Click me
Transcribed

Possible Aquatic Adaptations in Human

possible aquatic adaptations in human arguments for the waterside models (including the aquatic ape hypothesis) species : Homo sapiens proposed natural habitat : coasts & beaches water birth the natural way of swimming & floating pregnancy & infancy gender & sex walking & running subcutaneous fat layer - prevents heat loss - increases buoyancy - streamlines the body O 2 laboring in human - less painful, low risk - preferred by women - infant mortality & infection rates no higher than land births practiced in primitive cultures O infant are able to swim/dive rare condition of before being able to crawl/walk, no fear or harm caused by immersion e human is the best swimmer webbed toes 2 immersion relieves pain, longer scalp hair (becomes thicker & stronger during pregnancy) for the floating infant to cling on e facial hair & bald & diver among the apes, reduces stress hormones head streamlines (adrenaline) & facilitates "love" hormone (oxytocin) O capability lasts from birth to bipedalism may be enhanced by wading the head and force exerted on the death dark skin pigment blocks sunlight in tropical waters 3 neck for diving 0 first & the last toes fusiform, straight, streamlined body reduces drag O - for shallow water various swimming gaits like breaststroke, front crawl... or (like in seals) O foraging - supported by water buoyancy - overcame various more body fat, facial hair as a > 1 year voluntary movements, starts learning to swim, dive, walk.. O 4-12 months 0-4 months sexual signal protruding buttocks (in extreme case darker & smoother infant floating reflex: infant diving reflex: paddle-like feet with fused toes for skin during pregnancy for open sea immersion O above water opens eyes, holds breath, rhythmic rolls onto the back to reduced body hair & surface lower bone density increases buoyancy O steatopygia) as a platform for carrying baby O float & breathe O smooth skin surface both water & land disadvantages 0® limb movements to reduce drag O locomotion O propel forward O foreskin avoids infection in sea obligatory bipedalism & upright posture due to straight body plan & long legs (diving) © estrogen causes fat stored around water O large floating breasts help feeding while immersed O buttocks, thighs & hips to form the fusiform body O longer penis in response to deeper vagina @ scooper-like hands with thumb webbing for catching water O endurance running only recently evolved - pre-adaptations: strong legs, good balancing. - new adaptations: eccrine sweating, foot hair growth abundant body fat brown fat tissues pattern follows water flow O menstruation prevents heat loss & increases buoyancy O generates heat 3 longer vaginal canal synchronized with circalunar isolates the uterus flexible arms & from sea water O (tidal) cycle O shoulders produce steering strokes O curly hair fibers caused by oval underarm & pubic long legs produce powerful propelling force in swimming, diving & running O lower normal body hair reduces strong muscles in chin, cheek & lips multi-lobed temperature with arches, short toes... cross-section for turbulent flow in labia major, hymen & vaginal ridges waterproof the vagina, low pH ~4.5 & lactobacillus colony in vaginal canal inhibit waterborne pathogens O9 low fluctuations kidney (reniculi) rare condition of reducing drag O concave surfaces O as in marine for close contact like in aquatic webbed fingers e suckling, avoid water goes in O mammals O mammals inherited from ape utilize both drag- (fused later) O umbilical cord ancestors: based & lift-based - climbing, gymnastics - partial bipedalism & partial upright posture - opposable thumb long enough for propulsion O newborn to reach hidden estrus due to visual signals (genital swelling) & scent signals (pheromone) water surface O vernix caseosa (waxy substance with squalene on newborns) with waterproofing & antibacterial properties O6 newborn holds diving & foraging breath until not efficient in water O reaching water no practice of eating placenta (placentophagy) as not possible in water 6 surface O underwater foraging important to early Homo sapiens, still practicing among more face-to-face sex due to straight body plan, vagina coastal tribes directed towards the front fewer & larger red blood cells, higher - collecting shellfish & hunting fish for food, precious shells & pearls for trading head & upper body hair for - waterproofing & thermoregulation head & upper body – usually out of water; insulation in the lower parts myopia & astigmatism correct for light refraction in water 0 concentration of the gre hemoglobin O waterproofing - bimodal diving pattern similar to sea otters (serial short dives to <20m, enlarged semicircular canals give better balance under water & recent brain shrinkage round-shaped head (reduced brow ridge, flat face, flat