Genus Homo by Abigail Lofton https://padlet.com/al5091/m08sfomn3d6x by Abby Lofton en-us 2017-05-29 17:09:03 UTC 2023-07-08 20:14:31 UTC hello@padlet.com https://padlet-assets.s3.amazonaws.com/icons/Brightnessdown.png Speciation al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174279280 Genus Homo went through gradual speciation. Fossils have been identified as far back as 2.75 - 2.8 million years ago, showing that the genus has been in existence for a long time and evolution has occurred over quite a bit of time.  There are several examples of human speciation throughout the years, however one of the most important and relevant to present day homo sapiens would be the transition from homo neanderthalensis to homo sapien. Somewhere between 500,000 and 300,000 years ago, the ancestors of the Neanderthals left Africa and migrated to the Middle East, from that point they continued on to Europe and parts of Asia. Neanderthals lived in the Middle East and Europe until about 30,000 years ago, meaning there was a time where the humans leaving Africa about 50,000 years ago could have interbred with them before they went extinct. DNA sequence comparisons between the two species indicates that modern, non-African humans have about 1-4% Neanderthal DNA in their genomes. This variation, however, is not present in sub-Saharan Africans, since they are descended from humans that did not leave Africa and and thereby, because of geographical separation, never had the opportunity to interbreed with Neanderthals. We also know that the group that left Africa went through a reduction in population size to about 1200 individuals, whereas those that stayed behind maintained a larger population size (about 6000) over the same period. This shows the speciation through the point in time where the populations shifted to homo sapiens through several factors resulting inn the divergence of the genus homo and to further extinction of species apart from Homo Sapien. ]]> 2017-05-29 17:16:07 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174279280 Evolution al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174279358 Evolution of the genus homo has been divergent. Since the divergence from the ape lineage, approximately seven million years ago, hominids have taken their own divergent evolutionary path leading all the way to Homo Sapien Sapien 170,000 years ago. Evidence from molecular biology shows that humans and chimpanzees shared common ancestors about 5-8 million years ago. Human and Chimp genomes have been studied constantly to identify the divergence of the two species. Since this divergence, several species of early humans such as the handy man (Homo Habilis) and the Neanderthal Man (Homo Neanderthalensis). All of these species have gone extinct leaving only the wise man, or present day humans (Homo Sapien). Early humans first migrated out of Africa into Asia probably between 2 million and 1.8 million years ago. They entered Europe somewhat later, between 1.5 million and 1 million years. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60,000 years and to the Americas within the past 30,000 years or so. Over time, genetic change can alter a species' overall way of life, such as what it eats, how it grows, and where it can live. Human evolution took place as new genetic variations in early ancestor populations favored new abilities to adapt to environmental change and so altered the human way of life.


]]> 2017-05-29 17:16:46 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174279358 Isolation al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174279440 Isolation is a process by which two species that could otherwise produce hybrid offspring are prevented from doing so. Isolation occurred in the genus homo through the Out of Africa hypothesis, which outlines a theory that the first species of Homo, originated on the continent of Africa, and spread through Europe and Asia. As they diverged, they evolved into many different species. The radiation of species, occurred potentially four times in history, specifically, Homo sapiens spread in one of these migrations.  Homo sapiens most likely evolved in isolation within the continent of Africa, and only very recently spread globally, and as they moved, they caused the extinction of earlier species that had already migrated to the other continents. The extinction can be due to many different factors, a few of these include; being better adapted for survival and larger brains. The out of Africa Hypothesis was eventually adapted, because it was found that  the Homo sapien species, already existed in Europe and Asia, prior to the recent migration out of Africa. This would suggest that the Homo sapien species evolved simultaneously in Africa, Europe and Asia. Migration of the Homo sapien species out of Africa still occurred, and instead of causing extinction, they interbred with the Homo sapiens already present. This shows isolation because the different species mutated and changed once they had been separated and began to migrate.

