ANT 201: Week 5

Biological Species Concept

A species is defined as individuals that can interbreed and produce viable, fertile offspring.

Morphological Species Concept

A species is defined by similarities and differences in morphology.

Allopatric Speciation

Speciation that occurs due to geographic isolation.

Sympatric Speciation

Speciation that occurs within a population without geographic isolation.

Prezygotic Reproductive Isolation

Barriers that prevent fertilization from occurring.

Postzygotic Reproductive Isolation

Barriers to reproduction that occur after the formation of a zygote.

Phyletic Gradualism

The traditional idea that speciation occurs slowly over time.

Punctuated Equilibrium

The idea that speciation occurs in rapid bursts after long periods of stability.

Linnaeus

A taxonomist who created a system of nested categories based on similarities.

Binomial Nomenclature

The naming system in which a species is identified by a combination of its genus and species names.

Clade

A group of species that share evolutionary relationships.

Ancestral Trait

A trait that remains the same in both ancestors and descendants.

Derived Trait

A trait that has changed from the ancestral state and is unique to a specific clade.

Convergent Evolution

The evolution of similar traits in species that are not closely related.

Parsimony

The principle that the simplest scientific explanation is usually the most accurate.

Primates

A group of mammals that share common traits such as body hair, mammary glands, and larger brains.

Quadrupedalism

Locomotion on four limbs.

Bipedalism

Locomotion on two feet.

Stereoscopic Vision

The ability to perceive depth due to overlapping fields of vision in both eyes.

Prehensile Hands/Feet

Hands or feet with the ability to grasp objects.

Dental Formula

A numerical representation of the number and type of teeth in a species.

Strepsirrhines

A suborder of primates that retain more ancestral traits and have a higher reliance on smell.

Haplorhines

A suborder of primates that have a greater emphasis on vision and a reduced reliance on smell.

Platyrrhines

New World monkeys found in Central and South America.

Catarrhines

Old World monkeys found in Africa and Asia, including humans.

Cercopithecoids

A family of Old World monkeys that are widespread and have bilophodont molars.

Colobines

A subfamily of Old World monkeys that are mostly found in Asia and have specialized diets of leaves.

Hylobatids

Lesser apes found in Southeast Asia known for their brachiation and monogamous pairings.

Orangutans

Great apes found in Southeast Asia that are frugivorous, solitary, and highly sexually dimorphic.

Gorillas

Great apes found in Africa that are highly sexually dimorphic and primarily folivorous.

Chimpanzees

Great apes found in Africa that are frugivorous and exhibit knuckle-walking.

Bonobos

Great apes found in Africa that are slightly smaller than chimpanzees and exhibit face-to-face copulation and a matriarchal social structure.

Non-reproductive copulation

Engaging in sexual activity that does not result in reproduction.

Same-sex sexual encounters

Engaging in sexual activity with individuals of the same gender.

Oral and manual sexual touching or genito-genital rubbing

Engaging in sexual activity involving oral or manual stimulation or rubbing of the genitals.

Diffuse tension, pleasure

Experiencing a release of tension and pleasure during sexual activity.

Humans

Homo sapiens, the species to which modern humans belong.

Similarities with apes

Shared characteristics or traits between humans and apes.

No tail

Humans do not possess a tail like some other animals.

Body adapted for brachiation (except limb length)

Human bodies are not specifically adapted for brachiation (swinging from trees), except for their limb length.

Y-5 molars

Dental pattern in humans where the molars have a Y-shaped groove on the occlusal surface.

Extended life history

Humans have a longer period of development and maturation compared to other animals.

Similarities with African apes

Shared characteristics or traits between humans and African apes (gorillas, chimpanzees, and bonobos).

Share 96% of DNA w/ gorillas, 98% with Pan (chimps + bonobos)

Humans share approximately 96% of their DNA with gorillas and 98% with the combined DNA of chimpanzees and bonobos.

Knuckle-walking in ancestry [LCA]

The common ancestor of humans and apes is believed to have had a form of locomotion called knuckle-walking.

Vertical forehead

Humans have a forehead that is more vertical compared to other primates.

Mental eminence

The prominence of the chin in humans.

Bipedalism

The ability to walk on two feet.

Foramen magnum inferior

The position of the foramen magnum (opening at the base of the skull) is located more towards the bottom in humans compared to other primates.

Convergent big toe

The big toe in humans is positioned in line with the other toes, allowing for better balance and walking.