* Bipedalism: The AAH suggests that our ancestors evolved to walk upright in shallow water, where it was more efficient than walking on all fours.
* Hairlessness: Loss of body hair could have been an adaptation to reduce drag in the water.
* Subcutaneous fat: The AAH proposes that fat beneath the skin helped with buoyancy and insulation in the water.
* Larger brains: The hypothesis suggests that the development of a larger brain might be linked to the cognitive demands of navigating aquatic environments.
* Ability to hold our breath: Our relatively long breath-holding ability is proposed as an adaptation to diving.
Arguments for the AAH:
* Anatomical similarities with aquatic mammals: Human features like subcutaneous fat, hairlessness, and a tendency to store fat around the abdomen are observed in other aquatic mammals.
* Physiological adaptations: Human breath-holding abilities, the ability to control our breathing voluntarily, and the diving reflex are seen as potential adaptations to aquatic life.
* Fossil evidence: Some fossil discoveries, like the "Kenyanthropus platyops" skull, are interpreted by some as evidence of an aquatic phase in human evolution.
Arguments against the AAH:
* Lack of direct fossil evidence: There is no strong fossil evidence to confirm that human ancestors lived extensively in aquatic environments.
* Alternative explanations for human traits: Many of the traits cited as evidence for the AAH can be explained by other evolutionary pressures, such as arboreal living or savanna adaptations.
* Limited evidence for widespread aquatic adaptation: The AAH fails to explain why other primate species, which also lived in similar environments, did not develop the same traits.
Current status:
The AAH is widely considered to be discredited by the scientific community. The hypothesis lacks significant supporting evidence and has been challenged by the vast body of evidence that supports the traditional view of human evolution on land.
However, some aspects of the AAH, particularly the idea that water played a role in human evolution, are still debated by scientists.
It's important to note that the AAH is a hypothesis, not a proven theory. It is crucial to approach this theory critically and consider the scientific evidence before forming an opinion.