]]> 2017-05-29 17:17:35 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174279440 Genetic Drift al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174279489 Genetic Drift played a major role in human evolution. As the genus homo migrated across continents, their populations became separated, whch cause small genetic changes, which affected the evolution long term. Genetic drift can also result in rapid evolution of the gene pools of small, reproductively isolated populations. Our ancestors lived in such small populations for 99+% of the last 2.5 million years during which our genus Homo was evolving.  These small populations were more likely due to the lower access to resources and the higher death rates and harsher living conditions. Subsequently, genetic drift and other small population size effects must have frequently been a major factor in our evolution along with natural selection. ]]> 2017-05-29 17:18:11 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174279489 Descent with Modification al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174279567  Descent with modification is simply passing traits from parent to offspring, and this concept is one of the fundamental ideas behind Charles Darwin's theory of evolution. When this happens, the offspring is a combination of the genes of its parents through reproduction. This leads to changes, where if one organism has a mutation, their offspring will possess it and so on and so forth leading to larger populations with the same mutation that could eventually change so much over time that the mutation becomes the pathway to a new species. This has been done several times. As the populations split and adapted to their environments, the more traits that better suited the environment were passed on creating different species as the line descended. This can be seen in the length of the arms of genus homo. As they became more motile and moved to different areas their arms became more useful and them being longer became an advantage. These traits passed on through their kids and changed slightly with each passing and over enough time helped to create the Homo Sapien.]]> 2017-05-29 17:18:57 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174279567 External Characteristics al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174633969 All genus homo organisms have an “erect posture, a large cranium, two-footed gait, fully opposable thumbs, and well-developed tool-making ability,” which is what distinguishes them from other hominids.

]]> 2017-05-31 14:40:29 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174633969 Internal Characteristics al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174634121 All of the species in the genus homo are multi-cellular eukaryotes. They are all heterotrophs meaning they find energy by consuming other plants and animals. Food is ingested and digested in the stomach and food reserves are stored as glycogen of fat. They are all motile, meaning they can move independently and spontaneously.  Animals follow a definite growth pattern, the adults have a definite shape and size. Higher forms of animals exhibit well developed sensory and neuromotor mechanism. Most of the organisms are capable of locomotion. Reproduction is by copulation of male and female which is followed by development in embryonic stages. ]]> 2017-05-31 14:41:06 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174634121 Behavioral Characteristics al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174634207 Human Life cycle and reproduction varies greatly from other organisms, including other primates. Human beings give birth to relatively helpless newborns, breastfeed them for a short period of time, which is then followed by a longer period of dependency. There are also two rapid growth spurts usually around the ages of 7 and again during adolescence. No other known animals are known to have such growth spurts. 

]]> 2017-05-31 14:41:30 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174634207 Habitat Characteristics al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174634256 The habitat of hominids depend on the species, since the species became wiser and more able to change their environment as time continued on. The species Habilis of Handy Man mainly lived in grasslands. This climate was cooler and drier and was the best environment for new feeding strategies that included scavenging and tool use. As time continued and the species evolved, the climate of the earth also changed, changing several environments across the world. The glacial period that occurred from about 65,000  to 25,000 years ago shows that it was a period of rapid, severe and abrupt climate changes with profound environmental impacts. Although Neanderthals were physically adapted to the cold, the severe changes in conditions allowed no time for populations to recover. Even small advantages in biology, behavior or lifestyle, such as those mentioned above, would mean the difference between life and death. The archaeological record indicates that modern humans had a wider range of adaptations which would have helped in survival. Early modern humans were adapted to life in the tropics but by 40,000 years ago they occupied a range of environments across the continents of Africa, Europe, Asia and Australia. Within the last 20,000 years humans have also spread into the Americas. Today, our culture and technology allows us to live in most environments on our planet as well as some off our planet.]]> 2017-05-31 14:41:42 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174634256 Handy Man Taxonomy al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174634974
