Introduction This paper will explore the theory of evolution and its main contributing species. The Australopithecus is the most primitive common ancestor between humans and apes. Though its contributions to evolution were few, it was still a vital part in evolution being the first ape-like creatures to be known as related to modern humans. Homo sapiens are the first species that share a genus with modern humans. They are slightly more advanced than Australopithecines. Homo erectus are one of the better known of the genus Homo. Finally, Homo neanderthalensis, our closest relatives. The fossils found, the structure and the disappearance of these species will be discussed in further detail throughout this paper.
Australopithecus
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(Johanson & Edey, 1981) The next fossil of an Australopithecus was found by Robert Broom. Being larger and more bulky he decided to call it, Paranthropus (towards man) robustus. (Johanson & Edey, 1981) This name would later be changed to Australopithecus robustus because in the 1950s all African ape-men were to be known as Australopithecines. They were divided into two categories, a burlier more primitive type (Australopithecus robustus) and a slender more delicate type (Australopithecus africanus). (Figure 1) (Johanson & Edey, 1981) The most complete fossil of an Australopithecus was found by Donald Johanson in 1974 at Hadar, Ethiopia. (Figure 2) (Smithsonian Museum, 2016) Johanson and Timothy White named this new species of Australopithecus in 1978, Australopithecus afarensis. (Johnson & Bjelland, 2011) This nearly half complete skeleton is known as Lucy. (Johanson & Edey, 1981) She was about three and a half feet tall, she had a V-shaped jaw and had a tiny brain. (Johanson & Edey, 1981) Lucy’s species was more ape-like and primitive than that of the fossils found by Dart or Broom. (Johanson & Edey, 1981) Lucy provided a certainty about bipedalism (the ability to walk upright) that before had only been mere guesses. (Johanson & Edey, 1981) Bipedalism was shown by studying the structure of the fossils found. First noticed by Dart was that the foramen magnum (the holes where the spinal column nerves connected to the brain) was at the bottom
Australopithecus Boisei: Similar to the A. Aethiopicus in terms of the upper shape with the vertical line of bone
The changes in morphology that resulted from selection for bipedalism included a readjustment of the pelvis and changes in the major locomotive muscle attachments. Habitual bipedalism necessitated a reduction in the gap between the sacroiliac joint and acetabulum, with a reduced sagittal breadth. Though the pelvis of early hominids differs from that of modern humans, but still had the traits necessary for habitual bipedalism. The Australopithecine pelvis is more similar to humans than to chimpanzees (Lovejoy, 1988): The blade of the illium is longer and wider in chimpanzees than in Australopithecus or Homo. This obvious difference is due to the functions of the pelvis in each species’ body, like being a weight bearing bone versus. Australopithecus afarensis, particularly Lucy, had a mosaic of anatomical traits featuring both human and apelike features. The short pelvis and broad iliac blades which curve around the side forming the area of gluteal muscle attachment confirmed that Au. afarensis was at least a habitual biped (Lovejoy,
They found that Au. ramidus had very similar characteristics to Sahelanthropus Tchadensis an ancestor that dates to 6-7 million years ago. Ardi had a foot that was primitive and had an opposable big toe which was most likely used to grab on branches. She also had a long and curvy spine just like humans. Its pelvis was large like those of apes and had short and broad shoulders suggesting it had a lower center of mass and could possibly walk on one leg at a time. But it is also thought that it was still spending a lot of time in the trees as well. Thus, why it is thought to be intermediate form of bipedalism it lived in both worlds, walking upright, and climbing trees, equal success in both biospheres. Although Ardi is not the connection to apes it still served to prove that the ancestor of apes was a lot more primitive than we believed. There are still several questions to be answered in this puzzle called our ancestry. It may seem that more questions arise as more clues are found, but that is science, there would be no intrigue left if all questions were
Michel Brunet and his team found the fossil in the sand dunes of northern Chad after “a decade of digging”(Whitfield 2002). This discovery is most definitely a new one and one that will cause the reinterpretation of all previous hominid research. What makes this find so spectacular is that the structure of the skull suggests a being that walked upright, though it lived in a time when apes and chimpanzees also existed. “Sahelanthropus has many traits that shout ‘hominid’. These include smaller canines, and thicker tooth enamel than apes. And the point at the back of the skull where neck muscles attach suggests that Toumai walked upright”(Whitfield 2002). The key to this discovery, Brunet believes, is the back of the skull that suggests a muscle attachment for upright walking ability, which supports the scientist’s theory that
Afropithecus is a fairly large extinct ape- 50kg, characterized by a lack of a prehensile tail, long snout with procumbent incisors, generalized limb proportions and thick molar enamel. The braincase of Afropithecus is fairly small in size compared to other Miocene apes and Old World Monkeys from the same area. The primitive characteristics of Afropithecus suggest a relation to early catarrhines- such as Aegyptopithecus. And the post-cranial fossil record suggest that it was both arboreal and quadrupedal, similar to the proconsul that Afropithecus is categorized
As her named suggests, Lucy came from the Australopithecus genus, and was a member of the Hominini tribe, just like
However the minority of species that branch off from the human evolutionary tree and are either claimed by extinction or evolved down a second evolutionary branch, and what differences existed in them that differed from our ancestors. The species such as Australopithecus Boisei lived in the same time period to that of Australopithecus Africanus and Aferensis. However based off the information (See research booklet) it I notice that the A. Boisei has a significantly decreased brain to body weight
In terms of lower limb proportions comparing Australopithecines and Paranthropus, only a few post cranial remains have been discovered. Comparing the post cranial remains of these genera to those of modern day non-human and human apes can give great insight to the locomotion and stature of Paranthropus and Australopithecines.
