Ardipithecus ramidus - Revision history

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	[[Category:Cardiovascular system]]		[[Category:Cardiovascular system]]
	[[Category:Embryology]]		[[Category:Embryology]]
			==Ardipithecus ramidus==
			<gallery>
			File:Ardipithecus_ramidus.jpg\|Ardipithecus ramidus
			File:Map_of_the_fossil_sites_of_the_earliest_hominids_(35.8-3.3M_BP).svg\|Map of the fossil sites of the earliest hominids
			File:Ardipithecus_Gesamt1.jpg\|Ardipithecus ramidus
			File:Modell_eines_Schädels_des_Pan_troglodytes_(Schimpanse,_weiblich).jpg\|Model of a female chimpanzee skull
			File:Nut_cracking_Ardipithecus.png\|Nut cracking Ardipithecus
			</gallery>

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	{{~~jpg-image~~}}'''Ardipithecus ramidus''' is an extinct species of [[hominin]] that is believed to have lived about 4.4 million years ago during the early [[Pliocene]] epoch. The discovery of this species has significantly contributed to our understanding of human evolution, particularly regarding the nature of our ancestors' locomotion and their environment. The first fossils of ''Ardipithecus ramidus'' were discovered in the [[Afar Depression]] of [[Ethiopia]] in 1994 by a research team led by [[Tim D. White]], an American paleoanthropologist. The species name ''ramidus'', which means "root" in the Afar language, reflects the species' basal position in the human lineage tree.		{{Short description\|Structure in the developing heart}}
			{{Anatomy}}

	~~==Discovery and Significance==~~		The '''aorticopulmonary septum''' is a critical structure in the developing heart of the embryo. It plays a vital role in the separation of the aorta and the pulmonary artery, which are the major arteries that carry blood away from the heart. This septum is essential for the proper division of the outflow tract of the heart into the systemic and pulmonary circulations.
	The ~~discovery of ''Ardipithecus ramidus'' was groundbreaking because it provided evidence of a hominin species that lived earlier than the famous '~~'~~[[Australopithecus afarensis]]~~''~~, known from the specimen [[Lucy (Australopithecus)\|Lucy]]. '~~'~~A. ramidus~~'' is ~~characterized by~~ a ~~combination~~ of ~~traits that suggest~~ a ~~transitional form~~ of ~~bipedalism~~, ~~different~~ from ~~both the quadrupedal locomotion seen in modern [[Great Apes]] and~~ the ~~fully upright bipedalism of later hominins~~. This ~~has implications~~ for the ~~understanding~~ of the ~~evolution~~ of ~~walking on two legs, a key characteristic of humans~~.

	==~~Anatomy and Physiology~~==		==Development==
	~~''Ardipithecus ramidus'' had a small brain, similar in size to that of a modern chimpanzee,~~ and ~~its teeth suggest a diet that included both plants and small animals~~. The ~~structure~~ of ~~its limbs and pelvis indicates that while ''A. ramidus'' could walk on two legs, it also spent time in~~ the ~~trees~~, ~~suggesting an adaptation to both terrestrial and arboreal environments. This combination of features supports~~ the ~~hypothesis~~ that ~~bipedalism evolved in a forested environment rather than in open savannah, challenging previous theories about~~ the ~~environmental drivers of human evolution~~.		The aorticopulmonary septum develops from the [[neural crest cells]] and the [[truncus arteriosus]] during embryogenesis. The process begins with the migration of neural crest cells into the truncus arteriosus, which is the common arterial trunk that initially serves both the systemic and pulmonary circulations.

	~~==Habitat==~~		As development progresses, these cells contribute to the formation of the spiral septum, which divides the truncus arteriosus into the [[aorta]] and the [[pulmonary trunk]]. This division is crucial for establishing the separate pathways for oxygenated and deoxygenated blood, which is a hallmark of the mammalian circulatory system.
	~~The fossils~~ of ~~''Ardipithecus ramidus'' were found in what is now a desert region~~, ~~but geological~~ and ~~paleoenvironmental evidence indicates that~~ the ~~area was once a woodland, with a mix of trees and grasses~~. This ~~habitat would have provided both~~ the ~~arboreal~~ and ~~terrestrial resources necessary to support~~ the ~~species' versatile locomotion and diet~~.

	==~~Impact on the Understanding of Human Evolution~~==		==Function==
	The ~~discovery~~ of ~~''Ardipithecus ramidus'' has had a profound impact on~~ the ~~field of paleoanthropology. It has provided crucial evidence about~~ the ~~early stages of human evolution, particularly regarding the development of bipedalism~~ and the ~~nature of our ancestors' environments~~. ~~''A. ramidus'' challenges~~ the ~~notion that our ancestors evolved bipedalism as a direct response~~ to ~~moving from~~ the ~~forest~~ to the ~~savannah~~, ~~suggesting instead that this key human trait evolved in a more complex ecological context~~.		The primary function of the aorticopulmonary septum is to ensure that the [[aorta]] and the [[pulmonary artery]] are properly aligned with their respective ventricles. The aorta must connect to the left ventricle, which pumps oxygenated blood to the body, while the pulmonary artery must connect to the right ventricle, which pumps deoxygenated blood to the lungs.