Common Name - Handy Man
Kingdom - Animalia
Phylum - Chordata
Class - Mammalia
Order - Primate
Family - Hominid
Genus - Homo
Species - Habilis
]]> 2017-05-31 14:44:50 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174634974 Neanderthal Taxonomy al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174635135
Common Name - Neanderthal Man
Kingdom - Animalia
Phylum - Chordata
Class -  Mammalia
Order - Primate
Family - Hominid
Genus -  Homo
Species -  Neanderthalensis
]]> 2017-05-31 14:45:34 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174635135 Wise Man Taxonomy al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174636258  
Common Name - WIse Man (common human
Kingdom - Animalia
Phylum - Chordata
Class - Mammalia
Order - Primate
Family - Hominid
Genus - Homo
Species - Sapien 
]]> 2017-05-31 14:50:29 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174636258 Relatedness through Taxonomy al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174636829 Taxonomy shows the relatedness of organisms by providing different information on the origins of the organisms. For example, the handy man and the neanderthal man are greatly related. This can be seen how they posses the same domain, kingdom, phylum, class, order, family, and genus; only varying once their taxonomy reaches species, where the handy man is species Habilis and the neanderthal man is species Neanderthalensis. Having all of these similar groups in their taxonomy shows that the species are related to one another. Each grouping has different characteristics, and the more characteristics two organisms have in common the more similar and related they are the more taxonomy they have alike. The phylogenetic tree below shows how once the genus homo broke off from the line of apes, they continues to evolve reaching modern day humans.]]> 2017-05-31 14:52:58 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174636829 Homo Sapien Characteristics al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174831735 Homo sapiens skulls have a distinctive shape that differentiates them from earlier human species. Their body shape tends to vary, however, due to adaptation to a wide range of environments. The earliest Homo sapiens had a relatively simple culture, although it was more advanced than any previous species. Rare evidence for symbolic behaviour appears at a number of African sites about 100,000 years ago, but these artistic expressions appear more of a flicker of creativity than a sustained expression. It is not until about 40,000 years ago that complex and highly innovative cultures appear and include behaviour that we would recognise as typical of modern humans today. Many researchers believe this explosion of artistic material in the archaeological record about 40,000 years ago is due to a change in human cognition - perhaps humans developed a greater ability to think and communicate symbolically or memorise better. However, as there are obvious attempts at art before this, perhaps there are other reasons. One theory is that population size and structure play a key role as social learning is considered more beneficial to developing complex culture than individual innovations are. Bigger populations often accumulate more cultural attributes than isolated groups. All Homo sapiens were once hunter-gatherers living on wild plants and animals. It was only about 11,000 years ago that humans began to domesticate plants and animals although wild foods still remained important in the diet. Our species has a wide-ranging and essentially omnivorous diet. This has enabled us to utilise the food resources found in the wide variety of environments we inhabit.]]> 2017-06-01 15:10:46 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174831735 Homo Habilis Characteristics al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174831784 This species, one of the earliest members of the genus Homo, has a slightly larger braincase and smaller face and teeth than in Australopithecus or older hominin species. But it still retains some ape-like features, including long arms and a moderately-prognathic face, which is where the jaw stretches past the front of the face.
Height: average 3 ft 4 in - 4 ft 5 in (100 - 135 cm)
Weight: average 70 lbs (32 kg)
Early Homo had smaller teeth than Australopithecus,but their tooth enamel was still thick and their jaws were still strong, indicating their teeth were still adapted chewing some hard foods. Dental microwear studies suggest that the diet of Homo Habilis was flexible and versatile and that they were capable of eating a broad range of foods, including some tougher foods like leaves, woody plants, and some animal tissues, but that they did not routinely consume or specialize in eating hard foods like brittle nuts, seeds or dried meat.
]]> 2017-06-01 15:11:01 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174831784 Homo Neanderthalensis Charcteristics al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174831942 Neanderthals are our closest extinct human relative. Some defining features of their skulls include the large middle part of the face, angled cheekbones, and a huge nose for humidifying and warming cold, dry air. Their bodies were shorter and stockier than ours, another adaptation to living in cold environments. But their brains were just as large as ours and often larger - proportional to their brawnier bodies.