Bipedalism is one of the big six events that happened in the evolution of humans becoming what we are today. Bipedalism means standing, walking on two feet rather than walking on four feet like the other apes our primate family tree. To understand why humans walk using bipedalism anthropologist must look into the past. One of the most significant fossil evidence of bipedalism is a fossil named “Lucy”. Lucy was found in East Africa. She is an adult female that stood at about three and a half feet. Lucy is a significant find because she was the most complete fossil. Forty percent of her body was found, making her the most complete fossil for bipedalism. It is accepted that there is a close relation to the environment for the reason to why there
The Australopithecine are some of the earliest known hominids and they embody many characteristics that are associated with bipedalism. Bipedalism is a highly specialized and unusual form of primate locomotion that sets modern humans apart from all other living primates as we are the only extant obligate bipeds. Many evolutionary biologists and paleoanthropologists have devoted innumerable research hours to attempting to understand this unique form of locomotion and how it evolved. A number of interdependent morphological adaptations occurred over a long period of time to solve challenges posed by habitual bipedalism. As a result, there are differences that exist between early and late hominin species.
Introduction: In this lab we are trying to examine on evolution. To see the change over time. Evolution shows where an organism comes from, so if we retrace it to the beginning of its time we will be able to know more about the organism and its ancestors more reliable than an opinion. Measuring the skulls and comparing the the measurements can help us see how far the animal has came and how it changed over time. Also get to see who's related to who and how.
To begin this essay, Lovejoy appeals the notion of human uniqueness while focusing on human’s ability to be bipedal. By doing this, he introduces the possibilities of the first bipedal ancestor of humans while focusing the relation to other ape’s morphology. Lovejoy first discusses early Australopithecine as one the possibilities for a last common ancestor with chimpanzee, but quickly moves to Ardipithecus ramidus with their thesis of through examining the morphology and social behavioral structure of a CLCA , A. ramidcus can prove the African ape based models are not necessary. African apes models that are used to illustrate human and hominid behavior have become unreliable. To replace these models, Lovejoy proposes adaptive suites and explains
Who were the australopithecines? Australopithecine was the shared term for the genus of fossil hominid that existed among, “2 to 5 million years ago in the region of East Africa and is distinguished by a bipedal locomotion, but an undersized brain size” (Frisancho, 2006). Australopithecus is a different hominid genus that developed previously than Homo. In reality, genus Homo seems to have progressed from the genus Australopithecus. The hominid lineage diagram is assembled by genus, or by associated species in the instance of the initial assemblage. The particular relationships amongst these types are not well comprehended and undoubtedly several others are expecting to be found.
The Australopithecines were the first to walk upright, or became bipedal, although rather clumsily. Their walk was unsteady, judging by their bone structure (Figure 1.), and they most likely were quadrupedal the majority of the time. The Australopithecines had a brain about the size of an orange, high up cheekbones, and big molars. They were about three feet tall, and had small thumbs. Australopithecines, while definitely possessing some human characteristics, humans are still much closer to the chimps. Australopithecines were vegetarians; even if they knew that animals were edible, they still had no reliable means of killing animals for food. About 2 million years ago, highly evolved Australopithecines made the
Human evolution according to research started over 6 million years ago. The outcome of the evolution process is the current human beings. Scientific studies have revealed over the years a remarkable affinity between the chimpanzees/Apes and human beings. Even though this reality is not a definitive prove that human beings evolved from apes, it does show that the human beings are in one way or another related to other primates. Scientists suppose that the humans and the primates shared a common ancestor. The subject of what makes humans what they are and their origin has been the exclusive purpose leading to many scientific studies globally (Coolidge & Wynn, 2011). Studies believe that Africa was the origin of evolution millions of years ago. Fossil remains have been discovered in different parts of Africa as well as other regions of the world. Different hominins have been discovered around the world in the last 1 million years. Thus, the different discoveries have led to comparisons between the various species of hominins to clarify on their similarities as well as differences. This essay seeks to explain whether they were distinctively different species or regional versions of the same species.