ANP 206: Origin and Evolution of Species & Primate Diversity

Comprehensive practice vocabulary flashcards covering ANP 206 lecture topics on evolutionary mechanisms, speciation, reproductive isolating barriers, comparative anatomy, mammalian evolution, and primate diversity.

Biological Species Concept

A definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, and are reproductively isolated from other such groups.

Phylogenetic (Morphological) Species Concept

A definition of a species based on shared morphological and physical characteristics, primarily applied to extinct organisms and fossil taxa where reproductive capability cannot be directly observed.

Reproductive Isolating Barrier (RIB)

Any biological mechanism or physical barrier that prevents individuals of two different species from interbreeding and producing viable, fertile offspring, thereby enabling speciation.

Ecological (Habitat) Isolation

A prezygotic barrier where two species inhabit different ecological niches or physical habitats within the same general geographic area and therefore rarely encounter each other to mate.

Temporal Isolation

A prezygotic isolating barrier where species reproduce at different times of day, different seasons, or different years, preventing interbreeding.

Ethological (Behavioral) Isolation

A prezygotic barrier in which species display distinct behavioral patterns or courtship rituals, such as the conflicting patriarchal harem society of Hamadryas baboons versus the matriarchal female-choice society of Anubis baboons along Ethiopia's Awash River.

Mechanical Isolation

A prezygotic barrier where anatomical or structural differences in reproductive organs physically prevent successful copulation or pollination between different species.

Gametic Mortality (Incompatibility)

A prezygotic barrier where sperm and egg come into contact but cannot fertilize each other due to chemical incompatibilities or inhospitable reproductive tracts.

$\text{F}_1$ Inviability

A postzygotic barrier where fertilization takes place and a zygote forms, but genetic incompatibilities prevent normal embryonic development, resulting in death before or shortly after birth.

$\text{F}_1$ Sterility

A postzygotic reproductive barrier where interspecific mating yields a viable, healthy offspring that is physically incapable of producing functional gametes, exemplified by the sterile mule produced from a horse and donkey.

Hybrid Breakdown

A postzygotic barrier in which the first-generation ($\text{F}_1$) hybrids are viable and fertile, but subsequent generations ($\text{F}_2$ or backcrosses) suffer from reduced viability, sterility, or physical abnormalities.

Anagenesis

A pattern of straight-line, unbranched evolutionary change through time, in which a single lineage (Form A) transforms gradually into another (Form B) and further into another (Form C) without speciation splits.

Cladogenesis

Branching evolution where an ancestral lineage splits into two or more descendant species, thereby increasing taxonomic diversity over time.

Clade

A monophyletic group consisting of a common ancestor and all of its lineal evolutionary descendants.

Adaptive Radiation

The rapid diversification and speciation of a single ancestral lineage into a wide variety of ecological niches and forms, typically following the availability of new environmental opportunities or adaptive innovations.

Gradualism (Phyletic Gradualism)

The evolutionary model proposing that macroevolution occurs through the continuous, slow, and steady accumulation of small variations, predicting smooth morphological transitions in the fossil record.

Punctuated Equilibrium

The evolutionary hypothesis proposing that species experience long periods of evolutionary stasis (little or no change) interrupted by rapid bursts of speciation and significant morphological change.

Orthogenesis

The disproven misconception that biological evolution is directed toward a preordained, specific progressive goal or teleological outcome.

Exaptation (Misconception of Current Structures)

The principle that structures serving a specific modern function did not necessarily evolve initially for that purpose; for instance, upright bipedal walking evolved approximately $1.5\,\text{million years}$ before the manufacture of stone tools.

Homology (Homologous Trait)

Physical traits in different species that share structural similarities because they were inherited from a shared common ancestor, regardless of whether they serve the same functional purpose today.

Homoplasy (Analogous Trait)

A morphological trait shared by different species that performs a similar biological function but evolved independently through distinct developmental paths rather than being inherited from a common ancestor.

Parallel Evolution

A form of homoplasy occurring when closely related evolutionary lineages that recently diverged independently develop similar structural adaptations, such as the dental enlargement seen in both Australopithecus boisei and Australopithecus robustus approximately $3\,\text{million years ago}$.

Convergent Evolution

The independent evolution of superficially similar adaptations in distantly related evolutionary lineages facing similar environmental pressures, such as the morphological similarities between the marsupial Tasmanian wolf (Thylacine) and the placental North American Gray Wolf.

Primitive Trait

An ancestral trait or anatomical feature that has remained unchanged from the ancestral state of a broader taxonomic group.

Derived Trait

A newly modified or novel anatomical trait that has changed from the ancestral state within a specific evolutionary lineage.

