Homo litoreusHomo litoreusSeashore ManSeashore Man

Part onePart one

In a nutshellIn a nutshell

HowHow it happened it happened

Wetland and shoreline dwelling ancestral groups, omnivorous.Not specifically adapted, omnipotent.

Stage 1.

Rising and falling sealevels Rising and falling sealevels

Some small groups were trapped on isolated archipelagos.Living as beachcombers then was obligatory to survive.

Swimming and diving AND upright wading with stronger legs.Using hands to grab mollusks and crustaceans (fruits de mer).Controlled breathing stimulating vocalization.

Losing fur to prevent hypothermia (wet T-shirt effect), developing subcutaneous fat for insulation in water and a rapid reacting subcutaneous capillary system to overcome overheating on land(blushing) and “underheating” in water (pale). Stage 2.

Eventually man started his walkaboutEventually man started his walkabout

Sealevels falling:Freed from the isolated archipelagoman’s ancesters spread rapidly along riverbeds and coastlines. Walking, swimming, rafting and exploring inlands.

Getting better in walking, tool handling, killing and singing; still fond of water and salt...

His xenophobic nature guaranteeda very rapid dispersion.

Stage 3.

The whole possible storyThe whole possible story

HOW?HOW?

Part twoPart two What adaptive forces could lead to the specific What adaptive forces could lead to the specific

human traits he has today?human traits he has today? The starting point in this vision are NOT fossilized The starting point in this vision are NOT fossilized

and fragmented remains.and fragmented remains. Our bodies and our habits of today do give us the Our bodies and our habits of today do give us the

obvious clues...obvious clues...

The interglacial island hypothesisThe interglacial island hypothesis

This is the proposed repetitive “bottleneck” responsible for the adaptational mix of human features. Richard Little, Glacial Research Society, 2005

Matching with “outbursts” of new pre human Matching with “outbursts” of new pre human formsforms

Richard Little, Glacial Research Society, 2005

Homo Homo litoreuslitoreus

Seashore ManSeashore Man

Theory of shedding a fur on dry Theory of shedding a fur on dry savannah tested:savannah tested:

a kitchen table experimenta kitchen table experiment

What was the habitat where human ancestors What was the habitat where human ancestors

became bipedal and naked?became bipedal and naked?

The general opinion is: on the African savannahThe general opinion is: on the African savannah Man started being bipedalMan started being bipedal Shed his fur to overcome excess heating while Shed his fur to overcome excess heating while

huntinghunting Vertical position reduced radiated surface. Vertical position reduced radiated surface. Was able to spot possible dangers and prey in a Was able to spot possible dangers and prey in a

better waybetter way Freed hands enabling the use of toolsFreed hands enabling the use of tools

AustralopithecusAustralopithecus

The common picture....

But what about the lagging woman: does’t she seem in trouble...?

PaleoanthropologistsPaleoanthropologists

This picture is drawn by paleoanthropologists.This picture is drawn by paleoanthropologists. Is it biologically convincing?Is it biologically convincing? Are other suggestions plausible??Are other suggestions plausible?? Oldest fossil remains of hominoids are all bipedal; Oldest fossil remains of hominoids are all bipedal;

no partly knuckle walkers are found.no partly knuckle walkers are found. If it is the result of strong selective forces on a If it is the result of strong selective forces on a

small isolated group, fossils are scarce small isolated group, fossils are scarce A growing minority is tinkering with an other A growing minority is tinkering with an other

possibility …possibility …

Homo litoreus is a more proper name than Homo litoreus is a more proper name than

‘Aquatic Ape’ ‘Aquatic Ape’

In the sixties of the last century marine biologist sir Alistair In the sixties of the last century marine biologist sir Alistair HardyHardy

suggested a more aquatic stage in human evolution.suggested a more aquatic stage in human evolution. The ‘Aquatic Ape Theory’ was born (A.A.T.)The ‘Aquatic Ape Theory’ was born (A.A.T.)

Wading asks for stronger legs and could have lead to Wading asks for stronger legs and could have lead to bipedality..bipedality..

A wet fur results in strong cooling by frequently entering and A wet fur results in strong cooling by frequently entering and leaving the water (the wet T-shirt effect)leaving the water (the wet T-shirt effect)

Shedding fur and storing subcutaneous fat is an obvious Shedding fur and storing subcutaneous fat is an obvious solutionsolution

Controlled blood circulation in the outer skin guarantees Controlled blood circulation in the outer skin guarantees cooling (radiator effect); overall transpiration adds to this cooling (radiator effect); overall transpiration adds to this

Man has a more than average diving reflex and controllable Man has a more than average diving reflex and controllable breathingbreathing

His newborns are clearly water adaptedHis newborns are clearly water adapted

Fur, subcutaneous fat or neither?Fur, subcutaneous fat or neither?

A ridiculous proposalA ridiculous proposal

By P. wheeler, John Moore University Liverpool.