Height: Males: average 5 ft 5 in (164 cm); Females: average 5 ft 1 in (155 cm)

Weight: Males: average 143 lbs (65 kg); Females: average 119 lbs (54 kg)

Neanderthals made and used a diverse set of sophisticated tools, controlled fire, lived in shelters, made and wore clothing, were skilled hunters of large animals and also ate plant foods, and occasionally made symbolic or ornamental objects. There is evidence that Neanderthals deliberately buried their dead and occasionally even marked their graves with offerings, such as flowers. No other primates, and no earlier human species, had ever practiced this sophisticated and symbolic behavior.
]]> 2017-06-01 15:11:53 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174831942 Biochemistry al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174863755 Biochemistry is important in understanding evolution. Biochemistry is the study of the basic chemistry and processes that occur in cells. The biochemistry of all living things on Earth is incredibly similar, showing that all of Earth’s organisms share a common ancestry. Several experiments and observations have been done to find the similar proteins between neanderthals and the modern human Y chromosome. There were notable changes in the genes, three of which produced male-specific minor histocompatibility antigens;  receptors on the cellular surface of donated organs that are known to give an immunological response in some organ transplants. Antigens derived from one of these genes, known as KDM5D, are thought to elicit an immune response in some pregnant mothers against their male fetuses and lead to miscarriages. These incompatibilities may have been what separated the two species by discouraging the breeding between the two, eventually leading to the extinction of Homo Neanderthalensis. We show that genetic variants shared between modern humans and Neanderthals, but distinct from chimpanzees, are specifically enriched in genes involved in lipid catabolism in contemporary humans of European, but not East Asian descent. Excess of Neanderthal variants in lipid catabolism genes was further associated with signatures of recent positive selection. In agreement with observations made at the genome level, we show significant excess of lipid concentration and gene expression divergence in lipid catabolism pathways in Europeans, but not the other population groups. Furthermore, lipid catabolism genes showing increased expression divergence in Europeans contain an even higher proportion of Neanderthal sites than other lipid catabolism genes. Taken together, these observations indicate that lipid catabolism of contemporary Europeans was partially shaped by the genetic variants shared with Neanderthals. During harsh Ice-Age winters, carbohydrates were scarce and fat was in limited supply. But large game, the typical prey of the Neanderthal, thrived," said Ben-Dor. "This situation triggered an evolutionary adaptation to a high-protein diet -- an enlarged liver, expanded renal system and their corresponding morphological manifestations. All of these contributed to the Neanderthal evolutionary process." All in all, genus homo had very similar carbohydrates, lipids, and proteins. Today through genetic modification and easier access to resources, the population of homo sapien has been able to access more,  carbohydrates and lipids especially. ]]> 2017-06-01 17:55:17 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174863755 DNA al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174863952 Recently, nuclear DNA from a Neanderthal specimen from Vindija Cave has been sequenced, as well, using two different methods that yield similar results regarding Neanderthal and wise man lineages, with both analyses suggesting a date for the split between 460,000 and 700,000 years ago, though a population split of around 370,000 years is thought to have existed. The nuclear DNA results indicate about 30% of derived alleles in Homo sapiens are also in the Neanderthal lineage. This high frequency may suggest some gene flow between ancestral humans and Neanderthal populations. Fact is that the average male outside of Africa has between 3% and 5% Neanderthal DNA. Neanderthals were closely enough related to Homo sapiens that they could interbreed, but only if the male was Neanderthal and the female was a Homo sapien. Africa is the only inhabited continent where Neanderthal DNA is absent in the natives. This is because Neanderthals were originally from Europe and western Asia. They interbred with humans from Europe and Asia, where they crossed over to the Americas. ]]> 2017-06-01 17:56:21 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174863952 Chromosomal Analysis al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174864019 The Neanderthal mtDNA sequences were substantially different from modern human mtDNA. Researchers compared the Neanderthal to modern human and chimpanzee sequences. Most human sequences differ from each other by on average 8.0 substitutions, while the human and chimpanzee sequences differ by about 55.0 substitutions. The Neanderthal and modern human sequences differed by approximately 27.2 substitutions. Using this mtDNA information, the last common ancestor of