Homo sapiens - Human

Homo sapiens - Human 

 

Geographic Range

Humans are currently found throughout the world; in permanent settlements on all continents except Antarctica and on most habitable islands in all of the oceans. All available evidence suggests that humans originated in Africa.  

Anatomically modern Homo sapiens populations are known from the Middle East as long as 100,000 years ago, from east Asia as long as 67,000 years ago, and southern Australia as long as 60,000 years ago. European Homo sapiens fossils are known from 35,000 years ago. Homo sapiens populations were once thought to have colonized the New World approximately 11 to 13,000 years ago, but recent research indicates earlier dates of colonization. This is an area of active research. 

Biogeographic Regions; Nearctic native

                                     Palearctic native

                                     Oriental native

                                     Ethiopian native

                                     Neotrophical native

                                     Australian native

                                     Oceanic island native

Habitat

Humans are found in all terrestrial habitats worldwide. Humans extensively modify habitats as well, creating areas that are habitable by a much reduced set of other organisms, as in urban and agricultural areas. With the aid of technologies such as boats, humans also venture into many aquatic habitats, primarily to obtain food.  

Habitat Regions;

 temperate tropical,polar terrestrial 

Terrestrial Biomes;tundra,taiga,desert or dune,savanna or grassland,chaparral forest,rainforest,scrub forest                      mountain

  

Wetlands;

 marsh,swamp 

Other Habitat Features; urban,suburban,agricultural riparian,estuarine,intertidal or littoral caves

  

Physical Description

Humans are an exceptionally diverse species morphologically and many aspects of size vary substantially with environmental factors such as nutritional status. Historically there has been an effort to organize human physical variation into "races," although there is no scientific basis for the application of a race concept to human variation. Human physical variation is continuous and available evidence suggests that gene flow among human populations throughout their history has been the rule rather than the exception. 

Humans are characterized by their bipedalism and their lack of significant body hair. Males are generally larger than females, with more pronounced muscle development and generally more hair on the face and torso than females.  

Other Physical Features;

 endothermic, 

homoiothermic,bilateral symmetry,polymorphic,s

exual dimorphism;

male larger-

sexes shaped differently.

Reproduction

Human cultures are marked by a wide range of approaches to mating. Child-rearing in most cultures is accomplished with some degree of help and cooperation from other members of the group, including related and unrelated members. 

Mating System;monogamous,polyandrous,polygynous,polygynandrous(promicuous,cooperative breeder 

Humans are capable of breeding throughout the year. Gestation length is 40 weeks on average, a fairly long gestation length for a primate species with altricial young. Typically one young is born, although twins occur occasionally and multiple births rarely. Interbirth intervals, birth weights, time to weaning, independence, and sexual maturity all vary substantially with nutritional status of mothers and young and are influenced by cultural practices. 

Key Reproductive Features;

• iteroparous,year-round breeding,
• gonochoric/gonochoristic/dioecious (sexes separate),viviparous 
• Average gestation period-40 weeks
• Breeding interval-Human females can reproduce up to once every 10 months, although typical birth intervals are longer and vary substantially.
• Breeding season
• Humans can breed at any time of the year.
• Range number of offspring-1 (low)

Human infants are born in an altricial state and require intense and long-term care to ensure survival. Parental care is variable across human cultures, but generally the mother plays a large role in caring for infants through weaning. Family members and unrelated community members also often play large roles in caring for young. Human young experience an extended period of adolescence in which many essential skills and cultural knowledge are learned and practiced. Human social structures are complex and frequently young remain part of the same larger social groups as their parents and their paternal and maternal families. Social stature of parents often also plays a large role in the social stature of the young.  

