacity of a single genotype to produce varying phenotypes in response to different environmental conditions.

Taxon

A named group or category of organisms at any level within a biological classification system.

Lamarck

Jean-Baptiste Lamarck, an early evolutionary theorist who proposed that organisms inherit traits acquired through use and disuse during their lifetimes.

Binomial nomenclature

The formal system of naming species using a two-part Latinized name consisting of the genus and species epithet.

Competition for resources

The interaction among organisms striving for the same limited environmental resources, such as food, territory, or mates.

Adaptation

A feature or behavior evolved through natural selection that increases an organism's survival and reproductive success.

Natural Selection

The evolutionary mechanism where organisms with traits better suited to their environment are more likely to survive and reproduce.

Evolution

The change in genetic composition and allele frequencies of a population over successive generations.

Modern synthesis

The unification of Darwinian natural selection with Mendelian genetics to explain evolutionary processes.

Directional selection

Natural selection that favors individuals at one extreme of a phenotypic range, shifting population traits over time.

Genetic drift

Random fluctuations in allele frequencies within a population caused by chance events, especially in small populations.

Gene flow

The movement and exchange of genetic material between populations through migration and interbreeding.

Founder effect

A form of genetic drift occurring when a small subgroup forms a new population with limited genetic variation.

Selectionist theory

The evolutionary hypothesis that natural selection is the primary driver shaping genetic diversity within populations.

Neutral theory

The hypothesis that most evolutionary change at the molecular level is caused by random genetic drift of neutral mutations.

Major trends in hominin evolution

Key macroevolutionary changes over time, including obligate bipedalism, reduction in canine and molar size, dramatic brain enlargement, and increasing cultural/technological complexity.