Cladistics

A biological classification approach that groups organisms strictly based on shared derived traits (synapomorphies) while ignoring shared primitive traits.

Phenetics

A taxonomic approach that groups organisms according to overall physical and phenotypic similarity, tallying both primitive and derived shared traits without distinguishing homology from homoplasy.

Phylum Chordata

A major animal phylum characterized by a spinal cord, notochord, dorsal hollow nerve cord, pharyngeal gill slits at some stage of development, and a postanal tail; these traits evolved approximately $600\,\text{million years ago}$.

Subphylum Vertebrata

A taxonomic subdivision of Chordata characterized by bilateral symmetry and vertebrae (bones covering and shielding the spinal cord), which originated approximately $520\text{--}435\,\text{million years ago}$.

Class Mammalia

A class of warm-blooded vertebrates defined by body hair and the ability to nourish their offspring with milk from maternal mammary glands; first arose approximately $200\,\text{million years ago}$ during the Jurassic period.

Prototherians (Monotremes)

A subclass of primitive mammals that lay eggs rather than giving live birth, surviving modernly only as the platypus and two species of spiny anteater (echidna).

Metatherians (Marsupials)

A mammalian subclass that gives birth to an extremely immature, embryonic fetus and nurtures it within an external maternal pouch, exemplified by kangaroos and opossums.

Subclass Eutheria

Placental mammals that nurture developing embryos internally via a placenta, delivering a relatively mature fetus at birth.

Homeotherm

An organism capable of maintaining a constant internal body temperature through metabolic heat generation, allowing habitation of varied climates at a substantial energetic cost.

Heterodont

Possessing anatomically differentiated teeth (incisors, canines, premolars, and molars) designed to process diverse dietary items, typically limited in mammals to two successive sets (deciduous and permanent).

Mammary Glands

Specialized mammalian glands that supply nutrient-rich milk and protective immunities to newborn infants, demanding high maternal energetic investment.

Placenta

A temporary vascular organ in eutherians that supplies nourishment and gas exchange to the fetus within a safe uterine environment, requiring high maternal energetic input.

$K\text{-selected}$ Strategy

A reproductive strategy characterized by producing few offspring with substantial, long-term parental investment to maximize offspring survival (quality over quantity), prominent in primates and large mammals.

$r\text{-selected}$ Strategy

A reproductive strategy emphasizing the production of vast numbers of offspring with little to no parental care, as observed in animals such as oysters, fish, and frogs.

Cerebrum

The outer region of the vertebrate forebrain involved in sensory integration, memory, learning, and intelligence, which is significantly enlarged and convoluted in mammals.

Binocular Stereoscopic Vision

A visual system characterized by forward-facing, overlapping fields of vision (binocular) where both hemispheres of the brain receive inputs from both eyes (stereoscopic), creating precise 3D depth perception.

Prehensile Digits

Digits (fingers and toes) capable of grasping objects and wrapping securely around tree branches, protected by flattened nails rather than claws and supplied with expanded tactile pads rich in nerve endings.

Harry Harlow Infant Isolation Experiments

Psychological studies demonstrating that maternal bonds in primates rely heavily on contact comfort rather than just nutrition; monkeys raised with wire substitute mothers developed severe social ineptitude, hyper-aggression, and inability to parent.

Imo the Japanese Macaque

A Japanese macaque that invented sweet potato washing and wheat winnowing in water, novel behaviors that spread through social learning to the troop, proving that culture (shared, learned behavior) is not unique to humans.

Solitary Group

The smallest primate social organization, consisting solely of an adult female and her dependent offspring, exemplified by modern orangutans.

Monogamy

A primate mating system consisting of an exclusive sexual bond between one adult male and one adult female for an extended period, frequently correlating with high paternal investment (e.g., gibbons and langurs).

Polygyny

A polygamous social structure where one adult male mates with multiple adult females at the same time, as observed in gorillas and howler monkeys.

Polyandry

A rare primate mating pattern in which one reproductive adult female mates with multiple adult males simultaneously, seen in marmosets and tamarins due to high twinning rates ($80\%$) necessitating cooperative childcare.

Multimale/Multifemale Group

The most prevalent non-human primate social structure, consisting of multiple adult males, multiple adult females, and their dependent offspring, generally accompanied by promiscuous mating.

Primate Taxonomy

The hierarchical classification dividing the order Primates into suborders Prosimii (lemurs, lorises, tarsiers) and Anthropoidea (monkeys, apes, humans), further branching into Platyrrhini and Catarrhini.

Suborder Prosimii (Prosimians)

Primitive primates found primarily in Madagascar, mainland Africa, and Southeast Asia, possessing smaller relative brain sizes, unfused postorbital eye rings (not fully enclosed), greater reliance on olfaction, and frequently displaying vertical clinging and leaping.