Parental Investment

;altricial,

pre-fertilization 

 
• provisioning 
• protecting 
  • female 

 

pre-hatching/birth 

 
• provisioning 
  • female 
• protecting 
  • female 

 

pre-weaning/fledging 

 
• provisioning 
  • male 
  • female 
• protecting 
  • male 
  • female 

 

pre-independence 

 
• provisioning 
  • male 
  • female 
• protecting 
  • male 
  • female 

 

post-independence association with parents 

extended period of juvenile learning 

inherits maternal/paternal territory 

maternal position in the dominance hierarchy affects status of young

Lifespan / Longevity

Human lifespans vary tremendously with nutritional status and exposure to diseases and trauma. Humans can live more than 100 years; the longest lived human that has been documented was 122 years old. Most humans live 50 to 80 years old, providing they survive their most vulnerable childhood years. Average life expectancy in many parts of the developing world is from less than 40 years old to 65 years old. In the developed world average life expectancy can be over 80 years old.  

Typical lifespan Status: wild ,32 to 84 years

  

Behavior

Humans are one of the most behaviorally, socially, and culturally complex animal species. Ancient humans were nomadic hunter gatherers but the development of agriculture approximately 10,000 years ago revolutionized the way that humans live. Agriculture ultimately led to increases in regional human populations and concentration in urban centers, and dramatically altered the cultures, economies, and relationships among human populations. In general, humans are highly social animals that are active mainly during the day. Some human populations remain nomadic or migratory, while most live mainly in one general area. 

One of the most notable aspects of human biology and evolution is the extensive use of tools. Early human populations constructed sets of specialized tools, such as chisels and knife blades, from stones, bone, antler, and ivory. Human technological innovation is one of the most definitive human characteristics. Related to this innovation is the complex development of human art and symbolism, including written languages. 

Key Behaviors;

 

terricolous ,diurnal,nomadic,migratory,sedentary,territorial,social,colonial,dominance hierarchies

  

Communication and Perception

Like most primates, humans use vision extensively in perception and communication. Humans have excellent color vision, although visual acuity in low light is limited. Humans also use sounds extensively. 

Human languages represent one of the most complex systems of communication in the animal world, and the diversity of human languages is astounding. Touch is an important mode of perception, it is especially important in close social bonds. 

Humans have a moderately well developed sense of smell and taste, which is used to determine the suitability of foods and discover information about the environment and conspecifics.  

The evolution of complex language is considered one of the hallmarks of Homo sapiens. Archaic humans were capable of complex language, although Homo sapiens anatomy seems to have evolved to favor the production of complex sounds in anatomically modern humans.  

Communication Channels ;visual,tactile,acoustic,chemical 

Other Communication Modes;pheromones

 

Perception Channels;

 visual,acoustic 

Food Habits

Humans generally eat a highly variable omnivorous diet. The components of diets vary tremendously with regional availability of foods. Some human cultures restrict their diet to a vegetarian one, relying on plant sources of proteins. Foods are often extensively prepared and stored for future use. The use of fungal colonies, such as yeasts, for creating cultured foods, such as beer, bread, and cheeses, is widespread.  

Animal Foods;

birds 

mammals 

amphibians 

reptiles 

fish 

eggs 

blood 

body fluids carrion

 

insects 

terrestrial non-insect arthropods 

mollusks 

terrestrial worms 

aquatic crustaceans 

echinoderms 

other marine invertebrates

Plant Foods;

leaves 

roots and tubers 

wood, bark, or stems 

seeds, grains, and nuts 

fruit 

nectar 

pollen 

flowers 

sap or other plant fluids 

algae macroalgae

Other Foods;

fungus 

microbes

F

o

raging Behavior;

 stores or caches food 

Predation

Humans have few natural predators and often sit at or near the top of the food chain in regional ecosystems. Humans are sometimes opportunistically preyed on by large wild cats, such as tigers (Panthera tigris) and lions (Panthera leo). Other instances of large, carnivorous animals eating humans are often cases of mistaken identity or are opportunistic events. This includes cases involving large sharks, bears, monitor lizards, and crocodiles.

Known Predators

-tigers (Panthera tigris)

-lions (Panthera leo)

Ecosystem Roles

Humans act as top predators in many ecosystems, although they are also sometimes preyed on by larger predators, such as tigers. Humans modify habitats and ecological communities in countless ways, often substantially changing the interactions of nearly all other species in those habitats.  