	==~~Controversies and Challenges~~==		==Clinical significance==
	~~The interpretation~~ of ~~''Ardipithecus ramidus'' and its significance for understanding human evolution has not been without controversy. Some researchers have questioned~~ the ~~extent~~ to ~~which ''A. ramidus'' was bipedal~~, ~~as well as~~ the ~~reconstruction of its habitat. Despite these debates~~, ~~''A~~. ~~ramidus'' remains a pivotal species for understanding~~ the ~~early stages~~ of the ~~human lineage~~.		Defects in the formation of the aorticopulmonary septum can lead to congenital heart defects such as [[persistent truncus arteriosus]], where the septum fails to form properly, resulting in a single arterial trunk. Other related conditions include [[transposition of the great arteries]] and [[tetralogy of Fallot]], which involve improper alignment or separation of the aorta and pulmonary artery.

	[[~~Category~~:~~Prehistoric mammals~~ of ~~Africa]]~~		==Related pages==
	[[Category:~~Hominin fossils~~]]		* [[Heart development]]
	[[Category:~~Paleoanthropology~~]]		* [[Congenital heart defect]]
	~~{{Paleontology-stub}}~~		* [[Neural crest]]
			* [[Truncus arteriosus]]

			==Gallery==
			<gallery>
			File:Gray470.png\|Diagram showing the development of the heart in the human embryo.
			File:Gray471.png\|Illustration of the aorticopulmonary septum in the developing heart.
			</gallery>

			[[Category:Cardiovascular system]]
			[[Category:Embryology]]

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2024-04-02T21:53:09Z

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{{jpg-image}}'''Ardipithecus ramidus''' is an extinct species of [[hominin]] that is believed to have lived about 4.4 million years ago during the early [[Pliocene]] epoch. The discovery of this species has significantly contributed to our understanding of human evolution, particularly regarding the nature of our ancestors' locomotion and their environment. The first fossils of ''Ardipithecus ramidus'' were discovered in the [[Afar Depression]] of [[Ethiopia]] in 1994 by a research team led by [[Tim D. White]], an American paleoanthropologist. The species name ''ramidus'', which means "root" in the Afar language, reflects the species' basal position in the human lineage tree.

==Discovery and Significance==
The discovery of ''Ardipithecus ramidus'' was groundbreaking because it provided evidence of a hominin species that lived earlier than the famous ''[[Australopithecus afarensis]]'', known from the specimen [[Lucy (Australopithecus)|Lucy]]. ''A. ramidus'' is characterized by a combination of traits that suggest a transitional form of bipedalism, different from both the quadrupedal locomotion seen in modern [[Great Apes]] and the fully upright bipedalism of later hominins. This has implications for the understanding of the evolution of walking on two legs, a key characteristic of humans.

==Anatomy and Physiology==
''Ardipithecus ramidus'' had a small brain, similar in size to that of a modern chimpanzee, and its teeth suggest a diet that included both plants and small animals. The structure of its limbs and pelvis indicates that while ''A. ramidus'' could walk on two legs, it also spent time in the trees, suggesting an adaptation to both terrestrial and arboreal environments. This combination of features supports the hypothesis that bipedalism evolved in a forested environment rather than in open savannah, challenging previous theories about the environmental drivers of human evolution.

==Habitat==
The fossils of ''Ardipithecus ramidus'' were found in what is now a desert region, but geological and paleoenvironmental evidence indicates that the area was once a woodland, with a mix of trees and grasses. This habitat would have provided both the arboreal and terrestrial resources necessary to support the species' versatile locomotion and diet.

==Impact on the Understanding of Human Evolution==
The discovery of ''Ardipithecus ramidus'' has had a profound impact on the field of paleoanthropology. It has provided crucial evidence about the early stages of human evolution, particularly regarding the development of bipedalism and the nature of our ancestors' environments. ''A. ramidus'' challenges the notion that our ancestors evolved bipedalism as a direct response to moving from the forest to the savannah, suggesting instead that this key human trait evolved in a more complex ecological context.

==Controversies and Challenges==
The interpretation of ''Ardipithecus ramidus'' and its significance for understanding human evolution has not been without controversy. Some researchers have questioned the extent to which ''A. ramidus'' was bipedal, as well as the reconstruction of its habitat. Despite these debates, ''A. ramidus'' remains a pivotal species for understanding the early stages of the human lineage.

[[Category:Prehistoric mammals of Africa]]
[[Category:Hominin fossils]]
[[Category:Paleoanthropology]]
{{Paleontology-stub}}