ears) reduces drag O scalp hair blocks high utilization of lungs (VC/TLC > 75%) O agile neck for searching O - oral cavity modified for aquatic diet, later enabled speech spleen contracts sunlight in the tropical waters O due to change to riverine & terrestrial habitat to release extra separated by recovery intervals, in extreme cases dive to 100m) O on land (bipedalism) O good underwater vision by maximally constricting pupils 6 red blood cells 6 brain enlargement enabled by marine diet countercurrent senses attuned to aquatic environment brain enlargement enabled by marine diet (seafood, seaweed) - high availability & reliability - essential micronutrients (DHA, iodine, zinc, selenium..) O veins in limbs ear wax (contains sebum) repels water entering the ears0 able to equalize reduce heat loss color vision & eyebrows & eyelashes prevent water flow into eyes O ears at depth 6 from body O color blindness descended larynx allows mouth breathing for inhaling more air before dives / during swim © adapted to aquatic environment 6 flexible backbone paranasal sinuses assist the head floats brain enlargement & reorganization led to higher intelligence, creativity & syntactic ability O allows lift-based fine breath "dolphin kick" above water surface O sebaceous glands reduced smelling secret sebum better voluntary breath control for planning of control pre- adapted for speech under water 2 sense as useless in (with squalene) for waterproofing (in head, upper body, back) O downward nostrils avoid or above water e inhalation e water splashes in O multi-pyramidal kidneys excrete salt from sea water 6 thicker lips for syntax + speech/song = human language breathing pattern (quick inhale & slow exhale) similar to speech ® bradycardia: heartbeat reduces during immersion e upper lip & philtrum enable sealing of nostrils while diving © O testing allergens in seafood O sweat evaporates through the upper body (highest rate in head, upper body, back) O speech, song & facial expressions replaced body expressions as more efficient peripheral vasoconstriction: high output of water & - specialized oral cavity (small mouth, round jaw & palate, reduced teeth, round versatile tongue) for suction feeding of slippery seafood, pre-adapted for speech salt: abundant sweat & no salt hunger & high tolerance in salty taste since salt is everywhere in the sea 3 blood flow to limbs cuts dexterous, sensitive hands for collecting & hunting, started tool-making on the shore O down to save oxygen for important organs 6 tears, saturated expiration, dilute urine, watery faeces O enhanced above water surface O diving reflexes vocal learning, speech & song enabled by - fine breath control (for diving) - enhanced articulating apparatus (for aquatic diet) © remnant brown blood shift: blood fills lung low drinking vestigial air sacs (laryngeal saccule) used to aid floating fat tissues vessels & cavities in extreme capacity, low sweat (perhaps also tears) excretes - blunter molars with thick enamel for cracking hard generate heat (only in neck, umami taste is the depth to prevent organs crushed 6 tolerance to most prevalent in dehydration O in ape ancestors 6 excess salt 2 shellfish 6 upper chest) O seafood O References: 0 Hardy AC (1960) Was man more aquatic in the past? New Scientist 17 Mar 7 (174): 642-645 0 Morgan E (1982) The Aquatic Ape. Stein & Day Pub ® Morgan E (1990) The Scars of Evolution. Souvenir Press O Morgan E (1997) The Aquatic Ape Hypothesis. Penguin 6 Roede M, Wind J, Patrick J, Reynolds V (eds.) (1991) Aquatic Ape: Fact or Fiction? Souvenir Press 6 Vaneechoutte M, Kuliukas AV, Verhaegen M (eds.) (2011) Was Man More Aquatic in the Past? Fifty Years After Alister Hardy - Waterside Hypothesis of Human Evolution. Bentham Science Publishers O Cunnane SC, Stewart KM (eds.) (2010) Human Brain Evolution: The Influence of Freshwater and Marine Food Resources. Wiley-Blackwell ® Niemitz C (2010) The evolution of the upright posture and gait – a review and a new synthesis. Die Naturwissenschaften 97 (3): 241-263 O Odent M (1996) We are All Water Babies. Celestial Arts 0 Verhaegen M et al.: various publications in Medical Hypotheses (1985, 1987), Nutrition and Health (1993), Ecology Research Progress (2007) O unpublished idea composed by CHAN Wang Chak, email: albert.chak@gmail.com, Oct 2013

Possible Aquatic Adaptations in Human

shared by chakazul on Apr 02
3,198 views
2 shares
0 comments
According to the controversial idea(s) of "Waterside Evolution" (including the infamous "Aquatic Ape Hypothesis"), numerous features of human can be explained as adaptations to a semi-aquatic environm...

Designer

Bert Chakovsky

Source

Unknown. Add a source

Category

Science
Did you work on this visual? Claim credit!

Get a Quote

Embed Code

For hosted site:

Click the code to copy

For wordpress.com:

Click the code to copy
Customize size