Humans are parasitized by many species of internal and external parasites. Some research suggests that hairlessness in humans is an adaptation to reduce ectoparasite loads. 

Humans and human societies have evolved multiple relationships with other species, including commensal species and domesticated and companion species. Human commensals are too numerous to mention, but some important commensal species are house mice (Mus musculus), black rats (Rattus rattus), Norway rats (Rattus norvegicus), and Oriental cockroaches (Blatta orientalis). Important domestic species include domestic dogs (Canis lupus familiaris), pigs (Sus scrofa), cattle (Bos taurus), sheep (Ovis aries), goats (Capra hircus), chickens (Gallus gallus), guinea pigs (Cavia porcellus), horses (Equus caballus), llamas (Lama glama), camels (Camelus species), turkeys (Meleagris gallopavo), honeybees (Apis mellifera), and many other animals. Humans have also domesticated many species of plants for food and other uses, such as corn (Zea mays), rice (Oryza sativa), wheat (Triticum aestivum), manioc (Manihot esculenta), apples (Malus domestica), and soy (Glycine max).  

Economic Importance for Humans

-Economic Importance for Humans: Negative

Human interactions are often complex and negative at interpersonal levels and among social groups, cultures, and governments. Human activities often destroy or transform ecosystems, and these changes can have negative economic and/or medical impacts on other human populations. 

Conservation Status

Human populations are not monitored by conservation agencies. Although human populations worldwide are large and growing, some regional or isolated populations may be in decline as a result of economic disadvantage, disease, habitat degradation, emigration, and cultural erosion.

Other Comments

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    Earliest Homo sapiens appeared approximately 700,000 years ago, although anatomically modern humans are known from about 100,000 years ago. Patterns of colonization of the world by ancient humans and the details of interactions between ancient Homo sapiens and co-occurring Homo species are areas of active research.  

Evolution of Homo sapiens, Australopithecus and Hesperopithecus

Neanderthal

Neanderthal

In 1848 a strange skull was discovered on the military outpost of Gibraltar. It was undoubtedly human, but also had some of the heavy features of an ape... distinct brow ridges, and a forward projecting face.  As more remains were discovered one thing became clear, this creature had once lived right across Europe. The remains were named Homo neanderthalensis (Neanderthal man) an ancient and primitive form of human.

Their bodies were well equipped to cope with the Ice Age, so why did the Neanderthals die out when it ended?Still problem.

The archaeological evidence revealed that the earliest Neanderthals had lived in Europe about 200,000 years ago. But then, about 30,000 years ago, they disappeared,just at the time when the first modern humans appear in Europe. The story has it that our ancestors, modern humans, spread out of Africa about 100,000 years ago with better brains and more sophisticated tools. As they spread into Neanderthal territory, they simply out-competed their primitive cousins.

Reconstruction expert at The American Museum of Natural History in New York realized that it would be possible to create an entire composite skeleton from casts of partial skeletons. Gary Sawyer combined and rebuilt broken parts to create the most complete Neanderthal ever seen. This Neanderthal stood no more than 1.65 m (5' 4") tall, but he had a robust and powerful build - perfect for his Ice Age environment.Would he have stood up to the cold better than modern humans?

Cold adaptation

The popular image of the Ice Age is a period of unremitting freezing conditions. But over nearly a million years, Europe has seen huge climate swings including warm as well as cold periods. For much of the last 200,000 years, when Neanderthals were alive, the climate was mild, sometimes even warmer than today's. But they did also have to live through periods of intense cold.

Professor Trenton Holliday is a body plan expert from Tulane University, New Orleans. After seeing the skeleton, he believed it had comparatively short limbs and a deep, wide ribcage. This body plan minimizes the body's surface area to retain heat, and keeps vital organs embedded deep within the body to insulate them from the cold.

