Questions and Answers 100% Pass
What Species are closest related to humans? - ✔✔Bonobos and Chimpanzees
Derived hominoid traits - ✔✔-Larger brain
-Loss of tail
-Long arms
-Broad thorax
Derived human traits - ✔✔-Obligately bipedal
-Small canines
-Large brains
-Broad dietary niche and tool use
-Extended time to mature
Anagenetic model of human evolution vs. Cladogenetic model of human evolution -
✔✔Anagenetic model suggests that there was one single split (human lineage) This
theory is NOT likely.
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,Cladogenetic model suggests that our characteristics appeared at various different
times in several branches. This theory is more likely.
Features related to bipedalism:Foramen magnum orientation and position - ✔✔In
humans the Foramen magnum is located more towards the center vs. the back like in
animals. (shifted anteriorly and positioned more superiorly)
Features related to bipedalism: Cervical and Lumbar Lordosis - ✔✔There are 2 lordotic
(posteriorly facing) curves in the human spine and 1 kyphotic (anteriorly facing) curve,
Chimps have none
Features related to bipedalism: Valgus knee/Bicondylar angle - ✔✔Our femurs are
angled, which gives us the ability to pull our knees under our body.
Features related to bipedalism: Pelvis shape - ✔✔;short broad ilium rotated into the
sagittal plane
Chimps have a longer ilium that rotates into the coronal plane. Humans have a broad
and short Ilium that rotates into the sagittal plane.
Features related to bipedalism: Gluteal muscle actions on the lower extremity - ✔✔"Hip
stabilizing mechanism" Humans use hip extender muscles to stabilize the torso, muscles
are rotated with pelvis
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,Features related to bipedalism: Divergent vs. non divergent hallux - ✔✔"Foot shape and
function" Chimps have a divergent hallux (weight distributed throughout entire foot).
Humans have a non divergent hallux (weight distributed into arches of the foot).
Features related to bipedalism: Arches of the foot - ✔✔This makes humans footprint
and way of walking extremely unique.
Canine honing complex - ✔✔Humans have very small, non dimorphic canines, exant
nonhuman anthropoids have a functional complex that sharpens the canines that
weaponizes them. The first mandibular premolar is "sectorial" in chimps. The humans is
not.
Life History (5 stages) - ✔✔The way we break up the human lifetime into milestones. It
evolves like any other trait.
-Infancy
-Childhood
-Juvenile
-Adolescent
-Adult
Infancy - ✔✔Period from birth to weaning. Lasts on average 3-4 years.
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, Childhood - ✔✔Period between weaning and the eruption of M1. Even though you are
weaning, you are still incapable of fending for yourself. Its is a critical period for brain
development and social learning.
Juvenile - ✔✔Period between the eruption of M1 and puberty. Durning this time
humans grow in size and engage in lots of socialization and learning. The female
milestone is manarche and the male milestone is the first ejaculation.
Adolescent - ✔✔Period between sexual maturity and physical maturity. Even though
capable of being a parent, the body does not cease growth. During this time the body
experiences many changes such as growing underarm hair etc.
Adulthood - ✔✔Get a job, work, eat, sleep, etc.... Ends for women when they start
menopause.
Weaning - ✔✔Marks the time when you lose dependency on your mother for nutrition.
Happens on average at age 3-4. Human milk is low in fat and protein which means
babies have to be fed more often.
Lactational amenorrhea - ✔✔Ovulation is suppressed during nursing, this leads to an
average 4 year inter birth interval.
Senescence - ✔✔The condition or process of deterioration with age.
A loss of a cell's power of division and growth.
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