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Why isn't the world covered in poop?
| Content Provider | TED Ed |
|---|---|
| Author | Slade, Eleanor Manning, Paul |
| Description | There are more than 7,000 species of dung beetles known to science. While this seems quite diverse, dung beetles represent only a small amount of the 1.2 million species of insects currently described. There are numerous reasons why insects are thought to be so biologically diverse. One main reason is the phenomenon of complete metamorphosis, which is also known as holometaboly. Between 50-65% of all species are holometabolous insects, a group which uses a life cycle with four discrete developmental stages: egg, larva, pupa and adult. Each stage of the life cycle serves a different specialized function: eggs are especially good at withstanding stressful environments, larvae are specialized for consuming huge amounts of food, pupa are typically concealed and represent a period of change, and adults are specialized for dispersal (wings) and sexual reproduction. Because dung beetles feed on the dung of animals, they are often used as indicators of an ecosystem’s quality—like a “canary in the coal mine.” For example, if the mammal community living in a rainforest is intact, it will host a rich diversity of dung beetles in high abundance. If mammal communities become impoverished by poaching, or indirectly though habitat loss caused by logging, the associated dung beetle community will likewise become impoverished. By sampling the dung beetle community, scientists can indirectly learn about the quality of the overall habitat. Dung beetles were revered by the ancient Egyptians, who saw the life cycle of the dung beetle as the cycle of life and the resurrection of the dead, and associated the rolling of their balls of dung with the sun rolling across the sky. It is also thought that the pupae of the dung beetle gave the ancient Egyptians the idea of mummification. Now, scientists have uncovered the secrets of how dung beetles navigate and why they dance on their dung balls. Humans, birds, and seals are known to use the stars to navigate. But by putting blindfolds on dung beetles in a planetarium, scientists have discovered that dung beetles also use the Milky Way to navigate. They dance on their dung balls to help orient themselves. By putting tiny boots on dung beetles and using thermal imaging cameras, scientists were able to show that desert dung beetles use the cooler surface of the dung ball as a thermal refuge to help regulate their temperature from the hot temperatures of the ground. |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Science Technology Life Sciences Environmental Science Health Public Health |
| Content Type | Video Animation |
| Time Required | PT4M58S |
| Education Level | Class VII Class VIII Class IX Class X |
| Pedagogy | Lecture cum Demonstration |
| Resource Type | Video Lecture |
| Subject | Environmental Science |
