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Digestion – Oxidation reaction – Chemistry

By |2017-06-03T00:41:56+00:00June 3rd, 2017|Biology, Chemistry|

Kids eating food (thanks to USDA) When animals, including people like you, digest their food, they use an oxidation reaction to break down big hydrocarbon molecules like sugar into different molecules. In order for your cells to break down sugar molecules made of hydrogen and carbon atoms, they have to combine the sugar with oxygen, just [...]

Enzymes project – Bread and Spit – Science Activities -Biology

By |2017-05-28T17:33:50+00:00May 28th, 2017|Biology, Food|

A loaf of bread You can easily taste how your enzymes work breaking down your food into smaller pieces. Do this experiment right after lunch, when you'll have a lot of enzymes in your saliva. Get a slice of plain bread (a starch) and chew it slowly. Keep chewing for a long time, but [...]

Cell digestion – Parts of a cell – Cell Biology

By |2017-05-28T16:18:53+00:00May 28th, 2017|Biology|

Amoeba - a one-celled organism All cells have to have some way to get energy from outside themselves, or they will starve to death. The earliest, simplest cells, about 3.5 billion years ago, got their food by drifting around in the ocean until they came to a molecule of protein or another hydrocarbon. Then they let [...]

What is a hydra? Animal Biology and Evolution

By |2018-04-16T09:20:37+00:00May 28th, 2017|Biology|

Hydra evolution: a hydra budding new hydras For almost three billion years, the only living things on earth were one-celled creatures, either prokaryotes or eukaryotes. Early multi-cellular creatures Even today, the vast majority of the living things on earth are one-celled creatures - microbes. But about 600 million years ago, a few one-celled creatures began [...]

What does a stomach do? – Digestion and Evolution

By |2017-05-26T19:21:38+00:00May 26th, 2017|Biology|

Fish Stomach The first multi-cellular animals like hydras had no stomachs, or you could say they were all stomach, because they were shaped like a bag. Roundworms, a little later, were shaped like a tube, and the cells along that tube made mucus to protect the tube from the bacteria that digested food [...]

What does my liver do? Evolution and Digestion

By |2017-05-26T18:01:56+00:00May 26th, 2017|Biology|

Fish liver The earliest beginnings of what became the liver may have been relatives of segmented worms that lived about 600 million years ago. These worms evolved to have sections of their intestines that pinched out and made two little bags. Probably the worms used the bags to keep extra fat in, for when [...]

What are intestines? Evolution and Digestion

By |2017-09-17T09:06:21+00:00May 26th, 2017|Biology|

Whale intestines (from Medicine Chest) The first animals to have anything like an intestine evolved around 548 million years ago. These were roundworms, just a few millimeters long, and they had just a simple tube running from their mouth to their anus - no stomach in the middle. But already these roundworm guts [...]

Digestive System – Biology and Evolution

By |2018-04-13T14:31:40+00:00May 26th, 2017|Biology|

A hydra eating: the mouth is where all the tentacles come together,near the center of the picture.The hydra is eating the round bug in its stomach. Starting about 3.8 billion years ago, during the Archaean Era, one-celled creatures were the earliest living things. They just floated in the ocean and took in food in [...]