PowerPoint Presentation

D.3.6 State that, at various stages in hominid evolution, several species may have coexisted. 1Possible co-existance of several hominid speciesA. afarensis and A. africanus approximately 3 MYAH. erectus, H. neaderthalensis, and H. sapiens approximately 100,000 YA

Did they live in the same region or interact?Hard to saySo few AustralopithecinesEvidence that H. neaderthalensis, and H. sapiens probably interacted with each other but did not have fertile offsrpingSo few (tens of thousands of individuals)Spread over large areaMountains, rivers, etc could potentially prevent populations from interacting.

http://en.wikipedia.org/wiki/Human_evolution3

4Neoteny, also calledjuvenilisationorpedomorphism, is the retention, by adults in a species, of traits previously seen only in juveniles. Some human characteristics thought to be a result of neoteny.Lack of body hairSmall teeth and reduced numbers of teethProlonged growth periodLong life spanFlat face and thin skull bonesLactase production in adultsEpicanthic eye foldSmall noseLonger trunk relative to arms and legs5

Note that according to this interpretation of the fossil record Homo sapiens is not descended from Homo erectus or Homo neanderthalensis.

However, some postulate that Homo sapiens may have hybridised with Homo neanderthalenis.

This could have contributed to the disappearance of the neanderthals in much the same way that indigenous animals like dingos are in danger of extinction due to breeding with domestic dogs.http://en.wikipedia.org/wiki/File:Humanevolutionchart.png6TOKRead the article on Wikipedia about Homo floresiensisDiscovered in 2004 on the Indonesian island of Flores, it has stirred up controversy in the palaeoanthropological world. Is it a separate species or is it the remains of diseased Homo sapiens. You be the judge!

Short PBS video7D.3.7 Discuss the incompleteness of the fossil record and the resulting uncertainties about human evolution. It isnt easy to create a collection of fossils that clearly show the change of species from one to another. Fossils rarely result when an animal dies for the following reasons: Decomposition is usually rapid; soft body parts are rarely fossilisedScavengers usually break up skeletons and even chew up bonesThe conditions have to be just right for fossilisation to occur.Only a tiny, tiny, tiny fraction of all of the fossils in existence have been found.

8Skulls and teeth are usually the parts of the ancestral hominids that survive to be fossilized and foundTherefore there is a lot of conjecture as to where they all fit in the family tree. Hypotheses are often overturned by new discoveries that rewrite the relationships between the species.http://www.flickr.com/photos/brentdanley/2205021283/9http://www.flickr.com/photos/prfr/3196435827/The large gaps in the human evolution fossil record are consistent with punctuated equilibriumThe following four slides show how the gaps are filled over time with new discoveries. The graphs plot cranial size against the age of the fossil.10

1850http://en.wikipedia.org/wiki/Transitional_fossil111900http://en.wikipedia.org/wiki/Transitional_fossil

121950http://en.wikipedia.org/wiki/Transitional_fossil

132002http://en.wikipedia.org/wiki/Transitional_fossil

14Despite the fossil evidence we have so far, there are still large gaps in our knowledgeWe have nofossil for the last common ancestor of humans and chimpanzeesIt is believed to have lived 6-8 million years ago

Find out how this estimate was determinedhttp://www.flickr.com/photos/owenbooth/126288240/15D.3.8 Discuss the correlation between the change in diet and increase in brain size during hominid evolution.

The benefits of a bigger brain include:More complex toolsMastery of fireCookingWarmthProtectionGreater behavioural flexibility (less reliance on instinct and better able to learn and pass on knowledge necessary to adapt to an environment)

http://madsenworld.dk/anigif/light/flames.gifhttp://commons.wikimedia.org/wiki/File:Miscellaneous_stone_tools.jpg16

The cost of having a big brain:Longer gestation periodYears of development before young can look after themselvesMuch more brain development occurs post birth that for any other animal

In summary: Big brains are energetically expensive. The mother must take in lots of energy not only during pregnancy, but for a significant time after.

Hominids needed to increase their energy uptake.

http://www.flickr.com/photos/superbomba/2288271254/17Big brains.how?Bigger brains require more energy to functionEnergy must come from somewhereEat more food OR food that is richer in proteinHominidsate more meatMeat eating required a complex social systemhunt in groupsToolsImproved hunting techniquesHigh protein and high energy food provided requirements for bigger brainsWhat about the Neaderthals? Counter argument for this theory

The solution to this energy crisis was to swap a diet of these:http://www.flickr.com/photos/heydrienne/22080973/19For some chunks of this:The increase in brain size observed in hominid fossils has been closely correlated with an increased intake of meat.

A bigger brain made hunting and killing easier20What happened to the jaws and brow bones?Jaws got smaller due to change in diet. No longer needed to masticate (chew) such hard materialFood was being cooked to softenBrow bones-- functions to reinforce the weaker bones of the face in much the same way that the chin of modern humans reinforces their comparatively thin mandiblesNot chewing such tough material therefore need for large brow bone did not persist. D.3.9 Distinguish between genetic and cultural evolution. Well gosh, we know all about genetic evolution by now! In this context it refers to the genetic changes that have occurred during the evolution of hominids. -Body morphology*increased brain size*skull shape*Height*robustnuss*spine shape*position of knee-Number of chromosomesParticularities of biochemicals such as blood proteins22Cultural evolutionCultural evolution is the changing of ideas held and actions carried out by societies and the transmission of these ideas through social learning from one generation to the next.Use of fireAgriculture ToolsWeaponsReligionBeliefsLanguageArtTechnologyCustoms and rituals

D.3.10 Discuss the relative importance of genetic and cultural evolution in the recent evolution of humans.TOKRead this article:Are We Still Evolving?What do you think of the arguments for and against this proposition?24Importance of genetic and cultural evolutionSpeciesExample of cultureTools developedH. hablisOldowanSimple choppers, scrapers, and flakes of rockH. erectusAcheulianHand axes, cleavers, picksH. NeanderthalensisMousterianLarge flakes of uniform size produced from a core then trimmed to the desired tool H. sapiensSoultrian--Delicate blades for knives, burins (drills)--Other materals added (bone, antler, ivory)--Some tools are ceremonial

What does this tell us?As brain size increased so did quality of tool makingThere IS a connection between cultural and genetic evolution.Which came first?Last 30,000 evolution of H. sapiens has been largely cultural

However, we have not changed biologically in any significant way. We could take a baby from 80,000 years ago, raise it in a modern environment and it would be indistinguishable from other humans in terms of intelligence and social capabilities.The cultural evolution has spanned millions of years in three major stages: the nomadic (hunting), agricultural (settled), and industrial ages. http://www.flickr.com/photos/wallyg/415498335/27