To see if this would have helped him to survive, anthropology professor Leslie Aiello from UCL, teamed up with Dr George Havenith, who runs a laboratory studying the way modern humans retain heat at Lough borough University. They subjected two modern humans with very different body shapes to cooling in an ice bath. One had the long limbed, athletic shape of a runner, the other had a stockier, heavily-muscled body plan closer to that of a Neanderthal.

The heavily muscled person lasted longer in the ice bath, so it seems that Neanderthal would have had an advantage. His muscle would have acted as an insulator, and his deep chest did help to keep organs warm. Even so, the advantage doesn't mean that Neanderthal could have survived the icy extremes. This was a polar wasteland and his heavily muscled body plan needed a lot of feeding - about twice as much as we need today.

Neanderthal

Neanderthal Their bodies were well equipped to cope with the Ice Age, so why did the Neanderthals die out when it ended?

In 1848 a strange skull was discovered on the military outpost of Gibraltar. It was undoubtedly human, but also had some of the heavy features of an ape, distinct brow ridges, and a forward projecting face.As more remains were discovered one thing became clear, this creature had once lived right across Europe. The remains were named Homo neanderthalensis (Neanderthal man) an ancient and primitive form of human. The archaeological evidence revealed that the earliest Neanderthals had lived in Europe about 200,000 years ago. But then, about 30,000 years ago, they disappeared,just at the time when the first modern humans appear in Europe. The story has it that our ancestors, modern humans, spread out of Africa about 100,000 years ago with better brains and more sophisticated tools. As they spread into Neanderthal territory, they simply out-competed their primitive cousins. But was Neanderthal really the brutish ape-man of legend, or an effective rival to our own species? And how exactly had he been driven to extinction? What could be found out about this remarkable evolution from the bones themselves? To begin the investigation a skeleton was needed, and no complete Neanderthal had ever been found. Reconstruction expert at The American Museum of Natural History in New York realized that it would be possible to create an entire composite skeleton from casts of partial skeletons. Gary Sawyer combined and rebuilt broken parts to create the most complete Neanderthal ever seen. This Neanderthal stood no more than 1.65 m (5' 4") tall, but he had a robust and powerful build - perfect for his Ice Age environment. But would he have stood up to the cold better than modern humans? Cold adaptation The popular image of the Ice Age is a period of unremitting freezing conditions. But over nearly a million years, Europe has seen huge climate swings including warm as well as cold periods. For much of the last 200,000 years, when Neanderthals were alive, the climate was mild, sometimes even warmer than today's. But they did also have to live through periods of intense cold. Professor Trenton Holliday is a body plan expert from Tulane University, New Orleans. After seeing the skeleton, he believed it had comparatively short limbs and a deep, wide rib cage  This body plan minimizes the body's surface area to retain heat, and keeps vital organs embedded deep within the body to insulate them from the cold. To see if this would have helped him to survive, anthropology professor Leslie Aiello from UCL, teamed up with Dr George Havenith, who runs a laboratory studying the way modern humans retain heat at Loughborough University. They subjected two modern humans with very different body shapes to cooling in an ice bath. One had the long limbs, athletic shape of a runner, the other had a stockier, heavily-muscled body plan closer to that of a Neanderthal. The heavily muscled person lasted longer in the ice bath, so it seems that Neanderthal would have had an advantage. His muscle would have acted as an insulator, and his deep chest did help to keep organs warm. Even so, the advantage doesn't mean that Neanderthal could have survived the icy extremes. This was a polar wasteland and his heavily muscled body plan needed a lot of feeding - about twice as much as we need today. Hunting The archaeological record suggests that Neanderthals lived around the edges of forests where they hunted large animals like red deer, horse and wild cattle. The forests gave them firewood, and materials to construct shelters and spears. By studying Neanderthal stone spear points, Professor John Shea, from Stony Brook University, New York, has found that the shafts of Neanderthal spears would have been thick and heavy.  