The fur argument on the test…The fur argument on the test…

Hypothesis 1: subcutaneous fat reduces heat Hypothesis 1: subcutaneous fat reduces heat loss in water and is a disadvantage on land, loss in water and is a disadvantage on land, leading to overheating.leading to overheating.

2: A wet fur leads to strong cooling as result 2: A wet fur leads to strong cooling as result of heat loss to evaporationof heat loss to evaporation

3. A dry fur insulates on land, from the heat 3. A dry fur insulates on land, from the heat as well as from the coldas well as from the cold

How it is doneHow it is doneHow it is doneHow it is done

A kitchen table experiment

Equipment needed:Equipment needed:

3 1,5 liter PET 3 1,5 liter PET bottlesbottles

150 grams of 150 grams of VaselineVaseline

A woolen sockA woolen sock 3 Temperature 3 Temperature

sensorssensors A ventilatorA ventilator Warm and cold Warm and cold

waterwater

Subcutaneous fatSubcutaneous fat

1,5 litre bottle greased 1,5 litre bottle greased with 150 grams of with 150 grams of Vaseline = Vaseline = “subcutaneous fat”: “subcutaneous fat”: equals 10% of body equals 10% of body mass, just as in man; mass, just as in man;

Plastic foil as “skin”Plastic foil as “skin” 40° C water40° C water

1 blank, 1 fat and 1 sock1 blank, 1 fat and 1 sock

Measuring Measuring equipmentequipment

In the blank; a In the blank; a thermometerthermometer

In in the other two a In in the other two a thermal sensorthermal sensor

Submerged in cold running waterSubmerged in cold running water

Measuring in airMeasuring in air

Results in waterResults in waterSEASHORE MAN HYPOTHESIS

Timemin

blank fur fat

0 45 45 46 temperature

3 36 38 43 water Starting value in bottles

5 33 35 39 13 45 - 46

8 29 32 36

10 27 29 32

13 25 27 32

15 23 26 30

19 19,5 22 25,5

25 16,5 20 23

30 16 18,5 21

FatFurBlank

Conclusions for Conclusions for waterwater

If the temperature after 15 minutes cooling for If the temperature after 15 minutes cooling for the blank is 100%, then this is reached 11,3% the blank is 100%, then this is reached 11,3% later with fur; fat is 16,7% slowerlater with fur; fat is 16,7% slower

The hypothesis seems correctThe hypothesis seems correct More tests are needed to be sure:More tests are needed to be sure:

repeated by 40 students it showed same trendrepeated by 40 students it showed same trend NB: even in tropical conditions, coastal waters NB: even in tropical conditions, coastal waters

have a lower temperature than the body core. have a lower temperature than the body core. Heat loss due to happens anyway: an adaptation Heat loss due to happens anyway: an adaptation is obligatory.is obligatory.

Results in airResults in airMin.

blank fur fat Outside temparature 18,5

0 44 44 44 Water temperature 45

3 42 41,2 42,1

9 39 37,5 40 Total cooling Blank 16,516,5

14 35,5 34 37 Total cooling FurTotal cooling Fur 17.717.7

20 33 31 35 Total cooling Fat 13,5

25 30,5 28,5 32,5

30 28,5 26,3 30,5

cooling in air and sweating (18,5 - 16,5 degrees C.)

25

27

29

31

33

35

37

39

41

43

45

0 5 10 15 20 25 30 35

time (min)

degrees C.

nul

vacht

vet

fatblankfur

. . .

FatFurBlank

Conclusions for airConclusions for air

Cooling with a wet fur is the strongest. Fat cools the Cooling with a wet fur is the strongest. Fat cools the slowest. If the cooling after 15 minutes is 100%, fur slowest. If the cooling after 15 minutes is 100%, fur reaches it 7,5% earlier and fat 12,5% later. Fur and reaches it 7,5% earlier and fat 12,5% later. Fur and fat differ 20%fat differ 20%

It seems to proof the disadvantage of a wet furIt seems to proof the disadvantage of a wet furand the advantage of subcutaneous fat for and the advantage of subcutaneous fat for an in- and -out of the water lifestylean in- and -out of the water lifestyle

But at the same time it shows the possible But at the same time it shows the possible “handicap” of overheating under dry, sunny “handicap” of overheating under dry, sunny conditionsconditions

Total body transpiration and a controllable heat Total body transpiration and a controllable heat radiating blood stream in the skin are obvious radiating blood stream in the skin are obvious adaptations to this problemadaptations to this problem

Adapted to the savanna?Adapted to the savanna?

This simple kitchen table experiment shows: This simple kitchen table experiment shows: Man on the hot savannah would lose much Man on the hot savannah would lose much

water on evaporation to keep him cool.water on evaporation to keep him cool. He would be better off keeping an insulating He would be better off keeping an insulating

fur against sunburn and overheating.fur against sunburn and overheating.

