1.4: Culture and human uniqueness Flashcards
Uniqueness
What characterises a species
Are humans more closely related to chimps than gorillas? Are chimps more closely related to gorillas than humans?
Humans and chimps are more closely related than chimps and gorillas and humans and gorillas
List 5 anatomical differences between humans and other apes
Feet Hands/grip Brain structure Pelvis Larynx
Give 2 ways in which human and chimp feet differ
Human foot and abducted big toes points to walk straight
Human foot has a large heel, strong arch, and ankle adapted to walking long distances
Chimp foot and big toes curves sideways to cling onto branches for climbing
Chimp foot has a small heel, flexible midfoot (midtarsal break), and ankle adapted for climbing
How do human and chimp hands/grip differ?
Human thumbs are longer and straighter than chimp thumbs, so humans have a more precise grip – humans are more efficient with tools
Give 4 ways in which human and chimp brain structures differ
Chimps brains are 3x smaller than human brains
Chimps have a reduced frontal lobe
Chimps have no Broca’s or Wernicke’s area
Chimps have Brodmann’s area 10 and planum temporale, so they can make and receive calls, but not create speech nor process language
How do human and chimp pelvises differ?
Human pelvis is bowl shaped, allowing bipedalism
Chimp pelvis is not as round
How do human and chimp larynxes differ?
Human larynx positioning is lower, allowing speech
What is the percentage of genetic difference between humans and chimps, and how many genes are unique to humans?
1.2% genetic differences
97 genes are unique to humans
Give 3 examples of human specific genes and explain their function and how they might have led to the evolution of human specific adaptations
The ARHGAP11B gene stimulates creation of the folds and fissures on the brain (brain growth)
The FoxP2-2 mutations separate human and chimpanzee variants of the gene, people who have a defect in this gene have speech problems – gene is linked to more complex vocalisation and faster learning
The HCNS1 gene co-ordinates between the brain and hands and limbs, and therefore contributes to human bipedalism and tool making
Life history theory
The idea that you have to budget/adjust your time and resources to suit your probable lifespan
Give an example of one species with a fast life history and one species with a slow life history. Explain why their life histories differ.
Fast life history: mice; live with high predation rates, thus they grow fast, they reproduce very early and intensely to create a lot of low quality offspring
Slow life history: elephants; large, limited predation, few but high quality offspring, reproduce late
Give 4 examples of life history trade-offs
Clutch Size → offspring Quality
Length of reproductive span → Adult body size
Current reproduction → Later reproduction
Reproduction → Survivorship
What is the main time constraint of life?
Death
We must reproduce before death
Why does evolution not produce eternal life?
The longer you live, the more likely you are to die by accident
Give 9 features of human life history that are characteristic of slow life histories (compared to other apes)
Longest life span Later age of first reproduction Long term dependent children Long gestations Largest new-born size/mother weight ratio, fattest new born babies High caloric demanding babies Low daily investment in infants (cheaper lactation) Lower infant mortality rates Highest investment in quality
Do humans have slow or fast life history?
Humans have extremely slow life history (exaggerating Primate and Ape trends)
Why are human babies so fat?
Humans have the largest brain to body proportion
Babies are born with 30% of the brain ready
Brain doubles in size in first year of life
Baby brains consume 65% of total caloric intake
60-85% of babies basal metabolic rate goes to brain maintenance
Fat on babies is needed for body energy
Give 2 reasons why human fertility rates are higher than in other apes?
Shorter IBI (inter-birth interval) and lactation period
We rely on society/other family members to take care of our children
(Allows quantity and quality of offspring)
Give 5 features of human life history that are characteristic of fast life histories
Higher fertility (number of infants produced by year) Shorter lactation period Earlier weaning Shorter inter-birth Intervals (IBI) High investment in quantity
Why do women hit menopause only half way through their life span/have a shorter reproductive span than post-reproductive span?
To maximise both quality and quantity of produced babies through use of grandmothers
Explain the ‘grandmother hypothesis’
Mothers have reduced IBI to create offspring quantity
Healthier grandmothers are selected for, so they can feed the grandchildren while the mother invest in the next reproduction
Whales are the same in terms of menopause – convergence evolution
Explain Kaplan’s Model in reference to slow human life history and brain size
Time invested in brain growth is also time invested in learning for both sexes
Learning to obtain high quality food is important to provide for females and offspring
In 90% of mammal species, what is the role of fathers and mothers?
Fathers are not present
Mothers invest the most in offspring
Explain human father provisioning
Human males provide double the provisions they need, allowing offspring to be produced in large quantity and quality
Name the 5 special features of human life history
Women stop reproducing half way through their adult lives
Babies are expensive and have high survival rates
Humans have high natural fertility
Humans have very short IBI
Humans depend on social help for reproducing (cooperative breeding)
List and describe the three things that make human behaviour different from other primates
Cognition – language vs. sounds/callings; use of language to convey info and negotiate relationships, ability to empathise and subsequently create ‘mutual knowledge’ with language
Cooperation – not many animals cooperate, but social ones do; affiliative cooperation; hyper cooperation even with unknown people
Culture – cumulative culture by innovation, together with collective mutual knowledge, is an exclusively human trait