And if they hunted in woodland, then trying to throw these spears at animals would have been useless. So just how did Neanderthals hunt? Professor Holliday has identified a clue in the Neanderthal skeleton: he was much stronger on the right side than on the left, and his right forearm was particularly powerful, demonstrating a very powerful grip. To see how this muscle development might have related to hunting, Professor Steve Churchill, from Duke University, carried out another experiment. The results of this and Holliday's work suggest Neanderthal was an ambush hunter; waiting in a forest for his prey to stray close, and then attacking with a thrusting spear. Neanderthal was possibly the most carnivorous form of human ever to have lived. Intelligence But the brutality of his hunting methods didn't mean he was simple minded. Could the skeleton tell us more? Professor Ralph Holloway, from Columbia University, New York, is an expert on ancient brains. His assessment of the Neanderthal skull was startling. It was 20% larger than the average size of a modern human's brain, and anatomically identical. He could tell that this Neanderthal was right-handed and that that the areas of brain responsible for complex thought were just as advanced as ours. He should have had the ability to think like us. But one of the ways we use our brains is very particular. We talk. This ability makes us unique in the world today, and arguably makes us human. So was it possible to tell if Neanderthal could have spoken? A tiny bone in the throat, called the hyoid, offered a clue. This bone supports the soft tissue of the throat, and several groups of scientists are attempting to model that soft tissue from the bones and discover what he might have sounded like. Professor Bob Franciscus, from Iowa University, is part of a multi-national group attempting to do just that. By making scans of modern humans, he saw how the soft tissue of the vocal tracts depends on the position of the hyoid bone and the anchoring sites on the skull. Computer predictions were then be made to determine the shape of the modern human vocal tract from bone data alone. The same equations were then used with data from a Neanderthal skull to predict the shape of a Neanderthal vocal tract. The Neanderthal vocal tract seems to have been shorter and wider than a modern male human's, closer to that found today in modern human females. It's possible, then, that Neanderthal males had higher pitched voices than we might have expected. Together with a big chest, mouth, and huge nasal cavity, a big, harsh, high, sound might have resulted. But, crucially, the anatomy of the vocal tract is close enough to that of modern humans to indicate that anatomically there was no reason why Neanderthal could not have produced the complex range of sounds needed for speech. Powerful, better adapted to the cold, and perhaps just as intelligent... Neanderthal should have been invincible. So just how are we here, and Neanderthal is extinct? Extinction It seems that something much more random could have played a significant role. About 45,000 years ago, the climate of Europe went through a burst of very sudden switches between warm and cold conditions that would have transformed the Neanderthals' environment. The forests on which they depended began to recede, giving way to open plains. On these plains, Professor Shea believes, the Neanderthal thrusting spear and ambush strategy wouldn't have worked. So Neanderthals retreated with the forests, their population falling as their hunting grounds shrank. By comparison, modern humans made lighter stone points that could be fitted on to lighter spear shafts. These could be thrown, enabling our ancestors to hunt more effectively in an open landscape. Hunting in an open landscape also required high levels of mobility to follow migrating herds, and the agility to throw the spears themselves. So how did Neanderthal stand up to modern humans' ancestors in agility? Analyzing the inner ear of a Neanderthal, Professor Fred Spoor, from UCL, has discovered clues to Neanderthal's agility. The semi-circular canals of the inner ear provide sense of balance, and by studying a range of animals, he has found a high correlation between the size of the canals and agility. Throughout human evolution, the canals seem to have increased in size as our agility has increased. But Neanderthals have smaller canals than both modern humans and even earlier ancestors. This suggests they were less agile. Returning to the skeleton, Professor Holliday found an explanation for this - that the short limbs and wide pelvis of Neanderthals would have resulted in less efficient locomotion than modern humans. The energy costs in travelling would have been higher, and this would have been a serious evolutionary disadvantage. For Neanderthal, it was an ironic end. The very body plan that had made Neanderthal so well adapted to the Ice Age, had locked him into an evolutionary cul-de-sac. He might have been better adapted to the cold than the first modern humans, but as the landscape changed, it was our ancestors, who could take better advantage of the more open environment, who survived.   http://www.sciencedaily.com/releases/2008/12/081229105039.htm

