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Proterozoic Eon – eukaryotes to worms

By |2018-04-21T11:56:39+00:00June 24th, 2017|Biology, Geology|

Two and a half billion years ago, the Archaean Eon ended and the Proterozoic Eon began. Trillions of prokaryote cells lived in Earth's oceans. Some of these cells could photosynthesize their energy from sunlight, water, and carbon dioxide. These photosynthesizing cells pooped out a lot of oxygen. By about 2.3 billion years ago, the iron [...]

What are neurons? Nervous system evolution and biology

By |2017-05-27T15:24:43+00:00May 27th, 2017|Biology|

A network of neurons One-celled creatures like bacteria don't have neurons, because they can communicate within themselves through the use of enzymes, but all multicellular animals do have neurons. The simplest and earliest example of neurons is in hydras, which evolved around 600 million years ago. In hydras, neurons are not organized into [...]

How do eyes work? Evolution and Biology

By |2018-04-16T08:42:19+00:00May 27th, 2017|Biology|

A flatworm with eye-spots Living creatures have been able to tell if it's light out or not  for about two billion years. That's when some eukaryote cells evolved to be able to sense changes in their surroundings and react to them. For instance, some cells had eye spots, which could sense sunlight. When they sensed sunlight, [...]

What is a brain? Biology and Evolution

By |2017-05-26T23:54:10+00:00May 26th, 2017|Biology|

This is a mouse brain Flatworms were the first animals to evolve anything like a brain, but it's really just a thickened part of the main nerve at one end of the flatworm. That was about 550 million years ago, in the Proterozoic period. The first real brains were in fish. That's probably [...]

What is a muscle? Biology and Evolution

By |2017-05-26T23:42:02+00:00May 26th, 2017|Biology|

A black woman shows off her muscles One-celled creatures don't have any muscles; the ones that can move themselves use flagellae instead. Even after living creatures evolved that had a lot of cells, the early ones like hydras and sponges couldn't move. The earliest creatures that had muscles and could move on their own [...]

What are flatworms? Evolution and Biology

By |2018-04-16T08:26:45+00:00May 26th, 2017|Biology|

A flatworm The first flatworms, or platyhelminthes, probably evolved from something like a hydra about 550 million years ago. Like all other living things at this time, these early flatworms all lived in the ocean. A flatworm has a body shaped roughly like a bag, like the earlier hydras. Flatworms were the first [...]