that makes its own food through photosynthesis ..
An organism that makes its own food
There really could not be, unless animal life was wiped out and could start over, as they are the last common ancestors of animals (and eliminating all animal life would lead to great plant extinctions for starters, such as ). The biological commitments to those basic modes of existence had their own inertia, and it starts at the root, with the DNA. The primary unit of organization is a , which consists of a single ancestor and all of its descendants. The study of body features has been augmented by recent findings in molecular biology. Many organisms have had their , and many more will in the future. Many common features among diverse organisms are due to and not ancestry, as organisms independently developed similar solutions to life’s challenges. show that some animals were mobile before the Cambrian Explosion. Sponges were probably the but they were immobile except for their flagella drawing water through them, which carried food and oxygen in and waste out.
Energy and the Human Journey: Where We Have Been; …
The African woodlands and plains are extremely dangerous at night, just from roving predators, not to mention being stumbled into by elephants, rhinos, and water buffalos. Today’s African hunter-gatherers sleep around the campfire to keep predators and interlopers at bay; a sentinel keeps watch as everybody sleeps in shifts through the twelve-hour nights. They are safer from predation at night in camp than they are in daytime as they roam.The anatomy of habilines (members of ) spoke volumes about their lives. They had brains of about 640 ccs, with an estimated range of 600 to 700 ccs, nearly 50% larger than their australopithecine ancestors and nearly twice that of chimps, and the artifacts they left behind denoted advanced cognitive abilities. They stood about 1.5 meters tall (five feet), and weighed around 50 kilograms (120 pounds). With the first appearance of habilines about 2.3 mya, Oldowan culture spread widely in East Africa and also radiated to South Africa. Habiline skeletal adaptations to tree climbing meant that they slept there at night, just as their ancestral line did. Their teeth were large, which meant that they heavily chewed their food. Habiline sites have large rock hammers that they pounded food on, to break bones and crack nuts. Those habiline stone hammers may well have also been used to soften meat, roots, and other foods before eating them. Sleeping in trees meant that habilines were preyed on, mostly by big cats. Today, the leopard is the only regular predator of chimpanzees and gorillas, and at times. But if modern studies of chimpanzees are relevant, our ancestors engaged in warfare for the past several million years, and , so simian intra-species mass killings may have tens of millions of years of heritage. Habilines were not only wary of predators, but also of members of their own species.Monkeys, apes, and humans have many traits in common, and one is that members of "out-groups" are fair game. Chimpanzees are the only non-human animals today that form ranked hunting parties, and they are also the only ones that form hunting parties to . Distinct from the killer ape hypothesis, which posits that humans are instinctually violent, the chimpanzee violence hypothesis proposes that chimps only engage in warfare when it makes economic sense: when the benefits of eliminating rivals outweigh the risks/costs. Macaque wars and revolutions appear spontaneously, but chimp wars have calculation behind them, which befits a chimp’s advanced cognitive abilities; they plan murderous raids and carry them out. It is quite probable that the advancing toolset of protohumans was used for coalitionary killing when perceived benefits exceeded assessed risks/costs. Just as with , these traits probably also existed in our last common ancestor. Other animals also engage in intra-species violence, which includes spiders when key resources are scarce and contested, and when ant colonies have power imbalances, they can trigger invasion and extermination by the larger colony. But human and chimpanzee warfare is uniquely organized and calculating.Habilines and australopithecines coexisted, and the went extinct about 2.0 mya. Robust australopiths survived to about 1.2 mya (, ), and habilines , so they overlapped the tenure of a species about which there is no doubt of its genus: , which first appeared about 2.0-1.8 mya, and the first fossils are dated to 1.8 mya. is the first human-line species whose members could pass for humans on a city street, if they dressed up and wore minor prosthetics on their heads and faces. had a protruding nose and was probably relatively hairless, the first of the human line to be that way. That was probably related to shedding heat in new, hot environments, as well as cooling its large brain (molecular data with head and body lice supports arguments that the human line became relatively hairless even before australopiths). There are great controversies about that overlap among those three distinct lines that might all have ancestral relationships. Oldowan culture was a multi-species one. There is plenty of speculation that the rise of and its successors caused the extinction of other hominids, driving them to extinction by competition, predation, warfare, or some combination of them.