Homo sapiens neanderthalensis

Homo sapiens neanderthalensis (also Homo      neanderthalensis) 

Neandertal (or Neanderthal) man existed between 230,000 and 30,000 years ago. The average brain size is slightly larger than that of modern humans, about 1450 cc, but this is probably correlated with their greater bulk. The brain case however is longer and lower than that of modern humans, with a marked bulge at the back of the skull. Like erectus, they had a protruding jaw and receding forehead. The chin was usually weak. The midfacial area also protrudes, a feature that is not found in erectus or sapiens and may be an adaptation to cold. There are other minor anatomical differences from modern humans, the most unusual being some peculiarities of the shoulder blade, and of the pubic bone in the pelvis. Neandertals mostly lived in cold climates, and their body proportions are similar to those of modern cold-adapted peoples: short and solid, with short limbs. Men averaged about 168 cm (5'6") in height. Their bones are thick and heavy, and show signs of powerful muscle attachments. Neandertals would have been extraordinarily strong by modern standards, and their skeletons show that they endured brutally hard lives. A large number of tools and weapons have been found, more advanced than those of Homo erectus. Neandertals were formidable hunters, and are the first people known to have buried their dead, with the oldest known burial site being about 100,000 years old. They are found throughout Europe and the Middle East. Western European Neandertals usually have a more robust form, and are sometimes called "classic Neanderthals". Neandertals found elsewhere tend to be less excessively robust. (Trinkaus and Shipman 1992; Trinkaus and Howells 1979; Gore 1996).

 

THE MILESTONE OF HUMAN EVOLUTION....

The emergence of Homo sapiens..............

The latest chapter of human evolution begins with the emergence of Homo sapiens. The anatomy of Homo sapiens is unique among hominin species and appears first in East Africa, dating to roughly 160 thousand years ago (ka).  These unique features including changes in the skull and postcranial skeleton (skeleton minus skull) suggest changes in brain size and architecture and an adaptation to tropical environments.  These anatomical changes are linked to cognitive and behavioral changes that are equally unique among hominin species.  In particular, the archaeological evidence of behaviors thought to be unique to Homo sapiens, which appear first in Africa around 170 ka, highlight the importance of symbolism, complex cognitive behaviors, and a broad subsistence strategy (the strategy used to procure food).  The evolution of Homo sapiens is vitally important to defining our species in the broader context of human evolution and also has key to understanding the human condition, past and present.