In a water bound habitat his specific In a water bound habitat his specific adaptations subcutaneous fat and a adaptations subcutaneous fat and a controllable bloodstream in the skin are controllable bloodstream in the skin are more appropriate.more appropriate.

Sea Gypsies

http://www.motherjones.com/news/feature/2005/11/sea_change.html

Swimming pool EuropeSwimming pool Europe

The diving reflexThe diving reflex

Man shows a moderate diving reflex;Man shows a moderate diving reflex;research by dr. Erica Schagatay showed an average research by dr. Erica Schagatay showed an average slowing down of the heartbeat by 15 beats per slowing down of the heartbeat by 15 beats per minute.minute.

Students of the Zuyderzee College in the Netherlands Students of the Zuyderzee College in the Netherlands repeated her measurements in the lab and in the repeated her measurements in the lab and in the swimming pool, assisted by local scuba divers. swimming pool, assisted by local scuba divers.

Kitchentable versionKitchentable version

The principle..The principle..

In the labIn the lab

Cold water

In the labIn the lab

Measuring the heart beat lying down and face submerged in cold water

In the swimmingpoolIn the swimmingpool

Submerged 4m, assisted by scuba divers from diving club ‘De Zeewolf’, Emmeloordwww.dezeewolf.nl

resultsresults

  Heartbeats per minute

standing 119 52 98 

Laying down 119 45 79 

Face submerged 87 44 63 

4m submerged 61 45 56 

  highest lowest mean  

graphgraph

Standing laying down face submerged 4m deep

ProbabilityProbability

For laying down and laying down with For laying down and laying down with submergedsubmergedface the T value for coincidental difference is face the T value for coincidental difference is 16/√(283,5/30) = 16/3,07=5,374616/√(283,5/30) = 16/3,07=5,3746

P < 0,001P < 0,001

Our start….Our start….

http:www.urchinrock.com

Adaptations in newbornsAdaptations in newborns

They hold their breath when submergedThey hold their breath when submerged Can swim under waterCan swim under water Turn on their back with an “eskimo roll” of their legs; pop Turn on their back with an “eskimo roll” of their legs; pop

up like wearing a life jacket with free airwaysup like wearing a life jacket with free airways Are born with a thick protective layer of sebum, like some Are born with a thick protective layer of sebum, like some

species of sealsspecies of seals

Floating and swimming abilities Floating and swimming abilities precede walking and crawlingprecede walking and crawling

It is demonstrated in this film on drowning prevention for It is demonstrated in this film on drowning prevention for toddlers.toddlers.Source: YoutubeSource: Youtubebabies do it spontanuously, it can be reinforced by training.babies do it spontanuously, it can be reinforced by training.No swimming in earley infancy means missing the time frame No swimming in earley infancy means missing the time frame for imprinting.Older children have to start anew. for imprinting.Older children have to start anew.

Trained toddlerTrained toddler

Source: YoutubeSource: Youtube

SebumSebum

Skin fat or ‘sebum’ is Skin fat or ‘sebum’ is secreted by subcutaneous secreted by subcutaneous glands.glands.

The thin, waxy layer is water The thin, waxy layer is water repellant, contains an repellant, contains an infection blocking biofilm of infection blocking biofilm of skin bacteria and has UV skin bacteria and has UV filtering properties. filtering properties.

This also can be interpreted This also can be interpreted as a waterbound adaptation.as a waterbound adaptation.

SebumSebum

ABSTRACT Br J Dermatol. 1980 Dec;103(6):643-9.

Sebum levels during the first year of life.Agache P, Blanc D, Barrand C, Laurent R.

Skin surface lipid levels in forty-five newborn babies and 193 infants aged less than 12 months were determined by an optical density method, using samples collected on ground glass. Although there was a wide individual range, sebum levels in the first week of life were very high, and were of the same magnitude as in adults. Females displayed a different pattern of sebum excretion from males. On the first day of life, the levels in females were lower than in the males but a large increase took place between the 3rd and 6th day, followed by a fall, bringing the level below that of the males. At 6 months the levels were low in both sexes. These findings suggest that there is a strong stimulation of sebum secretion before birth which probably stops at or soon after birth. Androgen may be involved in this stimulation and the probable role of dehydroepiandrosterone (DHEA) is discussed.

ColofonColofon

D. Meijers MScD. Meijers MScbiology & general sciences, biology & general sciences, cartoonistcartoonist

http://www.andaman.org/BOOK/video/http://www.andaman.org/BOOK/video/textvideo.html George Webertextvideo.html George Weber

Urchin Rock underwater photographyUrchin Rock underwater photographyhttp://www.urchinrock.comhttp://www.urchinrock.com

http://www.motherjones.com/news/feature/http://www.motherjones.com/news/feature/2005/11/sea_change.html2005/11/sea_change.html 2007 2007