Gossiping Ape Flashcards
Comparison of Darwin and Wallace on Human Evolution
Charles Darwin emphasized natural selection shaping human traits, including mental capacities, while Alfred Wallace proposed that spiritual and intellectual development in humans exceeded natural selection and required divine intervention
Characteristics of Ardipithecus ramidus
1) lived approximately 4.4 million years ago, 2) exhibited both arboreal and bipedal traits, with a grasping big toe, 3) had a small brain size (~300-500 cc), similar to modern chimpanzees, and 4) likely walked upright on the ground but climbed trees for food and safety
Kevin Hunt’s Hypothesis on Bipedalism
Early hominids became bipedal to reach and carry food. Upright posture improved access to tree branches and facilitated efficient transport of food while walking
Aquatic Ape Theory of Bipedalism
Elaine Morgan proposed that early hominids adapted to semi-aquatic environments, developing bipedalism for wading in water, breath control for diving, and reduced body hair for streamlining
Kanzi’s Limitation in Making Stone Tools
Kanzi, a bonobo, lacked the precise hand morphology and motor control to effectively strike rocks and create sharp-edged tools
Consequences of Brain Modularity
1) specialization: different brain modules perform specific tasks, leading to expertise in areas like language or problem-solving and 2) isolation: damage to one module can impair a specific function without affecting others
Brain Module
A network of neurons dedicated to a specific cognitive function, such as memory, language, or social interaction
Williams Syndrome
A genetic condition caused by a deletion on chromosome 7, leading to unique social behaviors, strong verbal skills, musicality, and cognitive deficits in spatial reasoning
Evolving a Theory of Mind
Developing the ability to attribute thoughts, beliefs, and emotions to oneself and others, enabling complex social interactions and empathy
Andrew Whiten’s Selection Pressure for Brain Evolution
Larger brains in human ancestors evolved due to the need for social learning and problem-soling within complex social groups, fostering survival and reproduction
Kristen Hawke’s Study on Binumarien People
Supports sociobiology by showing how cultural practices like cooperative childcare and food sharing enhance group survival and mirror evolutionary principles
Hip-to-Waist Ratio and Attractiveness
Men prefer a 60-70% hip-to-waist ratio because it signals fertility and health, traits that are evolutionarily advantageous for reproduction
Male-Female Conflicts in Animals
Differences in reproductive strategies lead to conflicts, such as males prioritizing mating opportunities while females focus on offspring care
Ian Penton-Voak’s Survey on Women’s Preferences
Women preferred more masculine faces during ovulation, associated with genetic fitness, and more feminine faces during other cycle phases, signaling nurturing traits
Stephen J. Gould’s Biological Spandrels
Traits that arise as byproducts of evolution, not through direct selection
Language/Social Intelligence Module
Specialized brain regions facilitating communication, social interaction, and theory of mind, critical for human cultural and societal development
Evidence for Brain Modules
Observations from brain damage studies show specific deficits (e.g., loss of language) tied to localized brain regions, confirming modular specialization
Judy Kegl’s Nicaraguan Study (1986)
Observed deaf children creating a new sign language, demonstrating innate human capacity for language development and modular brain functions
Discovery of Australopithecus afarensis
“Lucy,” discovered in Ethiopia in the 1970s, dates to 3.2 million years ago, revealing critical evidence of early bipedalism and transitional traits
Australopithecus afarensis Traits
1) bipedal locomotion with evidence from pelvic and femoral structures, 2) chimp-like skull with human-like body, 3) small brain (~413 cc), and 4) arboreal traits like long arms, reduced canines, and an intermediate dental arcade
Paedomorphosis
Retention of juvenile ancestral traits in adults, as seen in human skulls with rounded craniums and less protruding jaws compared to chimpanzees
Examples of Biological Spandrels
1) umbilicus in land snails: a cylindrical space from shell coiling, not originally adaptive but later co-opted for egg storage in some species and 2) male nipples in humans: a byproduct of shared embryological development between sexes, functional in females for nursing but purposeless in males
Human Skull and Brian Evolution
1) humans retained juvenile features (paedomorphism) like rounded craniums and smaller jaws, compared to chimpanzees, 2) sexual selection favored youthful traits signaling fertility (e.g., large eyes, small noses), and 3) brain expansion was facilitated by proportional skull changes, enhancing cognitive and social intelligence