                                               Neandertal                           Homo sapiens
 Many of the unique features of Homo sapiens are found in the skull.  Brain size estimates suggest that the brain of Homo sapiens was larger than in other hominin species.  The average cranial capacity of Homo sapiens is roughly 1300 cubic centimeters, making the brains of this species absolutely smaller than those of Homo neanderthalensis. However, due to its gracile (small and lightly built) postcranial skeleton (see below), the brain of H. sapiens was larger relative to body size than that of H. neanderthalensis.  The skull itself is much taller than earlier hominin species and the skull is therefore much shorter (from front to back) in relation to its height.  The widest point of the Homo sapiens  skull is toward the top of the skull and the sides of the skull are nearly vertical.  Together with the extreme height of the skull, these features give the Homo sapiens skull a house-shaped (i.e., pentagon with straight walls) appearance when viewed from behind.  The skull of Homo sapiens  also generally lacks evidence of being strongly built (e.g., it lacks the large browridges and bony prominences seen in Homo neanderthalensis and Homo heidelbergensis).  However, the earliest representatives of the species maintain a fairly rugged appearance.  For instance, the browridges of early H. sapiens are fairly large, but differ in shape from those of H. neanderthalensis  and H. heidelbergensis.  The face of Homo sapiens is much smaller than those of earlier hominin species.  In addition the face is tucked under the brain case i.e., the face is located entirely below (rather than in front of) the front part of the brain.  The face of this species also bears a deep indentation (the canine fossa) below each of the orbits.  The teeth and mandible (lower jaw) are smaller than in earlier species and the mandible bears a prominent mental prominence (chin), which is not seen in any other hominin species.
Other unique features of the Homo sapiens skeleton are found in the postcranial skeleton.  The postcranial skeleton is very lightly built relative to earlier species and lacks the adaptations to cold environments found in Homo neanderthalensis e.g., thick, shortened limb bones and wide rib cages and hips.  These features of the postcranial skeleton are thought to reflect the fact that Homo sapiens evolved in tropical, African environments before migrating across the globe.  In these tropical environments, long and lean body proportions were favored because they maximized surface area (and therefore maximizing heat dissipation) while maintaining the same body mass.
 What is clear from the European fossil record is  the anatomy characteristic of Homo neanderthalensis disappeared rather rapidly between 50 and 30 ka and that this disappearance coincides with the migration of Homo sapiens into Europe from Africa.  Thus, questions about what exactly caused that disappearance are crucially important and stridently contended.  There is no evidence of warfare in Europe (or elsewhere) at this time.  Therefore, the notion that Homo sapiens actively exterminated Homo neanderthalensis is difficult to maintain.  Many people believe that the sophisticated symbolic and cognitive capabilities of Homo sapiens combined with their adaptation for hunting a large range of diverse prey allowed them to outcompete Homo neanderthalensis.  This point of view is particularly relevant in light of the dramatically shifting climate that was witnessed in Europe around the time that Homo sapiens arrived.  That is, Homo sapiens’ broad subsistence strategy and ability to cognitively adapt to difficult environments may have allowed them to spread quickly and widely during times when the climate shifted dramatically.  Homo neanderthalensis, on the other hand, may have had difficulty dealing with these drastic shifts in climate, due to their focus on hunting large game animals.  Other researchers suggest  Homo sapiens had a demographic, rather than a technological, edge on Homo neanderthalensis.  These scholars suggest  Homo sapiens maintained larger and more numerous populations and that, over time, the sheer numbers of Homo sapiens simply swamped out Homo neanderthalensis populations, which are thought to be smaller, more spread out, and less numerous.  Of course, it is very possible that both of these factors (i.e., technology and demography) acted in concert, resulting in the disappearance of the  Neanderthals .

People Today...
Are we genetically different from our Homo sapiens ancestors who lived 10-20,000 years ago?  The answer is almost certainly yes.  In fact, it is very likely that the rate of evolution for our species has continuously accelerated since the end of the last ice age, roughly 10,000 years ago.  This is mostly due to the fact that our human population has explosively grown and moved into new kinds of environments, including cities, where we have been subject to new natural selection pressures.  For instance, our larger and denser populations have made it far easier for contagious diseases, such as tuberculosis, small pox, the plague, and influenza to rapidly spread through communities and wreak havoc.  This has exerted strong selection for individuals who were fortunate to have immune systems that allowed them to survive.  There also has been a marked change in diet for most people since the end of the last ice age.  It is now less varied and predominantly vegetarian around the globe with a heavy dependence on foods made from cereal grains.  It is likely that the human species has been able to adapt to these and other new environmental pressures because it has acquired a steadily greater genetic diversity.  A larger population naturally has more mutations adding variation to its gene pool simply because there are more people.  This happens even if the mutation rate per person remains the same.  However, the mutation rate may have actually increased because we have been exposed to new kinds of man-made environmental pollution that can cause additional mutations.
It is not clear what all of the consequences of the environmental and behavioral changes for humans have been.  However, it does appear that the average human body size has become somewhat shorter over the last 10,000 years, and we have acquired widespread immunity to the more severe effects of some diseases such as measles and influenza.
Finally, can we say what direction human evolution will take in the future?  This is a fascinating question to consider but impossible to answer because of innumerable unknown factors.  Though, it is certain that we will continue to evolve until we reach the point of extinction.