Neanderthals and modern humans dates to approximately 550,000 to 690,000 years ago, which is about four times older than the modern human mtDNA pool. This is consistent with the idea that Neanderthals did not contribute substantially to modern human genome. Researchers have also studied ancient DNA from anatomically modern Homo sapiens from Europe dating to the same time period as the Neanderthals. Material from two Paglicci Cave, Italy individuals, dated to 23,000 and 25,000 years old, was sequenced. The Paglicci Homo sapiens mtDNA sequences were different from all Neanderthal mtDNA sequences but were within the range of variation for modern human mtDNA sequences. Mitochondrial DNA from the Paglicci specimens as well as other ancient humans fit within the range of modern humans, but the Neanderthals remain consistently genetically distinct. This shows that early anatomically modern Homo sapiens were not very different genetically from current modern humans, but were still different from Neanderthals. Though this evidence does not disprove the idea of Neanderthal and modern human admixture, it shows that moderns and Neanderthals did not have more genetic similarities that were subsequently lost. If interbreeding did occur, Neanderthal mtDNA sequences could have been lost due to genetic drift. The following picture is a female Karyotype of a Homo Sapien, showing the 23 pairs of chromosomes that is found in a couple of the Genus HOmo species.]]> 2017-06-01 17:56:43 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174864019 Fossils al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174898671 Early human fossils and archeological remains offer the most important clues about this ancient past. These remains include bones, tools and any other evidence left by earlier people. Usually, the remains were buried and preserved naturally. They are then found either on the surface or by digging in the ground. By studying fossilized bones, scientists learn about the physical appearance of earlier humans and how it changed. Bone size, shape, and markings left by muscles tell us how those predecessors moved around, held tools, and how the size of their brains changed over a long time. Archeological evidence refers to the things earlier people made and the places where scientists find them. By studying this type of evidence, archeologists can understand how early humans made and used tools and lived in their environments. 
All of the skull fossils below posses very similar traits. They all have a circular frame with an extended area for the teeth, as well the nose socket is very prominent and they all possess similar shaper cheekbones. These are similar structures between all six skulls, There are slight variations showing the change over time, but they all look very similar, leading up to the present day homo sapien.
The Pictures show the different shapes of the skulls of different species over time. The skulls develop and longer structure and a larger cranium that works with a larger brain size. The shape of the nose and teeth also change over time. A less defined brow bone also occurs, leading to the evolution of the genus homo.]]> 2017-06-01 23:38:57 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174898671 Natural Selection al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174943121 Much of the human characteristics today have been achieved through stabilizing natural selection. This is a type of natural selection that favors the average individuals in a population. Natural selection can be seen many times in the homo evolution. As conditions change, natural selection favors one allele or genetic variant over another. Genes that can facilitate a range of different forms under different environments can also help an organism adapt to changing conditions. Over the last 100,000 years there has been a continuation of the trend towards smaller molar teeth and a more gracile skeleton, such that the Upper Palaeolithic humans of 30,000 years are described as being 20-30% more robust than present-day people. This demonstrable trend in tooth size is probably linked to the use of food-processing techniques that reduce the need for prolonged chewing, and thus provides a good example of the results of natural selection in human populations.]]> 2017-06-02 08:44:50 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174943121 Skull of Homo Neanderthalensis al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174951441 2017-06-02 09:57:15 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174951441 Skull of Homo Erectus al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174951462 2017-06-02 09:57:28 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174951462 Skull of Homo Rudolfensis al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174951482 2017-06-02 09:57:40 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174951482 Skull of Homo Heidelbergensis al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174951503 2017-06-02 09:57:53 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174951503 Skull of Homo Habilis al5091 https://padlet.com/al5091/m08sfomn3d6x/wish/174951531 2017-06-02 09:58:11 UTC https://padlet.com/al5091/m08sfomn3d6x/wish/174951531