Tarsier (Infraorder Tarsiiformes)

A nocturnal, carnivorous Southeast Asian prosimian possessing dry noses, massive forward-facing eyes, an owl-convergent predatory habit on small vertebrates and insects, and an evolutionary position intermediate between prosimians and anthropoids.

Loris (Superfamily Lorisoidea)

Small, solitary, nocturnal primates found across Asia and mainland Africa, including slow stalkers (lorises) and active leapers and gum-feeders (galagos).

Lemur (Superfamily Lemuroidea)

A diverse group of primates endemic exclusively to Madagascar, isolated from mainland Africa for $120\,\text{million years}$ in the absence of competing anthropoids.

Aye-Aye (Daubentonia madagascariensis)

A nocturnal, solitary Madagascan lemur exhibiting woodpecker-convergent ecology, utilizing an elongated, skeletal middle finger to extract wood-boring insect larvae.

Ring-Tailed Lemur (Lemur catta)

A diurnal, terrestrial Madagascan lemur living in female-dominated social groups ($5\text{--}30$ individuals) that communicate and defend territory through specialized scent glands and male 'stink fights'.

Suborder Anthropoidea (Anthropoids)

The 'higher primates' (monkeys, apes, humans) characterized by larger body sizes, larger convoluted brains, fully enclosed bony eye sockets, diurnal activity (with one exception), and complex social systems.

Platyrrhini (New World Monkeys)

Anthropoid primates of Central and South America diverging $30\,\text{million years ago}$, characterized by four extra premolars (dental formula $2\text{-}1\text{-}3\text{-}3$), broad flat noses with side-facing nostrils, exclusive arboreality, and prehensile tails in certain species.

Callitrichidae

The smallest anthropoid primates, encompassing marmosets and tamarins; roughly $80\%$ of births yield twins, compelling polyandrous cooperative breeding.

Aotidae (Owl Monkeys)

A family of Central and South American New World monkeys containing $12$ species, notable as the only nocturnal anthropoids.

Atelidae

A family of large New World monkeys including spider monkeys and howler monkeys, characterized by long limbs, prehensile tails, and prominent vocal adaptations (howler monkeys are the loudest land mammals).

Catarrhini (Old World Anthropoids)

The anthropoid infraorder comprising Old World monkeys, apes, and humans, marked by downward-facing nostrils and a shared $2\text{-}1\text{-}2\text{-}3$ dental formula.

Subfamily Colobinae

Old World monkeys possessing a specialized four-chambered gut to ferment and digest leaves ($35\text{--}75\%$ folivorous) and neutralize plant toxins, typically living in uni-male groups in Africa and Asia.

Subfamily Cercopithecinae

Diverse, cheek-pouched Old World monkeys (e.g., baboons and macaques) that are largely terrestrial and form multi-male troops of up to $250$ individuals, serving as behavioral analogies for early hominid evolution.

Superfamily Hominoidea (Hominoids)

Apes and humans, anatomically defined by the absence of an external tail, suspensory climbing shoulders, arms longer than legs (except in modern humans), a wrist meniscus cartilage, high intelligence, and prolonged infant dependency.

$\text{Y-5}$ Molar Pattern

A derived mandibular lower molar morphology found in hominoids featuring five cusps separated by a Y-shaped groove pattern, distinguishing them from the four-cusped bilophodont molars of Old World monkeys.

Gibbons (Family Hylobatidae)

Lesser apes of Southeast Asian rainforests adapted for true brachiation with elongated hook-like hands, reduced thumbs, lifelong monogamous pair bonding, and an absence of sexual dimorphism in body size.

Gorillas (Genus Gorilla)

The largest living hominoids, characterized by extreme sexual dimorphism (males $\approx 350\,\text{lbs}$, females $\approx 155\,\text{lbs}$), a diet of approximately $85\%$ leaves, and uni-male harem groups.

Orangutans (Genus Pongo)

Vegetarian, largely frugivorous ($60\%$ fruit) Asian great apes native to Borneo and Sumatra, characterized by dispersed solitary social groupings of mothers and dependent offspring, related to ancestral Sivapithecus.

Common Chimpanzee (Pan troglodytes)

A great ape species inhabiting Central and West Africa, living in fluid fission-fusion communities of $50+$ individuals, characterized by male-dominated hierarchies, cooperative hunting and meat-sharing, inter-group warfare, and aggressive reproductive competition.

Bonobo (Pan paniscus)

A gracile great ape species separated from common chimps by the Congo River for $1\,\text{million years}$, forming peaceful, female-bonded, egalitarian social units that utilize frequent, often recreational sexual contact to alleviate tension and resolve social conflict.