Birds Above YouBeing in this section, you already know that birds are vertebrates. What is the other major thing to know about birds? They fly. Sure there are other vertebrates that fly (bats), but birds rule the sky. There are small hummingbirds that suck nectar from flowers. There are midsized crows with high levels of intelligence. Then there are massive eagles that are some of the most capable predators on Earth.
Moomy, Where Do Birds Come From?Birds weren't always here. Scientists believe special reptiles began to develop bird-like characteristics towards the end of the dinosaur era. A species called Archaeopteryx had traits such as feathers that may have allowed it to fly. Inside those dinosaurs, scientists also discovered a wishbone (it's big in the bird world). As we continue to discover more fossils, more species with feathers and small forelimbs are appearing in the evolutionary tree.
Over time, bird species developed very efficient respiratory systems, circulatory systems, and the ability to keep warm. The body heat of reptiles changes with the temperature of the environment while birds are endotherms, regulating their own body temperature.
Some Structure StuffWe have a section that goes into overall bird anatomy such as laying hard-shell eggs, no teeth, feathers, and hollow bones for a lighter skeleton. As with all nature, there is also a lot of specialization. Not all birds fly. Then what do they do? Ostriches (one of the oldest bird species) have very strong legs and can run very fast. Penguins have dense feathers and a waterproofing that allow them to swim underwater very efficiently. Something that has always interested us is the fact that there are hopping birds and walking birds. You should go out and look one day. You'll find little sparrows that hop on two legs and birds such as pigeons that walk like you and I. Take some time to figure out the advantage of that specialization.
Filling Different NichesAs Charles Darwin traveled the world, he studied many bird species and saw how they were able fill specific ecological niches that allowed different species to survive. Darwin looked at finch species and compared their food to the shape of their beaks. There were finches with long beaks that ate nectar from flowers and some with stubby strong beaks that allowed then to eat hard seeds. As with all species, birds developed different characteristics so that they could capitalize on available food sources and environments. Once they were able to establish themselves, they could reproduce and succeed as unique species.
Birds: The Common Loon (USGS Video)